WO2008038740A1 - Process and equipment for the recovery of phosphoric acid from phosphoric acid-containing water - Google Patents

Process and equipment for the recovery of phosphoric acid from phosphoric acid-containing water Download PDF

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Publication number
WO2008038740A1
WO2008038740A1 PCT/JP2007/068881 JP2007068881W WO2008038740A1 WO 2008038740 A1 WO2008038740 A1 WO 2008038740A1 JP 2007068881 W JP2007068881 W JP 2007068881W WO 2008038740 A1 WO2008038740 A1 WO 2008038740A1
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WO
WIPO (PCT)
Prior art keywords
phosphoric acid
water
concentrate
reverse osmosis
concentrated
Prior art date
Application number
PCT/JP2007/068881
Other languages
French (fr)
Japanese (ja)
Inventor
Nobuhiro Orita
Naoto Hitotsuyanagi
Original Assignee
Kurita Water Industries Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2006264640A external-priority patent/JP5135749B2/en
Priority claimed from JP2007093943A external-priority patent/JP5277559B2/en
Application filed by Kurita Water Industries Ltd. filed Critical Kurita Water Industries Ltd.
Priority to KR1020097005423A priority Critical patent/KR101433104B1/en
Priority to CN200780031927XA priority patent/CN101511452B/en
Publication of WO2008038740A1 publication Critical patent/WO2008038740A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/04—Feed pretreatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/18—Details relating to membrane separation process operations and control pH control
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/346—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from semiconductor processing, e.g. waste water from polishing of wafers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/40—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture or use of photosensitive materials

Definitions

  • the present invention relates to a method and apparatus for recovering phosphoric acid from phosphoric acid-containing water using a reverse osmosis device, and in particular, from a washing wastewater containing phosphoric acid after etching a liquid crystal substrate, a wafer or other electronic equipment.
  • the present invention relates to a method and apparatus for recovering phosphoric acid suitable for recovery of valuable materials such as acid and pure water which is treated water.
  • An etching solution containing phosphoric acid is used for etching liquid crystal substrates, wafers and other electronic devices.
  • the high-concentration waste etchant generated in the etching process is recovered and recycled, but the electronic equipment after etching is washed with pure water, and a large amount of low-concentration washing wastewater is generated.
  • Such washing wastewater contains components such as phosphoric acid, nitric acid, acetic acid, and other acid components, and metal ions and other impurities eluted by etching. Is pure water.
  • etching cleaning wastewater is treated by mixing with other wastewater.
  • a common treatment technique for wastewater containing phosphoric acid or hydrofluoric acid is coagulation sedimentation.
  • problems such as increased treatment costs due to the use of a large amount of chemicals and the generation of a large amount of sludge, and an increase in environmental burden.
  • an increase in water-soluble ions due to a large amount of chemicals added in the coagulation sedimentation treatment increases the power cost due to the increase in operating pressure in the reverse osmosis membrane process, the quality of the treated water, and the generation of scale.
  • the ion exchange method leads to an increase in the amount of regenerant used.
  • Patent Document 1 Japanese Patent Publication No. 2006-75820
  • ions such as phosphoric acid and nitric acid are removed with an ion exchange resin, and pure water and phosphate are recovered.
  • the ability to pass through H-cation resin to make sodium dihydrogen phosphate The regeneration of the thione resin consumes acids such as hydrochloric acid, and the sodium hydroxide used in the regeneration of the anion resin also wastes.
  • Patent Document 1 Japanese Patent Publication 2006—75820
  • An object of the present invention is to transport high-purity phosphoric acid useful as a recovered material from a phosphoric acid-containing water at low cost and efficiently, which can be transported in a high concentration liquid state with a simple configuration and operation. It is to propose a method and an apparatus for recovering recoverable phosphoric acid.
  • the present invention is a method and apparatus for recovering phosphoric acid from the following phosphate ion-containing water.
  • Reverse osmosis treatment is performed by supplying phosphoric acid-containing water to the reverse osmosis device under the condition of PH3 or less, acid other than phosphoric acid is permeated to the permeate chamber side together with water, and phosphoric acid is introduced to the concentrate chamber side.
  • a method for recovering phosphoric acid comprising concentrating and recovering a phosphoric acid concentrate.
  • Phosphoric acid-containing water is supplied to the reverse osmosis unit under conditions of PH3 or less and phosphoric acid concentration;! ⁇ 15 wt%, and membrane separation treatment is performed to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water. Then, the phosphoric acid is concentrated to the concentrated liquid chamber side, and the phosphoric acid concentrated liquid is recovered, and a method for recovering phosphoric acid is provided.
  • the above-mentioned (1) or (2) has a process of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and adding reverse phosphoric acid treatment water to the circulating concentrate. ) How to describe.
  • a reverse osmosis device that performs membrane separation treatment of phosphoric acid-containing water under a pH of 3 or less, allows acids other than phosphoric acid to permeate to the permeate chamber side together with water, and concentrates phosphoric acid to the concentrate chamber side;
  • a raw water supply unit for supplying phosphoric acid-containing water to the concentrate chamber side of the reverse osmosis membrane device under a condition of PH3 or less;
  • a phosphoric acid recovery apparatus comprising: a concentrated phosphoric acid solution extraction unit that extracts a concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device.
  • Membrane separation treatment is performed under conditions where the phosphoric acid-containing water is PH3 or less and the phosphoric acid concentration is! ⁇ 15% by weight to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water, and phosphoric acid is concentrated in the concentrate chamber.
  • a reverse osmosis device that concentrates to the side,
  • a phosphoric acid-containing water supply section for supplying phosphoric acid-containing water to a concentration chamber side of the reverse osmosis device under conditions of PH3 or less and phosphoric acid concentration;
  • a concentrated phosphoric acid solution extraction section for extracting the concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device, and a circulation path for circulating the concentrated phosphoric acid solution extracted from the concentrated phosphoric acid solution extraction unit to the concentrated liquid chamber side;
  • recovery apparatus characterized by having.
  • the phosphoric acid-containing water to be treated can be used without limitation as long as it contains phosphoric acid.
  • Phosphate ions 50-; 10000 mg / L, especially 50-200 Contains Omg / L, pH is 3 or less, especially 2.8 or less, in any case 1 or more, especially 1.
  • acid components such as nitrate ions and acetate ions, other anions, cations such as metal ions, and other impurities may be contained.
  • Phosphoric acid-containing water that is particularly preferable as a treatment target is low-concentration cleaning wastewater that is generated when pure water cleaning is performed after etching with a phosphoric acid-containing etching solution for liquid crystal substrates, wafers, and other electronic devices.
  • cleaning wastewater after etching include phosphate ions 50 to 2000 mg / L, nitrate ions 10 to 500 mg / L, acetate ions 5 to 300 mg / L, and ⁇ 1 ⁇ 8 to 2 ⁇ 8.
  • the phosphoric acid-containing water in order to recover phosphoric acid from phosphoric acid-containing water, is supplied to the reverse osmosis membrane device under conditions of ⁇ ⁇ 3 or less and phosphoric acid concentration; It is preferable to perform a membrane separation treatment. In the present invention, it is preferable to remove impurities including cations and / or anions as a pretreatment before supplying the phosphoric acid-containing water to the reverse osmosis membrane device.
  • precipitate separation removal of solids by filtration, etc., removal of cations such as metal ions by cation exchange resin, and removal of anions such as perchloric acid, molybdic acid and organic acid complexes by anion exchange resin, etc. be able to.
  • a pretreatment apparatus used in such a pretreatment process a general apparatus adopted for the above purpose is used. Is used.
  • cation exchange resin a strong acid or weak acid cation exchange resin can be used. However, when these strong thiones are exchanged and removed using the H-form strong acid force thione exchange resin, the acid component of the treatment liquid increases. It is preferable because it becomes easy to adjust the pH to 3 or less.
  • the cation exchange resin may be a chelate resin.
  • a strongly basic or weakly basic cation exchange resin can be used as the anion exchange resin.
  • the cation exchange resin is used in an acid form such as phosphoric acid form, and passes through phosphoric acid, nitric acid, acetic acid, etc. to remove other impurity anions.
  • the reverse osmosis device in the membrane separation step is also called an RO device, which is partitioned into a permeate chamber and a concentrate chamber by a reverse osmosis (RO) membrane,
  • the phosphoric acid concentration is 1 to; 15% by weight is supplied to the concentrated liquid chamber side to perform reverse osmosis membrane treatment, and acid other than phosphoric acid is permeated to the permeate liquid chamber side together with water. And is configured to concentrate phosphoric acid to the concentrate chamber side.
  • a phosphoric acid-containing water supply part for supplying phosphoric acid-containing water and a concentrated phosphoric acid liquid extracting part for taking out the concentrated phosphoric acid liquid.
  • a permeate extractor for taking out the permeate is formed on the permeate chamber side of the reverse osmosis membrane device.
  • a circulation path is formed between the concentrated phosphoric acid solution take-out part and the phosphoric acid-containing water supply part to circulate the concentrated phosphoric acid solution taken out from the concentrated phosphoric acid solution take-out part to the concentrated liquid chamber side.
  • Reverse osmosis membranes allow water to permeate by osmotic pressure, or conversely pressurize to a pressure higher than osmotic pressure to supply the liquid to be treated and allow water to permeate by reverse osmosis, while allowing salt, organic matter, and other solutes to pass through. It is a semi-permeable membrane that prevents it from passing through! /.
  • the material of the reverse osmosis membrane is not particularly limited as long as it has the above-mentioned characteristics, and examples thereof include a polyamide permeable membrane, a polyimide permeable membrane, a cellulose permeable membrane, and may be an asymmetric reverse permeable membrane.
  • a composite reverse osmosis membrane in which an active skin layer having substantially selective separability is formed on a microporous support is preferred.
  • the reverse osmosis device may be any device as long as it has such a reverse osmosis membrane. The thing provided with is preferable.
  • the membrane module is not particularly limited.
  • a tubular membrane module for example, a tubular membrane module, a planar membrane module, a spiral membrane module, and a hollow fiber membrane module can be cited.
  • a known apparatus can be used, and a highly permeable apparatus operated at a low pressure is preferable.
  • the phosphoric acid-containing water in the membrane separation step, is used under conditions of pH 3 or less, preferably 1 to 15% by weight, more preferably 2 to 10% by weight.
  • the membrane separation (reverse osmosis) treatment is performed by supplying to the reverse osmosis membrane device under the condition of%. If the phosphoric acid-containing water is obtained at a pH of 3 or less, the power that can be supplied to the reverse osmosis membrane device without adjusting the pH as it is. Adjusting the pH by adding a pH adjuster such as hydrochloric acid or nitric acid if necessary. You can!
  • the phosphoric acid concentration is concentrated to 1% by weight or more by performing membrane separation treatment while circulating the concentrate through the circulation path.
  • a batch-type treatment may be performed in which the circulating fluid is replaced when it is concentrated to 1% by weight or more.
  • the concentrated solution is circulated while circulating the concentrated solution concentrated to a phosphoric acid concentration; It is preferable to add low-concentration phosphoric acid-containing water to the solution and take out the concentrated solution partly as a phosphoric acid concentrated solution because an apparent one-time treatment can be performed.
  • reverse osmosis treatment is performed by adding diluted water to the circulating concentrate, thereby reducing the removal rate of acids other than phosphoric acid. Can be increased.
  • dilution water recovered water from which impurities have been removed from the permeated water can be used.
  • acids other than phosphoric acid such as nitric acid and acetic acid permeate through the reverse osmosis membrane together with water. Move to the liquid chamber side and take out from the permeate chamber side.
  • Phosphoric acid is prevented from permeating through the reverse osmosis membrane and remains on the concentrate chamber side to be concentrated, so that it can be recovered from the concentrate chamber side as a phosphoric acid concentrate.
  • the concentrate on the concentrate chamber side may be passed through temporarily or may be circulated to increase the concentration rate.
  • the reverse osmosis membrane blocking rate is higher than that of the nonionic substance even if the molecular weight is the same. It is said that it is overwhelmingly easy to stop.
  • the rejection rate of acids other than phosphoric acid such as nitric acid and acetic acid under pH 3 or lower
  • the rejection rate when a normal phosphoric acid-containing etching solution is treated with a film is 1% or less.
  • the blocking rate is the rate at which the reverse osmosis membrane blocks solute permeation, and is expressed by the following equation (1).
  • Rejection rate (%) (1— C / (C-C) 1/2 ) X 100 ⁇ ⁇ ⁇ (! (In formula (1), C is the solute concentration at the inlet of the feed liquid, C is the solute concentration at the outlet of the concentrate, and C is the permeability of
  • ((C-C) 1/2 ) represents a geometric mean
  • (C / (C-C) 1/2 ) represents a concentrated solution
  • the ratio of the solute concentration of the permeate to the (synergistic) average concentration of the solute For this reason, the lower the blocking rate, the more the solute permeates to the permeate side. Although it is easy to recognize that the rejection rate will not be negative in the normal concept, the rejection rate may be negative due to the composition of the equation (1), and in this case, the permeated liquid concentration is higher than the solute concentration of the concentrate. It shows that solutes with high solute concentration permeate with high permeability.
  • the rejection rate of acids other than phosphoric acid is negative.
  • the phosphoric acid concentration is 1% by weight or more, particularly 2% by weight or more, other than phosphoric acid remaining in the concentrate. This means that the acid concentration is low, and a highly concentrated phosphoric acid concentrate is obtained. If the concentration of phosphoric acid in the concentrate is too high, membrane treatment cannot be performed due to osmotic pressure, so the upper limit of the concentration of phosphoric acid in the concentrate is 15% by weight, preferably 10% by weight.
  • the permeated water of the reverse osmosis membrane device taken out from the permeate chamber side contains permeated acids such as phosphoric acid, nitric acid, and acetic acid, these permeates from the permeated water of the reverse osmosis membrane device. Pure water can be recovered by removing acid and other impurities with an impurity removing device. In this case, an ion exchange device using an ion exchange resin can be employed as the impurity removal device.
  • the anion exchange resin used here is preferably an OH type strongly basic cation or weakly basic cation exchange resin, and the cation exchange resin is preferably an H type strongly acidic cation exchange resin.
  • An electroregenerative ion exchange device is a device in which an ion exchange resin layer is partitioned by a cation exchange resin membrane and a cation exchange resin membrane, and a cathode and an anode are arranged at both ends. Ion exchange is performed by passing the liquid through the anode and regenerating while energizing.
  • the ion exchange resin used in the electric regeneration type ion exchange device is intended only for removal of acid and other anions, it is possible to fill only the anion exchange resin. In this case, a mixed bed of cation exchange resin and anion exchange resin can be filled.
  • the acid concentrate discharged by regeneration is a concentrate such as phosphoric acid, nitric acid, and acetic acid.
  • the phosphoric acid concentrated liquid taken out from the concentrated liquid chamber side has most of acids other than phosphoric acid such as nitric acid and acetic acid removed.
  • Purification by post-treatment can be performed to increase purity and concentration.
  • purification by post-treatment it is possible to purify by removing acids other than phosphoric acid from the phosphoric acid concentrate by anion exchange.
  • an anion exchange device is provided as a purification device, the concentrated solution is passed through the anion exchange resin layer, strong acid ions such as nitric acid are removed from the concentrated solution, and a high concentration containing almost no strong acid ions such as nitric acid is removed. Phosphoric acid can be recovered.
  • the purification device can be provided in the concentrated solution circulation line of the reverse osmosis device, but is preferably provided in a line for extracting the concentrated solution from the circulation line.
  • Anion exchange resin Is preferably an OH-type or PO-type strongly basic anion exchange resin.
  • acetic acid remains in the phosphoric acid concentrate, the acetic acid cannot be completely removed even by the anion exchange resin. Therefore, the volatile components such as acetic acid are removed to increase the purity and concentration of the recovered phosphoric acid solution.
  • concentrate the phosphoric acid concentrate with an evaporative concentrator remove volatile components together with water, concentrate, and collect high-concentration phosphoric acid containing almost no volatile components such as acetic acid. That power S.
  • a known apparatus such as a rotary evaporator can be used as the evaporative concentration apparatus.
  • the phosphoric acid recovered by the above is useful as a recovered material and can be transported in a high-concentration liquid state, and can be recovered as concentrated and highly pure phosphoric acid.
  • reverse osmosis treatment is performed under the condition of pH 3 or less.
  • phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, it is easily adjusted by injecting a pH adjuster such as hydrochloric acid. be able to.
  • the method and apparatus for recovery can be obtained by performing reverse osmosis treatment with a simple configuration and operation under conditions of pH 3 or lower, and in some cases, phosphoric acid concentration; It can be recovered as a concentrate.
  • the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be lowered, and high-purity concentrated phosphoric acid and pure water can be recovered.
  • reverse osmosis treatment is performed by supplying phosphoric acid-containing water to a reverse osmosis device under a pH of 3 or less, and an acid other than phosphoric acid together with water enters the permeate chamber side.
  • an acid other than phosphoric acid together with water enters the permeate chamber side.
  • the phosphoric acid-containing water is supplied to the reverse osmosis device under the conditions of pH 3 or lower and the phosphoric acid concentration;! Can be transported in a high-concentration liquid form with a simple configuration and operation by allowing water to permeate to the permeate chamber side with water, concentrating phosphoric acid to the concentrate chamber side, and collecting the phosphoric acid concentrate. , To recover high-purity phosphoric acid useful as a recovered material from phosphoric acid-containing water at a lower cost and more efficiently Can do.
  • FIG. 1 is a flow diagram of a phosphoric acid recovery method and apparatus in one embodiment.
  • FIG. 2 is a flow diagram of a phosphoric acid recovery method and apparatus according to another embodiment.
  • FIG. 3 is a graph showing the results of Example 3.
  • FIG. 1 is a flow diagram of a phosphoric acid recovery apparatus in one embodiment.
