WO2024051103A1 - Phosphogypsum recovery method - Google Patents

Phosphogypsum recovery method Download PDF

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Publication number
WO2024051103A1
WO2024051103A1 PCT/CN2023/077685 CN2023077685W WO2024051103A1 WO 2024051103 A1 WO2024051103 A1 WO 2024051103A1 CN 2023077685 W CN2023077685 W CN 2023077685W WO 2024051103 A1 WO2024051103 A1 WO 2024051103A1
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WIPO (PCT)
Prior art keywords
phosphogypsum
slurry
washing
acidolysis
tank
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PCT/CN2023/077685
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French (fr)
Chinese (zh)
Inventor
王浩
李长东
阮丁山
王威
郑海洋
丁代俊
Original Assignee
宜昌邦普循环科技有限公司
广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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Publication of WO2024051103A1 publication Critical patent/WO2024051103A1/en

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Classifications

    • 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
    • C04B11/266—Chemical gypsum
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • 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
    • C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B18/04—Waste materials; Refuse
    • C04B18/0445—Synthetic gypsum, e.g. phosphogypsum
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
    • C01P2006/65—Chroma (C*)
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

  • the invention belongs to the field of recycling, and specifically relates to a method for recycling phosphogypsum.
  • Phosphogypsum is the main by-product produced during the wet production of phosphoric acid. Its main component is calcium sulfate dihydrate. For every ton of phosphoric acid produced (calculated as P 2 O 5 ), approximately 4.5 to 5.5 tons of phosphogypsum by-products are produced. The composition of phosphogypsum is complex. In addition to calcium sulfate, there are also incompletely decomposed phosphate rock, phosphoric acid, silica, fluoride, metal cation precipitation, acid insoluble matter, organic matter remaining in the gypsum, etc. At present, the annual emission of phosphogypsum in my country is about 70 million tons, and the stock has exceeded 500 million tons. Therefore, the resource utilization of phosphogypsum has attracted much attention. Relevant reports show that the current comprehensive utilization rate of phosphogypsum resources is less than 30%, and large amounts of phosphogypsum are still stored in direct stacks.
  • phosphogypsum As phosphogypsum continues to accumulate, the storage capacity of the slag yard gradually shrinks. The accumulation of phosphogypsum not only occupies a large amount of land resources, but the soluble impurities in it seep through with rainwater, which will cause serious environmental pollution. Therefore, pretreatment of phosphogypsum to improve the quality and economic value of phosphogypsum is the key to solving the problem of phosphogypsum.
  • the current treatment methods for phosphogypsum include lime neutralization, water washing, flotation, flash burning, etc.
  • the cost of flotation equipment reagents is high and uneconomical; the flash burning method has a small processing capacity; the lime neutralization method can eliminate soluble phosphorus and fluorine elements, but the phosphorus element still remains in the gypsum, resulting in a waste of phosphorus resources.
  • the water washing method can effectively remove soluble impurities and recover some water-soluble phosphorus elements, but it is still unable to process insoluble phosphorus, which accounts for nearly twice as much as water-soluble phosphorus in phosphogypsum, and the proportion of water-soluble substances in phosphogypsum is low. , water washing and purification will not significantly increase the calcium sulfate dihydrate content.
  • one of the objects of the present invention is to provide a method for recovering phosphogypsum.
  • the second object of the present invention is to provide a kind of phosphogypsum.
  • the third object of the present invention is to provide an application of phosphogypsum in building materials.
  • the fourth object of the present invention is to provide a phosphogypsum recovery system.
  • a first aspect of the present invention provides a method for recovering phosphogypsum, which includes the following steps:
  • the carbonate is a soluble carbonate or a mixture of soluble carbonate and insoluble carbonate.
  • the soluble carbonate in the present invention can dissociate the calcium sulfate crystals in the phosphogypsum, thereby releasing the impurities contained in the calcium phosphate crystals and achieving the purpose of purifying the phosphogypsum.
  • the soluble carbonate is at least one of sodium carbonate and potassium carbonate.
  • the mass percentage of soluble carbonate is greater than 40%.
  • the insoluble carbonate is calcium carbonate.
  • the particle size of the calcium carbonate is no larger than 60 mesh.
  • the particles of calcium carbonate are larger than 60 mesh, calcium sulfate coating is likely to occur during the slow decomposition of calcium carbonate, resulting in incomplete reaction and affecting the purity of the final product.
  • the mass ratio of the phosphogypsum to the carbonate is (4-9):1; further preferably, the mass ratio of the phosphogypsum to the carbonate is (7-9):1.
  • the acid liquid used in the primary acidolysis step is at least one of nitric acid and sulfuric acid; further preferably, the acid liquid used in the primary acidolysis step is sulfuric acid.
  • the amount of sulfuric acid (calculated as pure sulfuric acid) is 18% to 22% of the mass of phosphogypsum.
  • the amount of sulfuric acid (calculated as pure sulfuric acid) is 6% to 8% of the mass of phosphogypsum.
  • the acid liquid used in the secondary acidolysis step is at least one of nitric acid and sulfuric acid; further preferably, the acid liquid used in the secondary acidolysis step is sulfuric acid.
  • the sulfuric acid added in the present invention has two destinations. One part reacts with calcium salt to form calcium sulfate precipitate and remains in the gypsum to improve the grade of gypsum. The remaining part returns to the phosphoric acid device with the lotion to reduce the sulfuric acid consumption of the phosphoric acid device.
  • the sulfuric acid is sulfuric acid with a mass fraction of 30% to 50%; further preferably, the sulfuric acid is sulfuric acid with a mass fraction of 35% to 45%.
  • the temperature of the primary acid hydrolysis is 25 to 90°C.
  • the temperature of the secondary acidolysis is 65-85°C.
  • the second acidolysis time is 1 to 2 hours.
  • the step of mixing phosphogypsum and carbonate for primary acidolysis is as follows: mixing phosphogypsum, carbonate and water to prepare slurry A, and then passing acid liquid from the bottom of slurry A and stirring to obtain slurry A containing Foam slurry; further preferably, the step of mixing phosphogypsum and carbonate for primary acidolysis is specifically: mixing phosphogypsum, carbonate and water to prepare slurry A, and then passing the acid solution from the bottom of slurry A And stir, the acid solution addition time is 15 to 50 minutes, and a foam-containing slurry is obtained.
  • the generated carbon dioxide gas can be hydraulically cut into fine particles to obtain Foamy slurry.
  • the acidolysis of the residual phosphate rock and the decomposition of the carbonate are carried out simultaneously, and carbon dioxide gas is generated.
  • the carbon dioxide gas is cut by hydraulic power (vigorous stirring) to generate fine foam, and the generated fine foam is mixed with the The reaction slurry is fully contacted and collides or adheres to separate the organic impurities from the phosphogypsum.
  • the stirring rate is 300-1000r/min; further preferably, the stirring rate is 300-600r/min; Still further preferably, the stirring rate is 300-500r/min; more preferably, the stirring rate is 350-500r/min.
  • the solid content of the slurry A is 30% to 50%.
  • the temperature of the slurry A is 25 to 90°C.
  • the recovery method further includes the step of letting the primary acid hydrolysis product stand. During the standing process, the primary acid hydrolysis product will separate into layers, with the upper layer being scum containing organic matter.
  • the step of removing the scum is as follows: using a scraper to scrape off the scum layer, and then filtering the scum layer.
  • the solid obtained by the filtration is decolorized residue, and the liquid obtained by the filtration is recovered for use in phosphogypsum. and carbonate to prepare slurry A.
  • the washing adopts a countercurrent washing method.
  • the countercurrent washing has a level of 3 to 5; further preferably, the countercurrent washing has a level of 4.
  • the discharge liquid of the next stage of counter-current washing is used as the washing liquid of the previous stage of counter-current washing.
  • the filter press step specifically includes: transporting the liquid obtained in the filter press step to the phosphoric acid production workshop as a raw material for phosphoric acid production, and preparing the solid obtained in the filter press step into slurry B and then filtering.
  • the solid content of the slurry B is 30% to 50%.
  • a second aspect of the present invention provides a phosphogypsum, which is produced by the method provided by the first aspect of the present invention.
  • the water-soluble phosphorus content in the phosphogypsum is not higher than 0.02%; further preferably, the water-soluble phosphorus content in the phosphogypsum is not higher than 0.016%.
  • the total phosphorus content in the phosphogypsum is not higher than 0.2%; further preferably, the total phosphorus content in the phosphogypsum is not higher than 0.14%.
  • the fluorine content in the phosphogypsum is not higher than 0.04%; further preferably, the fluorine content in the phosphogypsum is not higher than 0.018%.
  • the magnesium content in the phosphogypsum is not higher than 0.02%; further preferably, the magnesium content in the phosphogypsum is not higher than 0.009%.
  • the sodium content in the phosphogypsum is not higher than 0.04%; further preferably, the sodium content in the phosphogypsum is not higher than 0.019%.
  • the iron content in the phosphogypsum is not higher than 0.06%; further preferably, the iron content in the phosphogypsum is not higher than 0.04%.
  • the potassium content in the phosphogypsum is not higher than 0.04%; further preferably, the potassium content in the phosphogypsum is not higher than 0.025%.
  • the aluminum content in the phosphogypsum is not higher than 0.03%; further preferably, the aluminum content in the phosphogypsum Not higher than 0.01%.
  • the whiteness of the phosphogypsum is 70-90; further preferably, the whiteness of the phosphogypsum is 77-90; still more preferably, the whiteness of the phosphogypsum is 77-80.
  • the organic carbon content in the phosphogypsum is not higher than 0.03%; further preferably, the organic carbon content in the phosphogypsum is not higher than 0.014%.
  • a third aspect of the invention provides an application of phosphogypsum in building materials.
  • the building material is building plaster.
  • a fourth aspect of the present invention provides a phosphogypsum recovery system.
  • the recovery system is used to implement the phosphogypsum recovery method provided by the first aspect of the present invention.
  • the recovery system includes an acidolysis device, a square tank, Formation tank, filtration system and counter-current washing device.
  • the bottom of the acidolysis device is provided with a first acid liquid inlet.
  • the acidolysis device is connected to a square tank.
  • a scraper is provided on the square tank.
  • the square tank is connected to the formation tank.
  • the formation tank is provided with a second acid liquid inlet, the formation tank is connected to the filtration system, and the solid outlet of the filtration system is connected to the countercurrent washing device.
  • Phosphogypsum and carbonate are mixed and acidolyzed once in the acidolysis device, and then transported to a square tank.
  • the scum is removed by a scraper on the square tank, and then a second acidolysis is performed in the formation tank.
  • Purified phosphogypsum is obtained after pressure filtration through a filtration device and washing through a countercurrent washing device.
  • the mixture of phosphogypsum and carbonate in the present invention is transported to the acidolysis device after slurrying, and then the acid liquid is introduced from the first acid liquid inlet at the bottom of the acidolysis device, thereby realizing primary acidification in the acidolysis device.
  • Decomposition the product after one acidolysis is transported to a square tank, and left to stratify in the square tank.
  • the top of the square tank is a scum layer containing organic matter
  • the bottom of the square tank is the phosphogypsum slurry after one acidolysis.
  • the scraper machine on the tank scrapes off the scum layer, and the slurry after scraping off the scum is transported from the bottom of the square tank to the formation tank, and the acid liquid is introduced into the formation tank through the second acid inlet on the formation tank. , perform secondary acidolysis in the formation tank, and the product after the secondary acidolysis is passed into the filtration system for filtration, and then the solids filtered by the filtration system are washed countercurrently using a countercurrent washing device.
  • the first acid liquid inlet is connected to an acid liquid storage device.
  • the second acid liquid inlet is connected to an acid liquid storage device.
  • the filtration system includes a filter press device, a slurry adjusting device and a filtering device.
