CN101486536A - Sulfuric acid modified method for phosphogypsum - Google Patents
Sulfuric acid modified method for phosphogypsum Download PDFInfo
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- CN101486536A CN101486536A CNA2008100561890A CN200810056189A CN101486536A CN 101486536 A CN101486536 A CN 101486536A CN A2008100561890 A CNA2008100561890 A CN A2008100561890A CN 200810056189 A CN200810056189 A CN 200810056189A CN 101486536 A CN101486536 A CN 101486536A
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- phosphogypsum
- sulfuric acid
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/007—After-treatment of the dehydration products, e.g. aging, stabilisation
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B11/00—Calcium sulfate cements
- C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/08—Acids or salts thereof
- C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
- C04B22/142—Sulfates
- C04B22/143—Calcium-sulfate
- C04B22/144—Phosphogypsum
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Abstract
The invention relates to a sulphuric acid modifying method of phosphogypsum, which obtains the modified phosphogypsum by mixing sulphuric acid with a phosphogypsum material for reacting for 0.5 to 24 hours at the temperature between 10 and 90 DEG C, and then carrying out neutralizing treatment to a reaction product, thus leading the co-crystallized phosphorus in the phosphogypsum to be separated, and reducing the total phosphor content of the phosphogypsum; moreover, the phosphogypsum of different phosphor content can be obtained by selecting proper reaction conditions according to different demands, thus being suitable for different industrial production. The invention also provides a sulphuric acid modified phosphogypsum prepared by the method and the usage of the sulphuric acid modified phosphogypsum used as a cement material or an additive.
Description
Technical field
The present invention relates to a kind of sulfuric acid modified method of phosphogypsum, relate in particular to a kind of sulfuric acid modified impurity that removes in the phosphogypsum, especially method of eutectic phosphorus utilized, belong to phosphogypsum modification and comprehensive utilization field.
Background technology
Phosphogypsum is the solid trade waste that discharges in the Wet-process Phosphoric Acid Production process, produces 1 ton of phosphoric acid (with P
2O
5Meter) can produce the phosphogypsum of 4.5-5 ton.The phosphogypsum of China's year in 2006 discharging is near 3,000 ten thousand tons, and utilization ratio is but less than 20%.Follow developing rapidly of industry such as phosphate fertilizer, high-concentration phosphoric acid and washing composition, phosphogypsum slag quantity also will continue to increase.What phosphogypsum processing was now mainly adopted is that open-air the accumulation discharged, and wherein soil and underground water are infiltrated in the meeting under rainwash of the phosphorus of solubility and fluorine, and this not only takies a large amount of soils, contaminate environment, and causes very big burden for phosphoric acid enterprise.High residual phosphorus content in the phosphogypsum has not only reduced the percentage extraction of phosphoric acid, also influences the maximum resource utilization of phosphogypsum simultaneously.The phosphogypsum resource utilization is the big key that can the phosphate fertilizer industry realize Sustainable development.
The sulfate dihydrate calcium contents surpasses 90% in the phosphogypsum, is a kind of important reclaimed gypsum resource, but impurity such as the phosphorus in the phosphogypsum, F, organism are the principal elements that influences the phosphogypsum development and use.Cement is one of three big material of construction, and that will be able to mass consumption fall the phosphogypsum that these are piled into the mountain phosphogypsum if can be performed well in Cement industry.At present, phosphogypsum mainly comprises as the purposes of cement raw material: 1, be used as cement setting retarder; 2, phosphogypsum is reduced into calcining cement clinker behind the calcium oxide.Utilization on Cement industry has considerable influence but the phosphorus in the phosphogypsum is to phosphogypsum, during untreated phosphogypsum making cement retardant, phosphorus wherein can and cement in the Ca of CaO reaction generation indissoluble
3(PO
4)
2And be coated on C3S, C2S and gypsum surface, cause the delayed coagulation instability of phosphogypsum, or coagulate soon or time of coagulation long.When making producing sulfuric acid and jointly cement with phosphogypsum, phosphorus in the phosphogypsum can carry out the sintering of cement clinker together along with CaO, when the phosphorus content in the cement 0.3% when following (being converted into two hydration butts below 0.15%) cement is had mineralization, but the too high decomposition that will cause C3S, the quality of reduction cement clinker.Therefore how research removes phosphorus and other detrimental impurity in the phosphogypsum, significant to phosphogypsum resource utilization and environment protection emission.
The method that phosphogypsum modification processing is at present adopted usually is: methods such as washing, flotation, ammonia soln processing, citric acid treatment, ageing, screening, calcining and chemical combination processing.What methods such as washing, flotation, ammonia soln processing, citric acid treatment and ageing were paid close attention to mainly is solvable phosphorus and the portion phosphate precipitation that removes in the phosphogypsum, its treatment effect to eutectic phosphorus is undesirable, and also can produce a large amount of waste water in these method treating processess, cause serious environmental to pollute; Sieve, methods such as calcining and chemical combination processing are then paid close attention to and are changed the existence form of phosphorus in phosphogypsum, are not that phosphorus is therefrom deviate from.Though present research is towards phosphogypsum being applied to effort aspect the Cement industry, but owing to contain more eutectic phosphorus in the phosphogypsum, present method can't well be deviate from eutectic phosphorus, cause total phosphorus content higher, this has influenced the application of phosphogypsum as cement setting retarder, phosphogypsum system producing sulfuric acid and jointly cement and phosphogypsum system thiocarbamide jointly producing cement.