  • 1 is a raw water tank that stores raw water la.
  • 2 is a cation exchange tower having a cation exchange resin layer 2a.
  • 3 is a concentrate tank and stores the concentrate 3a.
  • a reverse osmosis device 4 is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a.
  • An anion exchange tower 5 has an anion exchange resin layer 5a.
  • 7 is a recovered water tank, which stores recovered water 7a.
  • 5b is a second anion exchange tower having an anion exchange resin layer 5c.
  • 8 is an evaporative concentrator that evaporates and separates volatile components with water and concentrates the phosphoric acid solution.
  • 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a.
  • P is a pressure pump, which is a raw water tank 1, a cation exchange tower 2, and a concentrated liquid tank.
  • the anion exchange tower 5 and the recovery water tank 7 constitute a permeate extraction section, and among these, the anion exchange tower 5 constitutes an impurity removing device.
  • the second canyon exchange column 5b, the evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid liquid take-out section, and among these, the second anion exchanging column 5b and the evaporating and concentrating device 8 constitute a refining device.
  • raw water la (phosphate ion-containing water) that has been subjected to precipitation separation, filtration, and the like as a pretreatment step is introduced into raw water tank 1 from line L1.
  • the raw water la in the raw water tank 1 is introduced into the cation exchange tower 2 from the line L2 and passed through, and the cation exchange resin layer 2a exchanges cations to exchange cations such as aluminum, indium and other metal ions contained in the raw water. Adsorb and remove.
  • the cation exchange resin layer 2a it is preferable to use an H-type strongly acidic cation exchange resin.
  • the weak thione water that is the treated water of the cation exchange tower 2 is introduced into the concentrate tank 3 from the line L5 and stored.
  • Phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or lower, and even when the pH is high, acid is generated by cation exchange as a pretreatment and becomes a state of pH 3 or lower.
  • it may be supplied to the reverse osmosis apparatus 4 as it is.
  • phosphoric acid-containing water can be obtained in a state close to pH 3, so it should be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L5 or concentrate tank 3. Power S can be.
  • the weak thione water (concentrate 3a) in the concentrate tank 3 is pressurized by the pressure pump P and introduced from the line L6 into the concentrate chamber 4c of the reverse osmosis device 4, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water to concentrate phosphoric acid to the concentrate chamber 4c side.
  • acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water to concentrate phosphoric acid to the concentrate chamber 4c side.
  • the permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced into the ayuon exchange tower 5 from the line L7, and is passed through the anion exchange resin layer 5a to exchange the anion.
  • the anions other than phosphate ions such as nitric acid and acetic acid contained in the permeate are removed by exchange adsorption and purified, and the treated water is taken out from the line L8 to the recovered water tank 7 and stored as recovered water 7a.
  • the anion exchange tower 5 employs the force of using the ayuon exchange resin layer 5a filled with the OH type strongly basic aion exchange resin and adopts a multi-layer or mixed bed type with the H form cation exchange resin to remove impurities other than the anion. It may be removed.
  • a regenerant containing an alkali such as 2 to 10% by weight of an aqueous alkali solution such as sodium hydroxide or potassium hydroxide is passed through the line L9. Regenerate and drain the eluted salt from line L10.
  • a regenerant containing acid When using a cation exchange resin, pass a regenerant containing acid. To play.
  • the concentrate concentrated in the concentrate chamber 4c of the reverse osmosis device 4 is introduced from the line LI 1 to the second anion exchange tower 5b, passed through the water, and is subjected to anion exchange in the anion exchange resin layer 5c for concentration.
  • the remaining anions other than phosphate ions, such as nitric acid and acetic acid, are removed by exchange adsorption and purified.
  • the anion exchange resin layer 5c is strongly basic anion exchange of OH type or PO type.
  • anion exchange resin layer 5c is saturated with anions other than phosphate ions, it is regenerated by passing a regenerant containing alkali from line L12, and the eluted salt is discharged from line L13.
  • the phosphoric acid solution from which the anions other than phosphate ions have been removed in the second anion exchange column 5b still contains a volatile component such as acetic acid, it is introduced into the evaporation concentrator 8 from the line L14, distilled, and water At the same time, the volatile components are evaporated and separated and discharged from line L15.
  • the concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L16 and stored as the recovered phosphoric acid solution 9a.
  • a known evaporating and concentrating device such as a rotary evaporator can be used.
  • the concentrated liquid in the concentrated liquid chamber 4c of the reverse osmosis device 4 is circulated from the line L17 or L18 to the concentrated liquid tank 3 to increase the concentration rate, and is stored with the concentrated liquid 3a by the force S.
  • the phosphoric acid solution 9a recovered by the above method is useful as a recovered material and can be transported practically because it is recovered in a high-concentration liquid state, and is recovered as concentrated phosphoric acid with high purity. it can.
  • reverse osmosis treatment is performed under the condition of pH 3 or less.
  • phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, and even if the pH is high, even as a pretreatment, it can be replaced by Since the pH is 3 or less, it is not necessary to adjust the pH if it is supplied as it is to treat it under the condition of pH 3 or less.
  • Chemicals such as acids and alkalis are limited to cations regenerants in cation exchange tower 2 and anion regenerants in anion exchange tower 5 and second anion exchange tower 5b. Necessary for recovering phosphoric acid. Not.
  • the recovery method and device can be recovered as a phosphate concentrate by reverse osmosis treatment under conditions of pH 3 or less with a simple configuration and operation. . As a result, the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
  • the phosphoric acid-containing water is supplied to the reverse osmosis device 4 under the condition of pH 3 or lower, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a.
  • the phosphoric acid By allowing the phosphoric acid to pass through the concentrated liquid chamber 4c and recovering pure water and phosphoric acid concentrated liquid, it can be transported as a high-concentration liquid with a simple configuration and operation. High-purity phosphoric acid and pure water useful as recovered materials can be efficiently recovered from phosphoric acid-containing water at low cost.
  • FIG. 2 is a flowchart of a phosphoric acid recovery method and apparatus according to another embodiment.
  • 1 is a raw water tank that stores raw water la.
  • 2 is a cation exchange tower having a cation exchange resin layer 2a.
  • 3 is a concentrate tank, which stores concentrate 3a.
  • Reference numeral 4 denotes a reverse osmosis device, which is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a.
  • An anion exchange tower 5 has an anion exchange resin layer 5a.
  • a desalination chamber 6a and a concentration chamber 6b are partitioned by an anion exchange membrane 6c, and a cathode chamber 6e is partitioned by a cation exchange membrane 6d outside the desalination chamber 6a.
  • the anode chamber 6g is partitioned by the force thione exchange membrane 6f on the outside, the mixed-salt-type ion exchange layers 6h and 6i are provided in the desalting chamber 6a and the concentration chamber 6b, the cathode ( ⁇ ) in the cathode chamber 6e, and the anode chamber 6g in the anode chamber 6g.
  • An anode (+) is provided.
  • Reference numeral 7 is a recovery water tank for storing recovered water 7a.
  • 8 is an evaporation concentrator that evaporates and separates volatile components together with water and concentrates the phosphoric acid solution.
  • 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a.
  • 10 is a biological denitrification device.
  • P is a pressure pump, and constitutes the raw water supply unit together with the raw water tank 1, the cation exchange tower 2, the anion exchange tower 5 and the concentrated liquid tank 4, and of these, the cation exchange tower 2 and the anion exchange Tower 5 constitutes the pretreatment device.
  • the electric regenerative ion exchange device 6 and the collection water tank 7 constitute a permeate extraction unit, and the electric regenerative ion exchange device 6 constitutes an impurity removal device.
  • the evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid solution extraction section, and the evaporating and concentrating device 8 constitutes a purification device.
  • the raw water la (phosphate ion-containing water), from which impurities have been removed by precipitation separation, filtration or the like as a pretreatment step, is introduced into the raw water tank 1 from the line L21.
  • original Raw water la in tank 1 is introduced from line L22 to cation exchange tower 2 and passed through, and cation exchange is performed in cation exchange resin layer 2a to exchange and adsorb cations such as aluminum, indium, and other metal ions contained in the raw water. And remove.
  • the cation exchange resin layer 2a it is preferable to use an H-type strongly acidic cation exchange resin.
  • the cation exchange resin layer 2a is saturated, it is regenerated by passing a regenerant containing an acid such as hydrochloric acid from the line L23, and the eluted cation is recovered from the line L24.
  • the weak thione water which is the treated water of the cation exchange tower 2, is introduced into the anion exchange tower 5 from the line L25 and passed therethrough, and the anion exchange resin layer 5a is used to exchange the anion so that perchloric acid contained in the raw water Aion such as molybdic acid or organic acid complex is removed by exchange adsorption.
  • the anion exchange resin layer 5a it is preferable to use a phosphoric acid type strongly basic cation exchange resin.
  • a regeneration agent containing alkali such as sodium hydroxide is passed through the line L26 to regenerate, and the eluted anion is recovered from the line L27.
  • acid such as phosphoric acid is passed through line L26 to make the anion exchange resin into phosphoric acid form.
  • the treated water of the anion exchange tower 5 is introduced into the concentrate tank 3 from the line L28.
  • Phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, and can be supplied to the reverse osmosis apparatus 4 as it is for reverse osmosis treatment under conditions of pH 3 or less.
  • phosphoric acid-containing water is obtained in a state close to pH 3, so it can be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L28 or concentrate tank 3. it can.
  • the phosphoric acid-containing water in the concentrate tank 3 is pressurized by the pressure pump P and introduced into the concentrate chamber 4c of the reverse osmosis device 4 from the line L31, and membrane separation (reverse osmosis treatment) is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water, and phosphoric acid is concentrated to the concentrate chamber 4c side.
  • membrane separation reverse osmosis treatment
  • the permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced from the line L35 into the desalination chamber 6a of the electric regenerative ion exchanger 6 and a voltage is applied between the anode (+) and the cathode (one).
  • the anions such as phosphoric acid, nitric acid, and acetic acid contained in the permeate and the remaining cations are removed by exchange adsorption for purification, and the treated water is taken out from the line L36 to the recovered water tank 7 and stored as recovered water 7a.
  • the anions such as acids adsorbed on the mixed bed ion exchange layer 6h pass through the anion exchange membrane 6c to the concentration chamber 6b and are adsorbed on the mixed bed ion exchange layer 6i.
  • the anion adsorbed by regeneration is eluted while flowing a part of the permeate from L37 to the concentrating chamber 6b, and sent to the biological denitrifier 10 from the line L38 for biological denitrification. Since the cations adsorbed on the mixed bed type ion exchange layer 6 h permeate the cathode chamber 6e, the electrode solution flows from the anode chamber 6g through the line L39 to the cathode chamber 6e and is discharged from the line L40.
  • a part of the concentrated liquid concentrated in the concentrated liquid chamber 4c of the reverse osmosis apparatus 4 and taken out from the line L34 is introduced into the evaporative concentration apparatus 8 and distilled to evaporate volatile components such as acetic acid together with water. Separated and discharged from line L41.
  • the concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L42 and stored as the recovered phosphoric acid solution 9a.
  • the evaporation concentrator 8 a known evaporation concentrator such as a rotary evaporator is used.
  • the recovered water 7a from the recovered water tank 7 is supplied as dilution water to the concentrated liquid tank 3 through the line L43 by the pump P2, and the circulating concentrated liquid 3a is diluted to perform reverse osmosis treatment.
  • the concentration of an acid other than phosphoric acid can be further reduced, and a high-purity phosphoric acid concentrate can be recovered.
  • the amount of the recovered water 7a supplied to the concentrate tank 3 is an amount that maintains the condition of the concentrated concentrate carboxylic acid concentration! As a result, the permeation efficiency of acids other than phosphoric acid due to high concentration of the circulating concentrated liquid can be prevented, and the phosphoric acid purity of the concentrated liquid can be increased.
  • the recovered phosphoric acid solution 9a recovered by the above method is useful as a recovered material, and can be transported practically because it is recovered in a high-concentration liquid state. It can be recovered as an acid. In this case, reverse osmosis treatment is performed under the condition of pH 3 or less.
  • the phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, it is not necessary to adjust pH especially if it is supplied as it is.
  • the chemicals such as acid and alkali are limited to the regenerant for cations in the cation exchange tower 2 and the regenerant for anions in the anion exchange tower 3, and are not necessary for recovering phosphoric acid or purifying permeate.
  • the recovery method and equipment can be recovered as a phosphate concentrate by reverse osmosis treatment under the conditions of pH 3 or less and phosphate concentration; Is possible.
  • the amount of chemicals used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
  • the phosphoric acid-containing water is supplied to the reverse osmosis apparatus 4 under the conditions of pH 3 or lower and phosphoric acid concentration; Osmosis treatment Simple structure and operation by allowing acid other than phosphoric acid to pass through to the permeate chamber 4b side with water, concentrating phosphoric acid to the concentrate chamber 4c side, and collecting pure water and phosphoric acid concentrate Therefore, high-purity phosphoric acid and pure water, which can be transported in a high-concentration liquid state and are useful as a recovered product, can be efficiently recovered from the phosphoric acid-containing water at low cost.
  • the embodiment of the present invention is not limited to FIGS. 1 and 2.
  • the second anion exchange column is connected to the line L34. It is also possible to install it at the front stage of the evaporation concentrator 8.
  • the reverse osmosis device 4 and the electric regenerative ion exchange device 6 for purifying the permeate are a simple demineralization chamber 6a and a concentration chamber 6b separated by an anion exchange membrane 6c.
  • An electric regenerative ion exchange apparatus is used, and an anion exchange membrane and a cation exchange membrane are alternately arranged between a cathode chamber and an anode chamber to form a desalting chamber and a concentration chamber. It is also possible to use a normal electrodeionization device in which a desalting chamber is filled with an ion exchanger.
  • Nitto Denko Corporation's reverse osmosis membrane ES-20 manufactured by Nitto Denko Co., Ltd. was passed through 0 ⁇ 7MPa of raw water with conductivity of 122mS / m containing diacid 550mg / L, nitric acid 50mg / L and acetic acid 50mg / L.
  • the solution was subjected to reverse osmosis treatment to obtain a 6-fold concentrated concentrate (brine) (Example 1).
  • a sodium hydroxide aqueous solution was poured into the raw water to adjust to PH6, and the same test was performed (Comparative Example 1).
  • Example 1 The results of the rejection rates of phosphoric acid, nitric acid, and acetic acid are shown in Table 1.
  • phosphoric acid was removed and nitric acid and acetic acid permeated and separated, whereas in Comparative Example 1, all were removed. It can be seen that they are not separated.
  • the waste water was treated with the equipment shown in Fig. 1 to recover phosphoric acid and pure water.
  • Cation exchange tower 2 was filled with 10 L of H-type strongly acidic cation exchange resin (DiaionSKlB, manufactured by Mitsubishi Chemical Corporation) and regenerated with hydrochloric acid.
  • the anion exchange tower 5 was filled with 10 L each of OH type strongly basic anion exchange resin (Diaion SA11A, manufactured by Mitsubishi Chemical Corporation) and regenerated with sodium hydroxide.
  • Second Anion Exchange Tower 5b is a PO-type strongly basic cation exchange resin (Made by Mitsubishi Chemical Corporation, Diaion SA).
  • 11A is filled with 10L, regenerated to OH form with sodium hydroxide, and then converted to PO form with phosphoric acid concentrate.
  • the reverse osmosis device 4 was reverse osmosis treated by passing 0.7 MPa through a device having a spiral membrane module of reverse osmosis membrane ES-20 manufactured by Nitto Denko Corporation and concentrated 6 times.
  • a rotary evaporator was used to concentrate the phosphoric acid concentration to 75%. Table 2 shows the concentration of each component in each process.
  • the concentration of phosphoric acid in the concentrate decreases linearly as the nitric acid rejection is negative when the concentration is 1% by weight or more, and the phosphoric acid concentration is 2% by weight or less, and the phosphoric acid concentration is 4%. It can be seen that the permeation of nitric acid is promoted at% or less. Similar results were obtained with acetic acid.
  • the present invention relates to a method and apparatus for recovering phosphoric acid and pure water from phosphoric acid-containing water, in particular a liquid. It can be used in a method and apparatus for recovering phosphoric acid and other valuable materials from the cleaning waste water after etching crystal substrates, wafers, and other electronic devices, and phosphoric acid suitable for recovering pure water as treated water.

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Abstract

A process and equipment which make it possible to recover high-purity phosphoric acid useful as a recycled matter in the form of a portable high-concentration liquid from phosphoric acid-containing water at high efficiency by simple constitution and operation. The process comprises subjecting phosphoric acid-containing water to both cation exchange and anion exchange, subjecting the resulting water to reverse osmosis under the condition of pH of 3 or below, preferably under the conditions of pH of 3 or below and a phosphoric acid concentration of 1 to 15wt%, to transmit acids (except phosphoric acid) and water to a permeating fluid chamber side with phosphoric acid concentrated on a concentrated fluid chamber side, desalting the permeating fluid with an ion exchanger to recover pure water, and evaporating the concentrated fluid with an evaporator to remove volatile components and water and recover a concentrated phosphoric acid solution.

Description

明 細 書  Specification
リン酸含有水からリン酸を回収する方法および装置  Method and apparatus for recovering phosphoric acid from phosphoric acid-containing water
技術分野  Technical field
[0001] 本発明は、リン酸含有水から逆浸透装置によりリン酸を回収する方法および装置に 関し、特に液晶基板やウェハーその他の電子機器をエッチングした後のリン酸を含 有する洗浄排水からリン酸などの有価物と処理水である純水の回収に適したリン酸を 回収する方法および装置に関するものである。  TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for recovering phosphoric acid from phosphoric acid-containing water using a reverse osmosis device, and in particular, from a washing wastewater containing phosphoric acid after etching a liquid crystal substrate, a wafer or other electronic equipment. The present invention relates to a method and apparatus for recovering phosphoric acid suitable for recovery of valuable materials such as acid and pure water which is treated water.