  • the filter press device is connected to the formation tank, the liquid outlet of the filter press device is connected to the phosphoric acid production system, and the solid outlet of the filter press device is connected to the conditioning tank.
  • the slurry device is connected, the slurry adjusting device is connected with the filter device, and the solid outlet of the filter device is connected with the countercurrent washing device.
  • the secondary acid hydrolysis product in the formation tank is transported to the filter press device for filtering.
  • the liquid after filtering by the filter press device is transported to the phosphoric acid production system through the liquid outlet to recover the phosphorus component in the phosphogypsum.
  • the phosphorus component is recovered It can then be used to produce phosphoric acid.
  • the solids after filtering by the filter press device are transported to the slurry adjustment device through the solid outlet on the filter press device for slurry adjustment. After the slurry is adjusted, the slurry is transported to the filter device for filtration. The solids filtered by the filter device are washed by the countercurrent washing device.
  • the recovery system further includes a pulp mixer, and the pulp mixer is connected to the acidolysis device.
  • the slurry mixing machine is used to slurry the mixture of phosphogypsum and carbonate.
  • the pulp mixer is connected to the liquid outlet of the filter device.
  • the liquid filtered by the filtration device is transported to the pulp mixing machine to be used as liquid for pulp mixing.
  • the pulp mixer is connected to a water source.
  • the filter device is a belt filter device.
  • the pulp adjusting device is connected to a water source.
  • the square tank is connected to a filter press, and the liquid outlet of the filter press is connected to a pulp mixer.
  • the scraper on the square tank scrapes the scum layer into the filter press for filtering.
  • the liquid when filtered by the filter press is transported to the pulp mixer through the discharge port of the filter press to be used as liquid for pulp mixing.
  • the solid produced by the filter press is decolorized residue.
  • the counter-current washing device has a washing level of 3 to 6 levels; further preferably, the counter-current washing device has a washing level of 4 levels.
  • the countercurrent washing device includes a first-level countercurrent washing area, a second-level countercurrent washing area, a third-level countercurrent washing area and a fourth-level countercurrent washing area.
  • the washing liquid inlet of the first-level counter-current washing zone is connected to the liquid outlet and the water source of the second-level counter-current washing zone respectively.
  • the liquid discharge port of the first-level countercurrent washing zone is connected to the pulp adjusting device.
  • the washing liquid inlet of the second-level counter-current washing zone is connected to the liquid outlet and the water source of the third-level counter-current washing zone respectively.
  • the washing liquid inlet of the third-stage counter-current washing zone is connected to the liquid outlet and the water source of the fourth-stage counter-current washing zone respectively.
  • the washing liquid inlet of the four-stage countercurrent washing zone is connected to a water source.
  • the water source is a process water source.
  • the beneficial effects of the present invention are: after the phosphogypsum recovery method in the present invention recovers the phosphogypsum, the contents of various impurities in the phosphogypsum are significantly reduced compared with before treatment, and the soluble phosphorus of the phosphogypsum is reduced. to less than 0.016%, the total phosphorus dropped to about 0.1%, the pH of the gypsum leachate increased from 1 to 2 to 6 to 7, the gypsum leachate can be discharged directly without treatment, and the contents of Mg, Na, Fe, K, Al and organic carbon were all the same. It has been greatly reduced. The whiteness of gypsum has increased from 22.71 to about 78.
  • the degree of purification of gypsum is much higher than that of conventional washing and acid hydrolysis processes.
  • the quality index of the treated phosphogypsum is better than the relevant requirements of the building gypsum powder standard. It can be Directly used as building plaster.
  • the recovery method in the present invention can realize the recovery of phosphorus in phosphogypsum, and the recovered phosphorus components are directly transported to the phosphoric acid production workshop for use in the production of phosphoric acid.
  • the waste liquid produced by filtration, washing and filter pressing in this recycling method can be recycled and reused, which improves the utilization rate of raw materials, reduces the treatment cost of waste liquid, and saves production costs.
  • the recycling system in the present invention has a high degree of automation, low labor intensity, simple equipment, low equipment cost, and easy maintenance. Automatic recycling of phosphogypsum can be realized, and the waste liquid during the recycling process can be directly recycled, resulting in high raw material utilization.
  • Figure 1 is a schematic flow chart of the recovery method of phosphogypsum in Examples 1 to 4 of the present invention.
  • Figure 2 is a schematic structural diagram of the recovery system in Embodiment 6 of the present invention.
  • Figure 3 is a schematic structural diagram of a countercurrent washing device in Embodiment 6 of the present invention.
  • Examples 1 to 4 to determine the component content of purified phosphogypsum are the quinoline phosphomolybdate gravimetric method, ICP-MS and the test method described in Q/520122K-002-2020.
  • This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the phosphogypsum is 0.4986%, and the total phosphorus It is 1.524%, and the pH of the leach solution is between 1 and 2;
  • step (6) The upper layer of scum scraped off in step (5) is sent to a filter press for filtering.
  • the filter cake is decolorized residue.
  • the filtrate is recovered and transported to step (2) for preparing slurry A;
  • step 10 Filter the slurry obtained in step (9).
  • the filtered filtrate can be recovered and transported to step (2) to prepare slurry A.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (10) the filtrate of the last level of washing during the 4-level countercurrent washing is used as the washing liquid in the previous level of washing.
  • the washing liquid of the last level of washing is process water.
  • the temperature and dosage of the process water are the same as those in the steps of this embodiment ((10)).
  • the process water in 2) is the same.
  • the final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
  • the water-soluble phosphorus in the purified gypsum is 0.0136%
  • the total phosphorus is 0.1142%
  • the water-soluble fluorine is 0.0167%
  • the free water content is 23.14%, dried at 45°C
  • the resulting gypsum is white powder with a whiteness of 78.92.
  • This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
  • step (6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration.
  • the filtrate after the filtration is recovered and processed and sent to step (2) for preparing slurry A;
  • step (5) The slurry after defoaming in step (5) is moved into the formation tank, and the diluent prepared in step (3) is added to the formation tank again.
  • Sulfuric acid the amount of dilute sulfuric acid added is 150kg;
  • step 10 Filter the slurry obtained in step (9).
  • the filtered filtrate can be recovered and transported to step (2) to prepare slurry A.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (10) the filtrate produced by the last level of washing during countercurrent washing is used as the washing liquid of the previous level of washing.
  • the washing liquid of the last level of washing is process water.
  • the temperature, composition and dosage of the process water are the same as those in the steps of this embodiment ( The process water in 2) is the same.
  • the final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
  • the water-soluble phosphorus in the purified gypsum is 0.0124%
  • the total phosphorus is 0.0912%
  • the water-soluble fluorine content is 0.0142%
  • the free water is 22.34%, dried at 45°C
  • the resulting gypsum is white powder with a whiteness of 78.31.
  • This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
  • step (6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration.
  • the filtrate after the filtration is recovered and processed and transported to step (2) for adjustment to slurry A;
  • step (7) Move the defoamed slurry in step (5) into the formation tank, and add the slurry prepared in step (3) to the formation tank again.
  • Dilute sulfuric acid the added amount of dilute sulfuric acid is 120kg;
  • step 10 Filter the slurry obtained in step (9).
  • the filtered filtrate can be recovered and transported to step (2) to prepare slurry A.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (10) the filtrate produced by the last level of washing during countercurrent washing is used as the washing liquid of the previous level of washing.
  • the washing liquid of the last level of washing is process water.
  • the temperature, composition and dosage of the process water are the same as those in the steps of this embodiment ( 2) Same.
  • the final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
  • the water-soluble phosphorus in the purified gypsum is 0.01214%
  • the total phosphorus is 0.1045%
  • the water-soluble fluorine content is 0.0134%
  • the free water is 22.58%, dried at 45°C
  • the resulting gypsum is white powder with a whiteness of 78.12.
  • This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
  • step (6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration.
  • the filtrate after the filtration is recovered and processed and transported to step (2) for adjustment to slurry A;
  • step (5) The slurry after defoaming in step (5) is moved into the formation tank, and the diluent prepared in step (3) is added to the formation tank again.
  • Sulfuric acid the amount of dilute sulfuric acid added is 120kg;
  • step 10 Filter the slurry obtained in step (9).
  • the filtered filtrate can be recovered and transported to step (2) to prepare slurry A.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (10) the filtrate from the last stage of washing in the 4-stage countercurrent washing is used as the washing liquid of the previous stage of washing.
  • the washing liquid of the last stage of washing is process water.
  • the temperature, composition and dosage of the process water are the same as those in this embodiment. Same as step (2).
  • the final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
  • the water-soluble phosphorus in the purified gypsum is 0.0114%
  • the total phosphorus is 0.1113%
  • the water-soluble fluorine content is 0.0127%
  • the free water is 21.64%, dried at 45°C
  • the resulting gypsum is white powder with a whiteness of 79.24.
  • This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
  • process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
  • Acid decolorization Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 950kg, and the adding time is controlled at 35min;
  • the filtrate of the last stage of countercurrent washing in step (11) is used as the washing liquid of the previous stage of countercurrent washing.
  • the washing liquid of the last stage of countercurrent washing is process water.
  • the amount of process water is 5.5 tons. , the temperature is controlled at 70°C;
  • the fluorine and water in the 5 batches of phosphogypsum were The contents of dissolved P 2 O 5 , total P 2 O 5 , Mg, Na, Fe, K, Al and organic carbon were greatly reduced. Among them, the whiteness of phosphogypsum increased from 22.71 to about 78. The soluble phosphorus is reduced to less than 0.016%, the total phosphorus is reduced to about 0.1%, the pH of the gypsum leachate is increased from 1 to 2 to 6 to 7, and can be directly discharged. The degree of purification of gypsum is much higher than that of conventional water washing in the existing technology. And the acid hydrolysis process, the quality index of the treated phosphogypsum is better than the relevant requirements of the building gypsum powder standard, and can be directly used in building materials.
  • this embodiment provides a phosphogypsum recovery system.
  • the phosphogypsum recovery methods in Embodiments 1 to 5 of the present invention can all be recovered using the recovery system in this embodiment.
  • the phosphogypsum recovery system in this embodiment includes a pulp mixing machine, an acidolysis device, a square tank, a formation tank, a filter press device, a filter press, a pulp mixing device, a filtering device and a countercurrent washing device.
  • the pulp mixing machine is equipped with Solid raw material inlet and liquid inlet. Add phosphogypsum and carbonate through the solid raw material inlet of the pulp mixer.
  • the liquid inlet of the pulp mixer is connected to the water source, the drain port of the filter device, and the drain port of the filter press through pipelines respectively. connection, the slurry outlet of the pulp mixer is connected to the acidolysis device.
  • the bottom of the acidolysis device is provided with a first acid liquid inlet.
  • the first acid liquid inlet is connected to the sulfuric acid storage device through a pipeline.
  • the acidolysis device is connected to a square tank. On the square tank It is equipped with a scraper, the square trough is connected to the filter press, the liquid outlet of the filter press is connected to the pulp mixing machine, the square trough is connected to the forming tank, the forming tank is provided with a second acid liquid inlet, and the second acid
  • the liquid inlet is connected to the sulfuric acid storage device, the formation tank is connected to the filter press device, the liquid outlet of the filter press device is connected to the phosphoric acid production system, the solid outlet of the filter press device is connected to the slurry mixing device, and the slurry mixing device is connected to the water source and water source through pipelines.
  • the countercurrent washing device is connected, the pulp mixing device is connected with the belt filter device, the liquid outlet of the belt filter device is connected with the pulp mixing machine, and the solid outlet of the belt filter device is connected with the countercurrent washing device.
  • the number of washing levels of the countercurrent washing device in this embodiment is 4.
  • the countercurrent washing device includes a first-level countercurrent washing area, a second-level countercurrent washing area, a third-level countercurrent washing area and a fourth-level countercurrent washing area.
  • the first-level countercurrent washing area The washing liquid inlet is connected to the water source and the drain port of the secondary countercurrent washing area.
