AU2002352521A1 - A method for the removal of metals from an aqueous solution using lime precipitation - Google Patents
A method for the removal of metals from an aqueous solution using lime precipitationInfo
- Publication number
- AU2002352521A1 AU2002352521A1 AU2002352521A AU2002352521A AU2002352521A1 AU 2002352521 A1 AU2002352521 A1 AU 2002352521A1 AU 2002352521 A AU2002352521 A AU 2002352521A AU 2002352521 A AU2002352521 A AU 2002352521A AU 2002352521 A1 AU2002352521 A1 AU 2002352521A1
- Authority
- AU
- Australia
- Prior art keywords
- neutralization
- stage
- reactor
- solution
- lime
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 35
- 235000008733 Citrus aurantifolia Nutrition 0.000 title claims description 29
- 235000011941 Tilia x europaea Nutrition 0.000 title claims description 29
- 239000004571 lime Substances 0.000 title claims description 29
- 239000002184 metal Substances 0.000 title claims description 21
- 229910052751 metal Inorganic materials 0.000 title claims description 21
- 239000007864 aqueous solution Substances 0.000 title claims description 15
- 150000002739 metals Chemical class 0.000 title claims description 15
- 238000001556 precipitation Methods 0.000 title claims description 9
- 238000006386 neutralization reaction Methods 0.000 claims description 60
- 239000000243 solution Substances 0.000 claims description 28
- 229910052602 gypsum Inorganic materials 0.000 claims description 20
- 239000010440 gypsum Substances 0.000 claims description 20
- 150000001875 compounds Chemical class 0.000 claims description 17
- 239000012527 feed solution Substances 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 15
- 238000005554 pickling Methods 0.000 claims description 13
- 239000002244 precipitate Substances 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 10
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 239000002002 slurry Substances 0.000 claims description 7
- 239000007787 solid Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000008267 milk Substances 0.000 claims description 5
- 210000004080 milk Anatomy 0.000 claims description 5
- 235000013336 milk Nutrition 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229920000642 polymer Polymers 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 3
- 239000000920 calcium hydroxide Substances 0.000 claims description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 3
- 150000002222 fluorine compounds Chemical class 0.000 claims description 3
- 239000008151 electrolyte solution Substances 0.000 claims description 2
- 230000003311 flocculating effect Effects 0.000 claims description 2
- 150000004679 hydroxides Chemical class 0.000 claims description 2
- 239000013078 crystal Substances 0.000 description 6
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000001117 sulphuric acid Substances 0.000 description 4
- 235000011149 sulphuric acid Nutrition 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 239000002562 thickening agent Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000005246 galvanizing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910000000 metal hydroxide Inorganic materials 0.000 description 2
- 150000004692 metal hydroxides Chemical class 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 description 2
- 235000011152 sodium sulphate Nutrition 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 241001210472 Medicago italica Species 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Description
A METHOD FOR THE REMOVAL OF METALS FROM AN AQUEOUS SOLUTION USING LIME PRECIPITATION
This invention relates to a method for the removal of metals from their aqueous solution with lime precipitation, in conditions where a precipitate of metal hydroxide and gypsum is formed, which settles well and is easy to filter. The metals are precipitated from their aqueous solutions at a high pH and the slurry is recirculated several times in the precipitation space, whereby the gypsum is precipitated as separate crystals instead of as a solid layer. The method is particularly suitable for neutralization of the aqueous solution from the pickling of refined steel. Using this method enables the removal of metals and fluoride from the water in question.
The layer of oxides generated on the surface of steel strip during annealing is removed by pickling. Often electrolytic pickling is performed first, where the oxide layer is removed from the strip using an electric current. Sodium sulphate solution is used as the electrolyte. The strip is fed through the solution and the anode reaction generates sulphuric acid, which acts as the pickling agent. The sulphuric acid is highly active when generated and is able to dissolve the oxides formed on the surface of the strip during annealing into sulphates. The rest of the oxides and the chrome-poor area of the steel strip are removed by mixed acid pickling, where nitric acid and hydrofluoric acid are in an aqueous solution. Often nowadays there is also some sulphuric acid in the solution, either directly as an addition or as a result of regeneration treatment.