背景技術  Background art
[0002] 液晶基板やウェハーその他の電子機器のエッチングには、リン酸を含むエッチング 液が用いられている。エッチング工程で発生する高濃度の廃エッチング液は回収し て再生利用されているが、エッチング後の電子機器は純水により洗浄され、低濃度の 洗浄排水が大量に生成する。このような洗浄排水はエッチング液の成分であるリン酸 、硝酸、酢酸、その他の酸成分等のほ力、、エッチングによって溶出した金属イオンそ の他の不純物が含まれてレ、る力 大部分は純水である。  An etching solution containing phosphoric acid is used for etching liquid crystal substrates, wafers and other electronic devices. The high-concentration waste etchant generated in the etching process is recovered and recycled, but the electronic equipment after etching is washed with pure water, and a large amount of low-concentration washing wastewater is generated. Such washing wastewater contains components such as phosphoric acid, nitric acid, acetic acid, and other acid components, and metal ions and other impurities eluted by etching. Is pure water.
[0003] このようなエッチング洗浄排水は、従来は他の排水と混合して処理されている。一 般的なリン酸やフッ酸を含む排水の処理技術としては、凝集沈殿処理が挙げられる。 しかしリン酸ゃフッ酸の凝集沈澱処理を行う場合、多量の薬剤使用と多量の汚泥発 生による処理コストの上昇、環境への負荷の増大などが問題となる。加えて、凝集沈 殿処理で多量に添加する薬剤による水溶性イオンの増加が、水回収するに当たり、 逆浸透膜プロセスの操作圧力上昇による動力コストの増大、処理水質の悪化、スケ ールの発生、また、イオン交換法では再生剤使用量の増加につながつている。  [0003] Conventionally, such etching cleaning wastewater is treated by mixing with other wastewater. A common treatment technique for wastewater containing phosphoric acid or hydrofluoric acid is coagulation sedimentation. However, when coagulating and precipitating with phosphoric acid or hydrofluoric acid, there are problems such as increased treatment costs due to the use of a large amount of chemicals and the generation of a large amount of sludge, and an increase in environmental burden. In addition, an increase in water-soluble ions due to a large amount of chemicals added in the coagulation sedimentation treatment increases the power cost due to the increase in operating pressure in the reverse osmosis membrane process, the quality of the treated water, and the generation of scale. In addition, the ion exchange method leads to an increase in the amount of regenerant used.
[0004] 特許文献 1 (日本国特許公開 2006— 75820号）には、イオン交換樹脂でリン酸、 硝酸などのイオンを除去し、純水およびリン酸塩の回収が行われている。し力、し、この 方法ではリン酸塩 (リン酸二水素ナトリウムなど）として回収している力 S、リン酸塩の販 路が殆どなぐリン酸のナトリウム塩は溶解度が小さいため、液状ではリン酸の含有率 が低ぐ運搬は困難であり、カリウム塩とするには苛性カリが高価である。またリン酸二 水素ナトリウムにするために H形カチオン樹脂に通液する方法が示されている力 力 チオン樹脂の再生で塩酸などの酸が消費され、ァニオン樹脂の再生で使用した水酸 化ナトリウムも無駄に排出されるなどの欠点があった。 [0004] In Patent Document 1 (Japanese Patent Publication No. 2006-75820), ions such as phosphoric acid and nitric acid are removed with an ion exchange resin, and pure water and phosphate are recovered. In this method, the strength S recovered as phosphate (sodium dihydrogen phosphate, etc.), and the sodium salt of phosphate, which has almost no market for phosphate, have low solubility. Carrying with low acid content is difficult, and caustic potash is expensive to make potassium salts. Also shown is the ability to pass through H-cation resin to make sodium dihydrogen phosphate. The regeneration of the thione resin consumes acids such as hydrochloric acid, and the sodium hydroxide used in the regeneration of the anion resin also wastes.
特許文献 1 :日本国特許公開 2006— 75820号  Patent Document 1: Japanese Patent Publication 2006—75820
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0005] 本発明の課題は、簡単な構成と操作により、高濃度の液状で運搬可能であり、回収 物として有用な高純度のリン酸を、リン酸含有水から低コストで、かつ効率よく回収で きるリン酸を回収する方法および装置を提案することである。 [0005] An object of the present invention is to transport high-purity phosphoric acid useful as a recovered material from a phosphoric acid-containing water at low cost and efficiently, which can be transported in a high concentration liquid state with a simple configuration and operation. It is to propose a method and an apparatus for recovering recoverable phosphoric acid.
課題を解決するための手段  Means for solving the problem
[0006] 本発明は、次のリン酸イオン含有水からリン酸を回収する方法および装置である。 [0006] The present invention is a method and apparatus for recovering phosphoric acid from the following phosphate ion-containing water.
(1) リン酸含有水からリン酸を回収する方法であって、  (1) A method for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下の条件下で逆浸透装置に供給して逆浸透処理を行い、リ ン酸以外の酸を水とともに透過液室側に透過させて、リン酸を濃縮液室側に濃縮し、 リン酸濃縮液を回収することを特徴とするリン酸の回収方法。  Reverse osmosis treatment is performed by supplying phosphoric acid-containing water to the reverse osmosis device under the condition of PH3 or less, acid other than phosphoric acid is permeated to the permeate chamber side together with water, and phosphoric acid is introduced to the concentrate chamber side. A method for recovering phosphoric acid, comprising concentrating and recovering a phosphoric acid concentrate.
(2) リン酸含有水からリン酸を回収する方法であって、  (2) A method for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で逆浸透装置に 供給して膜分離処理を行い、リン酸以外の酸を水とともに透過液室側に透過させて、 リン酸を濃縮液室側に濃縮し、リン酸濃縮液を回収することを特徴とするリン酸の回 収方法。  Phosphoric acid-containing water is supplied to the reverse osmosis unit under conditions of PH3 or less and phosphoric acid concentration;! ~ 15 wt%, and membrane separation treatment is performed to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water. Then, the phosphoric acid is concentrated to the concentrated liquid chamber side, and the phosphoric acid concentrated liquid is recovered, and a method for recovering phosphoric acid is provided.
(3) 濃縮液室の濃縮液を取出して濃縮液室へ循環する過程を有し、循環する濃 縮液に被処理リン酸含有水を加えて逆浸透処理を行う上記（1)または（2)記載の方 法。  (3) The above-mentioned (1) or (2) has a process of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and adding reverse phosphoric acid treatment water to the circulating concentrate. ) How to describe.
(4) 濃縮液室の濃縮液を取出して濃縮液室へ循環する過程を有し、循環する濃 縮液に希釈水を加えて膜分離処理を行う上記（ 1 )または（2)記載の方法。  (4) The method according to (1) or (2) above, wherein the method comprises the step of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and performing membrane separation treatment by adding dilution water to the circulating concentrate .
(5) リン酸含有水を逆浸透装置に供給する前に、前処理としてカチオンおよび/ またはァニオンを含む不純物の除去を行う上記（1)または（2)記載の方法。  (5) The method according to (1) or (2) above, wherein impurities containing cations and / or anions are removed as a pretreatment before supplying the phosphoric acid-containing water to the reverse osmosis device.
(6) 逆浸透装置の透過水から酸を含む不純物を除去して純水を回収する上記（1 )または（2)記載の方法。 (7) 不純物の除去を、イオン交換装置により行う上記（6)記載の方法。 (6) The method according to (1) or (2) above, wherein impurities containing acid are removed from the permeate of the reverse osmosis device to recover pure water. (7) The method according to (6) above, wherein the impurities are removed by an ion exchange device.
(8) リン酸濃縮液からァニオン交換によりリン酸以外の酸を除去して精製する上記 (1)または（2)記載の方法。  (8) The method according to (1) or (2) above, wherein the phosphoric acid concentrate is purified by removing an acid other than phosphoric acid by anion exchange.
(9) リン酸濃縮液を蒸発濃縮して、水とともに揮発性成分を除去して濃縮する上 記（1)または（2)記載の方法。  (9) The method according to (1) or (2) above, wherein the phosphoric acid concentrate is concentrated by evaporation to remove volatile components together with water and concentrated.
(10) リン酸含有水からリン酸を回収する装置であって、  (10) An apparatus for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下の条件下で膜分離処理して、リン酸以外の酸を水とともに 透過液室側に透過させ、リン酸を濃縮液室側に濃縮する逆浸透装置と、  A reverse osmosis device that performs membrane separation treatment of phosphoric acid-containing water under a pH of 3 or less, allows acids other than phosphoric acid to permeate to the permeate chamber side together with water, and concentrates phosphoric acid to the concentrate chamber side;
リン酸含有水を PH3以下の条件下で逆浸透膜装置の濃縮液室側に供給する原水 供給部と、  A raw water supply unit for supplying phosphoric acid-containing water to the concentrate chamber side of the reverse osmosis membrane device under a condition of PH3 or less;
逆浸透装置の透過液室側から透過液を取出す透過液取出部と、  A permeate extractor for extracting permeate from the permeate chamber side of the reverse osmosis device;
逆浸透装置の濃縮液室側から濃縮リン酸液を取出す濃縮リン酸液取出部と を有することを特徴とするリン酸回収装置。  A phosphoric acid recovery apparatus, comprising: a concentrated phosphoric acid solution extraction unit that extracts a concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device.
(11) リン酸含有水からリン酸を回収する装置であって、  (11) An apparatus for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で膜分離処理し て、リン酸以外の酸を水とともに透過液室側に透過させ、リン酸を濃縮液室側に濃縮 する逆浸透装置と、  Membrane separation treatment is performed under conditions where the phosphoric acid-containing water is PH3 or less and the phosphoric acid concentration is! ~ 15% by weight to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water, and phosphoric acid is concentrated in the concentrate chamber. A reverse osmosis device that concentrates to the side,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で逆浸透装置の 濃縮液室側に供給するリン酸含有水供給部と、  A phosphoric acid-containing water supply section for supplying phosphoric acid-containing water to a concentration chamber side of the reverse osmosis device under conditions of PH3 or less and phosphoric acid concentration;
逆浸透装置の透過液室側から透過液を取出す透過液取出部と、  A permeate extractor for extracting permeate from the permeate chamber side of the reverse osmosis device;
逆浸透装置の濃縮液室側から濃縮リン酸液を取出す濃縮リン酸液取出部と 濃縮リン酸液取出部から取出した濃縮リン酸液を濃縮液室側に循環する循環経路 と  A concentrated phosphoric acid solution extraction section for extracting the concentrated phosphoric acid solution from the concentrated liquid chamber side of the reverse osmosis device, and a circulation path for circulating the concentrated phosphoric acid solution extracted from the concentrated phosphoric acid solution extraction unit to the concentrated liquid chamber side;
を有することを特徴とするリン酸回収装置。  The phosphoric acid collection | recovery apparatus characterized by having.
(12) 循環経路を循環する濃縮液に希釈水を加える希釈水供給部を有する上記（ 10)または（11 )記載の装置。  (12) The apparatus according to (10) or (11) above, further comprising a dilution water supply unit for adding dilution water to the concentrate circulating in the circulation path.
(13) カチオンおよび/またはァニオンを含む不純物の除去を行う前処理装置を 原水供給部に有する上記（10)または（1 1)記載の装置。 (14) 逆浸透装置の透過水から酸を含む不純物を除去する不純物除去装置を有 する上記（10)または（11)記載の装置。 (13) The apparatus according to (10) or (11) above, wherein the raw water supply unit has a pretreatment apparatus for removing impurities including cations and / or anions. (14) The apparatus according to (10) or (11) above, further comprising an impurity removing device for removing impurities including acid from the permeated water of the reverse osmosis device.
(15) 不純物除去装置がイオン交換装置である上記（14)記載の装置。 (15) The apparatus according to (14), wherein the impurity removing apparatus is an ion exchange apparatus.
(16) リン酸濃縮液からァニオン交換によりリン酸以外の酸を除去する精製装置を 有する上記（ 10)または（ 11 )記載の装置。 (16) The apparatus according to (10) or (11) above, further comprising a purification apparatus for removing an acid other than phosphoric acid from the phosphoric acid concentrate by anion exchange.
(17) リン酸濃縮液を蒸発濃縮して、水とともに揮発性成分を除去して濃縮する蒸 発濃縮装置を有する上記（10)または（11)記載の装置。  (17) The apparatus according to (10) or (11) above, further comprising an evaporative concentration apparatus for evaporating and concentrating the phosphoric acid concentrate to remove volatile components together with water and concentrating.
[0007] 本発明において、処理の対象となるリン酸含有水は、リン酸を含有する水であれば 制限なく対象とすることができる力 リン酸イオン 50〜； 10000mg/L、特に 50〜200 Omg/L含有し、 pHは 3以下、特に 2. 8以下であって、いずれの場合も 1以上、特に 1. 8以上である酸性水が処理対象として好ましぐリン酸イオンのほ力、に、硝酸イオン 、酢酸イオン等の酸成分、その他のァニオン、ならびに金属イオン等のカチオン、そ の他の不純物が含まれていてもよい。本発明では特に硝酸イオン、酢酸イオン等の 他の酸成分を含むリン酸含有水から、硝酸イオン、酢酸イオン等の他の酸成分を除 去して、純度の高いリン酸を回収するのに適している。  [0007] In the present invention, the phosphoric acid-containing water to be treated can be used without limitation as long as it contains phosphoric acid. Phosphate ions 50-; 10000 mg / L, especially 50-200 Contains Omg / L, pH is 3 or less, especially 2.8 or less, in any case 1 or more, especially 1. In addition, acid components such as nitrate ions and acetate ions, other anions, cations such as metal ions, and other impurities may be contained. In the present invention, in order to recover highly pure phosphoric acid, in particular, other acid components such as nitrate ion and acetate ion are removed from phosphoric acid-containing water containing other acid components such as nitrate ion and acetate ion. Is suitable.
[0008] 特に処理対象として好ましいリン酸含有水は、液晶基板やウェハーその他の電子 機器のリン酸含有エッチング液によるエッチング後に、純水洗浄を行う際に発生する 低濃度の洗浄排水がある。このようなエッチング後の洗浄排水の例としては、リン酸ィ オン 50〜2000mg/L、硝酸イオン 10〜500mg/L、酢酸イオン 5〜300mg/Lを 含有し、 ρΗ1 · 8〜2· 8の酸性水がある。  [0008] Phosphoric acid-containing water that is particularly preferable as a treatment target is low-concentration cleaning wastewater that is generated when pure water cleaning is performed after etching with a phosphoric acid-containing etching solution for liquid crystal substrates, wafers, and other electronic devices. Examples of such cleaning wastewater after etching include phosphate ions 50 to 2000 mg / L, nitrate ions 10 to 500 mg / L, acetate ions 5 to 300 mg / L, and ρΗ1 · 8 to 2 · 8. There is acid water.
[0009] 本発明では、リン酸含有水からリン酸を回収するために、リン酸含有水を ρΗ3以下 、かつリン酸濃度;!〜 15重量％の条件下で逆浸透膜装置に供給して膜分離処理を 行うのが好ましい。また本発明では、リン酸含有水を逆浸透膜装置に供給する前に、 前処理としてカチオンおよび/またはァニオンを含む不純物の除去を行うのが好まし い。この場合、沈殿分離、濾過等による固形物の除去、ならびにカチオン交換樹脂 による金属イオン等のカチオンの除去、ならびにァニオン交換樹脂による過塩素酸 やモリブデン酸、有機酸錯体等のァニオンの除去などを行うことができる。このような 前処理工程に用いる前処理装置としては、上記目的に採用されている一般的な装置 が用いられる。 [0009] In the present invention, in order to recover phosphoric acid from phosphoric acid-containing water, the phosphoric acid-containing water is supplied to the reverse osmosis membrane device under conditions of ρ 以下 3 or less and phosphoric acid concentration; It is preferable to perform a membrane separation treatment. In the present invention, it is preferable to remove impurities including cations and / or anions as a pretreatment before supplying the phosphoric acid-containing water to the reverse osmosis membrane device. In this case, precipitate separation, removal of solids by filtration, etc., removal of cations such as metal ions by cation exchange resin, and removal of anions such as perchloric acid, molybdic acid and organic acid complexes by anion exchange resin, etc. be able to. As a pretreatment apparatus used in such a pretreatment process, a general apparatus adopted for the above purpose is used. Is used.
[0010] エッチング後の洗浄排水に含まれるインジウム、鉄、アルミニウム等の金属イオンは 膜分離工程における逆浸透 (RO)膜の目詰まりの原因となり、過塩素酸やモリブデン 酸などは高濃度になると膜損傷の原因となるので、これらのカチオンゃァニオンを除 去することにより、膜の目詰まりや損傷などが防止できるので好ましい。カチオン交換 樹脂としては、強酸性または弱酸性カチオン交換樹脂を用いることができるが、 H形 の強酸性力チオン交換樹脂を用いてこれらの力チオンを交換除去すると、処理液は 酸成分が増加して pH3以下に調整することが容易になるので好ましい。カチオン交 換樹脂としてはキレート樹脂でもよい。ァニオン交換樹脂としては、強塩基性または 弱塩基性カチオン交換樹脂を用いることができる。ァユオン交換樹脂はリン酸形等の 酸形で用い、リン酸、硝酸、酢酸等を素通りさせ、他の不純物ァニオンを除去する。  [0010] Metal ions such as indium, iron, and aluminum contained in the cleaning waste water after etching cause clogging of the reverse osmosis (RO) membrane in the membrane separation process, and perchloric acid, molybdic acid, etc. become high in concentration. Since it causes membrane damage, it is preferable to remove these cation anions because clogging or damage to the membrane can be prevented. As the cation exchange resin, a strong acid or weak acid cation exchange resin can be used. However, when these strong thiones are exchanged and removed using the H-form strong acid force thione exchange resin, the acid component of the treatment liquid increases. It is preferable because it becomes easy to adjust the pH to 3 or less. The cation exchange resin may be a chelate resin. As the anion exchange resin, a strongly basic or weakly basic cation exchange resin can be used. The cation exchange resin is used in an acid form such as phosphoric acid form, and passes through phosphoric acid, nitric acid, acetic acid, etc. to remove other impurity anions.