Eutectic phosphorus is CaSO in the phosphoric acid by wet process two water thing production processes
42H
2O crystallization in a large amount of phosphoric acid environment causes molecular size and SO
4 2-Similar HPO
4 2-Enter CaSO
42H
2Form in the O lattice.Eutectic phosphorus is present in the semi-hydrated gypsum lattice, stripping from lattice during aquation, the aquation of obstruction semi-hydrated gypsum; Eutectic phosphorus can reduce the degree of supersaturation of dihydrate gypsum crystallization, makes the dihydrate gypsum crystal alligatoring, and intensity reduces, and general pre-treatment can not be eliminated the influence of eutectic phosphorus.The eutectic phosphorus content is generally at 0.5%-0.8% (two hydration butts) in the phosphogypsum that the existing phosphoric acid by wet process two water thing production methods of China produce, make phosphorus content (phosphorus content) in the phosphogypsum be lower than 0.1% (two hydration butts) and be beneficial to a large amount of uses of phosphogypsum on Cement industry, deviating from of eutectic phosphorus just seems extremely important so.
Be used as the treatment process of the phosphogypsum of cement setting retarder at present, mainly contain the CaO neutralisation and dodge the burning method.Still have a large amount of eutectic phosphorus in the phosphogypsum after the CaO neutralisation is handled, eutectic phosphorus can discharge along with the phosphogypsum aquation cement is produced the influence the same with solvable phosphorus.Main treatment process when dodging the burning method and be present phosphogypsum as cement setting retarder, but energy consumption height, treatment capacity is little.Yang Zhaojuan etc. (" utilizing hydrothermal method phosphogypsum to be carried out the craft discussion of removal of impurities dehydration ", Qinghai University's journal (natural science edition), 2007, the 25th volume, the 2nd phase) a kind of method of using hydrothermal method phosphogypsum to be carried out the removal of impurities processed has been proposed, it is that phosphogypsum dry powder and hydrochloric acid or hydrochloric acid and NaCl mixing solutions are joined in the autoclave, reacts under 120-200 ℃ high temperature, can reduce to about 0.05% through the phosphorus content in the product that is obtained after this hydrothermal treatment consists.Though this method can obtain dephosphorization effect preferably, but its reaction process need be carried out under High Temperature High Pressure, the energy consumption height, treatment capacity is little, and wastewater discharge is big, because hydrochloric acid is volatile acid, in treating processes, can bring atmospheric pollution, and after handling, chlorion is difficult for removing, and the foreign matter content in the phosphogypsum product is higher.Utilize nitric acid treatment also can bring similar problem.
Therefore seek the method for a kind of easy, economy, environmental protection, with phosphorus, F, organism, especially impurity such as eutectic phosphorus is deviate from from phosphogypsum, is being issued to higher dephosphorization rate than the demulcent condition, is the problem that present phosphogypsum modification and Application Areas need to be resolved hurrily.
Summary of the invention
For solving the problems of the technologies described above, the object of the present invention is to provide a kind of sulfuric acid modified method of phosphogypsum, utilize sulfuric acid that phosphogypsum is carried out modification, the eutectic phosphorus in the effective elimination phosphogypsum, solvable phosphorus, calcium phosphate precipitation etc. reduce wherein organism and detrimental impurity such as fluorine simultaneously.
The present invention also aims to provide a kind of modified ardealite, utilizing above-mentioned sulfuric acid modified method that the higher phosphogypsum of eutectic phosphorus content is carried out modification handles, deviate from wherein each kind of impurity, eutectic phosphorus especially obtains phosphorus content and is reduced to a certain degree phosphogypsum.
The present invention also aims to provide the purposes of above-mentioned phosphogypsum, the ardealite instead plaster of paris is applied to the production of cement, gypsum building material product as cement raw material or additive.
For achieving the above object, the invention provides a kind of sulfuric acid modified method of phosphogypsum, it may further comprise the steps: sulfuric acid is mixed with the phosphogypsum raw material, and reaction is 0.5-24 hour under 10-90 ℃ temperature of reaction; Reaction product is carried out neutralizing treatment, obtain the phosphogypsum after the modification.
According to concrete scheme of the present invention, the sulfuric acid modified method of phosphogypsum provided by the invention can may further comprise the steps: the sulfuric acid that with volume fraction is 5%-98% mixes with the phosphogypsum raw material by solid-to-liquid ratio (g/mL) 1:0.5-1:6, and reaction is 0.5-12 hour under 10-90 ℃ temperature of reaction; Reacted phosphogypsum is washed, filter; Filter residue is carried out neutralizing treatment, obtain the phosphogypsum after the modification.
In actual production, the quality of the phosphogypsum of each plant produced is also incomplete same, and the different purposes of phosphogypsum has different requirements for the content of phosphorus, and those skilled in the art select suitable processing parameter to realize respectively according to above-mentioned different situations.According to the common practise of this area, phosphorus content and dephosphorization rate etc. all can be with P
2O
5As the benchmark that calculates, and can be scaled corresponding data in the two hydration butts.