In electrolytic pickling an aqueous solution is formed containing the metals dissolved from the surface of the steel strip. These metals are mainly iron, nickel and chrome. In order to prevent precipitation of the electrolyte bath a certain amount of the solution is removed and replaced. The removed solution and likewise the post-electric pickling steel strip flush water are combined for chrome(IV) reduction treatment. After reduction treatment the
solution is more acidic. The solution obtained is combined again with the flush water used for washing the steel strip after mixed aid pickling. The combined solution is routed to neutralization in order to remove the metals.
In DE publication 3822953 a method is described, whereby a hydrochloric acid solution of a hot-galvanizing bath is routed first to ion exchange and from there the solution containing acid and metals is taken on to neutralization. In the first neutralization step the pH is raised to 8.5 and the precipitate generated is taken to filtration, from where a filter cake is recovered containing iron and zinc. The overflow solution from precipitation is taken to a second neutralization step, where neutralization is performed with sulphuric acid to a pH of 7. Gypsum is precipitated at this stage, and the overflow is routed as circulating water back to the galvanizing bath via ion exchange.
When lime compounds are used in the neutralization of sulphate solutions there is a danger that the gypsum formed will precipitate as a solid layer on the precipitation reactor and piping and that this will increase the maintenance requirements for the equipment and pipes. This danger is particularly likely when the pH value of the solution to be neutralized is raised gradually using a lime compound to the value where the actual neutralization takes place, and if the mixing in the reactor is non-uniform (a blade mixer).
A method has now been developed whereby an aqueous solution containing in particular iron and nickel can be neutralized using a lime compound in order to remove the metals from the solution as metal hydroxides and the lime as crystalline gypsum. Fluorides are also removed from the aqueous solution. The method is particularly suitable for treatment of an electrolytic solution and pickling flush water from steel pickling. According to this method, neutralization takes place in at least two stages, where the first stage is performed at a pH value of minimum 10.5, and the second and subsequent stages at considerably lower values. The final stage is the
settling of the precipitate, from whence the gypsum- and metallic hydroxide- bearing precipitate is circulated back to the first neutralization stage, which promotes the formation of loose gypsum crystals. The essential features of the invention will be made apparent in the attached claims.
The invention is illustrated in Figure 1 , which presents the method as a flow sheet.
The explanation of the invention mainly describes the neutralization of an aqueous solution from the pickling of refined steel, but the invention is not limited only to this purpose, but can be used for other neutralization applications also. According to the method now developed, the majority of a metal-containing feed solution is routed to the first neutralization stage, into which a lime compound is also fed as a neutralizing agent, for example in the form of lime milk (Ca(OH)2). It has proved expedient to feed both the feed solution and the lime compound to the surface of the neutralization reactor solution. The feed solution and lime compound are fed from opposite sides of the reactor. The gypsum- and metallic hydroxide-containing underflow from settling is also fed with the lime compound into this stage, and it is beneficial to premix this into the lime compound just prior to feeding it into the neutralization reactor. A surplus of lime compound is added in relation to the metals to be precipitated and any possible free acid. The feed of the lime compound precipitate is specified so that in this neutralization stage the pH is raised to a value of at least 10.5, even up to 11.5, in other words far higher than ordinary neutralization levels. Most metals precipitate at a pH of 10 as for instance nickel, which precipitates as nickel hydroxide. It has been proven that the purification of the feed solution is intensified when the neutralization stage is held at a pH value of 0.5 - 1.5 units higher than in ordinary methods. The higher pH values used also accomplish the co-precipitation of impurities.
The slurry from the first neutralization stage is led in its entirety to the second stage, where a portion of the metal-containing feed solution is also taken, for
instance 5 - 30%. It is again advantageous to feed the feed solution and the first stage slurry to the surface of the neutralization reactor solution and to direct the said feeds from either side of the reactor centre as in the first stage. The feed solution regulates the pH value of the second neutralization stage, which is specified as somewhat lower than the pH of the first neutralization stage, e.g. 9.5 - 10.5. The neutralization stages are equipped with pH sensors to ease regulation. The neutralization stages are in series in relation to the gypsum-containing underflow and the lime compound, i.e. they flow through both or all the neutralization stages. The stages are mainly in series also in relation to the feed solution, since only 5 - 30% is fed directly into the second neutralization stage. The gypsum content of the neutralization stages is adjusted between 10 - 50 g/l, and this amount is advantageous for the formation of loose gypsum crystals. Gypsum crystals are precipitated and grow on top of one another and thus gypsum deposits in the immediate environment are avoided. It is beneficial for the formation of loose gypsum crystals that the pH is higher in the first neutralization stage than in subsequent stages, and that the pH is maintained at rather high levels, as presented above.