  • the drain port of the first-level countercurrent washing area is connected to the pulp mixing device.
  • the washing liquid inlet of the second-level counter-current washing zone is connected to the water source and the drain port of the third-level counter-current washing zone respectively; the washing liquid inlet of the third-level counter-current washing zone is connected to the water source and the drain port of the fourth-level counter-current washing zone respectively.
  • the washing liquid inlet of the four-stage counter-current washing zone is connected to the water source, and the washed solids in the four-stage counter-current washing zone are recovered phosphogypsum.
  • the slurry mixer When in use, first add phosphogypsum and carbonate and the sizing liquid into the slurry mixer for slurry mixing. After the slurry is mixed, the slurry is transported to the acidolysis device. Dilute sulfuric acid is introduced from the bottom of the acidolysis device and carried out once. After acidolysis reaction, the acidolysis product is then transported to a square tank and allowed to stand for stratification. The scraper on the square tank scrapes the scum layer into a filter press for filtering. The solid after filtering is decolorized residue. The liquid after filtering can be used in the pulp mixer to prepare phosphogypsum and carbonate slurry liquids.
  • the remaining slurry in the square tank is transported to the formation tank, and then sulfuric acid is added to the formation tank for a secondary acidolysis reaction.
  • the slurry is transported to the filter press device for filter press, and the liquid produced by the filter press is transported to Phosphoric acid production system is used to produce phosphoric acid, and the solids produced by filter press
  • the pulp is mixed through the pulp mixing device and then transported to the belt filter device for filtration.
  • the liquid used in the pulp mixing device comes from process water or the liquid discharged from the countercurrent washing device.
  • the liquid produced by the belt filter device is transported to the slurry mixer for use as liquid for slurry mixing.
  • the solid produced by the belt filter device is transported to the countercurrent washing device. After being washed by the countercurrent washing device, purified phosphogypsum is obtained.
  • the recovery method of phosphogypsum in this comparative example specifically includes the following steps:
  • This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
  • step (3) Place the material weighed in step (2) into a container, add 5.5 tons of process water and stir to form a uniform slurry.
  • the process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
  • Acid decolorization Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 1310kg, and the adding time is controlled at 35min;
  • step (7) The foamy liquid scraped out by the scraper in step (7) is sent to the filter press for filtration processing.
  • the filter cake is decolorized residue.
  • the filtrate after filtration is recovered and processed and sent to step (3) for use in seasoning slurry. ;
  • step 10 Filter the slurry A obtained in step (10).
  • the filtered filtrate can be recovered and transported to step (3) to prepare the slurry.
  • the filtered cake is subjected to 4-stage countercurrent washing to obtain purified phosphogypsum. ;
  • step (11) during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing.
  • the washing liquid in the first-level washing is process water, and the temperature, composition and dosage of the process water are the same as in step (3) of this comparative example.
  • the final filtrate from countercurrent washing in step (11) can be recovered and transported to step (10) to slurry the filter cake.
  • the components of the purified phosphogypsum obtained in this comparative example were analyzed.
  • the analysis results are shown in Table 2 below.
  • the analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 2 are based on the dry mass of purified phosphogypsum after removing free water.
  • Comparative Example 1 only performed one acidolysis step on phosphogypsum.
  • the content of water-soluble F, water-soluble P 2 O 5 , Mg, Na and other impurities in the recovered phosphogypsum are higher, it can be seen that the purity of the recovered phosphogypsum can be improved by using two acidolysis steps.
  • the recovery method of phosphogypsum in this comparative example specifically includes the following steps:
  • This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
  • step (6) Use a scraper to scrape off the upper black oily liquid in step (5) to separate the floating organic matter. Recover the oily liquid scraped off by the scraper and put activated carbon into it to absorb the organic matter. After the adsorption is completed, press the liquid Filter, and the obtained filter cake is decolorized residue. The filtrate after pressure filtration is recovered and processed and then transported to step (2) for use in seasoning slurry;
  • step (7) Perform pressure filtration on the complete slurry formed in step (7).
  • the filtrate recovered by the filtration pressure will be recycled and processed and sent to the phosphoric acid workshop as raw material for phosphoric acid production.
  • the filter cake after filtration is added with process water to make slurry.
  • the process water The temperature, composition and dosage are the same as step (2) of this comparative example to obtain slurry A;
  • step (8) Filter the slurry obtained in step (8).
  • the filtered filtrate can be recovered and transported to step (2) to prepare slurry A.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (9) during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing.
  • the washing liquid of the last stage of washing is process water.
  • the temperature, composition and dosage of the process water are the same as those in this comparative example. Same as step (2).
  • the final filtrate from countercurrent washing in step (9) can be recovered and transported to step (8) to slurry the filter cake.
  • the components of the purified phosphogypsum obtained in this comparative example were analyzed.
  • the analysis results are shown in Table 3 below.
  • the analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 3 are based on the dry mass of purified phosphogypsum after removing free water.
  • the recovery method of phosphogypsum in this comparative example specifically includes the following steps:
  • This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei province.
  • the phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
  • step (3) Place the material weighed in step (2) into a container, add 5.5 tons of process water and stir to form a uniform slurry.
  • the process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
  • Acid decolorization Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 950kg, and the adding time is controlled at 35min;
  • step (10) Filter the slurry obtained in step (10).
  • the filtered filtrate can be recovered and transported to step (3) to prepare the slurry.
  • the filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
  • step (11) during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing.
  • the washing liquid of the last stage of washing is process water.
  • the temperature, composition and dosage of the process water are the same as those in this comparative example.
  • Step (3) is the same.
  • the final filtrate from countercurrent washing in step (11) can be recovered and transported to step (10) to slurry the filter cake.
  • the components of the purified phosphogypsum obtained in this comparative example were analyzed.
  • the analysis results are shown in Table 4 below.
  • the analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 4 are based on the dry mass of purified phosphogypsum after removing free water.
  • Comparative Example 3 reduced the amount of soluble carbonate in carbonate when recovering phosphogypsum.
  • the water-soluble F, water-soluble P 2 O 5 , and water-soluble carbonate in the recovered phosphogypsum were The contents of impurities such as Mg and Na increased relatively, especially the total P 2 O 5 content increased significantly. It can be seen that when recovering phosphogypsum, adding carbonate in the first acidolysis step can significantly increase the recovered phosphorus.
  • the purity of gypsum reduces the impurity content of organic carbon, and when the content of soluble carbonate is greater than 40%, it is beneficial to release various impurities wrapped in phosphogypsum, making the recovered phosphogypsum higher in purity.

Abstract

Disclosed in the present invention is a phosphogypsum recovery method. The recovery method comprises the following steps: mixing phosphogypsum with carbonate for primary acidolysis, removing floating foam, performing secondary acidolysis, and then performing filter pressing and washing to obtain purified phosphogypsum. According to the phosphogypsum recovery method in the present invention, after recovery of phosphogypsum, performance indexes of the phosphogypsum are remarkably improved compared with those of the phosphogypsum before treatment, wherein the soluble phosphorus of the phosphogypsum is decreased to 0.016% or below, the total phosphorus is decreased to about 0.1%, the pH value of a gypsum leaching solution is increased from 1-2 to 6-7, the gypsum leaching solution can be directly discharged without treatment, the content of Mg, Na, Fe, K, Al and organic carbon is greatly reduced, the gypsum whiteness is increased from 22.71 to about 78, the purification degree of gypsum is far higher than that of conventional water washing and acidolysis processes, and the treated phosphogypsum has a quality index superior to the related requirements of building gypsum powder standards, and can be directly used as building gypsum.

Description

一种磷石膏的回收方法A kind of recycling method of phosphogypsum 技术领域Technical field
本发明属于回收领域，具体涉及一种磷石膏的回收方法。The invention belongs to the field of recycling, and specifically relates to a method for recycling phosphogypsum.
背景技术Background technique
磷石膏是采用湿法制取磷酸过程中产生的主要副产品，其主要成分为二水硫酸钙，每生产1吨磷酸(以P2O5计)产生约4.5～5.5吨磷石膏副产物。磷石膏的组成复杂，除含硫酸钙外，还有未完全分解的磷矿、残余在石膏中的磷酸、二氧化硅、氟化物、金属阳离子沉淀、酸不溶物、有机物等。目前我国磷石膏年排放量约7000万吨，存量已超过5亿吨，因此磷石膏的资源化利用问题备受重视。相关报道显示，当前磷石膏资源综合利用率不足30％，大量的磷石膏还是采取直接堆放的形式存放。Phosphogypsum is the main by-product produced during the wet production of phosphoric acid. Its main component is calcium sulfate dihydrate. For every ton of phosphoric acid produced (calculated as P 2 O 5 ), approximately 4.5 to 5.5 tons of phosphogypsum by-products are produced. The composition of phosphogypsum is complex. In addition to calcium sulfate, there are also incompletely decomposed phosphate rock, phosphoric acid, silica, fluoride, metal cation precipitation, acid insoluble matter, organic matter remaining in the gypsum, etc. At present, the annual emission of phosphogypsum in my country is about 70 million tons, and the stock has exceeded 500 million tons. Therefore, the resource utilization of phosphogypsum has attracted much attention. Relevant reports show that the current comprehensive utilization rate of phosphogypsum resources is less than 30%, and large amounts of phosphogypsum are still stored in direct stacks.
随着磷石膏不断累积，渣场库容逐渐缩小，磷石膏堆存不仅占用了大量的土地资源，其中可溶性的杂质随着雨水渗流，会造成严重的环境污染。因此对磷石膏进行预处理，提高磷石膏品质、提升其经济价值是解决磷石膏问题的关键。目前对磷石膏的处理方法有石灰中和法、水洗法、浮选法、闪烧法等。其中，浮选法设备试剂成本高，不经济；闪烧法处理量少；石灰中和法可以消除可溶磷、氟元素，但磷元素依旧留在石膏中，造成磷资源浪费。水洗法能够有效去除可溶性杂质，并能回收部分水溶性的磷元素，但是依旧无法处理磷石膏中占比超过水溶性磷近一倍的非水溶性磷，并且磷石膏中水溶性物质占比低，水洗净化对二水硫酸钙含量提升不大。As phosphogypsum continues to accumulate, the storage capacity of the slag yard gradually shrinks. The accumulation of phosphogypsum not only occupies a large amount of land resources, but the soluble impurities in it seep through with rainwater, which will cause serious environmental pollution. Therefore, pretreatment of phosphogypsum to improve the quality and economic value of phosphogypsum is the key to solving the problem of phosphogypsum. The current treatment methods for phosphogypsum include lime neutralization, water washing, flotation, flash burning, etc. Among them, the cost of flotation equipment reagents is high and uneconomical; the flash burning method has a small processing capacity; the lime neutralization method can eliminate soluble phosphorus and fluorine elements, but the phosphorus element still remains in the gypsum, resulting in a waste of phosphorus resources. The water washing method can effectively remove soluble impurities and recover some water-soluble phosphorus elements, but it is still unable to process insoluble phosphorus, which accounts for nearly twice as much as water-soluble phosphorus in phosphogypsum, and the proportion of water-soluble substances in phosphogypsum is low. , water washing and purification will not significantly increase the calcium sulfate dihydrate content.
发明内容Contents of the invention
为了克服上述现有技术存在的问题，本发明的目的之一在于提供一种磷石膏的回收方法。In order to overcome the above-mentioned problems in the prior art, one of the objects of the present invention is to provide a method for recovering phosphogypsum.
本发明的目的之二在于提供一种磷石膏。The second object of the present invention is to provide a kind of phosphogypsum.
本发明的目的之三在于提供一种磷石膏在建筑材料中的应用。The third object of the present invention is to provide an application of phosphogypsum in building materials.
本发明的目的之四在于提供一种磷石膏的回收***。The fourth object of the present invention is to provide a phosphogypsum recovery system.