According to concrete technical scheme of the present invention, phosphogypsum under a large amount of vitriolic environment, SO
4 2-Can displace the eutectic phosphorus in the phosphogypsum, make eutectic phosphorus deviate from and enter in the sulphuric acid soln, and to make the phosphogypsum crystalline transformation be needle-like crystal, fine crystals or indefinite form etc.For obtaining the phosphogypsum of higher quality, control production cost, the vitriolic volume fraction is preferably about 20-45%.
Under higher temperature phosphogypsum is handled, helped obtaining the phosphogypsum of higher quality, preferably control reaction temperature is about 20-70 ℃ in dephosphorizing method of the present invention.
According to the difference of phosphogypsum raw material, sulfuric acid concentration and temperature of reaction, can determine the suitable reaction times, the general reaction times may be controlled to 0.5-12 hour, can be controlled at about 1-4 hour according to the concrete operations needs.At lower sulfuric acid concentration with than under the low reaction temperatures, can the proper extension reaction times for improving dephosphorization rate; Otherwise under higher sulfuric acid concentration and higher reaction temperatures, the short reaction times for the treatment of processes control just can obtain needed, even higher dephosphorization rate.
In the reaction process, (solid-to-liquid ratio of the present invention if no special instructions for solid-to-liquid ratio, all refer to solid masses and liquid volume ratio, solid masses unit is gram, liquid volume unit is a milliliter, for different units, solid-to-liquid ratio numerical value can convert according to its mutual conversion relation) also reaction there is certain influence, increase (for example solid-to-liquid ratio gradually becomes 1:6 by 1:0.5) with the vitriolic amount, the phosphorus content of the phosphogypsum after modification is handled also can reduce gradually, take all factors into consideration economic benefit, preferred solid-to-liquid ratio scope is about 1:1-1:4.
In sulfuric acid modified method of the present invention, after phosphogypsum raw material and the sulfuric acid reaction, earlier phosphogypsum is carried out washing and filtering (washing and filtration can be carried out simultaneously), then the filter residue that obtains is utilized CaO, Ca (OH)
2Or CaCO
3Deng being neutralized to neutrality, obtain the phosphogypsum after the modification; Perhaps after phosphogypsum raw material and sulfuric acid reaction, the residual a certain amount of sulfuric acid of meeting after washing, can utilize CaO, Ca (OH) earlier in the mixed solution that contains phosphogypsum of gained
2Or CaCO
3Be neutralized to neutrality Deng the mixed solution that will contain phosphogypsum, and then filter the phosphogypsum obtain after the modification.
In the sulfuric acid modified method of phosphogypsum provided by the present invention, sulfuric acid concentration, temperature of reaction, solid-to-liquid ratio and reaction times are for the dephosphorization rate of phosphogypsum, the phosphorus content of the phosphogypsum after the modification has bigger influence in other words, but these parameters are not individually the processing of phosphogypsum to be exerted an influence, but collaborative mutually acting in conjunction, therefore, in the technical scheme of the present invention, should take all factors into consideration various requirement, choose suitable parameters and make up phosphogypsum is handled.
According to concrete technical scheme of the present invention, handled phosphogypsum raw material can be without pretreated phosphogypsum (promptly directly being used to carry out modification processing of the present invention from the phosphogypsum of each plant produced), the phosphogypsum (phosphogypsum that all can have a large amount of ageings to handle usually on the ardealite storage yard of each factory after the phosphogypsum of drying treatment or ageing in advance handled, phosphogypsum sulfuric acid modified method provided by the present invention also is suitable for for these phosphogypsum raw materials) etc., sulfuric acid modified method of the present invention all is suitable for for any phosphogypsum (promptly needing to deviate from the phosphogypsum of eutectic phosphorus) that contains a certain amount of eutectic phosphorus; Wherein, drying treatment can adopt the mode of phosphogypsum drying treatment under 130-400 ℃ high temperature is carried out in advance, carry out after the drying treatment sulfuric acid modified in advance again to phosphogypsum like this, needed vitriolic amount in the time of can reducing the phosphorus that displaces in the phosphogypsum greatly, the sulfuric acid of volume fraction about 10% just can reach P in the phosphogypsum after the modification
2O
5It is about 0.01% that content is reduced to, and this is because high temperature can make the dihydrate gypsum dehydration, destroys dihydrate gypsum crystal, makes crystal become fragile, make eutectic phosphorus deviate to become be more prone to.
Detrimental impurity in the phosphogypsum mainly is impurity such as phosphorus impurities such as solvable phosphorus, eutectic phosphorus, calcium phosphate precipitation, a small amount of unreacted Rock Phosphate (72Min BPL) and F, organism, metal ion, wherein a small amount of unreacted Rock Phosphate (72Min BPL) be since phosphorus ore at H
3PO
4-H
2SO
4-H
2When decomposing the system phosphoric acid by wet process in the O system, the calcium sulfate that ground phosphate rock is generated wraps up and can not continue to decompose to produce.The sulfuric acid of higher concentration has the effect of certain destruction calcium sulfate dihydrate crystals, can make the ground phosphate rock that is wrapped that reaction takes place to continue slowly.Present two-step approach phosphoric acid by wet process two water thing production technique make unreacted Rock Phosphate (72Min BPL) content reach very low level, can consider.In the impurity that phosphogypsum comprised, solvable phosphorus, F, organism can be water-washed away, calcium phosphate precipitation, metal ion be dissolved the entering in the sulphuric acid soln of energy in sulphuric acid environment, in the sulfuric acid modified phosphogypsum of washing, solvable phosphorus, F, organism, calcium phosphate precipitation, metal ion etc. can both be washed off.Use CaO, Ca (OH) then
2Or CaCO
3After neutralizing the sulfuric acid of not cleaning, just can obtain detrimental impurity such as phosphorous hardly, F, organism, pH is the neutral phosphogypsum, makes the character of phosphogypsum approach natural dihydrate gypsum more, not only has been beneficial to the phosphogypsum comprehensive utilization but also has been beneficial to the environment protection emission of phosphogypsum.