[0011] 本発明で膜分離工程における逆浸透装置は、 RO装置とも呼ばれ、逆浸透 (RO) 膜により透過液室と濃縮液室とに区画され、リン酸含有水を pH3以下の条件下で、ま た好ましくはさらにリン酸濃度 1〜； 15重量％の条件下で濃縮液室側に供給して逆浸 透膜処理を行い、リン酸以外の酸を水とともに透過液室側に透過させるとともに、リン 酸を濃縮液室側に濃縮させるように構成される。逆浸透膜装置の濃縮液室側には、 リン酸含有水を供給するリン酸含有水供給部、ならびに濃縮リン酸液を取出す濃縮リ ン酸液取出部が形成される。逆浸透膜装置の透過液室側には、透過液を取出す透 過液取出部が形成される。濃縮リン酸液取出部とリン酸含有水供給部間には、濃縮 リン酸液取出部から取出した濃縮リン酸液を濃縮液室側に循環する循環経路が形成 される。逆浸透膜は、浸透圧により水を透過させ、あるいは逆に浸透圧よりも高圧に 加圧して被処理液を供給して逆浸透により水を透過させ、一方塩分、有機物、その 他の溶質を透過させな!/、で阻止する半透膜である。  [0011] In the present invention, the reverse osmosis device in the membrane separation step is also called an RO device, which is partitioned into a permeate chamber and a concentrate chamber by a reverse osmosis (RO) membrane, In addition, preferably, the phosphoric acid concentration is 1 to; 15% by weight is supplied to the concentrated liquid chamber side to perform reverse osmosis membrane treatment, and acid other than phosphoric acid is permeated to the permeate liquid chamber side together with water. And is configured to concentrate phosphoric acid to the concentrate chamber side. On the concentrated liquid chamber side of the reverse osmosis membrane device, there are formed a phosphoric acid-containing water supply part for supplying phosphoric acid-containing water and a concentrated phosphoric acid liquid extracting part for taking out the concentrated phosphoric acid liquid. On the permeate chamber side of the reverse osmosis membrane device, a permeate extractor for taking out the permeate is formed. A circulation path is formed between the concentrated phosphoric acid solution take-out part and the phosphoric acid-containing water supply part to circulate the concentrated phosphoric acid solution taken out from the concentrated phosphoric acid solution take-out part to the concentrated liquid chamber side. Reverse osmosis membranes allow water to permeate by osmotic pressure, or conversely pressurize to a pressure higher than osmotic pressure to supply the liquid to be treated and allow water to permeate by reverse osmosis, while allowing salt, organic matter, and other solutes to pass through. It is a semi-permeable membrane that prevents it from passing through! /.
[0012] 逆浸透膜の材質としては、上記の特性を有する限り特に制限されず、例えばポリア ミド系透過膜、ポリイミド系透過膜、セルロース系透過膜などが挙げられ、非対称逆浸 透膜でもよいが、微多孔性支持体上に実質的に選択分離性を有する活性なスキン 層を形成した複合逆浸透膜が好ましレ、。逆浸透装置はこのような逆浸透膜を備える ものであればよいが、逆浸透膜と支持機構、集水機構等が一体化した膜モジュール を備えるものが好ましい。膜モジュールとしては特に制限はなぐ例えば管状膜モジ ユール、平面膜モジュール、スパイラル膜モジュール、中空糸膜モジュールなどを挙 げること力 Sできる。これらを備える逆浸透装置としては公知のものが使用でき、低圧で 操作される高透過性のものが好ましレ、。 [0012] The material of the reverse osmosis membrane is not particularly limited as long as it has the above-mentioned characteristics, and examples thereof include a polyamide permeable membrane, a polyimide permeable membrane, a cellulose permeable membrane, and may be an asymmetric reverse permeable membrane. However, a composite reverse osmosis membrane in which an active skin layer having substantially selective separability is formed on a microporous support is preferred. The reverse osmosis device may be any device as long as it has such a reverse osmosis membrane. The thing provided with is preferable. The membrane module is not particularly limited. For example, a tubular membrane module, a planar membrane module, a spiral membrane module, and a hollow fiber membrane module can be cited. As the reverse osmosis apparatus equipped with these, a known apparatus can be used, and a highly permeable apparatus operated at a low pressure is preferable.
[0013] 本発明では膜分離工程において、リン酸含有水を pH3以下の条件下で、また好ま しくはさらにリン酸濃度 1〜； 15重量％の条件下で、さらに好ましくは 2〜； 10重量％の 条件下で逆浸透膜装置に供給して膜分離 (逆浸透)処理を行う。リン酸含有水が pH 3以下の状態で得られる場合には、そのまま pH調整することなく逆浸透膜装置に供 給すること力できる力 必要により塩酸、硝酸等の pH調整剤の添加により pH調整し てもよ!/、。前処理にお!/、てカチオン交換樹脂により金属イオン等のカチオンの除去を 行うことにより pH3以下に調整される場合も同様である。液晶基板やウェハー等のェ ツチング後の洗浄排水は、通常 pH3以下の状態で得られるので、 pH調整することな く逆浸透膜装置に供給することができ、 pH調整する場合でも pH調整剤の添加量は 少なくなる。  [0013] In the present invention, in the membrane separation step, the phosphoric acid-containing water is used under conditions of pH 3 or less, preferably 1 to 15% by weight, more preferably 2 to 10% by weight. The membrane separation (reverse osmosis) treatment is performed by supplying to the reverse osmosis membrane device under the condition of%. If the phosphoric acid-containing water is obtained at a pH of 3 or less, the power that can be supplied to the reverse osmosis membrane device without adjusting the pH as it is. Adjusting the pH by adding a pH adjuster such as hydrochloric acid or nitric acid if necessary. You can! / The same applies to the case where the pH is adjusted to 3 or lower by removing cations such as metal ions with a cation exchange resin in the pretreatment! Cleaning wastewater after etching of liquid crystal substrates and wafers is usually obtained at a pH of 3 or less, so it can be supplied to the reverse osmosis membrane device without adjusting the pH. The amount added is reduced.
[0014] リン酸含有水がリン酸濃度;!〜 15重量％で得られる場合は、そのまま膜分離処理を 行って逆浸透による分離を行うことができるが、リン酸濃度 1重量％未満の場合は、 循環経路を通して濃縮液を循環しながら膜分離処理を行うことにより、リン酸濃度 1重 量％以上に濃縮することができる。あるいは別途設けた RO装置などの濃縮装置によ つて予め濃縮処理してもよいし、回収した高濃度リン酸液を添加しても良い。  [0014] When the phosphoric acid-containing water is obtained at a phosphoric acid concentration;! To 15% by weight, separation by reverse osmosis can be performed by performing a membrane separation treatment as it is, but when the phosphoric acid concentration is less than 1% by weight. Can be concentrated to a phosphoric acid concentration of 1% by weight or more by performing membrane separation treatment while circulating the concentrate through the circulation path. Alternatively, it may be concentrated in advance by a concentrating device such as a RO device provided separately, or the recovered high concentration phosphoric acid solution may be added.
[0015] 循環経路を通して濃縮液を循環しながら膜分離処理を行うことにより、リン酸濃度を 1重量％以上に濃縮する場合、低濃度のリン酸含有水を循環しながら濃縮し、リン酸 濃度 1重量％以上に濃縮された時点で循環液を入れ替える回分式の処理を行って もよいが、リン酸濃度;!〜 15重量％に濃縮された濃縮液を循環しながら、循環する濃 縮液に低濃度の被処理リン酸含有水を加え、濃縮液を一部ずつリン酸濃縮液として 取出すと、見掛け上一過式の処理が行えるので好ましい。濃縮液室の濃縮液を取出 して濃縮液室へ循環する過程にぉレ、て、循環する濃縮液に希釈水を加えて逆浸透 処理を行うことにより、リン酸以外の酸の除去率を高めることができる。希釈水としては 透過水から不純物を除去した回収水を使用することができる。 [0016] リン酸含有水を pH3以下の条件下で逆浸透装置に供給して膜分離処理を行うと、 硝酸、酢酸等のリン酸以外の酸は、水とともに逆浸透膜を透過して透過液室側に移 行し、透過液室側から取出される。リン酸は逆浸透膜の透過を阻止され、濃縮液室 側に残留して濃縮されるので、濃縮液室側からリン酸濃縮液として回収することがで きる。濃縮液室側の濃縮液は一過式に通過させてもよぐまた循環させて濃縮率を上 げてもよい。リン酸含有水を pH3以下 (かつリン酸濃度 1重量％未満の）条件下で逆 浸透装置に供給して膜分離処理を行う場合、逆浸透装置に供給するリン酸含有水の 圧力は 0· 3〜3MPa、好ましくは 0. 5〜； ! · 5MPaとすることができる。 [0015] When the phosphoric acid concentration is concentrated to 1% by weight or more by performing membrane separation treatment while circulating the concentrate through the circulation path, the phosphoric acid concentration is concentrated while circulating low-concentration phosphoric acid-containing water. A batch-type treatment may be performed in which the circulating fluid is replaced when it is concentrated to 1% by weight or more. However, the concentrated solution is circulated while circulating the concentrated solution concentrated to a phosphoric acid concentration; It is preferable to add low-concentration phosphoric acid-containing water to the solution and take out the concentrated solution partly as a phosphoric acid concentrated solution because an apparent one-time treatment can be performed. In the process of removing the concentrate from the concentrate chamber and circulating it to the concentrate chamber, reverse osmosis treatment is performed by adding diluted water to the circulating concentrate, thereby reducing the removal rate of acids other than phosphoric acid. Can be increased. As dilution water, recovered water from which impurities have been removed from the permeated water can be used. [0016] When phosphoric acid-containing water is supplied to a reverse osmosis device under a pH of 3 or less and subjected to membrane separation treatment, acids other than phosphoric acid such as nitric acid and acetic acid permeate through the reverse osmosis membrane together with water. Move to the liquid chamber side and take out from the permeate chamber side. Phosphoric acid is prevented from permeating through the reverse osmosis membrane and remains on the concentrate chamber side to be concentrated, so that it can be recovered from the concentrate chamber side as a phosphoric acid concentrate. The concentrate on the concentrate chamber side may be passed through temporarily or may be circulated to increase the concentration rate. When supplying phosphoric acid-containing water to a reverse osmosis device under the condition of pH 3 or less (and phosphoric acid concentration is less than 1% by weight), the pressure of the phosphoric acid-containing water supplied to the reverse osmosis device is 0 · 3 to 3 MPa, preferably 0.5 to 5!
[0017] 濃縮液には少量のリン酸以外の酸が残留するが、リン酸濃度;!〜 15重量％の条件 下で膜分離処理を行うと、リン酸以外の酸の阻止率が低くなり、透過率が高くなるの で、高純度のリン酸濃縮液を回収することができる。リン酸含有水を pH3以下、かつリ ン酸濃度;!〜 15重量％の条件下で逆浸透装置に供給して膜分離処理を行う場合、 逆浸透装置に供給するリン酸含有水の圧力は 0. 3〜5MPa、好ましくは 0. 5〜3MP aとすること力 Sでさる。  [0017] Although a small amount of acid other than phosphoric acid remains in the concentrated solution, when the membrane separation treatment is performed under the condition of phosphoric acid concentration:! To 15% by weight, the blocking rate of acids other than phosphoric acid becomes low. Since the transmittance is increased, a high-purity phosphoric acid concentrate can be recovered. When membrane separation treatment is performed by supplying phosphoric acid-containing water to a reverse osmosis device under a pH of 3 or less and a phosphoric acid concentration;! ~ 15 wt%, the pressure of the phosphoric acid-containing water supplied to the reverse osmosis device is The force S is adjusted to 0.3 to 5 MPa, preferably 0.5 to 3 MPa.
[0018] 逆浸透膜の透過においてイオン性物質と非イオン性物質の透過を比較すると、逆 浸透膜阻止率は、同じ程度の分子量であっても、非イオン性物質に比べてイオン性 物質の方が圧倒的に阻止されやすいと言われている。し力、し本発明者等が研究を重 ねた結果、このような常識とは異なり、リン酸が解離しにくい pH3以下の条件下で逆 浸透膜処理すると、リン酸の阻止率は硝酸や酢酸よりも圧倒的に高くなり、硝酸や酢 酸等のリン酸以外の酸とリン酸とを分別して回収できることが分力、つた。低 pH下でリン 酸が逆浸透膜に強く阻止される理由は、リン酸が重リン酸の形態となって分子量が大 きくなり、阻止率がアップしたためであると推測される。  [0018] When the permeation of the ionic substance and the nonionic substance is compared in the permeation of the reverse osmosis membrane, the reverse osmosis membrane blocking rate is higher than that of the nonionic substance even if the molecular weight is the same. It is said that it is overwhelmingly easy to stop. As a result of research conducted by the present inventors, unlike this common sense, when a reverse osmosis membrane treatment is performed under conditions where pH is less than pH 3 where phosphoric acid is difficult to dissociate, the rejection rate of phosphoric acid is reduced to nitric acid or It was overwhelmingly higher than acetic acid, and it was possible to separate and recover acids other than phosphoric acid such as nitric acid and acetic acid from phosphoric acid. The reason why phosphoric acid is strongly blocked by the reverse osmosis membrane at low pH is presumed to be that phosphoric acid is in the form of heavy phosphoric acid, resulting in an increased molecular weight and an increased blocking rate.
[0019] pH3以下の条件下での硝酸、酢酸等のリン酸以外の酸の阻止率は低ぐ通常のリ ン酸含有エッチング液を膜処理する場合の阻止率は 1 %以下であるが、リン酸濃度 が高いほどリン酸以外の酸の阻止率は低くなり、リン酸濃度 1重量％以上ではリン酸 以外の酸の阻止率がマイナスになる。ここで阻止率とは、逆浸透膜が溶質の透過を 阻止する割合であり、次の式（1)で示される。  [0019] While the rejection rate of acids other than phosphoric acid such as nitric acid and acetic acid under pH 3 or lower is low, the rejection rate when a normal phosphoric acid-containing etching solution is treated with a film is 1% or less. The higher the concentration of phosphoric acid, the lower the blocking rate of acids other than phosphoric acid, and the blocking rate of acids other than phosphoric acid becomes negative when the phosphoric acid concentration is 1% by weight or more. Here, the blocking rate is the rate at which the reverse osmosis membrane blocks solute permeation, and is expressed by the following equation (1).
阻止率（％) = (1— C / (C - C ) 1/2) X 100 · · · (!) (式（1)中、 Cは供給液入口の溶質濃度、 Cは濃縮液出口の溶質濃度、 Cはの透 Rejection rate (%) = (1— C / (C-C) 1/2 ) X 100 · · · (!) (In formula (1), C is the solute concentration at the inlet of the feed liquid, C is the solute concentration at the outlet of the concentrate, and C is the permeability of
1 2 3 過液の溶質濃度である。 )  1 2 3 Excess liquid solute concentration. )
[0020] 式（1)において、 ( (C - C ) 1/2)は相乗平均を示し、 (C / (C - C ) 1/2)は濃縮液 [0020] In the formula (1), ((C-C) 1/2 ) represents a geometric mean, and (C / (C-C) 1/2 ) represents a concentrated solution.
1 2 3 1 2  1 2 3 1 2
の溶質の (相乗）平均濃度に対する透過液の溶質濃度の比を示す。このため阻止率 が低いほど、溶質が透過液側に透過することを示している。通常の観念では阻止率 がマイナスになることはないと認識されやすいが、式（1)では式の構成から阻止率が マイナスになることがあり、この場合、濃縮液の溶質濃度よりも透過液の溶質濃度が 高ぐ溶質が高透過率で透過することを示している。  The ratio of the solute concentration of the permeate to the (synergistic) average concentration of the solute. For this reason, the lower the blocking rate, the more the solute permeates to the permeate side. Although it is easy to recognize that the rejection rate will not be negative in the normal concept, the rejection rate may be negative due to the composition of the equation (1), and in this case, the permeated liquid concentration is higher than the solute concentration of the concentrate. It shows that solutes with high solute concentration permeate with high permeability.
[0021] リン酸濃度 1重量％以上でリン酸以外の酸の阻止率がマイナスになるということは、 リン酸濃度 1重量％以上、特に 2重量％以上では濃縮液中に残留するリン酸以外の 酸濃度は低くなり、純度の高いリン酸濃縮液が得られることを意味する。濃縮液のリン 酸濃度が高過ぎると浸透圧の関係で膜処理が行えなくなるので、濃縮液のリン酸濃 度の上限は 15重量％、好ましくは 10重量％とされる。このようなリン酸濃度の濃縮液 を循環しながら、循環する濃縮液に被処理リン酸含有水を加え、濃縮液を一部ずつ リン酸濃縮液として取出して一過式の処理を行うと、上記リン酸濃度を維持して効率 よく処理をネ亍うこと力 Sできる。  [0021] When the phosphoric acid concentration is 1% by weight or more, the rejection rate of acids other than phosphoric acid is negative. When the phosphoric acid concentration is 1% by weight or more, particularly 2% by weight or more, other than phosphoric acid remaining in the concentrate. This means that the acid concentration is low, and a highly concentrated phosphoric acid concentrate is obtained. If the concentration of phosphoric acid in the concentrate is too high, membrane treatment cannot be performed due to osmotic pressure, so the upper limit of the concentration of phosphoric acid in the concentrate is 15% by weight, preferably 10% by weight. While circulating the concentrated solution with such a phosphoric acid concentration, adding water to be treated with phosphoric acid to the circulating concentrated solution and taking out the concentrated solution partly as a phosphoric acid concentrated solution, It is possible to maintain the above-mentioned phosphoric acid concentration and efficiently carry out treatment.