Each neutralization stage takes place in a separate reactor, equipped with baffles and a suitable mixing element for the purpose. Such is for instance a helix-type mixer as described in US patent 5,182,087, which has a structure with two tubes circling around a shaft, making 1/3 - 2 revolutions around the shaft. A mixing element can achieve a powerful vertical circulation in neutrali- zation reactors, upward from the sides of the reactor and downward at the centre of the reactor and from there again to the sides of the reactor. A powerful circulation in itself is enough to reduce the adhesion of particles to the structure of the neutralization reactor. The diameter of the mixing element is 50 - 80% of that of the neutralization reactor. This kind of mixer cannot leave to rotate in a small cavity of gypsum, as can happen with a blade mixer in a gypsum-forming environment. Thanks to the strong vertical circulation, the mixing of the feed solution and the lime compound and the
increase in the pH of the solution are swift, and occur within 1 - 15 seconds. In conventional neutralization, mixing and pH increase require several minutes.
The large size of the mixer in relation to the diameter of the reactor enables the whole of the reactor volume to be kept well mixed even at low rotation speeds, such as for instance 30 rpm. Thus the shear forces caused by the mixing element also remain small. When the materials to be fed into the reactors are routed to the surface of the reactor solution, the flow obtained with the mixing element downward from the centre mixes the materials together well and circulates them within the reactor.
From the final neutralization stage the precipitate is taken to settling, and a flocculant, a polymer that flocculates solids is also conducted there. Most of the gypsum-containing underflow is circulated back to the first neutralization stage and only a portion is removed totally from the neutralizing circuit. It is advantageous that the underflow is recirculated between 5 - 15 times on average, before being removed from the circuit. Flocculant consumption is low, only 50 - 150 g per tonne of solids fed to the settling stage. Underflow circulation promotes the formation of gypsum as crystals and also improves the quality of the metallic hydroxide precipitate as well as its settling and filtering properties. The intensity of mixing in the neutralization reactors is adjusted so that the floes generated are not broken up by the effect of the mixing.
When the underflow is recirculated, the flocculant is also recirculated in the neutralization stages, and this means that the amount of flocculant to be added can be kept small. Since the mixing intensity of the reactors is altogether low, the underflow floes are not broken to any great extent, which also keeps the flocculant consumption low. The underflow to be removed from the settling stage contains gypsum precipitate and metallic hydroxides, and this is taken further to filtration. The metal-free overflow is so pure, that it
can be routed back to several different points where water is used. The process is not temperature-sensitive, and can operate within a wide range of temperatures, between 5 - 95 °C.
The invention is described further using the following examples:
Example 1
A metal-containing solution was treated in two neutralization reactors, connected in series. The volume of each reactor was 5 I. The mixer use'd in each was a helix mixer, with a rate of 0.9 W/l. The temperature of the reactors was 50 ° C.
The content of the feed solution is shown in Table 1 below. The metals were in nitrate and fluoride form. In addition, there was 17g/l of sodium sulphate, and the pH of the solution was 1.7. The solution to be treated was fed to the solution surface of the first reactor at 4.1 l/h. A surplus of lime was fed into the reactor for neutralization as lime milk slurry, so that the lime milk content was 40 g/l and the flow rate 0.52 l/h.
In the first neutralization stage the pH of the slurry rose to 10.9. In the second neutralization stage the pH was adjusted to a value of 10.0 by feeding 0.95 l/h of feed solution to the surface of the solution. The attached table shows that it was possible to remove the metals and fluorides almost completely using the method and that the solution is suitable for circulation to various points of use. Table 1
Example 2
As in the previous example, a metal-containing solution was treated in a neutralization line, comprising two neutralization reactors. The volume of each reactor was 62 m3 and the diameter of the settling reactor 27 m. Helix mixers were used as the mixing element in both reactors, where the helix tubes rotated around the mixing shaft for Vz cycle. The diameter of the mixer was 2.8 m and the rotation speed 30 rpm.
In a certain run 72 m3/h of feed solution was processed, of which 55 m3/h was fed into the first reactor and 17 m3/h into the second. 24 m3/h of the underflow from the settling reactor (thickener) was circulated back to the first reactor, and 0.8 m3/h of lime milk with a Ca(OH)2 content of 230 kg/m3 was mixed with it. The solution routed to the reactor was directed to the surface of the reactor near the inner edge of the baffle, however clearly to the front side of the baffle. The lime/underflow precipitate on the other hand was routed to the surface in a corresponding manner in the vicinity of the baffle located on the other side of the centre.