The present invention also provides a kind of modified ardealite, and it is according to aforesaid method, by the phosphogypsum of sulfuric acid modified preparation.
The phosphogypsum that process provided by the present invention is sulfuric acid modified, the eutectic phosphorus that it contains can be by sulfuric acid (SO under a large amount of vitriolic environment
4 2-) displace, therefore reduced the content of its eutectic phosphorus, also can deviate from other impurity in the phosphogypsum simultaneously, the total phosphorus content that obtains at last in the phosphogypsum also can be reduced to a certain degree, thereby can reach the requirement as cement raw material.
The phosphorus content of the phosphogypsum after sulfuric acid modified is less than 0.1% (phosphorus content can reach 0.01% under more excellent processing condition) and added CaO, Ca (OH)
2Or CaCO
3Wait and regulate the pH value, can make a small amount of solvable phosphorus of not cleaning fully in the washing and filtering process all change the Ca of indissoluble into
3(PO
4)
2The content of solvable phosphorus approaches 0, and the content of impurity such as F and organism is also lower after the modification, and phosphogypsum contains very little calcium sulfate dihydrate crystals after the modification, can improve the flowability of phosphogypsum, washability is also comparatively good, and its specific surface area is big, becomes active higher in the CaS process in reduction with carbon; Phosphorus content only plays the decomposition that mineralization can not cause C3S less than 0.1% pair of cement.
Therefore, the present invention also provides the purposes of above-mentioned phosphogypsum as cement raw material or additive simultaneously.
Modified ardealite is joined in the cement clinker as cement setting retarder, and the aquation by phosphogypsum forms the slow down aquation of the C3S in the cement of one deck coating, transfers the purpose of coagulating thereby reach slow setting.During the phosphogypsum system of utilization producing sulfuric acid and jointly cement, phosphogypsum is generated sulfurated lime under the reduction of carbon, make sulfurate calcium oxidation generate sulfurous gas and calcium oxide again, sulfurous gas is used to make sulfuric acid, and calcium oxide is used for producing cement clinker.Similar reaction principle, modified ardealite of the present invention can also be used to make the thiocarbamide jointly producing cement, can generate CaCO when phosphogypsum system thiocarbamide jointly producing cement
3, CaCO
3At high temperature resolve into calcium oxide, and calcium oxide can be used for preparing cement clinker.Therefore can satisfy phosphogypsum and make the requirement of producing cement clinker after the desulfurization such as producing sulfuric acid and jointly cement, also can satisfy phosphogypsum after sulfuric acid modified simultaneously as the requirement of cement setting retarder.Because the eutectic phosphorus content can reach below 0.05% in the phosphogypsum after handling according to modification of the present invention, final phosphorus content can reach below 0.1%, has overcome the drawback of utilizing phosphogypsum at present and being brought when being used to produce cement.
As one of characteristics of the present invention, after handling phosphogypsum, phosphorated sulfuric acid can also be got back to and be used to produce phosphoric acid in the production, and therefore the sulfuric acid modified method cost of phosphogypsum provided by the invention is low, method simple, it is few to produce waste water, can reclaim the phosphor resource in the phosphogypsum.
The employed equipment of sulfuric acid modified dephosphorizing method of phosphogypsum provided by the present invention is fairly simple, and can just wash solvable phosphorus off with less water, deviates from eutectic phosphorus effectively, and phosphorus can be reclaimed.
On the other hand, contain a certain amount of rare earth element in the phosphorus ore, in the process of utilizing this phosphorus ore to produce, there is the rare earth element of 50%-70% can enter in the phosphogypsum of producing, and rare earth element also be eutectic in phosphogypsum, therefore when phosphogypsum being carried out modification according to sulfuric acid modified method provided by the invention and handling, rare earth element also can be deviate from, enter into sulphuric acid soln, this helps the enrichment and the extraction of rare earth element.
Phosphogypsum foreign matter content after sulfuric acid modified seldom carries out recrystallization to it under proper condition and can obtain gypsum crystals such as purer αBan Shuishigao crystal, β semi-hydrated gypsum crystal.