[0022] 濃縮液を循環しながら膜処理を行う際、濃縮液の循環回数を多くするほど、リン酸 以外の酸が逆浸透膜と接して膜を透過する機会が多くなり、濃縮液中のリン酸以外 の酸の濃度をさらに低くすることができる。このときリン酸濃度が 15重量％を超えると 浸透圧（操作圧）が高くなりすぎ、膜処理が行えなくなるので、濃縮液に希釈水をカロ え希釈して循環し、逆浸透処理を行うことにより、さらにリン酸以外の酸の濃度を低く すること力 Sでき、高純度のリン酸濃縮液を回収することができる。希釈水としては透過 水から不純物を除去した回収水を循環して使用することができる。  [0022] When the membrane treatment is performed while circulating the concentrate, the greater the number of times the concentrate is circulated, the greater the opportunity for acids other than phosphoric acid to contact the reverse osmosis membrane and permeate the membrane. The concentration of acids other than phosphoric acid can be further reduced. At this time, if the phosphoric acid concentration exceeds 15% by weight, the osmotic pressure (operating pressure) becomes too high and the membrane treatment cannot be performed. Thus, it is possible to further reduce the concentration of acids other than phosphoric acid, and a high-purity phosphoric acid concentrate can be recovered. As the dilution water, recovered water from which impurities have been removed from the permeated water can be circulated for use.
[0023] 透過液室側から取出される逆浸透膜装置の透過水は、透過したリン酸、硝酸、酢 酸等の酸を含んでレ、るので、逆浸透膜装置の透過水からこれらの酸その他の不純物 を不純物除去装置によって除去することにより、純水を回収することができる。この場 合、不純物除去装置としてはイオン交換樹脂を用いるイオン交換装置を採用すること ができる。透過水をァニオン交換樹脂層に通水することにより、これら酸、その他のァ 二オンを除去し、またカチオン交換樹脂層およびァニオン交換樹脂層、またはこれら の混床に通水することにより、酢酸や硝酸等のリン酸以外の酸、その他のァニオン、 ならびに残留するカチオンを除去し、純水を回収することができる。ここで用いるァニ オン交換樹脂としては、 OH形強塩基性あるレ、は弱塩基性ァユオン交換樹脂が好ま しぐまたカチオン交換樹脂としては、 H形強酸性カチオン交換樹脂が好ましい。 [0023] Since the permeated water of the reverse osmosis membrane device taken out from the permeate chamber side contains permeated acids such as phosphoric acid, nitric acid, and acetic acid, these permeates from the permeated water of the reverse osmosis membrane device. Pure water can be recovered by removing acid and other impurities with an impurity removing device. In this case, an ion exchange device using an ion exchange resin can be employed as the impurity removal device. By passing permeate through the anion exchange resin layer, these acids and other By removing the dione and passing water through the cation exchange resin layer and the anion exchange resin layer or a mixed bed thereof, acids other than phosphoric acid such as acetic acid and nitric acid, other anions, and residual cations are removed. In addition, pure water can be recovered. The anion exchange resin used here is preferably an OH type strongly basic cation or weakly basic cation exchange resin, and the cation exchange resin is preferably an H type strongly acidic cation exchange resin.
[0024] 一般的なイオン交換装置では、イオン交換樹脂の再生におレ、てカチオン交換樹脂 の再生には酸、ァニオン交換樹脂の再生にはアルカリを再生剤として使用する力 こ のような再生方法では再生剤が必要な上、再生廃液が発生するなどの不利があるた め、電気再生式イオン交換装置を採用するのが好ましい。電気再生式イオン交換装 置は、イオン交換樹脂層をカチオン交換樹脂膜およびァユオン交換樹膜で区画し、 両端部に陰極および陽極を配置した装置であり、電気透析装置と同様に、陰極およ び陽極に通電して再生しながら通液してイオン交換を行う。この場合、再生のための 特別の操作および再生剤が不要で、連続して酸その他の不純物を取り出し、純水を 回収することができる。電気再生式イオン交換装置に用いるイオン交換樹脂は、酸そ の他のァニオンの除去のみを目的とする場合は、ァニオン交換樹脂のみを充填する ことができる力 残留する他のカチオンの除去も目的とする場合は、カチオン交換樹 脂およびァニオン交換樹脂の混床を充填することができる。再生により排出される酸 濃縮液はリン酸、硝酸、酢酸等の濃縮液となっているので、生物脱窒法により処理す ること力 Sでさる。 [0024] In a general ion exchange apparatus, the regeneration using an acid as a regenerant for regenerating the ion exchange resin, the acid for regenerating the cation exchange resin, and the alkali for regenerating the anion exchange resin. Since the method requires a regenerant and has disadvantages such as generation of regenerated waste liquid, it is preferable to employ an electric regenerative ion exchanger. An electroregenerative ion exchange device is a device in which an ion exchange resin layer is partitioned by a cation exchange resin membrane and a cation exchange resin membrane, and a cathode and an anode are arranged at both ends. Ion exchange is performed by passing the liquid through the anode and regenerating while energizing. In this case, no special operation and regenerant for regeneration are required, and acid and other impurities can be continuously taken out and pure water can be recovered. If the ion exchange resin used in the electric regeneration type ion exchange device is intended only for removal of acid and other anions, it is possible to fill only the anion exchange resin. In this case, a mixed bed of cation exchange resin and anion exchange resin can be filled. The acid concentrate discharged by regeneration is a concentrate such as phosphoric acid, nitric acid, and acetic acid.
[0025] 一方、濃縮液室側から取出されるリン酸濃縮液は、硝酸や酢酸等のリン酸以外の 酸の大部分は除去されているが、さらにこれらを除去して回収リン酸液の純度、濃度 を高めるために後処理による精製を行うことができる。後処理による精製として、リン 酸濃縮液からァニオン交換によりリン酸以外の酸を除去して精製することができる。こ の場合、精製装置としてァニオン交換装置を設けて、濃縮液をァニオン交換樹脂層 に通水し、濃縮液から硝酸などの強酸イオンを除去し、硝酸などの強酸イオンを殆ど 含まない高濃度のリン酸を回収することができる。逆浸透装置が濃縮液を循環して濃 縮を行う場合、精製装置は逆浸透装置の濃縮液循環ラインに設けることができるが、 循環ラインから濃縮液を抜き出すラインに設けることが好ましい。ァニオン交換樹脂 は、 OH形または PO形の強塩基性ァニオン交換樹脂が好ましい。 [0025] On the other hand, the phosphoric acid concentrated liquid taken out from the concentrated liquid chamber side has most of acids other than phosphoric acid such as nitric acid and acetic acid removed. Purification by post-treatment can be performed to increase purity and concentration. As purification by post-treatment, it is possible to purify by removing acids other than phosphoric acid from the phosphoric acid concentrate by anion exchange. In this case, an anion exchange device is provided as a purification device, the concentrated solution is passed through the anion exchange resin layer, strong acid ions such as nitric acid are removed from the concentrated solution, and a high concentration containing almost no strong acid ions such as nitric acid is removed. Phosphoric acid can be recovered. When the reverse osmosis device circulates the concentrated solution to perform concentration, the purification device can be provided in the concentrated solution circulation line of the reverse osmosis device, but is preferably provided in a line for extracting the concentrated solution from the circulation line. Anion exchange resin Is preferably an OH-type or PO-type strongly basic anion exchange resin.
4  Four
[0026] リン酸濃縮液中に酢酸が残留している場合、酢酸はァニオン交換樹脂によっても完 全に除去できないので、酢酸等の揮発性成分を除去して回収リン酸液の純度、濃度 を高めるためには、リン酸濃縮液を蒸発濃縮装置で蒸発濃縮して、水とともに揮発性 成分を除去して濃縮し、酢酸などの揮発性成分を殆ど含まない高濃度のリン酸を回 収すること力 Sできる。蒸発濃縮装置としては、ロータリエバポレータ等の公知の装置が 使用できる。  [0026] If acetic acid remains in the phosphoric acid concentrate, the acetic acid cannot be completely removed even by the anion exchange resin. Therefore, the volatile components such as acetic acid are removed to increase the purity and concentration of the recovered phosphoric acid solution. To increase the concentration, concentrate the phosphoric acid concentrate with an evaporative concentrator, remove volatile components together with water, concentrate, and collect high-concentration phosphoric acid containing almost no volatile components such as acetic acid. That power S. A known apparatus such as a rotary evaporator can be used as the evaporative concentration apparatus.
[0027] 上記により回収されるリン酸は、回収物として有用であり、かつ高濃度の液状で運 搬可能であり、し力、も高純度の濃縮リン酸として回収できる。この場合、 pH3以下の 条件下で逆浸透処理するが、原水としてのリン酸含有水は通常 PH3以下の酸性の 状態で得られるので、塩酸等の pH調整剤を注入することにより容易に調整すること ができる。  [0027] The phosphoric acid recovered by the above is useful as a recovered material and can be transported in a high-concentration liquid state, and can be recovered as concentrated and highly pure phosphoric acid. In this case, reverse osmosis treatment is performed under the condition of pH 3 or less. However, since phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, it is easily adjusted by injecting a pH adjuster such as hydrochloric acid. be able to.
[0028] また回収のための方法および装置は、簡単な構成と操作により、 pH3以下、場合に よってはさらにリン酸濃度;!〜 15重量％の条件下で逆浸透処理することにより、リン酸 濃縮液として回収することが可能である。これにより再生剤の使用量、廃棄物の生成 量を少なくし、処理コストを低くして、高純度の濃縮リン酸および純水を回収すること ができる。  [0028] In addition, the method and apparatus for recovery can be obtained by performing reverse osmosis treatment with a simple configuration and operation under conditions of pH 3 or lower, and in some cases, phosphoric acid concentration; It can be recovered as a concentrate. As a result, the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be lowered, and high-purity concentrated phosphoric acid and pure water can be recovered.
発明の効果  The invention's effect
[0029] 以上の通り本発明によれば、リン酸含有水を pH3以下の条件下で逆浸透装置に供 給して逆浸透処理を行い、リン酸以外の酸を水とともに透過液室側に透過させて、リ ン酸を濃縮液室側に濃縮し、リン酸濃縮液を回収することにより、簡単な構成と操作 により、高濃度の液状で運搬可能であり、回収物として有用な高純度のリン酸を、リン 酸含有水から低コストで、かつ効率よく回収することができる。  [0029] As described above, according to the present invention, reverse osmosis treatment is performed by supplying phosphoric acid-containing water to a reverse osmosis device under a pH of 3 or less, and an acid other than phosphoric acid together with water enters the permeate chamber side. By permeating and concentrating phosphoric acid to the concentrate chamber side, and recovering the phosphoric acid concentrate, it can be transported in a highly concentrated liquid form with a simple configuration and operation. This phosphoric acid can be efficiently recovered from phosphoric acid-containing water at low cost.
[0030] また本発明によれば、リン酸含有水を pH3以下、かつリン酸濃度;!〜 15重量％の 条件下で逆浸透装置に供給して逆浸透処理を行い、リン酸以外の酸を水とともに透 過液室側に透過させて、リン酸を濃縮液室側に濃縮し、リン酸濃縮液を回収すること により、簡単な構成と操作により、高濃度の液状で運搬可能であり、回収物として有 用な高純度のリン酸を、リン酸含有水からさらに低コストで、かつ効率よく回収すること ができる。 [0030] Further, according to the present invention, the phosphoric acid-containing water is supplied to the reverse osmosis device under the conditions of pH 3 or lower and the phosphoric acid concentration;! Can be transported in a high-concentration liquid form with a simple configuration and operation by allowing water to permeate to the permeate chamber side with water, concentrating phosphoric acid to the concentrate chamber side, and collecting the phosphoric acid concentrate. , To recover high-purity phosphoric acid useful as a recovered material from phosphoric acid-containing water at a lower cost and more efficiently Can do.
図面の簡単な説明  Brief Description of Drawings
[0031] [図 1]図 1は一実施形態におけるリン酸回収方法および装置のフロー図である。  FIG. 1 is a flow diagram of a phosphoric acid recovery method and apparatus in one embodiment.
[図 2]図 2は他の実施形態におけるリン酸回収方法および装置のフロー図である。  FIG. 2 is a flow diagram of a phosphoric acid recovery method and apparatus according to another embodiment.
[図 3]図 3は実施例 3の結果を示すグラフである。  FIG. 3 is a graph showing the results of Example 3.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0032] 本発明の一実施形態を図 1により説明する。図 1は一実施形態におけるリン酸回収 装置のフロー図である。 1は原水槽で、原水 laを貯留する。 2はカチオン交換塔で、 カチオン交換樹脂層 2aを有する。 3は濃縮液槽で、濃縮液 3aを貯留する。 4は逆浸 透装置で、逆浸透膜 4aにより、透過液室 4bと濃縮液室 4cに区画されている。 5はァ 二オン交換塔で、ァニオン交換樹脂層 5aを有する。 7は回収水槽で、回収水 7aを貯 留する。 5bは第 2ァニオン交換塔で、ァニオン交換樹脂層 5cを有する。 8は蒸発濃 縮装置で、蒸留により揮発性成分を水とともに蒸発させて分離し、リン酸液を濃縮す る。 9は回収リン酸槽で、回収リン酸液 9aを貯留する。  An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flow diagram of a phosphoric acid recovery apparatus in one embodiment. 1 is a raw water tank that stores raw water la. 2 is a cation exchange tower having a cation exchange resin layer 2a. 3 is a concentrate tank and stores the concentrate 3a. A reverse osmosis device 4 is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a. An anion exchange tower 5 has an anion exchange resin layer 5a. 7 is a recovered water tank, which stores recovered water 7a. 5b is a second anion exchange tower having an anion exchange resin layer 5c. 8 is an evaporative concentrator that evaporates and separates volatile components with water and concentrates the phosphoric acid solution. 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a.
[0033] 図 1において、 Pは加圧ポンプであり、原水槽 1、カチオン交換塔 2および濃縮液槽  [0033] In FIG. 1, P is a pressure pump, which is a raw water tank 1, a cation exchange tower 2, and a concentrated liquid tank.
3とともに原水供給部を構成し、このうちカチオン交換塔 2が前処理装置を構成する。 ァニオン交換塔 5および回収水槽 7は透過液取出部を構成し、このうちァニオン交換 塔 5は不純物除去装置を構成する。また第 2ァユオン交換塔 5b、蒸発濃縮装置 8お よび回収リン酸槽 9は濃縮リン酸液取出部を構成し、このうち第 2ァニオン交換塔 5b および蒸発濃縮装置 8は精製装置を構成する。  3 together with the raw water supply section, of which the cation exchange tower 2 constitutes the pretreatment device. The anion exchange tower 5 and the recovery water tank 7 constitute a permeate extraction section, and among these, the anion exchange tower 5 constitutes an impurity removing device. Further, the second canyon exchange column 5b, the evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid liquid take-out section, and among these, the second anion exchanging column 5b and the evaporating and concentrating device 8 constitute a refining device.
[0034] 上記のリン酸回収装置では、前処理工程として沈殿分離、濾過等による不純物の 除去を行った原水 la (リン酸イオン含有水）をライン L1から原水槽 1に導入する。原 水槽 1の原水 laはライン L2からカチオン交換塔 2に導入して通水し、カチオン交換 樹脂層 2aでカチオン交換して、原水に含まれるアルミニウム、インジウム、その他の 金属イオン等のカチオンを交換吸着して除去する。カチオン交換樹脂層 2aには H形 の強酸性カチオン交換樹脂を用いるのが好ましい。カチオン交換樹脂層 2aが飽和し たときは、ライン L3から塩酸等の酸を含む再生剤を通液して再生し、溶離したカチォ ンをライン L4から回収する。 [0035] カチオン交換塔 2の処理水である脱力チオン水をライン L5から濃縮液槽 3に導入し て貯留する。原水としてのリン酸含有水は通常 pH3以下の酸性の状態で得られ、ま た pHが高い場合でも前処理としてのカチオン交換により酸が生成して pH3以下の状 態になるので、 pH3以下の条件で逆浸透処理するには、そのまま逆浸透装置 4に供 給すればよい。 pHが高い原水を pH調整する場合は、リン酸含有水は pH3に近い状 態で得られるので、ライン L5または濃縮液槽 3に塩酸等の pH調整剤を注入すること により容易に調整すること力 Sできる。 [0034] In the above phosphoric acid recovery apparatus, raw water la (phosphate ion-containing water) that has been subjected to precipitation separation, filtration, and the like as a pretreatment step is introduced into raw water tank 1 from line L1. The raw water la in the raw water tank 1 is introduced into the cation exchange tower 2 from the line L2 and passed through, and the cation exchange resin layer 2a exchanges cations to exchange cations such as aluminum, indium and other metal ions contained in the raw water. Adsorb and remove. For the cation exchange resin layer 2a, it is preferable to use an H-type strongly acidic cation exchange resin. When the cation exchange resin layer 2a is saturated, it is regenerated by passing a regenerant containing an acid such as hydrochloric acid from the line L3, and the eluted catalyst is recovered from the line L4. [0035] The weak thione water that is the treated water of the cation exchange tower 2 is introduced into the concentrate tank 3 from the line L5 and stored. Phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or lower, and even when the pH is high, acid is generated by cation exchange as a pretreatment and becomes a state of pH 3 or lower. In order to perform reverse osmosis treatment under conditions, it may be supplied to the reverse osmosis apparatus 4 as it is. When adjusting pH of raw water with high pH, phosphoric acid-containing water can be obtained in a state close to pH 3, so it should be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L5 or concentrate tank 3. Power S can be.