The flocculating polymer used was Fennopol A305, at a content of 0.5 g/l. About 1m3/h of the solution in question was added, in other words about 70 g per tonne of solids fed into the thickener. The amount of flocculant is about 1/3 of that normally used. Nevertheless the above amount was sufficient to keep the thickener feed in a flocculated state and to keep the overflow clear. Thus another benefit of our method is the reduction of flocculant consumption.
Claims (20)
1. A method for the removal of metals from their aqueous solution as metallic hydroxides and gypsum using lime precipitation, characterized in that the precipitation is made in at least two neutralization stages, where the majority of the metal-containing feed solution is routed to the first neutralization stage, where the pH is adjusted using a lime compound to a value of at least 10.5 and in the second stage the pH is adjusted using the feed solution to at least 9.5; after the final neutralization stage the precipitate is settled in a settling stage, from where the metallic hydroxide-gypsum slurry is recirculated to the first neutralization stage.
2. A method according to claim 1 , characterized in that the pH value of the first neutralization stage is 10.5 - 11.5.
3. A method according to claim 1 , characterized in that the pH value of the second neutralization stage is 9.5 - 10.5.
4. A method according to claim 1 , characterized in that the aqueous solution contains nickel and iron.
5. A method according to claim 1 , characterized in that the aqueous solution contains nickel, iron and chrome.
6. A method according to claim 1 , characterized in that the aqueous solution contains fluorides, which are removed during neutralization.
7. A method according to claim 1 , characterized in that 5 - 30 % of the metal-containing feed solution is routed to the second neutralization stage.
8. A method according to claim 1 , characterized in that neutralization is performed with lime milk Ca(OH)2.
9. A method according to claim 1 , characterized in that the amount of gypsum is adjusted to be 10 - 50 g/l in the neutralization stages.
10. A method according to claim 1 , characterized in that neutralization takes place at a temperature between 5 - 95° C.
11. A method according to claim 1 , characterized in that the neutralization stages are equipped with pH sensors.
12. A method according to claim 1 , characterized in that the neutralization stages are located in series in relation to the gypsum- containing underflow and lime compound.
13. A method according to claim 1 , characterized in that both the feed solution and the lime compound are fed to the surface of the solution in the reactor in the neutralization stages.
14. A method according to claim 13, characterized in that the feed solution and the lime compound are fed to opposite sides of the reactor.
15. A method according to claim 1 , characterized in that the metallic hydroxide-gypsum slurry is premixed into the lime compound before being fed into the neutralization reactors.
16. A method according to claim 1 , characterized in that each neutrali- zation stage takes place in a reactor that is equipped with a helix-type mixing element.
17. A method according to claim 16, characterized in that the diameter of the mixing element is 50 - 80% that of the neutralization reactor.
18. A method according to claim 1, characterized in that a polymer to flocculate solids is fed into the settling stage.
19. A method according to claim 18, characterized in that the amount of the flocculating polymer is 50 - 150 g per tonne of solids fed into the settling stage.