In sum, the sulfuric acid modified method of phosphogypsum provided by the invention has the following advantages:
1, can effectively reduce the phosphorus content of eutectic phosphorus especially in the phosphogypsum, the phosphorus content of the modified ardealite of acquisition is reduced to below 0.1% (the two hydration butts);
2, can reduce the content of detrimental impurity such as phosphorus in the phosphogypsum, F, organism, metal ion, and can reclaim phosphor resource and rare earth element in the phosphogypsum as far as possible, help the phosphogypsum comprehensive utilization in every respect and the innoxious discharging of phosphogypsum;
3, the sulphuric acid soln after modification is handled can turn back in the phosphoric acid production and be reused, and does not produce or only produce a small amount of waste water;
4, than other method of modifying, method conditions needed of the present invention relatively relaxes, and need not High Temperature High Pressure, and energy consumption is low, and cost is low, and treatment capacity is big, is suitable for industrial application;
5, according to different needs, can control reaction conditions, obtain the different phosphogypsum of phosphorus content, make it can replace the plaster of paris to be applied in the production of cement, gypsum building material product, for example make producing sulfuric acid and jointly cement or phosphogypsum system thiocarbamide jointly producing cement as cement setting retarder in the manufacture of cement and phosphogypsum, and the production of gypsum crystals such as αBan Shuishigao, β semi-hydrated gypsum.
Description of drawings
Fig. 1 is the biomicroscope image of the crystalline structure of untreated phosphogypsum (phosphorus content 0.69%).
Fig. 2 is the biomicroscope image of the crystalline structure of the phosphogypsum (phosphorus content 0.54%) of the sulfuric acid modified processing of process.
Fig. 3 is the biomicroscope image of the crystalline structure of the phosphogypsum (phosphorus content 0.33%) of the sulfuric acid modified processing of process.
Fig. 4 is the biomicroscope image of the crystalline structure of the phosphogypsum (phosphorus content 0.06%) of the sulfuric acid modified processing of process.
Fig. 5 is the biomicroscope image of the crystalline structure of the phosphogypsum (phosphorus content 0.02%) of the sulfuric acid modified processing of process.
The graphic representation of the influence of the phosphorus content of the phosphogypsum of Fig. 6 after to be the sulfuric acid volume fraction to modification handle.
The graphic representation of the influence of the phosphorus content of the phosphogypsum of Fig. 7 after to be temperature to modification handle.
The graphic representation of the influence of the phosphorus content of the phosphogypsum of Fig. 8 after to be solid-to-liquid ratio to modification handle.
The graphic representation of the influence of the phosphorus content of the phosphogypsum of Fig. 9 after to be the reaction times to modification handle.
Embodiment
Below describe the enforcement of technical solution of the present invention and the beneficial effect that is had in detail by specific embodiment, but but can not form any qualification to practical range of the present invention.
Embodiment 1:
Be that 50% sulfuric acid mixes with phosphogypsum raw material (phosphorus content 0.67%) by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 80 ℃ temperature of reaction; With reacted phosphogypsum washing, filter, filter residue is through CaCO
3Neutralizing treatment obtains the phosphogypsum after the modification.
The phosphorus content of the phosphogypsum after the modification detects, and concrete grammar is as follows:
1, with the phosphogypsum after the modification in loft drier with about about 65 ℃ Heating temperature drying treatment 4h, wherein, about the thick 2cm of phosphogypsum material, make butt phosphogypsum sample;
2, take by weighing butt phosphogypsum sample 10g (being accurate to 0.0001) after the modification, put into the 250mL beaker, add 30mL HNO
3(the nitric acid mass concentration is about 65-68%, be commercially available analytical pure nitric acid) and 10mL HCl (HCl is commercially available analytical pure hydrochloric acid, mass concentration is about 36%-38%), slowly be heated to boiling (boiling kept about 45 minutes), be cooled to room temperature, move in the 250mL volumetric flask, be diluted with water to scale, filter, draw in the 250mL beaker that filtrate 25mL joins nitric acid that 10mL volume ratio 1:1 is housed (the commercially available analytical pure nitric acid that is about to mass concentration and is 65%-68% and distilled water 1:1 by volume mix the nitric acid that obtains) and 65mL water, be heated to boiling, adding quinoline molybdenum lemon paulownia reagent 35mL again boils 1min and makes phosphorus precipitation, be cooled to room temperature then, filter with No. 4 husky core glass crucibles, to neutral (utilizing the pH test paper to detect at any time in the washing process), the baking oven taking-up cooling in dry 45 minutes of putting into then about 180 ℃ is weighed with the throw out washing.
3, calculate insoluble P in the phosphogypsum sample according to following formula
2O
5Mass percent (
):
Wherein, G
1: dried throw out quality (g); G: the quality (g) of the butt phosphogypsum sample that takes by weighing; The meaning of "/% " is meant that the result is a percentage ratio, promptly is converted to equal sign the right and is " * % ".The phosphorus content of unmodified phosphogypsum also can be measured with reference to aforesaid method.
Calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.02%, P
2O
5Extrusion rate is about 97.01%.P
2O
5Extrusion rate=(phosphorus content of the phosphorus content of phosphogypsum/unmodified phosphogypsum after 1-modification) * 100%.