为了实现上述目的，本发明所采取的技术方案是：In order to achieve the above objects, the technical solutions adopted by the present invention are:
本发明的第一个方面提供了一种磷石膏的回收方法，包括以下步骤：A first aspect of the present invention provides a method for recovering phosphogypsum, which includes the following steps:
将磷石膏与碳酸盐混合进行一次酸解，去除浮沫，再进行二次酸解，然后压滤并洗涤，得到纯化后的磷石膏。Mix phosphogypsum and carbonate for primary acidolysis to remove scum, then perform secondary acidolysis, and then filter and wash to obtain purified phosphogypsum.
优选地，所述碳酸盐为可溶性碳酸盐或由可溶性碳酸盐和不溶性碳酸盐混配而成。本发明中的可溶性碳酸盐可以解离磷石膏中的硫酸钙晶体，从而使磷酸钙晶体中包裹的杂质释放出来，实现纯化磷石膏的目的。 Preferably, the carbonate is a soluble carbonate or a mixture of soluble carbonate and insoluble carbonate. The soluble carbonate in the present invention can dissociate the calcium sulfate crystals in the phosphogypsum, thereby releasing the impurities contained in the calcium phosphate crystals and achieving the purpose of purifying the phosphogypsum.
优选地，所述可溶性碳酸盐为碳酸钠、碳酸钾中的至少一种。Preferably, the soluble carbonate is at least one of sodium carbonate and potassium carbonate.
优选地，以碳酸盐的总质量为基准，可溶性碳酸盐的质量百分数大于40％。Preferably, based on the total mass of carbonate, the mass percentage of soluble carbonate is greater than 40%.
优选地，所述不溶性碳酸盐为碳酸钙。Preferably, the insoluble carbonate is calcium carbonate.
优选地，所述碳酸钙的粒径不大于60目。当碳酸钙的颗粒大于60目时，碳酸钙在慢速分解过程中易出现硫酸钙包覆现象，导致反应进行不彻底，影响最终产品的纯度。Preferably, the particle size of the calcium carbonate is no larger than 60 mesh. When the particles of calcium carbonate are larger than 60 mesh, calcium sulfate coating is likely to occur during the slow decomposition of calcium carbonate, resulting in incomplete reaction and affecting the purity of the final product.
优选地，所述磷石膏与碳酸盐的质量比为(4～9)：1；进一步优选地，所述磷石膏与碳酸盐的质量比为(7～9)：1。Preferably, the mass ratio of the phosphogypsum to the carbonate is (4-9):1; further preferably, the mass ratio of the phosphogypsum to the carbonate is (7-9):1.
优选地，所述一次酸解步骤所用的酸液为硝酸、硫酸中的至少一种；进一步优选地，所述一次酸解步骤所用的酸液为硫酸。Preferably, the acid liquid used in the primary acidolysis step is at least one of nitric acid and sulfuric acid; further preferably, the acid liquid used in the primary acidolysis step is sulfuric acid.
优选地，所述一次酸解步骤中，硫酸(以纯硫酸计)的加入量为磷石膏质量的18％～22％。Preferably, in the first acidolysis step, the amount of sulfuric acid (calculated as pure sulfuric acid) is 18% to 22% of the mass of phosphogypsum.
优选地，所述二次酸解步骤中，硫酸(以纯硫酸计)的加入量为磷石膏质量的6％～8％。Preferably, in the secondary acidolysis step, the amount of sulfuric acid (calculated as pure sulfuric acid) is 6% to 8% of the mass of phosphogypsum.
优选地，所述二次酸解步骤所用的酸液为硝酸、硫酸中的至少一种；进一步优选地，所述二次酸解步骤所用的酸液为硫酸。Preferably, the acid liquid used in the secondary acidolysis step is at least one of nitric acid and sulfuric acid; further preferably, the acid liquid used in the secondary acidolysis step is sulfuric acid.
本发明添加的硫酸有两个去处，一部分与钙盐反应形成硫酸钙沉淀留在石膏中提升石膏的品级，剩余的随洗液一起回到磷酸装置，降低磷酸装置的硫酸消耗。The sulfuric acid added in the present invention has two destinations. One part reacts with calcium salt to form calcium sulfate precipitate and remains in the gypsum to improve the grade of gypsum. The remaining part returns to the phosphoric acid device with the lotion to reduce the sulfuric acid consumption of the phosphoric acid device.
优选地，所述硫酸为质量分数为30％～50％的硫酸；进一步优选地，所述硫酸为质量分数为35％～45％的硫酸。Preferably, the sulfuric acid is sulfuric acid with a mass fraction of 30% to 50%; further preferably, the sulfuric acid is sulfuric acid with a mass fraction of 35% to 45%.
优选地，所述一次酸解的温度为25～90℃。Preferably, the temperature of the primary acid hydrolysis is 25 to 90°C.
优选地，所述二次酸解的温度为65～85℃。Preferably, the temperature of the secondary acidolysis is 65-85°C.
优选地，所述二次酸解时间为1～2h。Preferably, the second acidolysis time is 1 to 2 hours.
优选地，所述将磷石膏与碳酸盐混合进行一次酸解步骤具体为：将磷石膏、碳酸盐和水混合制得浆液A，然后从浆液A底部通入酸液并搅拌，得到含沫料浆；进一步优选地，所述将磷石膏与碳酸盐混合进行一次酸解步骤具体为：将磷石膏、碳酸盐和水混合制得浆液A，然后从浆液A底部通入酸液并搅拌，酸液添加时间为15～50min，得到含沫料浆。从浆液A底部通入酸液并控制添加速率，可以避免酸液与碳酸盐剧烈反应使生成的二氧化碳大量逸出，此外，通过搅拌步骤可以使生成的二氧化碳气体被水力切割成细沫，得到含沫浆料。所述浆液A与稀硫酸充分反应的过程中残余磷矿的酸解与碳酸盐的分解同时进行，会生成二氧化碳气体，二氧化碳气体被水力(大力搅拌)切割生成细沫，生成的细沫与反应料浆充分接触并发生碰撞或粘附使有机物杂质从磷石膏上分离。Preferably, the step of mixing phosphogypsum and carbonate for primary acidolysis is as follows: mixing phosphogypsum, carbonate and water to prepare slurry A, and then passing acid liquid from the bottom of slurry A and stirring to obtain slurry A containing Foam slurry; further preferably, the step of mixing phosphogypsum and carbonate for primary acidolysis is specifically: mixing phosphogypsum, carbonate and water to prepare slurry A, and then passing the acid solution from the bottom of slurry A And stir, the acid solution addition time is 15 to 50 minutes, and a foam-containing slurry is obtained. Introducing the acid solution from the bottom of slurry A and controlling the addition rate can avoid the violent reaction between the acid solution and the carbonate, causing the generated carbon dioxide to escape in large quantities. In addition, through the stirring step, the generated carbon dioxide gas can be hydraulically cut into fine particles to obtain Foamy slurry. During the full reaction between the slurry A and dilute sulfuric acid, the acidolysis of the residual phosphate rock and the decomposition of the carbonate are carried out simultaneously, and carbon dioxide gas is generated. The carbon dioxide gas is cut by hydraulic power (vigorous stirring) to generate fine foam, and the generated fine foam is mixed with the The reaction slurry is fully contacted and collides or adheres to separate the organic impurities from the phosphogypsum.
优选地，所述搅拌速率为300～1000r/min；进一步优选地，所述搅拌速率为300～600r/min； 再进一步优选地，所述搅拌速率为300～500r/min；更优选地，所述搅拌速率为350～500r/min。Preferably, the stirring rate is 300-1000r/min; further preferably, the stirring rate is 300-600r/min; Still further preferably, the stirring rate is 300-500r/min; more preferably, the stirring rate is 350-500r/min.
优选地，所述浆液A的固含量为30％～50％。Preferably, the solid content of the slurry A is 30% to 50%.
优选地，所述浆液A的温度为25～90℃。Preferably, the temperature of the slurry A is 25 to 90°C.
优选地，所述回收方法还包括将一次酸解产物静置的步骤。在静置过程中，一次酸解产物会分层，上层为浮沫，浮沫中含有有机物。Preferably, the recovery method further includes the step of letting the primary acid hydrolysis product stand. During the standing process, the primary acid hydrolysis product will separate into layers, with the upper layer being scum containing organic matter.
优选地，所述去除浮沫的步骤具体为：采用刮板机将浮沫层刮除，然后将浮沫层进行压滤，压滤所得固体为脱色渣，压滤所得液体回收用于磷石膏和碳酸盐制取浆液A所使用的溶剂。Preferably, the step of removing the scum is as follows: using a scraper to scrape off the scum layer, and then filtering the scum layer. The solid obtained by the filtration is decolorized residue, and the liquid obtained by the filtration is recovered for use in phosphogypsum. and carbonate to prepare slurry A.
优选地，所述洗涤采用逆流洗涤的方法。Preferably, the washing adopts a countercurrent washing method.
优选地，所述逆流洗涤的级数为3～5级；进一步优选地，所述逆流洗涤的级数为4级。Preferably, the countercurrent washing has a level of 3 to 5; further preferably, the countercurrent washing has a level of 4.
优选地，所述下一级逆流洗涤的排出液用作上一级逆流洗涤的洗液。Preferably, the discharge liquid of the next stage of counter-current washing is used as the washing liquid of the previous stage of counter-current washing.
优选地，所述压滤步骤具体为：将压滤步骤得到的液体作为磷酸生产原料输送至磷酸生产车间，并将压滤步骤得到的固体调制成浆液B后过滤。Preferably, the filter press step specifically includes: transporting the liquid obtained in the filter press step to the phosphoric acid production workshop as a raw material for phosphoric acid production, and preparing the solid obtained in the filter press step into slurry B and then filtering.
优选地，所述浆液B的固含量为30％～50％。Preferably, the solid content of the slurry B is 30% to 50%.
本发明的第二个方面提供了一种磷石膏，采用本发明第一个方面提供的方法制得。A second aspect of the present invention provides a phosphogypsum, which is produced by the method provided by the first aspect of the present invention.
优选地，所述磷石膏中的水溶性磷含量不高于0.02％；进一步优选地，所述磷石膏中的水溶性磷含量不高于0.016％。Preferably, the water-soluble phosphorus content in the phosphogypsum is not higher than 0.02%; further preferably, the water-soluble phosphorus content in the phosphogypsum is not higher than 0.016%.
优选地，所述磷石膏中的总磷含量不高于0.2％；进一步优选地，所述磷石膏中的总磷含量不高于0.14％。Preferably, the total phosphorus content in the phosphogypsum is not higher than 0.2%; further preferably, the total phosphorus content in the phosphogypsum is not higher than 0.14%.
优选地，所述磷石膏中的氟含量不高于0.04％；进一步优选地，所述磷石膏中的氟含量不高于0.018％。Preferably, the fluorine content in the phosphogypsum is not higher than 0.04%; further preferably, the fluorine content in the phosphogypsum is not higher than 0.018%.
优选地，所述磷石膏中的镁含量不高于0.02％；进一步优选地，所述磷石膏中的镁含量不高于0.009％。Preferably, the magnesium content in the phosphogypsum is not higher than 0.02%; further preferably, the magnesium content in the phosphogypsum is not higher than 0.009%.
优选地，所述磷石膏中的钠含量不高于0.04％；进一步优选地，所述磷石膏中的钠含量不高于0.019％。Preferably, the sodium content in the phosphogypsum is not higher than 0.04%; further preferably, the sodium content in the phosphogypsum is not higher than 0.019%.
优选地，所述磷石膏中的铁含量不高于0.06％；进一步优选地，所述磷石膏中的铁含量不高于0.04％。Preferably, the iron content in the phosphogypsum is not higher than 0.06%; further preferably, the iron content in the phosphogypsum is not higher than 0.04%.