[0036] 濃縮液槽 3の脱力チオン水（濃縮液 3a)は加圧ポンプ Pで加圧してライン L6から逆 浸透装置 4の濃縮液室 4cに導入し、逆浸透膜 4aにより逆浸透処理を行って、硝酸、 酢酸等のリン酸以外の酸を水とともに透過液室 4b側に透過させて、リン酸を濃縮液 室 4c側に濃縮する。リン酸含有水を中和して中性の状態で逆浸透処理すると、硝酸 、酢酸等のリン酸以外の酸の塩と、リン酸の塩のいずれも逆浸透膜 4aを透過せず、 濃縮液室 4c側に濃縮される。これに対してリン酸含有水を中和することなぐ pH3以 下の条件下で逆浸透装置 4に導入して逆浸透処理を行うと、リン酸は逆浸透膜 4aに より透過を阻止されて濃縮液室 4c側に濃縮されるが、硝酸、酢酸等のリン酸以外の 酸は水とともに透過液室 4b側に透過して分離される。逆浸透装置 4に導入するリン酸 含有水は脱力チオンされているため、逆浸透膜 4aの目詰まりがなぐ逆浸透処理の 効率は高く維持される。  [0036] The weak thione water (concentrate 3a) in the concentrate tank 3 is pressurized by the pressure pump P and introduced from the line L6 into the concentrate chamber 4c of the reverse osmosis device 4, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water to concentrate phosphoric acid to the concentrate chamber 4c side. When neutralizing the phosphate-containing water and performing reverse osmosis treatment, neither acid salts other than phosphoric acid, such as nitric acid and acetic acid, and phosphoric acid salts pass through the reverse osmosis membrane 4a and are concentrated. Concentrated to the liquid chamber 4c side. On the other hand, if the reverse osmosis treatment is carried out by introducing it into the reverse osmosis device 4 under the condition of pH 3 or less without neutralizing the phosphoric acid-containing water, the phosphoric acid is blocked from permeation by the reverse osmosis membrane 4a. Although concentrated to the concentrated liquid chamber 4c side, acids other than phosphoric acid such as nitric acid and acetic acid permeate to the permeated liquid chamber 4b side together with water and are separated. Since the phosphoric acid-containing water introduced into the reverse osmosis device 4 is weakly thioneed, the efficiency of the reverse osmosis treatment in which the reverse osmosis membrane 4a is not clogged is kept high.
[0037] 逆浸透装置 4の透過液室 4bに透過した透過液はライン L7からァユオン交換塔 5へ 導入し、ァニオン交換樹脂層 5aに通水してァニオン交換する。これにより透過液に含 まれる硝酸、酢酸等のリン酸イオン以外のァニオンを交換吸着により除去して精製を 行い、処理水はライン L8から回収水槽 7へ取り出し、回収水 7aとして貯留する。ァニ オン交換塔 5は OH形の強塩基性ァユオン交換樹脂を充填したァユオン交換樹脂層 5aを用いる力 H形カチオン交換樹脂との複層または混床式を採用し、ァニオン以 外の不純物を除去してもよい。ァニオン交換樹脂層 5aがリン酸イオン以外のァニオン で飽和したときは、ライン L9から水酸化ナトリウム、水酸化カリウム等の 2〜； 10重量％ のアルカリ水溶液のようなアルカリを含む再生剤を通液して再生し、溶離した塩をライ ン L10から排出する。カチオン交換樹脂を用いる場合は、酸を含む再生剤を通液し て再生する。 [0037] The permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced into the ayuon exchange tower 5 from the line L7, and is passed through the anion exchange resin layer 5a to exchange the anion. As a result, the anions other than phosphate ions such as nitric acid and acetic acid contained in the permeate are removed by exchange adsorption and purified, and the treated water is taken out from the line L8 to the recovered water tank 7 and stored as recovered water 7a. The anion exchange tower 5 employs the force of using the ayuon exchange resin layer 5a filled with the OH type strongly basic aion exchange resin and adopts a multi-layer or mixed bed type with the H form cation exchange resin to remove impurities other than the anion. It may be removed. When the anion exchange resin layer 5a is saturated with anions other than phosphate ions, a regenerant containing an alkali such as 2 to 10% by weight of an aqueous alkali solution such as sodium hydroxide or potassium hydroxide is passed through the line L9. Regenerate and drain the eluted salt from line L10. When using a cation exchange resin, pass a regenerant containing acid. To play.
[0038] 逆浸透装置 4の濃縮液室 4cで濃縮された濃縮液はライン LI 1から第 2ァニオン交 換塔 5bへ導入して通水し、ァニオン交換樹脂層 5cでァニオン交換して、濃縮液に残 留する硝酸、酢酸等のリン酸イオン以外のァニオンを交換吸着して除去し、精製を行 う。この場合、ァニオン交換樹脂層 5cは OH形または PO形の強塩基性ァニオン交  [0038] The concentrate concentrated in the concentrate chamber 4c of the reverse osmosis device 4 is introduced from the line LI 1 to the second anion exchange tower 5b, passed through the water, and is subjected to anion exchange in the anion exchange resin layer 5c for concentration. The remaining anions other than phosphate ions, such as nitric acid and acetic acid, are removed by exchange adsorption and purified. In this case, the anion exchange resin layer 5c is strongly basic anion exchange of OH type or PO type.
4  Four
換樹脂を用レ、る。硝酸等のリン酸イオン以外のァニオンのァニオン交換樹脂に対す る選択性は低 pH域でリン酸イオンよりも高いので、リン酸イオンとの分離は容易であ る。ァニオン交換樹脂層 5cがリン酸イオン以外のァニオンで飽和したときは、ライン L 12からアルカリを含む再生剤を通液して再生し、溶離した塩をライン L13から排出す  Use a replacement resin. Since the selectivity of anions other than phosphate ions such as nitric acid to anion exchange resins is higher than phosphate ions at low pH, separation from phosphate ions is easy. When the anion exchange resin layer 5c is saturated with anions other than phosphate ions, it is regenerated by passing a regenerant containing alkali from line L12, and the eluted salt is discharged from line L13.
[0039] 第 2ァニオン交換塔 5bでリン酸イオン以外のァニオンを除去したリン酸溶液が酢酸 等の揮発性成分をなお含む場合は、ライン L14から蒸発濃縮装置 8に導入して蒸留 し、水とともに揮発性成分を蒸発させて分離し、ライン L15から排出する。蒸発濃縮 装置 8で揮発性成分を除去し濃縮したリン酸濃縮液は、ライン L16から回収リン酸槽 9に導入し、回収リン酸液 9aとして貯留する。蒸発濃縮装置 8としてはロータリエバポ レータ等の公知の蒸発濃縮装置を用いることができる。逆浸透装置 4の濃縮液室 4c の濃縮液はライン L17または L18から濃縮液槽 3へ循環して濃縮率を高め、濃縮液 3 aとして貯留すること力 Sでさる。 [0039] If the phosphoric acid solution from which the anions other than phosphate ions have been removed in the second anion exchange column 5b still contains a volatile component such as acetic acid, it is introduced into the evaporation concentrator 8 from the line L14, distilled, and water At the same time, the volatile components are evaporated and separated and discharged from line L15. The concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L16 and stored as the recovered phosphoric acid solution 9a. As the evaporating and concentrating device 8, a known evaporating and concentrating device such as a rotary evaporator can be used. The concentrated liquid in the concentrated liquid chamber 4c of the reverse osmosis device 4 is circulated from the line L17 or L18 to the concentrated liquid tank 3 to increase the concentration rate, and is stored with the concentrated liquid 3a by the force S.
[0040] 上記の方法で回収されるリン酸液 9aは、回収物として有用であり、かつ高濃度の液 状で回収されるため実用上運搬可能であり、しかも高純度の濃縮リン酸として回収で きる。この場合、 pH3以下の条件下で逆浸透処理するが、原水としてのリン酸含有水 は通常 pH3以下の酸性の状態で得られ、また pHが高レ、場合でも前処理としての力 チオン交換により pH3以下の状態になるので、 pH3以下の条件で処理するには、そ のまま供給すればよぐ特に pH調整する必要がない。酸、アルカリ等の薬剤はカチ オン交換塔 2におけるカチオン用の再生剤、ならびにァニオン交換塔 5および第 2ァ 二オン交換塔 5bにおけるァニオン用の再生剤に限られ、リン酸回収用としては必要 でない。また回収のための方法および装置は、簡単な構成と操作により、 pH3以下 の条件下で逆浸透処理することにより、リン酸濃縮液として回収することが可能である 。これにより再生剤の使用量、廃棄物の生成量を少なくし、処理コストを低くして、高 純度の濃縮リン酸および純水を回収することができる。 [0040] The phosphoric acid solution 9a recovered by the above method is useful as a recovered material and can be transported practically because it is recovered in a high-concentration liquid state, and is recovered as concentrated phosphoric acid with high purity. it can. In this case, reverse osmosis treatment is performed under the condition of pH 3 or less. However, phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, and even if the pH is high, even as a pretreatment, it can be replaced by Since the pH is 3 or less, it is not necessary to adjust the pH if it is supplied as it is to treat it under the condition of pH 3 or less. Chemicals such as acids and alkalis are limited to cations regenerants in cation exchange tower 2 and anion regenerants in anion exchange tower 5 and second anion exchange tower 5b. Necessary for recovering phosphoric acid. Not. The recovery method and device can be recovered as a phosphate concentrate by reverse osmosis treatment under conditions of pH 3 or less with a simple configuration and operation. . As a result, the amount of regenerant used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
[0041] 以上の通り、リン酸含有水を pH3以下の条件下で逆浸透装置 4に供給して逆浸透 膜 4aにより逆浸透処理を行い、リン酸以外の酸を水とともに透過液室 4b側に透過さ せて、リン酸を濃縮液室 4c側に濃縮し、純水およびリン酸濃縮液を回収することによ り、簡単な構成と操作により、高濃度の液状で運搬可能であり、回収物として有用な 高純度のリン酸および純水を、リン酸含有水から低コストで、かつ効率よく回収するこ と力 Sできる。 [0041] As described above, the phosphoric acid-containing water is supplied to the reverse osmosis device 4 under the condition of pH 3 or lower, and reverse osmosis treatment is performed by the reverse osmosis membrane 4a. By allowing the phosphoric acid to pass through the concentrated liquid chamber 4c and recovering pure water and phosphoric acid concentrated liquid, it can be transported as a high-concentration liquid with a simple configuration and operation. High-purity phosphoric acid and pure water useful as recovered materials can be efficiently recovered from phosphoric acid-containing water at low cost.
[0042] 次に本発明の他の実施形態を図 2により説明する。図 2は他の実施形態におけるリ ン酸回収方法および装置のフロー図である。 1は原水槽で、原水 laを貯留する。 2は カチオン交換塔で、カチオン交換樹脂層 2aを有する。 3は濃縮液槽で、濃縮液 3aを 貯留する。 4は逆浸透装置で、逆浸透膜 4aにより、透過液室 4bと濃縮液室 4cに区画 されている。 5はァニオン交換塔で、ァニオン交換樹脂層 5aを有する。 6は電気再生 式イオン交換装置で、脱塩室 6aと濃縮室 6bがァニオン交換膜 6cで区画され、脱塩 室 6aの外側にカチオン交換膜 6dにより陰極室 6eが区画され、濃縮室 6bの外側に力 チオン交換膜 6fにより陽極室 6gが区画され、脱塩室 6aと濃縮室 6bに混床式イオン 交換層 6h、 6iが設けられ、陰極室 6eに陰極（―）、陽極室 6gに陽極（+ )が設けられ ている。 7は回収水槽で、回収水 7aを貯留する。 8は蒸発濃縮装置で、蒸留により揮 発性成分を水とともに蒸発させて分離し、リン酸液を濃縮する。 9は回収リン酸槽で、 回収リン酸液 9aを貯留する。 10は生物脱窒装置である。  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flowchart of a phosphoric acid recovery method and apparatus according to another embodiment. 1 is a raw water tank that stores raw water la. 2 is a cation exchange tower having a cation exchange resin layer 2a. 3 is a concentrate tank, which stores concentrate 3a. Reference numeral 4 denotes a reverse osmosis device, which is divided into a permeate chamber 4b and a concentrate chamber 4c by a reverse osmosis membrane 4a. An anion exchange tower 5 has an anion exchange resin layer 5a. 6 is an electric regenerative ion exchange device in which a desalination chamber 6a and a concentration chamber 6b are partitioned by an anion exchange membrane 6c, and a cathode chamber 6e is partitioned by a cation exchange membrane 6d outside the desalination chamber 6a. The anode chamber 6g is partitioned by the force thione exchange membrane 6f on the outside, the mixed-salt-type ion exchange layers 6h and 6i are provided in the desalting chamber 6a and the concentration chamber 6b, the cathode (−) in the cathode chamber 6e, and the anode chamber 6g in the anode chamber 6g. An anode (+) is provided. Reference numeral 7 is a recovery water tank for storing recovered water 7a. 8 is an evaporation concentrator that evaporates and separates volatile components together with water and concentrates the phosphoric acid solution. 9 is a recovered phosphoric acid tank, which stores the recovered phosphoric acid solution 9a. 10 is a biological denitrification device.
[0043] 図 2において、 Pは加圧ポンプであり、原水槽 1、カチオン交換塔 2、ァニオン交換 塔 5および濃縮液槽 4とともに原水供給部を構成し、このうちカチオン交換塔 2および ァニオン交換塔 5が前処理装置を構成する。電気再生式イオン交換装置 6および回 収水槽 7は透過液取出部を構成し、このうち電気再生式イオン交換装置 6は不純物 除去装置を構成する。また蒸発濃縮装置 8および回収リン酸槽 9は濃縮リン酸液取 出部を構成し、このうち蒸発濃縮装置 8は精製装置を構成する。  [0043] In FIG. 2, P is a pressure pump, and constitutes the raw water supply unit together with the raw water tank 1, the cation exchange tower 2, the anion exchange tower 5 and the concentrated liquid tank 4, and of these, the cation exchange tower 2 and the anion exchange Tower 5 constitutes the pretreatment device. The electric regenerative ion exchange device 6 and the collection water tank 7 constitute a permeate extraction unit, and the electric regenerative ion exchange device 6 constitutes an impurity removal device. The evaporating and concentrating device 8 and the recovered phosphoric acid tank 9 constitute a concentrated phosphoric acid solution extraction section, and the evaporating and concentrating device 8 constitutes a purification device.
[0044] 上記のリン酸回収装置では、前処理工程として沈殿分離、濾過等による不純物の 除去を行った原水 la (リン酸イオン含有水）をライン L21から原水槽 1に導入する。原 水槽 1の原水 laはライン L22からカチオン交換塔 2に導入して通水し、カチオン交換 樹脂層 2aでカチオン交換して、原水に含まれるアルミニウムやインジウム、その他の 金属イオン等のカチオンを交換吸着して除去する。カチオン交換樹脂層 2aには H形 の強酸性カチオン交換樹脂を用いるのが好ましい。カチオン交換樹脂層 2aが飽和し たときは、ライン L23から塩酸等の酸を含む再生剤を通液して再生し、溶離したカチ オンをライン L24から回収する。 [0044] In the phosphoric acid recovery apparatus, the raw water la (phosphate ion-containing water), from which impurities have been removed by precipitation separation, filtration or the like as a pretreatment step, is introduced into the raw water tank 1 from the line L21. original Raw water la in tank 1 is introduced from line L22 to cation exchange tower 2 and passed through, and cation exchange is performed in cation exchange resin layer 2a to exchange and adsorb cations such as aluminum, indium, and other metal ions contained in the raw water. And remove. For the cation exchange resin layer 2a, it is preferable to use an H-type strongly acidic cation exchange resin. When the cation exchange resin layer 2a is saturated, it is regenerated by passing a regenerant containing an acid such as hydrochloric acid from the line L23, and the eluted cation is recovered from the line L24.
[0045] カチオン交換塔 2の処理水である脱力チオン水をライン L25からァニオン交換塔 5 に導入して通水し、ァニオン交換樹脂層 5aでァニオン交換して、原水に含まれる過 塩素酸やモリブデン酸、有機酸錯体等のァユオンを交換吸着して除去する。ァニォ ン交換樹脂層 5aにはリン酸形の強塩基性ァユオン交換樹脂を用いるのが好ましい。 ァニオン交換樹脂層 5aが飽和したときは、ライン L26から水酸化ナトリウム等のアル カリを含む再生剤を通液して再生し、溶離したァニオンをライン L27から回収する。そ の後、ライン L26からリン酸などの酸を通液し、ァニオン交換樹脂をリン酸形とする。  [0045] The weak thione water, which is the treated water of the cation exchange tower 2, is introduced into the anion exchange tower 5 from the line L25 and passed therethrough, and the anion exchange resin layer 5a is used to exchange the anion so that perchloric acid contained in the raw water Aion such as molybdic acid or organic acid complex is removed by exchange adsorption. For the anion exchange resin layer 5a, it is preferable to use a phosphoric acid type strongly basic cation exchange resin. When the anion exchange resin layer 5a is saturated, a regeneration agent containing alkali such as sodium hydroxide is passed through the line L26 to regenerate, and the eluted anion is recovered from the line L27. Then, acid such as phosphoric acid is passed through line L26 to make the anion exchange resin into phosphoric acid form.