Employed quinoline molybdenum lemon paulownia reagent is the conventional reagent that is used to measure phosphorus content in this area in the embodiments of the invention; Quinoline molybdenum lemon paulownia reagent is added in the solution, if contain phosphorus in the solution, quinoline molybdenum lemon paulownia reagent will generate precipitation with phosphorus, just can be by weighting method (be among the embodiment 1 in the phosphogypsum after the detection modification method of phosphorus content) mensuration phosphorus content.Quinoline molybdenum lemon paulownia reagent is that those skilled in the art are available, also can adopt the method that is prepared as follows to obtain: solution A: the 70g Sodium orthomolybdate is dissolved in the 100mL water; Solution B: 60g citric acid (solid) is dissolved in the 100mL water, adds 85mL nitric acid (the nitric acid mass concentration is about 65-68%, promptly commercially available analytical pure nitric acid); Solution C: solution A is added in the solution B mixing; Solution D: 35mL nitric acid and 100mL water are mixed, and add the 5mL quinoline; Solution E: solution D is added in the solution C, and mixing leaves standstill a night, uses filter paper filtering, adds 280mL acetone in filtrate, and water is diluted to 1000mL with mixed solution.Solution E is quinoline molybdenum lemon paulownia reagent, and it is stored in the polyethylene bottle, is put in the dark place, the lucifuge preservation of being Protected from Heat.
Embodiment 2:
Be that 30% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 60 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.02%, P
2O
5Extrusion rate is about 97.01%.
Embodiment 3:
Be that 30% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 80 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.01%, P
2O
5Extrusion rate is about 98.55%.
Embodiment 4:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:4 with volume fraction, reaction is 1.5 hours under 40 ℃ temperature of reaction; With reacted phosphogypsum washing, filter, filter residue is through CaCO
3Neutralizing treatment obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.03%, P
2O
5Extrusion rate is about 95.88%.
Embodiment 5:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:6 with volume fraction, reaction is 1.5 hours under 40 ℃ temperature of reaction; With reacted phosphogypsum washing, filter, filter residue is through Ca (OH)
2Neutralizing treatment obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.02%, P
2O
5Extrusion rate is about 97.01%.
Embodiment 6:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:4 with volume fraction, reaction is 2 hours under 40 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.03%, P
2O
5Extrusion rate is about 95.88%.
Embodiment 7:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:4 with volume fraction, reaction is 4 hours under 40 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.01%, P
2O
5Extrusion rate is about 98.55%.
Embodiment 8:
Be that 20% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 20 ℃ temperature of reaction; With reacted phosphogypsum washing, filter, filter residue is through CaCO
3Neutralizing treatment obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.54%.
Embodiment 9:
Be that 30% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 20 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.33%.
Embodiment 10:
Be that 40% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 20 ℃ temperature of reaction; With reacted phosphogypsum washing, filter, filter residue is through CaCO
3Neutralizing treatment obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.06%.
Embodiment 11:
Be that 50% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 20 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.02%.
Embodiment 12:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1.5 hours under 40 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.13%, P
2O
5Extrusion rate is about 81.16%.
Embodiment 13:
Be that 35% sulfuric acid mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:2 with volume fraction, reaction is 1 hour under 40 ℃ temperature of reaction; With the washing of reacted phosphogypsum, filter, filter residue is through the CaO neutralizing treatment, obtains the phosphogypsum after the modification.
Detect the phosphorus content (detection method is with embodiment 1) of the phosphogypsum after the modification, calculate insoluble P in the phosphogypsum after the modification
2O
5Mass percent be about 0.20%, P
2O
5Extrusion rate is about 71.01%.
Parameter to modification after the influence experiment of phosphorus content in the phosphogypsum
The dephosphorization effect of sulfuric acid modified phosphogypsum is subjected to multiple parameter and factor affecting.In experimentation, in order to guarantee the repeatability of experimental result, the contriver selects H
2SO
4Volume fraction, temperature of reaction, solid-to-liquid ratio and reaction times four parameters experimentize as single factor method research object, but do not do orthogonal experiment and find out optimized parameter, the phosphogypsum quality difference of each plant produced in actual production, the different purposes of phosphogypsum are also inequality for the requirement of phosphorus content.Those skilled in the art select suitable parameters voluntarily according to the difference of phosphogypsum raw material and the difference of the purposes after the modification, make the different phosphogypsum product of phosphorus content and can realize.
Following experimental data also can be considered specific embodiments of the invention, experimental data within acceptable scope of that but those skilled in the art obtains according to following experiment condition, error (as the phosphorus content measured etc.), do not influence the accuracy of this experiment, but can not be interpreted as any restriction that the practical range of technical solution of the present invention is done.Test used phosphogypsum sample and pick up from Guizhou Xiyang Fertilizer Industry Co., Ltd., the sample obtain manner is for taking at random.
1, change the sulfuric acid volume fraction, 20 ℃ of fixation reaction temperature, reaction times 1.5h, solid-to-liquid ratio are 1:2, and concrete experimental data and test-results are as shown in table 1, and the phosphorus content curve after the modification that is obtained in the phosphogypsum as shown in Figure 6.As seen from Figure 6, reducing rapidly appears in sulfuric acid volume fraction curve when 25%-45%.Find the sulfuric acid volume fraction less than 25% o'clock by microscopic examination, the phosphogypsum crystal after the modification changes little, is platelike crystal or contains a small amount of needle-like crystal and tiny platelike crystal (as depicted in figs. 1 and 2).The sulfuric acid volume fraction increases (as shown in Figure 3 and Figure 4) gradually greater than needle-like crystal and tiny platelike crystal in the phosphogypsum crystal of modification in 25% o'clock, when the sulfuric acid volume fraction reached 50%, the phosphogypsum crystal after the modification became indefinite form (as shown in Figure 5) entirely.Because sulfuric acid destroyed the phosphogypsum crystal, allow eutectic phosphorus in the phosphogypsum be exposed in a large amount of sulphuric acid environment and make SO
4 2-Can displace the eutectic phosphorus in the phosphogypsum, thereby reach the purpose of dephosphorization.The sulfuric acid volume fraction may be that sulfuric acid reaction falls calcium phosphate precipitation in the phosphogypsum and the eutectic phosphorus of phosphogypsum plane of crystal is being deviate to cause in a large amount of sulphuric acid environment gradually less than the slow decline of curve that occurred in 25% o'clock.