优选地，所述磷石膏中的钾含量不高于0.04％；进一步优选地，所述磷石膏中的钾含量不高于0.025％。Preferably, the potassium content in the phosphogypsum is not higher than 0.04%; further preferably, the potassium content in the phosphogypsum is not higher than 0.025%.
优选地，所述磷石膏中的铝含量不高于0.03％；进一步优选地，所述磷石膏中的铝含量 不高于0.01％。Preferably, the aluminum content in the phosphogypsum is not higher than 0.03%; further preferably, the aluminum content in the phosphogypsum Not higher than 0.01%.
优选地，所述磷石膏的白度为70～90；进一步优选地，所述磷石膏的白度为77～90；再进一步优选地，所述磷石膏的白度为77～80。Preferably, the whiteness of the phosphogypsum is 70-90; further preferably, the whiteness of the phosphogypsum is 77-90; still more preferably, the whiteness of the phosphogypsum is 77-80.
优选地，所述磷石膏中的有机碳含量不高于0.03％；进一步优选地，所述磷石膏中的有机碳含量不高于0.014％。Preferably, the organic carbon content in the phosphogypsum is not higher than 0.03%; further preferably, the organic carbon content in the phosphogypsum is not higher than 0.014%.
本发明的第三个方面提供了一种磷石膏在建筑材料中的应用。A third aspect of the invention provides an application of phosphogypsum in building materials.
优选地，所述建筑材料为建筑石膏。Preferably, the building material is building plaster.
本发明的第四个方面提供了一种磷石膏的回收***，所述回收***用于实施本发明第一个方面提供的磷石膏的回收方法，所述回收***包括酸解装置、方形槽、成化槽、过滤***及逆流洗涤装置，所述酸解装置底部设有第一酸液入口，酸解装置与方形槽连接，方形槽上设有刮板机，方形槽与成化槽连接，成化槽上设有第二酸液入口，成化槽与过滤***连接，过滤***的固体出口与逆流洗涤装置连接。将磷石膏与碳酸盐混合并在酸解装置中进行一次酸解，然后输送至方形槽内，通过方形槽上的刮板机去除浮沫，然后在成化槽中进行二次酸解，通过过滤装置进行压滤并通过逆流洗涤装置洗涤后得到纯化后的磷石膏。A fourth aspect of the present invention provides a phosphogypsum recovery system. The recovery system is used to implement the phosphogypsum recovery method provided by the first aspect of the present invention. The recovery system includes an acidolysis device, a square tank, Formation tank, filtration system and counter-current washing device. The bottom of the acidolysis device is provided with a first acid liquid inlet. The acidolysis device is connected to a square tank. A scraper is provided on the square tank. The square tank is connected to the formation tank. The formation tank is provided with a second acid liquid inlet, the formation tank is connected to the filtration system, and the solid outlet of the filtration system is connected to the countercurrent washing device. Phosphogypsum and carbonate are mixed and acidolyzed once in the acidolysis device, and then transported to a square tank. The scum is removed by a scraper on the square tank, and then a second acidolysis is performed in the formation tank. Purified phosphogypsum is obtained after pressure filtration through a filtration device and washing through a countercurrent washing device.
本发明中的磷石膏和碳酸盐的混合物经过调浆后输送至酸解装置中，然后从酸解装置底部的第一酸液入口通入酸液，从而实现在酸解装置中进行一次酸解，一次酸解后的产物输送至方形槽内，并在方形槽内静置分层，方形槽顶部是含有有机物的浮沫层，方形槽底部是一次酸解后的磷石膏浆液，使用方形槽上的刮板机将浮沫层刮除，刮除浮沫后的浆液从方形槽底部输送至成化槽，通过成化槽上的第二酸液入口向成化槽内通入酸液，在成化槽内进行二次酸解，二次酸解后的产物通入过滤***中进行过滤，然后对过滤***过滤后的固体使用逆流洗涤装置进行逆流洗涤。The mixture of phosphogypsum and carbonate in the present invention is transported to the acidolysis device after slurrying, and then the acid liquid is introduced from the first acid liquid inlet at the bottom of the acidolysis device, thereby realizing primary acidification in the acidolysis device. Decomposition, the product after one acidolysis is transported to a square tank, and left to stratify in the square tank. The top of the square tank is a scum layer containing organic matter, and the bottom of the square tank is the phosphogypsum slurry after one acidolysis. Use a square tank The scraper machine on the tank scrapes off the scum layer, and the slurry after scraping off the scum is transported from the bottom of the square tank to the formation tank, and the acid liquid is introduced into the formation tank through the second acid inlet on the formation tank. , perform secondary acidolysis in the formation tank, and the product after the secondary acidolysis is passed into the filtration system for filtration, and then the solids filtered by the filtration system are washed countercurrently using a countercurrent washing device.
优选地，所述第一酸液入口与酸液储存装置连接。Preferably, the first acid liquid inlet is connected to an acid liquid storage device.
优选地，所述第二酸液入口与酸液储存装置连接。Preferably, the second acid liquid inlet is connected to an acid liquid storage device.
优选地，所述过滤***包括压滤装置、调浆装置及过滤装置，所述压滤装置与成化槽连接，压滤装置的液体出口与磷酸生产***连接，压滤装置的固体出口与调浆装置连接，调浆装置与过滤装置连接，过滤装置的固体出口与逆流洗涤装置连接。成化槽中的二次酸解产物输送至压滤装置进行压滤，压滤装置压滤后的液体通过液体出口输送至磷酸生产***，用于回收磷石膏中的磷成分，磷成分被回收后可以用于生产磷酸。压滤装置压滤后的固体通过压滤装置上的固体出口输送至调浆装置进行调浆，调浆后将浆液输送至过滤装置进行过滤，过滤装置过滤后的固体通过逆流洗涤装置进行洗涤。 Preferably, the filtration system includes a filter press device, a slurry adjusting device and a filtering device. The filter press device is connected to the formation tank, the liquid outlet of the filter press device is connected to the phosphoric acid production system, and the solid outlet of the filter press device is connected to the conditioning tank. The slurry device is connected, the slurry adjusting device is connected with the filter device, and the solid outlet of the filter device is connected with the countercurrent washing device. The secondary acid hydrolysis product in the formation tank is transported to the filter press device for filtering. The liquid after filtering by the filter press device is transported to the phosphoric acid production system through the liquid outlet to recover the phosphorus component in the phosphogypsum. The phosphorus component is recovered It can then be used to produce phosphoric acid. The solids after filtering by the filter press device are transported to the slurry adjustment device through the solid outlet on the filter press device for slurry adjustment. After the slurry is adjusted, the slurry is transported to the filter device for filtration. The solids filtered by the filter device are washed by the countercurrent washing device.
优选地，所述回收***还包括调浆机，所述调浆机与酸解装置连接。所述调浆机用于将磷石膏和碳酸盐的混合物进行调浆。Preferably, the recovery system further includes a pulp mixer, and the pulp mixer is connected to the acidolysis device. The slurry mixing machine is used to slurry the mixture of phosphogypsum and carbonate.
优选地，所述调浆机与过滤装置的液体出口连接。过滤装置过滤后的液体输送至调浆机作为调浆的液体使用。Preferably, the pulp mixer is connected to the liquid outlet of the filter device. The liquid filtered by the filtration device is transported to the pulp mixing machine to be used as liquid for pulp mixing.
优选地，所述调浆机与水源连接。Preferably, the pulp mixer is connected to a water source.
优选地，所述过滤装置为带式过滤装置。Preferably, the filter device is a belt filter device.
优选地，所述调浆装置与水源连接。Preferably, the pulp adjusting device is connected to a water source.
优选地，所述方形槽与压滤机连接，压滤机的排液口与调浆机连接。方形槽上的刮板机将浮沫层刮到压滤机中进行压滤，压滤机压滤时的液体通过压滤机排液口输送至调浆机作为调浆的液体使用。压滤机压滤产生的固体为脱色渣。Preferably, the square tank is connected to a filter press, and the liquid outlet of the filter press is connected to a pulp mixer. The scraper on the square tank scrapes the scum layer into the filter press for filtering. The liquid when filtered by the filter press is transported to the pulp mixer through the discharge port of the filter press to be used as liquid for pulp mixing. The solid produced by the filter press is decolorized residue.
优选地，所述逆流洗涤装置的洗涤级数为3～6级；进一步优选地，所述逆流洗涤装置的洗涤级数为4级。Preferably, the counter-current washing device has a washing level of 3 to 6 levels; further preferably, the counter-current washing device has a washing level of 4 levels.
优选地，所述逆流洗涤装置包括一级逆流洗涤区、二级逆流洗涤区、三级逆流洗涤区及四级逆流洗涤区。Preferably, the countercurrent washing device includes a first-level countercurrent washing area, a second-level countercurrent washing area, a third-level countercurrent washing area and a fourth-level countercurrent washing area.
优选地，所述一级逆流洗涤区的洗液入口分别与二级逆流洗涤区的排液口和水源连接。Preferably, the washing liquid inlet of the first-level counter-current washing zone is connected to the liquid outlet and the water source of the second-level counter-current washing zone respectively.
优选地，所述一级逆流洗涤区的排液口与调浆装置连接。Preferably, the liquid discharge port of the first-level countercurrent washing zone is connected to the pulp adjusting device.
优选地，所述二级逆流洗涤区的洗液入口分别与三级逆流洗涤区的排液口和水源连接。Preferably, the washing liquid inlet of the second-level counter-current washing zone is connected to the liquid outlet and the water source of the third-level counter-current washing zone respectively.
优选地，所述三级逆流洗涤区的洗液入口分别与四级逆流洗涤区的排液口和水源连接。Preferably, the washing liquid inlet of the third-stage counter-current washing zone is connected to the liquid outlet and the water source of the fourth-stage counter-current washing zone respectively.
优选地，所述四级逆流洗涤区的洗液入口与水源连接。Preferably, the washing liquid inlet of the four-stage countercurrent washing zone is connected to a water source.
优选地，所述水源为工艺水水源。Preferably, the water source is a process water source.
本发明的有益效果是：本发明中的磷石膏的回收方法在对磷石膏进行回收后，磷石膏中的各种杂质含量均较未处理前有显著的降低，其中磷石膏的可溶磷降至0.016％以下，总磷降至0.1％左右，石膏浸出液的pH由1～2提升至6～7，石膏浸出液无需处理可直接排出，Mg、Na、Fe、K、Al和有机碳的含量均获得了极大的降低，石膏白度由22.71提升至78左右，石膏的净化程度要远高于常规水洗和酸解工艺，处理后的磷石膏质量指标优于建筑石膏粉标准的相关要求，可直接用作建筑石膏。The beneficial effects of the present invention are: after the phosphogypsum recovery method in the present invention recovers the phosphogypsum, the contents of various impurities in the phosphogypsum are significantly reduced compared with before treatment, and the soluble phosphorus of the phosphogypsum is reduced. to less than 0.016%, the total phosphorus dropped to about 0.1%, the pH of the gypsum leachate increased from 1 to 2 to 6 to 7, the gypsum leachate can be discharged directly without treatment, and the contents of Mg, Na, Fe, K, Al and organic carbon were all the same. It has been greatly reduced. The whiteness of gypsum has increased from 22.71 to about 78. The degree of purification of gypsum is much higher than that of conventional washing and acid hydrolysis processes. The quality index of the treated phosphogypsum is better than the relevant requirements of the building gypsum powder standard. It can be Directly used as building plaster.
此外，本发明中的回收方法可以实现对磷石膏中的磷进行回收，回收后的磷成分直接输送至磷酸生产车间，用于生产磷酸。本回收方法过滤、洗涤和压滤产生的废液均可以回收再利用，提高了原料的利用率，降低了废液的处理成本，节约了生产成本。In addition, the recovery method in the present invention can realize the recovery of phosphorus in phosphogypsum, and the recovered phosphorus components are directly transported to the phosphoric acid production workshop for use in the production of phosphoric acid. The waste liquid produced by filtration, washing and filter pressing in this recycling method can be recycled and reused, which improves the utilization rate of raw materials, reduces the treatment cost of waste liquid, and saves production costs.