[0046] ァニオン交換塔 5の処理水をライン L28から濃縮液槽 3に導入する。原水としてのリ ン酸含有水は通常 PH3以下の酸性の状態で得られ pH3以下の条件で逆浸透処理 するには、そのまま逆浸透装置 4に供給すればよい。 pHが高い原水を pH調整する 場合は、リン酸含有水は pH3に近い状態で得られるので、ライン L28または濃縮液 槽 3に塩酸等の pH調整剤を注入することにより容易に調整することができる。  [0046] The treated water of the anion exchange tower 5 is introduced into the concentrate tank 3 from the line L28. Phosphoric acid-containing water as raw water is usually obtained in an acidic state of PH 3 or less, and can be supplied to the reverse osmosis apparatus 4 as it is for reverse osmosis treatment under conditions of pH 3 or less. When adjusting the pH of raw water with high pH, phosphoric acid-containing water is obtained in a state close to pH 3, so it can be easily adjusted by injecting a pH adjuster such as hydrochloric acid into line L28 or concentrate tank 3. it can.
[0047] 濃縮液槽 3のリン酸含有水は加圧ポンプ Pで加圧してライン L31から逆浸透装置 4 の濃縮液室 4cに導入し、逆浸透膜 4aにより膜分離 (逆浸透処理)を行って、硝酸、酢 酸等のリン酸以外の酸を水とともに透過液室 4b側に透過させて、リン酸を濃縮液室 4 c側に濃縮する。リン酸含有水を中和して中性の状態で逆浸透処理すると、硝酸、酢 酸等のリン酸以外の酸の塩と、リン酸塩のいずれも逆浸透膜 4aを透過せず、濃縮液 室 4c側に濃縮される。これに対してリン酸含有水を中和することなぐ pH3以下の条 件下で逆浸透装置 4に導入して逆浸透処理を行うと、リン酸は逆浸透膜 4aにより透 過を阻止されて濃縮液室 4c側に濃縮されるが、硝酸、酢酸等のリン酸以外の酸は水 とともに透過液室 4b側に透過して分離される。逆浸透装置 4に導入するリン酸含有 水は脱力チオンされているため、逆浸透膜 4aの目詰まりがなぐ逆浸透処理の効率 は高く維持される。 [0047] The phosphoric acid-containing water in the concentrate tank 3 is pressurized by the pressure pump P and introduced into the concentrate chamber 4c of the reverse osmosis device 4 from the line L31, and membrane separation (reverse osmosis treatment) is performed by the reverse osmosis membrane 4a. Then, acid other than phosphoric acid such as nitric acid and acetic acid is allowed to permeate to the permeate chamber 4b side together with water, and phosphoric acid is concentrated to the concentrate chamber 4c side. When the phosphate-containing water is neutralized and subjected to reverse osmosis treatment in a neutral state, neither acid salts other than phosphoric acid such as nitric acid and acetic acid and phosphates pass through the reverse osmosis membrane 4a and are concentrated. Concentrated to the liquid chamber 4c side. On the other hand, when the reverse osmosis treatment is carried out by introducing it into the reverse osmosis device 4 under the condition of pH 3 or less without neutralizing the phosphoric acid-containing water, the phosphoric acid is prevented from permeating by the reverse osmosis membrane 4a. Although concentrated to the concentrate chamber 4c side, acids other than phosphoric acid such as nitric acid and acetic acid permeate to the permeate chamber 4b side together with water and are separated. Since the water containing phosphoric acid introduced into the reverse osmosis device 4 is weakly thione, the efficiency of the reverse osmosis treatment prevents clogging of the reverse osmosis membrane 4a. Is kept high.
[0048] ライン L28から得られる原水としてのリン酸含有水がリン酸濃度;!〜 15重量％で得 られる場合は、そのまま膜分離処理を行って逆浸透による分離を行うことができるが、 リン酸濃度 1重量％未満の場合は、濃縮液室 4cからライン L32を通して取出した濃 縮液を、循環経路であるライン L33から濃縮液槽 3に循環しながら膜分離処理を行う ことにより、リン酸濃度 1重量％以上に濃縮することができる。この場合、低濃度のリン 酸含有水を循環しながら濃縮し、リン酸濃度 1重量％以上に濃縮された時点で循環 液を入れ替える回分式の処理を行ってもよいが、リン酸濃度;!〜 15重量％に濃縮さ れた濃縮液を循環しながら、循環する濃縮液に低濃度の被処理リン酸含有水を加え 、濃縮液を一部ずつライン L34からリン酸濃縮液として取出すと、見掛け上一過式の 処理が行えるので好まし!/、。  [0048] When the phosphoric acid-containing water as raw water obtained from the line L28 is obtained at a phosphoric acid concentration;! To 15% by weight, separation by reverse osmosis can be carried out as it is by performing a membrane separation treatment. When the acid concentration is less than 1% by weight, the concentrated solution taken out from the concentrate chamber 4c through the line L32 is subjected to membrane separation treatment while circulating through the line L33, which is the circulation path, to the concentrate tank 3, thereby obtaining phosphoric acid. It can be concentrated to a concentration of 1% by weight or more. In this case, it is possible to carry out a batch-type process in which low-concentration phosphoric acid-containing water is concentrated while circulating, and the circulating fluid is replaced when the phosphoric acid concentration is concentrated to 1% by weight or more. While circulating the concentrate concentrated to -15% by weight, adding low-concentration treated phosphoric acid-containing water to the circulating concentrate, and removing the concentrate partly from the line L34 as a phosphate concentrate. Apparently, it is possible to perform a one-time process.
[0049] 逆浸透装置 4の透過液室 4bに透過した透過液はライン L35から電気再生式イオン 交換装置 6の脱塩室 6aへ導入し、陽極（ + )と陰極（一）間に電圧を印加して電気再 生しながら、イオン交換により脱塩する。これにより透過液に含まれるリン酸、硝酸、酢 酸等のァニオン、ならびに残留するカチオンを交換吸着により除去して精製を行い、 処理水はライン L36から回収水槽 7へ取り出し、回収水 7aとして貯留する。脱塩室 6a では、混床式イオン交換層 6hに吸着された酸等のァニオンがァニオン交換膜 6cを 通して濃縮室 6bへ透過し、混床式イオン交換層 6iに吸着されるので、ライン L37から 透過液の一部を濃縮室 6bへ流しながら再生により吸着されたァニオンを溶離させ、 ライン L38から生物脱窒装置 10へ送って生物脱窒処理する。混床式イオン交換層 6 hに吸着されたカチオンは陰極室 6eへ透過するので、陽極室 6gからライン L39を通 して陰極室 6eへ電極液を流し、ライン L40から排出する。  [0049] The permeate that has permeated through the permeate chamber 4b of the reverse osmosis device 4 is introduced from the line L35 into the desalination chamber 6a of the electric regenerative ion exchanger 6 and a voltage is applied between the anode (+) and the cathode (one). Desalinate by ion exchange while applying electricity and regenerating electricity. As a result, the anions such as phosphoric acid, nitric acid, and acetic acid contained in the permeate and the remaining cations are removed by exchange adsorption for purification, and the treated water is taken out from the line L36 to the recovered water tank 7 and stored as recovered water 7a. To do. In the desalination chamber 6a, the anions such as acids adsorbed on the mixed bed ion exchange layer 6h pass through the anion exchange membrane 6c to the concentration chamber 6b and are adsorbed on the mixed bed ion exchange layer 6i. The anion adsorbed by regeneration is eluted while flowing a part of the permeate from L37 to the concentrating chamber 6b, and sent to the biological denitrifier 10 from the line L38 for biological denitrification. Since the cations adsorbed on the mixed bed type ion exchange layer 6 h permeate the cathode chamber 6e, the electrode solution flows from the anode chamber 6g through the line L39 to the cathode chamber 6e and is discharged from the line L40.
[0050] 逆浸透装置 4の濃縮液室 4cで濃縮され、ライン L34から取出される濃縮液の一部 は、蒸発濃縮装置 8に導入して蒸留し、水とともに酢酸等の揮発性成分を蒸発させて 分離し、ライン L41から排出する。蒸発濃縮装置 8で揮発性成分を除去し濃縮したリ ン酸濃縮液は、ライン L42から回収リン酸槽 9に導入し、回収リン酸液 9aとして貯留 する。蒸発濃縮装置 8としてはロータリエバポレータ等の公知の蒸発濃縮装置を用い ること力 Sでさる。 [0051] 逆浸透装置 4における膜分離 (逆浸透処理)を、リン酸含有水が pH3以下、かつリ ン酸濃度;!〜 15重量％の条件下で行うことにより、リン酸以外の酸を高透過率で透過 させ、リン酸の純度を高めることができる力 濃縮液中のリン酸以外の酸の濃度をさら に低くするためには、濃縮液を循環して膜分離の機会を多くすることにより、これらの 酸が透過する機会を多くして透過率を高めることができる。この場合、水の透過も起こ るため、循環液は濃縮されることになる。このため循環する濃縮液に希釈水を加えて 逆浸透処理を行うことにより、リン酸以外の酸の除去率を高めることができる。希釈水 としては透過水から不純物を除去した回収水を使用することができる。 [0050] A part of the concentrated liquid concentrated in the concentrated liquid chamber 4c of the reverse osmosis apparatus 4 and taken out from the line L34 is introduced into the evaporative concentration apparatus 8 and distilled to evaporate volatile components such as acetic acid together with water. Separated and discharged from line L41. The concentrated phosphoric acid solution obtained by removing the volatile components by the evaporation concentrating device 8 is introduced into the recovered phosphoric acid tank 9 from the line L42 and stored as the recovered phosphoric acid solution 9a. As the evaporation concentrator 8, a known evaporation concentrator such as a rotary evaporator is used. [0051] By performing membrane separation (reverse osmosis treatment) in the reverse osmosis device 4 under conditions where the phosphoric acid-containing water has a pH of 3 or less and a phosphoric acid concentration; The ability to permeate with high permeability and increase the purity of phosphoric acid. To further reduce the concentration of acids other than phosphoric acid in the concentrate, increase the chances of membrane separation by circulating the concentrate. As a result, it is possible to increase the transmittance by increasing the opportunities for these acids to permeate. In this case, water permeation also occurs, so the circulating fluid is concentrated. For this reason, the removal rate of acids other than phosphoric acid can be improved by adding dilution water to the circulating concentrated liquid and performing reverse osmosis treatment. As dilution water, recovered water obtained by removing impurities from permeated water can be used.
[0052] このため図 2では、希釈水として回収水槽 7から回収水 7aを、ポンプ P2によりライン L43を通して濃縮液槽 3へ供給し、循環する濃縮液 3aを希釈して逆浸透処理を行う ことにより、さらにリン酸以外の酸の濃度を低くすることができ、高純度のリン酸濃縮液 を回収すること力できる。濃縮液槽 3へ供給する回収水 7aの量は、循環する濃縮液 カ^ン酸濃度;!〜 15重量％の条件を維持する量である。これにより循環する濃縮液 が高濃縮されることによるリン酸以外の酸の透過効率が低下するのを防止して、濃縮 液のリン酸純度を高めることができる。  [0052] Therefore, in FIG. 2, the recovered water 7a from the recovered water tank 7 is supplied as dilution water to the concentrated liquid tank 3 through the line L43 by the pump P2, and the circulating concentrated liquid 3a is diluted to perform reverse osmosis treatment. Thus, the concentration of an acid other than phosphoric acid can be further reduced, and a high-purity phosphoric acid concentrate can be recovered. The amount of the recovered water 7a supplied to the concentrate tank 3 is an amount that maintains the condition of the concentrated concentrate carboxylic acid concentration! As a result, the permeation efficiency of acids other than phosphoric acid due to high concentration of the circulating concentrated liquid can be prevented, and the phosphoric acid purity of the concentrated liquid can be increased.
[0053] 上記の方法で回収される回収リン酸液 9aは、回収物として有用であり、かつ高濃度 の液状で回収されるため実用上運搬可能であり、し力、も高純度の濃縮リン酸として回 収できる。この場合、 pH3以下の条件下で逆浸透処理するが、原水としてのリン酸含 有水は通常 pH3以下の酸性の状態で得られるのでそのまま供給すればよぐ特に p H調整する必要がない。酸、アルカリ等の薬剤はカチオン交換塔 2におけるカチオン 用の再生剤、ならびにァニオン交換塔 3におけるァニオン用の再生剤に限られ、リン 酸回収用ならびに透過水の精製用としては必要でない。また回収のための方法およ び装置は、簡単な構成と操作により、 pH3以下、かつリン酸濃度;!〜 15重量％の条 件下で逆浸透処理することにより、リン酸濃縮液として回収することが可能である。こ れにより薬剤の使用量、廃棄物の生成量を少なくし、処理コストを低くして、高純度の 濃縮リン酸および純水を回収することができる。  [0053] The recovered phosphoric acid solution 9a recovered by the above method is useful as a recovered material, and can be transported practically because it is recovered in a high-concentration liquid state. It can be recovered as an acid. In this case, reverse osmosis treatment is performed under the condition of pH 3 or less. However, since the phosphoric acid-containing water as raw water is usually obtained in an acidic state of pH 3 or less, it is not necessary to adjust pH especially if it is supplied as it is. The chemicals such as acid and alkali are limited to the regenerant for cations in the cation exchange tower 2 and the regenerant for anions in the anion exchange tower 3, and are not necessary for recovering phosphoric acid or purifying permeate. The recovery method and equipment can be recovered as a phosphate concentrate by reverse osmosis treatment under the conditions of pH 3 or less and phosphate concentration; Is possible. As a result, the amount of chemicals used and the amount of waste generated can be reduced, the processing cost can be reduced, and high-purity concentrated phosphoric acid and pure water can be recovered.
[0054] 図 2のリン酸回収方法および装置では、リン酸含有水を pH3以下、かつリン酸濃度 ；!〜 15重量％の条件下で逆浸透装置 4に供給して逆浸透膜 4aにより逆浸透処理を 行い、リン酸以外の酸を水とともに透過液室 4b側に透過させて、リン酸を濃縮液室 4c 側に濃縮し、純水およびリン酸濃縮液を回収することにより、簡単な構成と操作によ つて、高濃度の液状で運搬可能であり、回収物として有用な高純度のリン酸および純 水を、リン酸含有水から低コストで、かつ効率よく回収することができる。 In the phosphoric acid recovery method and apparatus of FIG. 2, the phosphoric acid-containing water is supplied to the reverse osmosis apparatus 4 under the conditions of pH 3 or lower and phosphoric acid concentration; Osmosis treatment Simple structure and operation by allowing acid other than phosphoric acid to pass through to the permeate chamber 4b side with water, concentrating phosphoric acid to the concentrate chamber 4c side, and collecting pure water and phosphoric acid concentrate Therefore, high-purity phosphoric acid and pure water, which can be transported in a high-concentration liquid state and are useful as a recovered product, can be efficiently recovered from the phosphoric acid-containing water at low cost.
[0055] なお、本発明の実施の形態は図 1、 2に限定されるものでなぐ例えば、図 2におい て回収リン酸液の純度を更に高めるために、第 2のァニオン交換塔をライン L34の蒸 発濃縮装置 8の前段に設けることもできる。また、本実施の形態では、逆浸透装置 4 力、らの透過液を精製する電気再生式イオン交換装置 6は、脱塩室 6aと濃縮室 6bとが ァニオン交換膜 6cで区画された簡易の電気再生式イオン交換装置が用いられてい るが、陰極室と陽極室との間に陰イオン交換膜と陽イオン交換膜とを交互に配列して 脱塩室と濃縮室とを形成し、該脱塩室にイオン交換体を充填した通常の電気脱ィォ ン装置を用いることもできる。 Note that the embodiment of the present invention is not limited to FIGS. 1 and 2. For example, in FIG. 2, in order to further increase the purity of the recovered phosphoric acid solution, the second anion exchange column is connected to the line L34. It is also possible to install it at the front stage of the evaporation concentrator 8. Further, in this embodiment, the reverse osmosis device 4 and the electric regenerative ion exchange device 6 for purifying the permeate are a simple demineralization chamber 6a and a concentration chamber 6b separated by an anion exchange membrane 6c. An electric regenerative ion exchange apparatus is used, and an anion exchange membrane and a cation exchange membrane are alternately arranged between a cathode chamber and an anode chamber to form a desalting chamber and a concentration chamber. It is also possible to use a normal electrodeionization device in which a desalting chamber is filled with an ion exchanger.
実施例  Example
[0056] 以下、本発明の実施例について説明する。各例において、％は阻止率以外、なら びに特別な指示以外は重量％を示す。  Hereinafter, examples of the present invention will be described. In each example, “%” indicates a percentage other than the blocking rate and “% by weight” unless otherwise specified.
[0057] 〔実施例 1、比較例 1〕： [Example 1, Comparative Example 1]:
<逆浸透処理〉：  <Reverse osmosis treatment>:
ジン酸 550mg/L、硝酸 50mg/L、酢酸 50mg/Lを含む伝導率 122mS/m、 p Η2· 4の原水を、 日東電工（株）製の逆浸透膜 ES— 20に 0· 7MPaで通液して逆浸 透処理し、 6倍濃縮の濃縮液 (ブライン)を得た（実施例 1)。一方、原水に水酸化ナト リウム水溶液を注入して PH6に調整し、同様に試験した（比較例 1)。リン酸、硝酸、 酢酸の阻止率の結果を表 1に示すが、実施例 1ではリン酸は除去され、硝酸、酢酸は 透過して分離されるのに対し、比較例 1ではすべてが除去され、分離されないことが 分かる。  Nitto Denko Corporation's reverse osmosis membrane ES-20 manufactured by Nitto Denko Co., Ltd. was passed through 0 ~ 7MPa of raw water with conductivity of 122mS / m containing diacid 550mg / L, nitric acid 50mg / L and acetic acid 50mg / L. The solution was subjected to reverse osmosis treatment to obtain a 6-fold concentrated concentrate (brine) (Example 1). On the other hand, a sodium hydroxide aqueous solution was poured into the raw water to adjust to PH6, and the same test was performed (Comparative Example 1). The results of the rejection rates of phosphoric acid, nitric acid, and acetic acid are shown in Table 1. In Example 1, phosphoric acid was removed and nitric acid and acetic acid permeated and separated, whereas in Comparative Example 1, all were removed. It can be seen that they are not separated.