20. A method according to claim 1 , characterized in that a metal- containing aqueous solution is formed from the electrolyte solution used in pickling steel and the pickling flush water.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20011413 | 2001-06-29 | ||
FI20011413A FI115533B (en) | 2001-06-29 | 2001-06-29 | Process for removing metals from aqueous solutions by lime precipitation |
PCT/FI2002/000523 WO2003002774A1 (en) | 2001-06-29 | 2002-06-14 | A method for the removal of metals from an aqueous solution using lime precipitation |
Publications (2)
Publication Number | Publication Date |
---|---|
AU2002352521A1 true AU2002352521A1 (en) | 2003-05-15 |
AU2002352521B2 AU2002352521B2 (en) | 2007-11-22 |
Family
ID=8561543
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU2002352521A Expired AU2002352521B2 (en) | 2001-06-29 | 2002-06-14 | A method for the removal of metals from an aqueous solution using lime precipitation |
Country Status (18)
Country | Link |
---|---|
US (1) | US7247282B2 (en) |
EP (1) | EP1412546B1 (en) |
JP (1) | JP2004530559A (en) |
CN (1) | CN100420759C (en) |
AT (1) | ATE319864T1 (en) |
AU (1) | AU2002352521B2 (en) |
BG (1) | BG66305B1 (en) |
BR (1) | BR0210735B1 (en) |
CA (1) | CA2450345C (en) |
DE (1) | DE60209739T2 (en) |
EA (1) | EA005306B1 (en) |
ES (1) | ES2259714T3 (en) |
FI (1) | FI115533B (en) |
MX (1) | MXPA03011778A (en) |
PE (1) | PE20030030A1 (en) |
PL (1) | PL196851B1 (en) |
WO (1) | WO2003002774A1 (en) |
ZA (1) | ZA200309893B (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI20030612A (en) * | 2003-04-23 | 2004-10-24 | Outokumpu Oy | Process for the treatment of waste materials arising in a metallurgical process |
US20090145856A1 (en) * | 2007-12-11 | 2009-06-11 | Raymond Letize A | Acid recycle process with iron removal |
RU2448054C2 (en) * | 2010-07-08 | 2012-04-20 | Государственное образовательное учреждение высшего профессионального образования "Орловский государственный технический университет" (ОрелГТУ) | Method of purifying acidic waste water from heavy metal sulphates |
JP5867165B2 (en) * | 2012-03-02 | 2016-02-24 | 住友金属鉱山株式会社 | Method for detecting nickel contained in wastewater |
CN102814058B (en) * | 2012-09-17 | 2014-07-16 | 工信华鑫科技有限公司 | Method for implementing nickel-magnesium separation, enrichment and purification by using heavy metal adsorbing material |
CA3076455A1 (en) * | 2017-09-20 | 2019-03-28 | Smr Technologies Limited | Suitable reagent for the treatment of high-sulphate waters |
CN109111081B (en) * | 2018-09-06 | 2021-12-14 | 安徽省通源环境节能股份有限公司 | Sludge high-dry dehydration and dehydration filtrate pretreatment process and treatment system thereof |
AU2020239801B2 (en) * | 2019-10-28 | 2022-06-16 | China Enfi Engineering Corporation | Method for treating metal-containing solution |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3375066A (en) * | 1963-08-24 | 1968-03-26 | Yawata Chem Ind Co Ltd | Process for the continuous production of gypsum and iron oxide from waste sulfuric acid pickle liquor and a calcium compound |
SE351444B (en) * | 1970-11-03 | 1972-11-27 | Nordstjernan Rederi Ab | |
SU565075A1 (en) * | 1974-06-11 | 1977-07-15 | Уральский ордена Трудового Красного Знамени политехнический институт им.С.М.Кирова | Method for recovering waste nitrogen-hydrofluoric pickling solutions |
CA1040868A (en) * | 1975-04-02 | 1978-10-24 | Inco Ltd. | Process for recovery of valuable metals from solution using neutralization by lime or limestone |
US4606829A (en) * | 1984-06-13 | 1986-08-19 | Bethlehem Steel Corporation | Removal of complexed zinc-cyanide from wastewater with improved sludge stability |
CN86205151U (en) * | 1986-07-19 | 1987-08-26 | 山西省榆次市环境保护设备厂 | Continuous desposer for acidic sewage |
DE3822953A1 (en) * | 1988-07-07 | 1990-01-11 | Ulrich Dipl Ing Schwarz | Process for regenerating an iron- and/or zinc-containing hydrochloric acid bath |
SU1696569A1 (en) * | 1989-02-17 | 1991-12-07 | Предприятие П/Я М-5314 | Method of neutralizing hydrofluoric acid base spent solutions |
US5120447A (en) * | 1991-03-06 | 1992-06-09 | Gte Products Corporation | Method for removing heavy metals from wastewater |
CN2101670U (en) * | 1991-09-16 | 1992-04-15 | 烟台市环境保护技术应用所 | Device for removing heavy metal ion from waste water |
US5403495A (en) * | 1992-03-13 | 1995-04-04 | Tetra Technologies, Inc. | Fluoride removal system |