本发明中的回收***自动化程度高，劳动强度低，设备简单，设备成本低，维护方便， 可以实现对磷石膏的自动化回收，回收过程中的废液可以直接循环使用，原料利用率高。The recycling system in the present invention has a high degree of automation, low labor intensity, simple equipment, low equipment cost, and easy maintenance. Automatic recycling of phosphogypsum can be realized, and the waste liquid during the recycling process can be directly recycled, resulting in high raw material utilization.
附图说明Description of the drawings
图1为本发明实施例1～4中磷石膏的回收方法的流程示意图。Figure 1 is a schematic flow chart of the recovery method of phosphogypsum in Examples 1 to 4 of the present invention.
图2为本发明实施例6中的回收***的结构示意图。Figure 2 is a schematic structural diagram of the recovery system in Embodiment 6 of the present invention.
图3为本发明实施例6中的逆流洗涤装置的结构示意图。Figure 3 is a schematic structural diagram of a countercurrent washing device in Embodiment 6 of the present invention.
具体实施方式Detailed ways
以下结合附图和实例对本发明的具体实施作进一步详细说明，但本发明的实施和保护不限于此。需要指出的是，以下若为有未特别详细说明之过程，均是本领域技术人员可参照现有技术实现或理解的。所用试剂或仪器未注明生产厂商者，视为可以通过市售购买得到的常规产品。The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any process that is not specifically described in detail below can be implemented or understood by those skilled in the art with reference to the existing technology. If the manufacturer of the reagents or instruments used is not indicated, they are regarded as conventional products that can be purchased commercially.
实施例1～4中所采用测定净化磷石膏的成分含量的方法为磷钼酸喹啉重量法、ICP-MS和Q/520122K-002-2020中记载的测试方法。The methods used in Examples 1 to 4 to determine the component content of purified phosphogypsum are the quinoline phosphomolybdate gravimetric method, ICP-MS and the test method described in Q/520122K-002-2020.
实施例1Example 1
本实施例中磷石膏的回收方法，具体包括以下步骤：The method for recovering phosphogypsum in this embodiment specifically includes the following steps:
(1)本实施例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，磷石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the phosphogypsum is 0.4986%, and the total phosphorus It is 1.524%, and the pH of the leach solution is between 1 and 2;
(2)依次称取该磷石膏900kg、纯碱100kg，将两者混合得到混合物；将磷石膏与纯碱的混合物和工艺水按重量比1:2的比例配成混合料浆，工艺水的温度为30℃，充分搅拌使液固两相均匀分布，获得料浆A；(2) Weigh 900kg of phosphogypsum and 100kg of soda ash in sequence, and mix the two to obtain a mixture; prepare a mixed slurry with the mixture of phosphogypsum and soda ash and process water in a weight ratio of 1:2. The temperature of the process water is 30°C, stir thoroughly to evenly distribute the liquid and solid phases to obtain slurry A;
(3)配制质量分数为40％的稀硫酸；(3) Prepare dilute sulfuric acid with a mass fraction of 40%;
(4)酸解脱色：将料浆A移入反应容器，容器内的搅拌速度为350r/min，将步骤(3)所得的硫酸溶液从反应容器底部加入至料浆中，硫酸溶液的加入量为450kg，硫酸添加时间控制在25min；(4) Acid decolorization: Move slurry A into the reaction container, the stirring speed in the container is 350r/min, add the sulfuric acid solution obtained in step (3) into the slurry from the bottom of the reaction container, the amount of sulfuric acid solution added is 450kg, the sulfuric acid addition time is controlled at 25 minutes;
(5)硫酸添加完毕后继续搅拌20min，随后将带沫料浆移入方形槽静置30min，静置完成后刮去料浆表面的上层浮沫，实现有机杂质与石膏料浆的分离；(5) After the addition of sulfuric acid, continue stirring for 20 minutes, then move the foamed slurry into a square tank and let it stand for 30 minutes. After standing, scrape off the upper layer of foam on the surface of the slurry to separate organic impurities from the gypsum slurry;
(6)步骤(5)中刮除的上层浮沫送至压滤机进行压滤，滤饼为脱色渣，滤液回收处理后输送至步骤(2)用于调制料浆A；(6) The upper layer of scum scraped off in step (5) is sent to a filter press for filtering. The filter cake is decolorized residue. The filtrate is recovered and transported to step (2) for preparing slurry A;
(7)步骤(5)中去除上层浮沫后的料浆移入成化槽，并向成化槽中再次加入步骤(3)配制的稀硫酸，硫酸溶液的加入量为180kg； (7) The slurry after removing the upper layer of scum in step (5) is moved into the formation tank, and the dilute sulfuric acid prepared in step (3) is added to the formation tank again. The amount of sulfuric acid solution added is 180kg;
(8)成化槽加蒸汽保温，温度控制在75℃，并不停地对料浆进行搅拌，成化时间控制在1.5h；(8) Add steam to the formation tank for heat preservation, control the temperature at 75°C, stir the slurry continuously, and control the formation time at 1.5 hours;
(9)将成化完成的料浆进行压滤，滤液回收处理后作为磷酸生产原料送至磷酸车间，滤饼用工艺水进行调浆，工艺水的温度及用量与本实施例步骤(2)中的工艺水相同；(9) The slurry that has been formed is filtered, and the filtrate is recycled and processed and sent to the phosphoric acid workshop as a raw material for phosphoric acid production. The filter cake is slurried with process water. The temperature and amount of process water are the same as in step (2) of this embodiment. The process water is the same;
(10)将步骤(9)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(2)用以调制浆料A，滤饼经4级逆流洗涤后获得净化磷石膏；(10) Filter the slurry obtained in step (9). The filtered filtrate can be recovered and transported to step (2) to prepare slurry A. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(10)中4级逆流洗涤时后一级洗涤的滤液作为上一级洗涤时的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度及用量与本实施例步骤(2)中的工艺水相同。步骤(10)中逆流洗涤最终滤液可以回收并输送至步骤(9)对压滤滤饼进行调浆。In step (10), the filtrate of the last level of washing during the 4-level countercurrent washing is used as the washing liquid in the previous level of washing. The washing liquid of the last level of washing is process water. The temperature and dosage of the process water are the same as those in the steps of this embodiment ((10)). The process water in 2) is the same. The final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
测试本实施例中获得的净化磷石膏的成分含量可得：净化后的石膏中水溶磷为0.0136％，总磷为0.1142％，水溶氟为0.0167％，游离水含量为23.14％，45℃烘干后的石膏为白色粉末，白度为78.92。Testing the component content of the purified phosphogypsum obtained in this example shows: the water-soluble phosphorus in the purified gypsum is 0.0136%, the total phosphorus is 0.1142%, the water-soluble fluorine is 0.0167%, and the free water content is 23.14%, dried at 45°C The resulting gypsum is white powder with a whiteness of 78.92.
实施例2Example 2
本实施例中磷石膏的回收方法，具体包括以下步骤：The method for recovering phosphogypsum in this embodiment specifically includes the following steps:
(1)本实施例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
(2)按质量比m石膏：m纯碱：m石灰粉＝7:0.5:0.5的比例依次称取磷石膏875kg、纯碱62.5kg、石灰粉62.5kg，随后将三种物料混合；将混合物和工艺水按重量比1:2的比例配成混合料浆，工艺水由水和蒸汽冷凝液配制而成，温度控制在55℃，充分搅拌使液固两相均匀分布，获得料浆A；(2) Weigh 875kg of phosphogypsum, 62.5kg of soda ash, and 62.5kg of lime powder in sequence according to the mass ratio of m gypsum : m soda ash : m lime powder = 7:0.5:0.5, and then mix the three materials; mix the mixture with the process Water is prepared into a mixed slurry at a weight ratio of 1:2. The process water is prepared from water and steam condensate. The temperature is controlled at 55°C. Stir thoroughly to evenly distribute the liquid and solid phases to obtain slurry A;
(3)配制质量分数为35％的稀硫酸；(3) Prepare dilute sulfuric acid with a mass fraction of 35%;
(4)酸解脱色：将料浆A移入至反应容器，容器内的搅拌速度为400r/min，将步骤(3)所得的硫酸溶液从反应容器底部加入至料浆中，硫酸溶液的加入量为550kg，硫酸添加时间控制在35min；(4) Acid decolorization: Move slurry A into the reaction container. The stirring speed in the container is 400r/min. Add the sulfuric acid solution obtained in step (3) to the slurry from the bottom of the reaction container. The amount of sulfuric acid solution added is 550kg, and the sulfuric acid addition time is controlled at 35 minutes;
(5)硫酸添加完毕后继续搅拌20min，随后将带沫料浆移入方形槽静置30min，静置完成后刮去料浆表面的浮沫，实现有机杂质与石膏料浆的分离；(5) After the addition of sulfuric acid, continue stirring for 20 minutes, then move the foamed slurry into a square tank and let it stand for 30 minutes. After standing, scrape off the foam on the surface of the slurry to separate organic impurities from the gypsum slurry;
(6)将步骤(5)中刮去的料浆表面的浮沫送至压滤机压滤，压滤后的滤液回收处理后输送至步骤(2)用于调制料浆A；(6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration. The filtrate after the filtration is recovered and processed and sent to step (2) for preparing slurry A;
(7)步骤(5)中除沫后的料浆移入成化槽，并向成化槽中再次加入步骤(3)配制的稀 硫酸，稀硫酸的加入量为150kg；(7) The slurry after defoaming in step (5) is moved into the formation tank, and the diluent prepared in step (3) is added to the formation tank again. Sulfuric acid, the amount of dilute sulfuric acid added is 150kg;
(8)成化槽加蒸汽保温，温度控制在70℃，并不停地对料浆进行搅拌，成化时间控制在1h；(8) Add steam to the formation tank for heat preservation, control the temperature at 70°C, stir the slurry continuously, and control the formation time at 1 hour;
(9)将成化完成的料浆进行压滤，滤液回收处理后作为磷酸生产原料送至磷酸车间，滤饼用工艺水进行调浆，工艺水的温度、成分及用量与本实施例步骤(2)所用工艺水相同；(9) Carry out pressure filtration on the completed slurry, and send the filtrate to the phosphoric acid workshop as a raw material for phosphoric acid production after recycling. The filter cake is slurried with process water. The temperature, composition and dosage of the process water are the same as in step (2) of this embodiment. ) The process water used is the same;
(10)将步骤(9)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(2)用以调制浆料A，滤饼经4级逆流洗涤后获得净化磷石膏；(10) Filter the slurry obtained in step (9). The filtered filtrate can be recovered and transported to step (2) to prepare slurry A. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(10)中逆流洗涤时后一级洗涤产生的滤液作为上一级洗涤的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本实施例步骤(2)中的工艺水相同。步骤(10)中逆流洗涤最终滤液可以回收并输送至步骤(9)对压滤滤饼进行调浆。In step (10), the filtrate produced by the last level of washing during countercurrent washing is used as the washing liquid of the previous level of washing. The washing liquid of the last level of washing is process water. The temperature, composition and dosage of the process water are the same as those in the steps of this embodiment ( The process water in 2) is the same. The final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
测试本实施例中获得的净化磷石膏的成分含量可得：净化后的石膏中水溶磷为0.0124％，总磷为0.0912％，水溶氟含量为0.0142％，游离水为22.34％，45℃烘干后的石膏为白色粉末，白度为78.31。Testing the component content of the purified phosphogypsum obtained in this example shows: the water-soluble phosphorus in the purified gypsum is 0.0124%, the total phosphorus is 0.0912%, the water-soluble fluorine content is 0.0142%, and the free water is 22.34%, dried at 45°C The resulting gypsum is white powder with a whiteness of 78.31.