[0058] [表 1] 表 1 除去率 [0058] [Table 1] Table 1 Removal rate
Figure imgf000021_0001
Figure imgf000021_0001
[0059] 〔実施例 2〕：  [0059] [Example 2]:
<リン酸および純水の回収〉：  <Recovery of phosphoric acid and pure water>:
ジン酸 550mg/:L、石肖酸 50mg/:L、醉酸 50mg/:L、インジクム 0· 3mg/L,ナ卜!; ゥム lmg/Lを含む伝導率 122mS/m、 pH2. 4の液晶基板のエッチング後の洗浄 排水を図 1の装置で処理し、リン酸および純水を回収した。カチオン交換塔 2は H形 強酸性カチオン交換樹脂（三菱化学 (株)製、 DiaionSKlB)を 10L充填し、塩酸で 再生した。ァニオン交換塔 5は OH形強塩基性ァニオン交換樹脂（三菱化学 (株)製 、 Diaion SA11A)をそれぞれ 10L充填し、水酸化ナトリウムで再生した。第 2ァニ オン交換塔 5bは PO形強塩基性ァユオン交換樹脂（三菱化学 (株)製、 Diaion SA  Diacid 550mg /: L, isosuccinic acid 50mg /: L, oxalic acid 50mg /: L, indicum 0.3mg / L, sodium !; conductivity 122mS / m with hum lmg / L, pH 2.4 Cleaning wastewater after etching of the liquid crystal substrate The waste water was treated with the equipment shown in Fig. 1 to recover phosphoric acid and pure water. Cation exchange tower 2 was filled with 10 L of H-type strongly acidic cation exchange resin (DiaionSKlB, manufactured by Mitsubishi Chemical Corporation) and regenerated with hydrochloric acid. The anion exchange tower 5 was filled with 10 L each of OH type strongly basic anion exchange resin (Diaion SA11A, manufactured by Mitsubishi Chemical Corporation) and regenerated with sodium hydroxide. Second Anion Exchange Tower 5b is a PO-type strongly basic cation exchange resin (Made by Mitsubishi Chemical Corporation, Diaion SA).
4  Four
11A)を 10L充填し、水酸化ナトリウムで OH形に再生後、リン酸濃縮液で PO形にし  11A) is filled with 10L, regenerated to OH form with sodium hydroxide, and then converted to PO form with phosphoric acid concentrate.
4 た。逆浸透装置 4として日東電工 (株)製の逆浸透膜 ES - 20のスパイラル膜モジュ ールを有する装置に 0. 7MPaで通液して逆浸透処理し、 6倍濃縮した。蒸発濃縮装 置 8としてはロータリエバポレータを用いて、リン酸濃度 75%に濃縮した。各工程にお ける各成分の濃度を表 2に示す。  4 The reverse osmosis device 4 was reverse osmosis treated by passing 0.7 MPa through a device having a spiral membrane module of reverse osmosis membrane ES-20 manufactured by Nitto Denko Corporation and concentrated 6 times. As the evaporative concentration apparatus 8, a rotary evaporator was used to concentrate the phosphoric acid concentration to 75%. Table 2 shows the concentration of each component in each process.
[0060] [表 2] [0060] [Table 2]
表 2 Table 2
Figure imgf000022_0001
Figure imgf000022_0001
[0061] 〔参考例 1、 2〕：  [0061] [Reference Examples 1 and 2]:
<逆浸透処理〉：  <Reverse osmosis treatment>:
ジン酸 550mg/L、硝酸 50mg/L、酢酸 50mg/Lを含む伝導率 122mS/m、 p Η2· 4の原水を、 日東電工（株）製の逆浸透膜 ES— 20に 0· 7MPaで通液して逆浸 透処理し、 5倍濃縮の濃縮液 (ブライン)を得た (参考例 1)。一方、原水に水酸化ナト リウム水溶液を注入して PH6に調整し、同様に試験した（参考例 2)。リン酸、硝酸、 酢酸の阻止率の結果を表 3に示すが、参考例 1ではリン酸は阻止され、硝酸、酢酸は 透過しているのに対し、参考例 2ではすべてが阻止され、透過しないことが分かる。  Pass raw water with conductivity 122mS / m, p Η2 · 4 containing diacid 550mg / L, nitric acid 50mg / L, acetic acid 50mg / L, through reverse osmosis membrane ES-20 manufactured by Nitto Denko Corporation at 0.7MPa The solution was subjected to reverse osmosis treatment to obtain a concentrated solution (brine) having a 5-fold concentration (Reference Example 1). On the other hand, a sodium hydroxide aqueous solution was poured into the raw water to adjust to PH6, and the same test was performed (Reference Example 2). The results of the rejection rates of phosphoric acid, nitric acid, and acetic acid are shown in Table 3. In Reference Example 1, phosphoric acid was blocked and nitric acid and acetic acid were permeated, whereas in Reference Example 2, all were blocked and permeated. I understand that I don't.
[0062] [表 3] [0062] [Table 3]
表 3 阻止率  Table 3 Blockage rate
Figure imgf000022_0002
Figure imgf000022_0002
[0063] 〔実施例 3〕：  [Example 3]:
参考例 1において、濃縮液の循環を回数を高めて上げていったときの濃縮液中のリ ン酸濃度の変化と、硝酸の阻止率との関係を図 3に示す。 In Reference Example 1, the concentration in the concentrate when the circulation rate of the concentrate is increased Figure 3 shows the relationship between changes in acid concentration and the rejection rate of nitric acid.
図 3より、濃縮液中のリン酸濃度が 1重量％以上で硝酸の阻止率がマイナスとなつ て直線的に低下し、特にリン酸濃度が 2重量％以下、さらにはリン酸濃度が 4重量％ 以下で硝酸の透過が促進されることが分かる。酢酸についても同様の結果が得られ た。  From Fig. 3, the concentration of phosphoric acid in the concentrate decreases linearly as the nitric acid rejection is negative when the concentration is 1% by weight or more, and the phosphoric acid concentration is 2% by weight or less, and the phosphoric acid concentration is 4%. It can be seen that the permeation of nitric acid is promoted at% or less. Similar results were obtained with acetic acid.
[0064] 〔実施例 4、 5〕：  [Examples 4 and 5]:
図 2の装置において、参考例 1と同じ逆浸透膜を用い、参考例 1と同じリン酸含有水 を H形強酸性カチオン交換樹脂（三菱化学 (株)製、 DiaionSKlB)を充填したカチ オン交換塔とリン酸形弱塩性ァユオン交換樹脂（三菱化学 (株)製、 DiaiOnWA30) を充填したァユオン交換塔で処理後、逆浸透装置に供給し濃縮液の希釈を行わな いで循環しながら、膜分離を行って 100倍濃縮した（実施例 4)、ならびに透過液を電 気再生式イオン交換装置で脱塩した回収水を希釈水として濃縮液槽に供給し (供給 原水量の 20容量％)、濃縮液を希釈して循環しながら、膜分離を行って 100倍濃縮 した（実施例 5)ときの濃縮液中の溶質濃度を表 4に示す。参考例 1で得られた濃縮 液を蒸留により全体で 100倍濃縮したと仮定して、計算により求めた溶質濃度を参考 例 1として併記する。 In the equipment shown in Fig. 2, the same reverse osmosis membrane as in Reference Example 1 was used, and the cation exchange was performed by filling the same phosphoric acid-containing water as in Reference Example 1 with H-type strongly acidic cation exchange resin (Made by Mitsubishi Chemical Corporation, DiaionSKlB). tower and phosphorus acid form weakly saline Ayuon exchange resin (Mitsubishi Chemical Co., Diai O nWA30) after treatment with Ayuon exchange tower filled with, while circulating in not such is supplied to the reverse osmosis unit to perform dilution of concentrate Then, the membrane was separated and concentrated 100 times (Example 4), and the recovered water obtained by desalting the permeate with an electric regeneration type ion exchanger was supplied as dilution water to the concentrate tank (20 volumes of the raw water supplied). Table 4 shows the solute concentrations in the concentrate when the membrane was separated and concentrated 100 times (Example 5) while diluting and circulating the concentrate. Assuming that the concentrated solution obtained in Reference Example 1 was concentrated 100 times by distillation, the calculated solute concentration is also shown as Reference Example 1.
[0065] [表 4]  [0065] [Table 4]
表 4 溶質濃度  Table 4 Solute concentration
Figure imgf000023_0001
Figure imgf000023_0001
[0066] 表 4より、濃縮液中のリン酸濃度が 1重量％以上となる条件で逆浸透処理を行うこと により、濃縮液中のリン酸以外の酸濃度が低下し、さらに濃縮液を希釈して循環しな 力 ¾逆浸透処理を行うことにより、濃縮液中のリン酸以外の酸濃度がさらに低下し、高 純度のリン酸濃縮液を回収できることが分かる。  [0066] From Table 4, by performing reverse osmosis treatment under conditions where the concentration of phosphoric acid in the concentrated solution is 1% by weight or more, the concentration of acids other than phosphoric acid in the concentrated solution decreases, and the concentrated solution is further diluted. Thus, it can be seen that by performing reverse osmosis treatment without circulating force, the concentration of acids other than phosphoric acid in the concentrate is further reduced, and a high-purity phosphoric acid concentrate can be recovered.
発明の利用可能性  Applicability of invention
[0067] 本発明は、リン酸含有水からリン酸および純水を回収する方法および装置、特に液 晶基板やウェハーその他の電子機器をエッチングした後の洗浄排水からリン酸など の有価物と、処理水である純水の回収に適したリン酸を回収する方法および装置に 利用可能である。 [0067] The present invention relates to a method and apparatus for recovering phosphoric acid and pure water from phosphoric acid-containing water, in particular a liquid. It can be used in a method and apparatus for recovering phosphoric acid and other valuable materials from the cleaning waste water after etching crystal substrates, wafers, and other electronic devices, and phosphoric acid suitable for recovering pure water as treated water.

Claims

請求の範囲 The scope of the claims
[1] リン酸含有水からリン酸を回収する方法であって、  [1] A method for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下の条件下で逆浸透装置に供給して逆浸透処理を行い、リ ン酸以外の酸を水とともに透過液室側に透過させて、リン酸を濃縮液室側に濃縮し、 リン酸濃縮液を回収することを特徴とするリン酸の回収方法。  Reverse osmosis treatment is performed by supplying phosphoric acid-containing water to the reverse osmosis device under the condition of PH3 or less, acid other than phosphoric acid is permeated to the permeate chamber side together with water, and phosphoric acid is introduced to the concentrate chamber side. A method for recovering phosphoric acid, comprising concentrating and recovering a phosphoric acid concentrate.
[2] リン酸含有水からリン酸を回収する方法であって、 [2] A method of recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で逆浸透装置に 供給して膜分離処理を行い、リン酸以外の酸を水とともに透過液室側に透過させて、 リン酸を濃縮液室側に濃縮し、リン酸濃縮液を回収することを特徴とするリン酸の回 収方法。  Phosphoric acid-containing water is supplied to the reverse osmosis unit under conditions of PH3 or less and phosphoric acid concentration;! ~ 15 wt%, and membrane separation treatment is performed to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water. Then, the phosphoric acid is concentrated to the concentrated liquid chamber side, and the phosphoric acid concentrated liquid is recovered, and a method for recovering phosphoric acid is provided.
[3] 濃縮液室の濃縮液を取出して濃縮液室へ循環する過程を有し、循環する濃縮液 に被処理リン酸含有水を加えて逆浸透処理を行う請求項 1または 2記載の方法。  [3] The method according to claim 1 or 2, further comprising the step of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and performing reverse osmosis treatment by adding water to be treated containing phosphoric acid to the circulating concentrate. .
[4] 濃縮液室の濃縮液を取出して濃縮液室へ循環する過程を有し、循環する濃縮液 に希釈水を加えて膜分離処理を行う請求項 1または 2記載の方法。 [4] The method according to claim 1 or 2, further comprising a step of taking out the concentrate from the concentrate chamber and circulating it to the concentrate chamber, and performing membrane separation treatment by adding dilution water to the circulating concentrate.
[5] リン酸含有水を逆浸透装置に供給する前に、前処理としてカチオンおよび/または ァニオンを含む不純物の除去を行う請求項 1または 2記載の方法。 [5] The method according to claim 1 or 2, wherein impurities containing cations and / or anions are removed as a pretreatment before supplying the phosphoric acid-containing water to the reverse osmosis device.
[6] 逆浸透装置の透過水から酸を含む不純物を除去して純水を回収する請求項 1また は 2記載の方法。 6. The method according to claim 1 or 2, wherein the pure water is recovered by removing impurities including acid from the permeated water of the reverse osmosis device.
[7] 不純物の除去を、イオン交換装置により行う請求項 6記載の方法。  7. The method according to claim 6, wherein the impurities are removed by an ion exchange device.
[8] リン酸濃縮液からァニオン交換によりリン酸以外の酸を除去して精製する請求項 1 または 2記載の方法。 [8] The method according to claim 1 or 2, wherein the phosphoric acid concentrate is purified by removing acids other than phosphoric acid by anion exchange.
[9] リン酸濃縮液を蒸発濃縮して、水とともに揮発性成分を除去して濃縮する請求項 1 または 2記載の方法。  [9] The method according to claim 1 or 2, wherein the phosphoric acid concentrate is evaporated and concentrated to remove volatile components together with water and concentrate.
[10] リン酸含有水からリン酸を回収する装置であって、 [10] An apparatus for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下の条件下で膜分離処理して、リン酸以外の酸を水とともに 透過液室側に透過させ、リン酸を濃縮液室側に濃縮する逆浸透装置と、  A reverse osmosis device that performs membrane separation treatment of phosphoric acid-containing water under a pH of 3 or less, allows acids other than phosphoric acid to permeate to the permeate chamber side together with water, and concentrates phosphoric acid to the concentrate chamber side;
リン酸含有水を PH3以下の条件下で逆浸透膜装置の濃縮液室側に供給する原水 供給部と、 逆浸透装置の透過液室側から透過液を取出す透過液取出部と、 逆浸透装置の濃縮液室側から濃縮リン酸液を取出す濃縮リン酸液取出部と を有することを特徴とするリン酸回収装置。 A raw water supply unit for supplying phosphoric acid-containing water to the concentrate chamber side of the reverse osmosis membrane device under a condition of PH3 or less; Phosphoric acid characterized by having a permeate take-out portion for taking out permeate from the permeate chamber side of the reverse osmosis device and a concentrated phosphate solution take-out portion for taking out concentrated phosphoric acid solution from the concentrate chamber side of the reverse osmosis device Recovery device.
[11] リン酸含有水からリン酸を回収する装置であって、 [11] An apparatus for recovering phosphoric acid from phosphoric acid-containing water,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で膜分離処理し て、リン酸以外の酸を水とともに透過液室側に透過させ、リン酸を濃縮液室側に濃縮 する逆浸透装置と、  Membrane separation treatment is performed under conditions where the phosphoric acid-containing water is PH3 or less and the phosphoric acid concentration is! ~ 15% by weight to allow acids other than phosphoric acid to permeate to the permeate chamber side together with water, and phosphoric acid is concentrated in the concentrate chamber. A reverse osmosis device that concentrates to the side,
リン酸含有水を PH3以下、かつリン酸濃度;!〜 15重量％の条件下で逆浸透装置の 濃縮液室側に供給するリン酸含有水供給部と、  A phosphoric acid-containing water supply section for supplying phosphoric acid-containing water to a concentration chamber side of the reverse osmosis device under conditions of PH3 or less and phosphoric acid concentration;
逆浸透装置の透過液室側から透過液を取出す透過液取出部と、  A permeate extractor for extracting permeate from the permeate chamber side of the reverse osmosis device;
逆浸透装置の濃縮液室側から濃縮リン酸液を取出す濃縮リン酸液取出部と 濃縮リン酸液取出部から取出した濃縮リン酸液を濃縮液室側に循環する循環経路 と  A concentrated phosphoric acid solution take-out section for taking out the concentrated phosphoric acid solution from the concentrate solution chamber side of the reverse osmosis device;
を有することを特徴とするリン酸回収装置。  The phosphoric acid collection | recovery apparatus characterized by having.
[12] 循環経路を循環する濃縮液に希釈水を加える希釈水供給部を有する請求項 10ま たは 11記載の装置。 12. The apparatus according to claim 10, further comprising a dilution water supply unit for adding dilution water to the concentrate circulating in the circulation path.
[13] カチオンおよび/またはァニオンを含む不純物の除去を行う前処理装置を原水供 給部に有する請求項 10または 1 1記載の装置。  [13] The apparatus according to claim 10 or 11, wherein the raw water supply unit has a pretreatment apparatus for removing impurities including cations and / or anions.
[14] 逆浸透装置の透過水から酸を含む不純物を除去する不純物除去装置を有する請 求項 10な!/、し 11記載の装置。 [14] The apparatus according to claim 10, further comprising an impurity removing device for removing impurities including acid from the permeated water of the reverse osmosis device.
[15] 不純物除去装置がイオン交換装置である請求項 14記載の装置。 15. The apparatus according to claim 14, wherein the impurity removing device is an ion exchange device.
[16] リン酸濃縮液からァニオン交換によりリン酸以外の酸を除去する精製装置を有する 請求項 10または 11記載の装置。 [16] The apparatus according to [10] or [11], further comprising a purifier for removing acids other than phosphoric acid from the phosphoric acid concentrate by anion exchange.
[17] リン酸濃縮液を蒸発濃縮して、水とともに揮発性成分を除去して濃縮する蒸発濃縮 装置を有する請求項 10または 11記載の装置。 [17] The apparatus according to [10] or [11], further comprising an evaporating and concentrating apparatus for evaporating and concentrating the phosphoric acid concentrated liquid to remove the volatile component together with water and concentrating.
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