Table 1, H
2SO
4The influence of phosphorus content in the phosphogypsum of volume fraction after to modification
| H 2SO 4Volume fraction | 0％ | 10％ | 20％ | 30％ | 40％ | 50％ |
| P 2O 5Percentage composition/% | 0.69 | 0.58 | 0.54 | 0.33 | 0.06 | 0.02 |
| P 2O 5Extrusion rate/% | 0.0 | 15.94 | 21.73 | 52.17 | 91.03 | 97.01 |
Annotate: 20 ℃ of fixation reaction temperature, reaction times 1.5h, solid-to-liquid ratio 1:2
2, change temperature, fixation response time, solid-to-liquid ratio, sulfuric acid volume fraction, concrete experimental data and experimental result are as shown in table 2.Experimental phenomena is similar with changing the sulfuric acid volume fraction, and with the rising of temperature, the phosphorus content in the phosphogypsum after the modification reduces gradually, the rapid reduction (as shown in Figure 7) of phosphorus content also can occur in a certain temperature range.The phosphogypsum crystal changes too, and the low more crystal of phosphorus content is more little to level off to indefinite form more.
The influence of phosphorus content in table 2, the temperature of reaction phosphogypsum after to modification
| |
40 |
50 |
60℃ | 70℃ | 80℃ | 90℃ |
| P 2O 5Percentage composition/% | 0.31 | 0.06 | 0.02 | 0.01 | 0.01 | 0.01 |
| P 2O 5Extrusion rate/% | 55.07 | 91.30 | 97.01 | 98.55 | 98.55 | 98.55 |
Annotate: fixedly sulfuric acid concentration 30%, reaction times 1.5h, solid-to-liquid ratio 1:2
3, change solid-to-liquid ratio, fixation response time, temperature of reaction, sulfuric acid volume fraction, concrete experimental data and experimental result are as shown in table 3.Solid-to-liquid ratio is accessory to the influential effect of dephosphorization, but with the increase of vitriolic amount, the phosphorus content of phosphogypsum can reduce (as shown in Figure 8) gradually.Increase the vitriolic amount phosphogypsum can be contacted with sulfuric acid more fully, fast reaction speed reduces the reaction times.
The influence of phosphorus content in table 3, the solid-to-liquid ratio phosphogypsum after to modification
| Solid-to-liquid ratio | 1：1 | 1：2 | 1：3 | 1：4 | 1：5 | 1：6 | 1：7 | 1：8 |
| P 2O 5Percentage composition/% | 0.26 | 0.13 | 0.06 | 0.03 | 0.02 | 0.02 | 0.02 | 0.01 |
| P 2O 5Extrusion rate/% | 62.32 | 81.16 | 91.30 | 95.88 | 97.01 | 97.01 | 97.01 | 98.55 |
Annotate: fixedly sulfuric acid concentration 35%, reaction times 1.5h, temperature of reaction are 40 ℃
4, change the reaction times, fixedly solid-to-liquid ratio, sulfuric acid volume fraction, temperature of reaction, specifically experimental data and experimental result are as shown in table 4.The influential effect of reaction times to dephosphorization also is accessory, and along with the increase in reaction times, the phosphorus content of phosphogypsum also can reduce (as shown in Figure 9) gradually.Increase the reaction times and also be in order to allow the phosphogypsum can be fully and sulfuric acid reaction, reach best dephosphorization effect.