实施例3Example 3
本实施例中磷石膏的回收方法，具体包括以下步骤：The method for recovering phosphogypsum in this embodiment specifically includes the following steps:
(1)本实施例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
(2)按照m磷石膏：m纯碱：m石灰粉＝8:0.4:0.6的质量比依次称取磷石膏800kg、纯碱40kg、石灰粉60kg混合；将混合物和工艺水按重量比1:2的比例配成混合料浆，工艺水由清水和蒸汽冷凝液配制而成，温度控制在60℃，充分搅拌使液固两相均匀分布，获得料浆A；(2) Weigh 800kg of phosphogypsum, 40kg of soda ash, and 60kg of lime powder in sequence according to the mass ratio of m phosphogypsum : m soda ash : m lime powder = 8:0.4:0.6; mix the mixture and process water in a weight ratio of 1:2 The proportion is formulated into a mixed slurry. The process water is prepared from clean water and steam condensate. The temperature is controlled at 60°C. Stir thoroughly to make the liquid and solid phases evenly distributed to obtain slurry A;
(3)配制质量分数为45％的稀硫酸；(3) Prepare dilute sulfuric acid with a mass fraction of 45%;
(4)酸解脱色：将料浆A移入至反应容器，容器内的搅拌速度为400r/min，将步骤(3)所得的硫酸溶液从反应容器底部加入至料浆中，硫酸溶液的加入量为370kg，硫酸添加时间控制在25min；(4) Acid decolorization: Move slurry A into the reaction container. The stirring speed in the container is 400r/min. Add the sulfuric acid solution obtained in step (3) to the slurry from the bottom of the reaction container. The amount of sulfuric acid solution added is 370kg, and the sulfuric acid addition time is controlled at 25 minutes;
(5)硫酸添加完毕后继续搅拌20min，随后将带沫料浆移入方形槽静置30min，静置完成后刮去料浆表面的浮沫，实现有机杂质与石膏料浆的分离；(5) After the addition of sulfuric acid, continue stirring for 20 minutes, then move the foamed slurry into a square tank and let it stand for 30 minutes. After standing, scrape off the foam on the surface of the slurry to separate organic impurities from the gypsum slurry;
(6)将步骤(5)中刮去的料浆表面的浮沫送至压滤机压滤，压滤后的滤液回收处理后输送至步骤(2)用于调至料浆A；(6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration. The filtrate after the filtration is recovered and processed and transported to step (2) for adjustment to slurry A;
(7)将步骤(5)中除沫后的料浆移入成化槽，并向成化槽中再次加入步骤(3)配制的 稀硫酸，稀硫酸的加入量为120kg；(7) Move the defoamed slurry in step (5) into the formation tank, and add the slurry prepared in step (3) to the formation tank again. Dilute sulfuric acid, the added amount of dilute sulfuric acid is 120kg;
(8)成化槽加蒸汽保温，温度控制在70℃，并不停地对料浆进行搅拌，成化时间控制在2h；(8) Add steam to the formation tank for heat preservation, control the temperature at 70°C, and stir the slurry continuously, and the formation time is controlled at 2 hours;
(9)将成化完成的料浆进行压滤，滤液回收处理后作为磷酸生产原料输送至磷酸车间，滤饼用工艺水进行调浆，工艺水的温度、成分及用量与本实施例步骤(2)所用工艺水相同；(9) Carry out pressure filtration of the slurry that has been completed. The filtrate is recovered and processed and transported to the phosphoric acid workshop as a raw material for phosphoric acid production. The filter cake is slurried with process water. The temperature, composition and dosage of the process water are the same as in step (2) of this embodiment. ) The process water used is the same;
(10)将步骤(9)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(2)用以调制浆料A，滤饼经4级逆流洗涤后获得净化磷石膏；(10) Filter the slurry obtained in step (9). The filtered filtrate can be recovered and transported to step (2) to prepare slurry A. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(10)中逆流洗涤时后一级洗涤产生的滤液作为上一级洗涤的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本实施例步骤(2)相同。步骤(10)中逆流洗涤最终滤液可以回收并输送至步骤(9)对压滤滤饼进行调浆。In step (10), the filtrate produced by the last level of washing during countercurrent washing is used as the washing liquid of the previous level of washing. The washing liquid of the last level of washing is process water. The temperature, composition and dosage of the process water are the same as those in the steps of this embodiment ( 2) Same. The final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
测试本实施例中获得的净化磷石膏的成分含量可得：净化后的石膏中水溶磷为0.01214％，总磷为0.1045％，水溶氟含量为0.0134％，游离水为22.58％，45℃烘干后的石膏为白色粉末，白度为78.12。Testing the component content of the purified phosphogypsum obtained in this example shows: the water-soluble phosphorus in the purified gypsum is 0.01214%, the total phosphorus is 0.1045%, the water-soluble fluorine content is 0.0134%, and the free water is 22.58%, dried at 45°C The resulting gypsum is white powder with a whiteness of 78.12.
实施例4Example 4
本实施例中磷石膏的回收方法，具体包括以下步骤：The method for recovering phosphogypsum in this embodiment specifically includes the following steps:
(1)本实施例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
(2)称取磷石膏700kg、纯碱80kg、石灰粉40kg混合；将混合物和工艺水按重量比1:1.7的比例配成混合料浆，工艺水由清水和蒸汽冷凝液配制而成，温度控制在60℃，充分搅拌使液固两相均匀分布，获得料浆A；(2) Weigh 700kg of phosphogypsum, 80kg of soda ash, and 40kg of lime powder and mix them; mix the mixture and process water into a mixed slurry in a weight ratio of 1:1.7. The process water is made of clean water and steam condensate, and the temperature is controlled At 60°C, stir thoroughly to evenly distribute the liquid and solid phases to obtain slurry A;
(3)配制质量分数为40％的稀硫酸；(3) Prepare dilute sulfuric acid with a mass fraction of 40%;
(4)酸解脱色：将料浆A移入至反应容器，容器内的搅拌速度为400r/min，将步骤(3)所得的硫酸溶液从反应容器底部加入至料浆中，硫酸溶液的加入量为380kg，硫酸添加时间控制在30min；(4) Acid decolorization: Move slurry A into the reaction container. The stirring speed in the container is 400r/min. Add the sulfuric acid solution obtained in step (3) to the slurry from the bottom of the reaction container. The amount of sulfuric acid solution added is 380kg, and the sulfuric acid addition time is controlled at 30 minutes;
(5)硫酸添加完毕后继续搅拌20min，随后将带沫料浆移入方形槽静置30min，静置完成后刮去料浆表面的浮沫，实现有机杂质与石膏料浆的分离；(5) After the addition of sulfuric acid, continue stirring for 20 minutes, then move the foamed slurry into a square tank and let it stand for 30 minutes. After standing, scrape off the foam on the surface of the slurry to separate organic impurities from the gypsum slurry;
(6)将步骤(5)中刮去的料浆表面的浮沫送至压滤机压滤，压滤后的滤液回收处理后输送至步骤(2)用于调至料浆A；(6) Send the scum on the surface of the slurry scraped off in step (5) to a filter press for filtration. The filtrate after the filtration is recovered and processed and transported to step (2) for adjustment to slurry A;
(7)步骤(5)中除沫后的料浆移入成化槽，并向成化槽中再次加入步骤(3)配制的稀 硫酸，稀硫酸的加入量为120kg；(7) The slurry after defoaming in step (5) is moved into the formation tank, and the diluent prepared in step (3) is added to the formation tank again. Sulfuric acid, the amount of dilute sulfuric acid added is 120kg;
(8)成化槽加蒸汽保温，温度控制在65℃，并不停地对料浆进行搅拌，成化时间控制在1h；(8) Add steam to the formation tank for heat preservation, control the temperature at 65°C, stir the slurry continuously, and control the formation time at 1 hour;
(9)将成化完成的料浆进行压滤，滤液回收处理后作为磷酸生产原料输送至磷酸车间，滤饼用工艺水进行调浆，工艺水的温度、成分及用量与本实施例步骤(2)所用工艺水相同；(9) The completed slurry is filtered, and the filtrate is recovered and processed as a raw material for phosphoric acid production and transported to the phosphoric acid workshop. The filter cake is slurried with process water. The temperature, composition, and dosage of the process water are the same as in step (2) of this embodiment. ) The process water used is the same;
(10)将步骤(9)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(2)用以调制浆料A，滤饼经4级逆流洗涤后获得净化磷石膏；(10) Filter the slurry obtained in step (9). The filtered filtrate can be recovered and transported to step (2) to prepare slurry A. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(10)中4级逆流洗涤时后一级洗涤时的滤液作为上一级洗涤的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本实施例步骤(2)相同。步骤(10)中逆流洗涤最终滤液可以回收并输送至步骤(9)对压滤滤饼进行调浆。In step (10), the filtrate from the last stage of washing in the 4-stage countercurrent washing is used as the washing liquid of the previous stage of washing. The washing liquid of the last stage of washing is process water. The temperature, composition and dosage of the process water are the same as those in this embodiment. Same as step (2). The final filtrate from countercurrent washing in step (10) can be recovered and transported to step (9) to slurry the filter cake.
测试本实施例中获得的净化磷石膏的成分含量可得：净化后的石膏中水溶磷为0.0114％，总磷为0.1113％，水溶氟含量为0.0127％，游离水为21.64％，45℃烘干后的石膏为白色粉末，白度为79.24。Testing the component content of the purified phosphogypsum obtained in this example shows: the water-soluble phosphorus in the purified gypsum is 0.0114%, the total phosphorus is 0.1113%, the water-soluble fluorine content is 0.0127%, and the free water is 21.64%, dried at 45°C The resulting gypsum is white powder with a whiteness of 79.24.
本发明实施例1～4中的磷石膏的回收方法的流程示意图如图1所示。The schematic flow chart of the phosphogypsum recovery method in Examples 1 to 4 of the present invention is shown in Figure 1.