US5266210A (en) * | 1992-04-15 | 1993-11-30 | Mclaughlin Water Engineers, Ltd. | Process for removing heavy metals from water |
SE508836C2 (en) * | 1993-04-20 | 1998-11-09 | Boliden Contech Ab | Process for purification of industrial wastewater by two-stage precipitation |
US5753125A (en) * | 1995-05-19 | 1998-05-19 | Kreisler; Lawrence | Method for recovering and separating metals from waste streams |
WO1999001383A1 (en) * | 1997-07-02 | 1999-01-14 | Csir | Treatment of acidic water containing dissolved ferrous cations |
SE514409C2 (en) * | 1999-06-17 | 2001-02-19 | Boliden Mineral Ab | Process for total precipitation of valuable metals from an acidic lacquer solution |
DE10003495C2 (en) * | 2000-01-27 | 2003-04-03 | Wacker Polymer Systems Gmbh | Hydrophobing agent for the hydrophobization of gypsum-bound building materials, process for its production and its use |
-
2001
- 2001-06-29 FI FI20011413A patent/FI115533B/en not_active IP Right Cessation
-
2002
- 2002-06-14 DE DE60209739T patent/DE60209739T2/en not_active Expired - Lifetime
- 2002-06-14 US US10/481,844 patent/US7247282B2/en not_active Expired - Lifetime
- 2002-06-14 EP EP02751200A patent/EP1412546B1/en not_active Expired - Lifetime
- 2002-06-14 PL PL366544A patent/PL196851B1/en unknown
- 2002-06-14 AU AU2002352521A patent/AU2002352521B2/en not_active Expired
- 2002-06-14 WO PCT/FI2002/000523 patent/WO2003002774A1/en active IP Right Grant
- 2002-06-14 AT AT02751200T patent/ATE319864T1/en not_active IP Right Cessation
- 2002-06-14 CN CNB028130847A patent/CN100420759C/en not_active Expired - Lifetime
- 2002-06-14 BR BRPI0210735-0A patent/BR0210735B1/en not_active IP Right Cessation
- 2002-06-14 MX MXPA03011778A patent/MXPA03011778A/en active IP Right Grant
- 2002-06-14 EA EA200400100A patent/EA005306B1/en not_active IP Right Cessation
- 2002-06-14 CA CA2450345A patent/CA2450345C/en not_active Expired - Lifetime
- 2002-06-14 ES ES02751200T patent/ES2259714T3/en not_active Expired - Lifetime
- 2002-06-14 JP JP2003508738A patent/JP2004530559A/en not_active Abandoned
- 2002-06-25 PE PE2002000554A patent/PE20030030A1/en active IP Right Grant
-
2003
- 2003-12-09 BG BG108431A patent/BG66305B1/en unknown
- 2003-12-22 ZA ZA200309893A patent/ZA200309893B/en unknown
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4680126A (en) | Separation and recovery of reusable heavy metal hydroxides from metal finishing wastewaters | |
KR100200021B1 (en) | Method of treating waste water to remove harmful ion by coagulating sedimentation | |
AU775839B2 (en) | Process for reducing the concentration of dissolved metals and metalloids in an aqueous solution | |
JPS5840192A (en) | Treatment of industrial waste water | |
EP1178014A1 (en) | Process for treating chromate waste liquid | |
WO2019131832A1 (en) | Wastewater treatment method | |
CN108358409A (en) | A kind of steel wire rope sludge and spent acid method for innocent treatment | |
CA2450345C (en) | A method for the removal of metals from an aqueous solution using lime precipitation | |
AU2002352521A1 (en) | A method for the removal of metals from an aqueous solution using lime precipitation | |
JP2000202461A (en) | Treatment of heavy metal complex-containing waste liquid | |
JP4272122B2 (en) | Coagulated water treatment method and apparatus | |
JP3945216B2 (en) | Waste acid gypsum manufacturing method | |
JP3229277B2 (en) | Wastewater treatment method | |
JPH0986925A (en) | Production of alumina gel using surface-treatment waste water of aluminum material and production of crystalline aluminum hydroxide | |
CN114772793A (en) | Method for delaying calcium sulfate scaling in desulfurization wastewater pretreatment and unhardening processes | |
JP2009224273A (en) | Method of processing waste electrolyte | |
JPH05337474A (en) | Treatment of waste water containing heavy metal | |
JP5693992B2 (en) | Method for recovering dissolved iron from wastewater containing various metal ions | |
JP3225777B2 (en) | Wastewater treatment method | |
JP3632226B2 (en) | Method for treating metal-containing wastewater | |
JP3684477B2 (en) | Treatment method for petroleum combustion ash | |
JP3226634B2 (en) | Purification method of iron chloride waste liquid containing a small amount of chromium ion | |
JP2010222159A (en) | Processing method of aluminum hydroxide-containing solution | |
JPH10180266A (en) | Treatment of waste liquid of electroless nickel plating | |
CN115180748A (en) | Waste acid treatment method |