The influence of phosphorus content in table 4, the reaction times phosphogypsum after to modification
| Time/h | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 |
| P 2O 5Percentage composition/% | 0.39 | 0.20 | 0.12 | 0.03 | 0.02 | 0.02 | 0.02 | 0.01 |
| P 2O 5Extrusion rate/% | 43.48 | 71.01 | 82.61 | 95.88 | 97.01 | 97.01 | 97.01 | 98.55 |
Annotate: fixedly sulfuric acid concentration 35%, solid-to-liquid ratio 1:2, temperature of reaction are 40 ℃
The dephosphorization effect of sulfuric acid modified phosphogypsum mainly is subjected to H
2SO
4Volume fraction, temperature of reaction, solid-to-liquid ratio and reaction times four factor affecting, stirring intensity also has certain influence but influences less.The dephosphorization effect of sulfuric acid modified phosphogypsum can be with H
2SO
4The increase in volume fraction, temperature of reaction, solid-to-liquid ratio and reaction times and respective change, the dephosphorization rate maximum can reach more than 98%.H wherein
2SO
4The phosphorus content of volume fraction, the temperature of reaction phosphogypsum after to modification has the greatest impact, and the phosphorus content that can occur phosphogypsum when reaching certain condition sharply reduces.The cardinal principle of technical scheme of the present invention is exactly under a large amount of sulphuric acid environment, makes SO
4 2-Displace the eutectic phosphorus in the phosphogypsum, make eutectic phosphorus deviate to enter in the sulphuric acid soln; Increase sulfuric acid with sulfuric acid concentration is also good more to the crystal damage effect of phosphogypsum, and the eutectic phosphorus in the phosphogypsum crystal is exposed in the sulphuric acid environment.Therefore, in this reaction process, when sulfuric acid concentration was big, it is many more that the eutectic phosphorus in the phosphogypsum is deviate from, and the phosphorus content of the phosphogypsum that the reaction back obtains is low more; When under being reflected at comparatively high temps, carrying out, the deviating from of eutectic phosphorus also than good under the lesser temps.Solid-to-liquid ratio and reaction times are similar to the influence of dephosphorization effect, work as H
2SO
4Volume fraction, temperature of reaction are when felicity condition, and downcurve preferably can appear in the influence of the phosphorus content of the phosphogypsum of solid-to-liquid ratio after to modification, the phosphorus content of phosphogypsum descend very fast (as Fig. 8 and shown in Figure 9); Work as H
2SO
4When volume fraction, temperature of reaction were all low, the phosphorus content of phosphogypsum was also slower with the decline of the variation (for example tapering to 1:6 by 1:0.5) of solid-to-liquid ratio and reaction times prolongation.The vitriolic amount that in fact change of solid-to-liquid ratio changes is in the reaction process to be added, and also there is bigger relation in the reaction times with sulfuric acid volume fraction and temperature of reaction is therefore in conjunction with experiment of single factor H as can be known
2SO
4Volume fraction and temperature of reaction are to influence the principal element that eutectic phosphorus is deviate from effect, and the solid-to-liquid ratio of phosphogypsum and sulphuric acid soln and reaction times are secondary cause, and in addition, high-intensity stirring also can help sulfuric acid to destroy CaSO
42H
2The crystal of O, and reach the effect that promotes dephosphorization, but its role should belong to complementary effect, can not produce substantial effect to treatment effect.
In sum, the sulfuric acid modified method of phosphogypsum provided by the present invention is applicable to that any phosphogypsum that contains eutectic phosphorus is carried out modification to be handled, and phosphorus content can be reduced to about 0.01% in the product that obtains after the processing.Difference according to the purposes of phosphogypsum, can control the processing parameter of method of modifying of the present invention, obtain the phosphogypsum of different phosphate content, so that be applicable to and make different purposes such as producing sulfuric acid and jointly cement, thiocarbamide jointly producing cement and αBan Shuishigao crystal, β semi-hydrated gypsum crystal as cement setting retarder.
The above only is a better embodiment of the present invention, can not limit claim of the present invention with this.Have in the technical field under all and know that usually the knowledgeable complies with equivalence modification or variation that spirit of the present invention is done, all should be covered by in the claim scope of the present invention.
Claims (10)
1, a kind of sulfuric acid modified method of phosphogypsum, it may further comprise the steps:
Sulfuric acid is mixed with the phosphogypsum raw material, and reaction is 0.5-24 hour under 10-90 ℃ temperature of reaction;
Reaction product is carried out neutralizing treatment, obtain the phosphogypsum after the modification.
2, the method for claim 1, wherein this method may further comprise the steps:
The sulfuric acid that with volume fraction is 5%-98% mixes with the phosphogypsum raw material by solid-to-liquid ratio 1:0.5-1:6, and reaction is 0.5-12 hour under 10-90 ℃ temperature of reaction;
Reacted phosphogypsum is washed, filter;
Filter residue is carried out neutralizing treatment, obtain the phosphogypsum after the modification.
3, method as claimed in claim 2, wherein, described vitriolic volume fraction is 20-45%.
4, method as claimed in claim 1 or 2, wherein, described temperature of reaction is 20-70 ℃.
5, method as claimed in claim 1 or 2, wherein, the described reaction times is 1-4 hour.
6, method as claimed in claim 2, wherein, described solid-to-liquid ratio is 1: 1-1: 4.
7, method as claimed in claim 1 or 2, wherein, described phosphogypsum raw material comprises the phosphogypsum after handling without pretreated phosphogypsum, the phosphogypsum of drying treatment or ageing in advance.
8, method as claimed in claim 1 or 2, wherein, described neutralizing treatment adopts CaO, Ca (OH)
2Or CaCO
3Carry out.
9, a kind of modified ardealite, it is according to each described method of claim 1-8, by the phosphogypsum of sulfuric acid modified preparation.
10, the described modified ardealite of claim 9 is as the purposes of cement raw material or additive.
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| CN102381785A (en) * | 2011-10-20 | 2012-03-21 | 瓮福（集团）有限责任公司 | Method for recovering waste water containing phosphorus |
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| CN105859167A (en) * | 2015-01-21 | 2016-08-17 | 中国科学院过程工程研究所 | Method for preparing white and high-purity anhydrous calcium sulfate by phosphogypsum |
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| CN115477485A (en) * | 2022-09-06 | 2022-12-16 | 常州大学 | Method for preparing alpha-hemihydrate gypsum by using azo dye sulfuric acid wastewater |
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