实施例5：Example 5:
本实施例中磷石膏的回收方法，具体包括以下步骤：The method for recovering phosphogypsum in this embodiment specifically includes the following steps:
(1)本实施例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The color of the phosphogypsum is gray-black, the whiteness is 22.71, the free water content is 25.71%, the water-soluble phosphorus content of the gypsum is 0.4986%, and the total phosphorus is 1.524%, the pH of the leach solution is between 1 and 2;
(2)按照m磷石膏：m纯碱：m石灰粉＝9:1:1的质量比称取各物质混合，共称取5个批次并编号a、b、c、d、e，每批次2.2吨；(2) Weigh and mix each substance according to the mass ratio of m phosphogypsum : m soda ash : m lime powder = 9:1:1. Weigh a total of 5 batches and number them a, b, c, d, e. Each batch 2.2 tons;
(3)将批次a置于容器中，加5.5吨工艺水后搅拌调成均匀的料浆，工艺水由清水和蒸汽冷凝液混配而成，温度控制在70℃；(3) Place batch A in a container, add 5.5 tons of process water and stir to form a uniform slurry. The process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
(4)配制质量分数为40％的稀磷酸；(4) Prepare dilute phosphoric acid with a mass fraction of 40%;
(5)酸解脱色：将步骤(3)配制的料浆移入反应容器，并在400r/min的转速下不停地搅拌，将步骤(4)配制的稀硫酸从反应容器底部加入料浆中，稀硫酸的加入量为950kg，加入时间控制在35min；(5) Acid decolorization: Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 950kg, and the adding time is controlled at 35min;
(6)反应完全后继续搅拌20min，然后将反应后的料浆排入方形槽静置30min，使石膏料浆与有机浮沫充分分层；(6) After the reaction is complete, continue stirring for 20 minutes, then discharge the reacted slurry into a square tank and let it stand for 30 minutes to fully stratify the gypsum slurry and organic foam;
(7)用刮板机刮去上层浮沫，方形槽底流送至成化槽； (7) Use a scraper to scrape off the upper layer of scum, and send the bottom flow of the square tank to the forming tank;
(8)带沫液体送至压滤机压滤处理，滤饼为脱色渣，滤液回收获得滤液A；(8) The foamy liquid is sent to a filter press for filtration treatment. The filter cake is decolorized residue, and the filtrate is recovered to obtain filtrate A;
(9)底流送至成化槽，加360kg步骤(4)配制的稀硫酸，成化槽加蒸汽保温，温度控制在65℃，并不停地对料浆进行搅拌，成化时间控制在2h；(9) The underflow is sent to the formation tank, and 360kg of dilute sulfuric acid prepared in step (4) is added. Steam is added to the formation tank to keep it warm. The temperature is controlled at 65°C, and the slurry is constantly stirred. The formation time is controlled at 2 hours. ;
(10)将成化完全后的料浆进行压滤，压滤回收的滤液回收处理后送至磷酸车间作为磷酸生产原料，压滤后的滤饼加工艺水调浆，工艺水的温度、成分及用量同本实施例步骤(3)，获得料浆A；(10) The slurry after complete formation is filtered, and the filtrate recovered by the filter is recycled and processed and sent to the phosphoric acid workshop as a raw material for phosphoric acid production. The filter cake after filtering is added with process water to make slurry. The temperature, composition and The dosage is the same as step (3) of this embodiment to obtain slurry A;
(11)料浆A充分搅拌后送至过滤装置过滤，过滤装置过滤后的滤液回收获得滤液B，滤饼经过4级逆流洗涤获得净化磷石膏，产生的洗涤液回收获得滤液C；(11) Slurry A is fully stirred and then sent to the filtering device for filtration. The filtrate filtered by the filtering device is recovered to obtain filtrate B. The filter cake is subjected to 4-stage countercurrent washing to obtain purified phosphogypsum. The generated washing liquid is recovered to obtain filtrate C;
(12)步骤(11)中4级逆流洗涤中后一级逆流洗涤的滤液作为上一级逆流洗涤的洗涤液使用，最后一级逆流洗涤的洗液为工艺水，工艺水的用量为5.5吨，温度控制在70℃；(12) The filtrate of the last stage of countercurrent washing in step (11) is used as the washing liquid of the previous stage of countercurrent washing. The washing liquid of the last stage of countercurrent washing is process water. The amount of process water is 5.5 tons. , the temperature is controlled at 70℃;
(13)将回收的滤液A、滤液B混合后对批次b的混合物料进行调浆，重复步骤(5)～步骤(11)，该重复步骤(10)中所用的工艺水更换为滤液C；(13) Mix the recovered filtrate A and filtrate B and slurry the mixed material of batch b. Repeat steps (5) to (11). The process water used in the repeated step (10) is replaced with filtrate C. ;
(14)按步骤(5)～步骤(10)依次处理剩余的3个批次的石膏；(14) Process the remaining three batches of gypsum in sequence according to steps (5) to (10);
对5个批次回收后的石膏进行分析，分析结果见下表1，所采用的分析方法为磷钼酸喹啉重量法(用以分析磷成分)、ICP-MS(用以分析金属成分)和Q/520122K-002-2020中记载的测试方法(用以分析有机碳成分)，表1中的数据是以净化后的磷石膏除游离水后的干基质量为基准。Five batches of recycled gypsum were analyzed. The analysis results are shown in Table 1 below. The analysis methods used were quinoline phosphomolybdate gravimetric method (used to analyze phosphorus components) and ICP-MS (used to analyze metal components). And the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon components), the data in Table 1 is based on the dry mass of purified phosphogypsum after removing free water.
表1实施例5中5个批次回收后的磷石膏成分分析结果
Table 1 Analysis results of phosphogypsum components after recovery of 5 batches in Example 5
按照本发明实施例5中的方法处理5个批次的磷石膏后，5个批次的磷石膏中的氟、水 溶P2O5、总P2O5、Mg、Na、Fe、K、Al和有机碳的含量均获得了极大的降低，其中，磷石膏的白度由22.71提高至78左右，磷石膏的可溶磷降至0.016％以下，总磷降至0.1％左右，石膏浸出液pH由1～2提升至6～7，可直接排出，石膏的净化程度要远高于现有技术中的常规水洗和酸解工艺，处理后的磷石膏质量指标优于建筑石膏粉标准的相关要求，可以直接用于建筑材料。After processing 5 batches of phosphogypsum according to the method in Example 5 of the present invention, the fluorine and water in the 5 batches of phosphogypsum were The contents of dissolved P 2 O 5 , total P 2 O 5 , Mg, Na, Fe, K, Al and organic carbon were greatly reduced. Among them, the whiteness of phosphogypsum increased from 22.71 to about 78. The soluble phosphorus is reduced to less than 0.016%, the total phosphorus is reduced to about 0.1%, the pH of the gypsum leachate is increased from 1 to 2 to 6 to 7, and can be directly discharged. The degree of purification of gypsum is much higher than that of conventional water washing in the existing technology. And the acid hydrolysis process, the quality index of the treated phosphogypsum is better than the relevant requirements of the building gypsum powder standard, and can be directly used in building materials.
实施例6Example 6
如图2和图3所示，本实施例提供了一种磷石膏的回收***，本发明实施例1～5中的磷石膏的回收方法均可以采用本实施例中的回收***进行回收。As shown in Figures 2 and 3, this embodiment provides a phosphogypsum recovery system. The phosphogypsum recovery methods in Embodiments 1 to 5 of the present invention can all be recovered using the recovery system in this embodiment.
本实施例中的磷石膏的回收***包括调浆机、酸解装置、方形槽、成化槽、压滤装置、压滤机、调浆装置、过滤装置及逆流洗涤装置，调浆机设有固体原料入口和液体入口，通过调浆机的固体原料入口将磷石膏和碳酸盐加入，调浆机的液体入口分别与水源、过滤装置的排液口、压滤机的排液口通过管道连接，调浆机的浆液出口与酸解装置连接，酸解装置底部设有第一酸液入口，第一酸液入口与硫酸储存装置通过管道连接，酸解装置与方形槽连接，方形槽上设有刮板机，方形槽与压滤机连接，压滤机的排液口与调浆机连接，方形槽与成化槽连接，成化槽上设有第二酸液入口，第二酸液入口与硫酸储存装置连接，成化槽与压滤装置连接，压滤装置的液体出口与磷酸生产***连接，压滤装置的固体出口与调浆装置连接，调浆装置通过管道分别与水源、逆流洗涤装置连接，调浆装置与带式过滤装置连接，带式过滤装置的排液口与调浆机连接，带式过滤装置的固体出口与逆流洗涤装置连接。本实施例中的逆流洗涤装置的洗涤级数为4级，逆流洗涤装置包括一级逆流洗涤区、二级逆流洗涤区、三级逆流洗涤区及四级逆流洗涤区，一级逆流洗涤区的洗液入口分别与水源和二级逆流洗涤区的排液口连接。一级逆流洗涤区的排液口与调浆装置连接。二级逆流洗涤区的洗液入口分别与水源与三级逆流洗涤区的排液口连接；三级逆流洗涤区的洗液入口分别与水源与四级逆流洗涤区的排液口连接。四级逆流洗涤区的洗液入口与水源连接，四级逆流洗涤区洗涤后的固体为回收后的磷石膏。The phosphogypsum recovery system in this embodiment includes a pulp mixing machine, an acidolysis device, a square tank, a formation tank, a filter press device, a filter press, a pulp mixing device, a filtering device and a countercurrent washing device. The pulp mixing machine is equipped with Solid raw material inlet and liquid inlet. Add phosphogypsum and carbonate through the solid raw material inlet of the pulp mixer. The liquid inlet of the pulp mixer is connected to the water source, the drain port of the filter device, and the drain port of the filter press through pipelines respectively. connection, the slurry outlet of the pulp mixer is connected to the acidolysis device. The bottom of the acidolysis device is provided with a first acid liquid inlet. The first acid liquid inlet is connected to the sulfuric acid storage device through a pipeline. The acidolysis device is connected to a square tank. On the square tank It is equipped with a scraper, the square trough is connected to the filter press, the liquid outlet of the filter press is connected to the pulp mixing machine, the square trough is connected to the forming tank, the forming tank is provided with a second acid liquid inlet, and the second acid The liquid inlet is connected to the sulfuric acid storage device, the formation tank is connected to the filter press device, the liquid outlet of the filter press device is connected to the phosphoric acid production system, the solid outlet of the filter press device is connected to the slurry mixing device, and the slurry mixing device is connected to the water source and water source through pipelines. The countercurrent washing device is connected, the pulp mixing device is connected with the belt filter device, the liquid outlet of the belt filter device is connected with the pulp mixing machine, and the solid outlet of the belt filter device is connected with the countercurrent washing device. The number of washing levels of the countercurrent washing device in this embodiment is 4. The countercurrent washing device includes a first-level countercurrent washing area, a second-level countercurrent washing area, a third-level countercurrent washing area and a fourth-level countercurrent washing area. The first-level countercurrent washing area The washing liquid inlet is connected to the water source and the drain port of the secondary countercurrent washing area. The drain port of the first-level countercurrent washing area is connected to the pulp mixing device. The washing liquid inlet of the second-level counter-current washing zone is connected to the water source and the drain port of the third-level counter-current washing zone respectively; the washing liquid inlet of the third-level counter-current washing zone is connected to the water source and the drain port of the fourth-level counter-current washing zone respectively. The washing liquid inlet of the four-stage counter-current washing zone is connected to the water source, and the washed solids in the four-stage counter-current washing zone are recovered phosphogypsum.
在使用时，先将磷石膏和碳酸盐以及调浆液体加入调浆机中进行调浆，调浆后将浆液输送至酸解装置中，从酸解装置的底部通入稀硫酸并进行一次酸解反应，然后将酸解产物输送至方形槽内静置分层，通过方形槽上的刮板机将浮沫层刮入压滤机中进行压滤，压滤后的固体为脱色渣，压滤后的液体可以用于调浆机调制磷石膏和碳酸盐浆液的液体。方形槽内剩余的浆液输送至成化槽，然后向成化槽中加入硫酸进行二次酸解反应，二次酸解后将浆液输送至压滤装置进行压滤，压滤产生的液体输送至磷酸生产***用于生产磷酸，压滤产生的固体 通过调浆装置进行调浆后输送至带式过滤装置进行过滤，调浆装置中所使用的液体来源于工艺水或逆流洗涤装置所排出的液体。带式过滤装置过滤产生的液体输送至调浆机用作调浆的液体，带式过滤装置产生的固体输送至逆流洗涤装置，通过逆流洗涤装置进行洗涤后，制得纯化后的磷石膏。When in use, first add phosphogypsum and carbonate and the sizing liquid into the slurry mixer for slurry mixing. After the slurry is mixed, the slurry is transported to the acidolysis device. Dilute sulfuric acid is introduced from the bottom of the acidolysis device and carried out once. After acidolysis reaction, the acidolysis product is then transported to a square tank and allowed to stand for stratification. The scraper on the square tank scrapes the scum layer into a filter press for filtering. The solid after filtering is decolorized residue. The liquid after filtering can be used in the pulp mixer to prepare phosphogypsum and carbonate slurry liquids. The remaining slurry in the square tank is transported to the formation tank, and then sulfuric acid is added to the formation tank for a secondary acidolysis reaction. After the secondary acidolysis, the slurry is transported to the filter press device for filter press, and the liquid produced by the filter press is transported to Phosphoric acid production system is used to produce phosphoric acid, and the solids produced by filter press The pulp is mixed through the pulp mixing device and then transported to the belt filter device for filtration. The liquid used in the pulp mixing device comes from process water or the liquid discharged from the countercurrent washing device. The liquid produced by the belt filter device is transported to the slurry mixer for use as liquid for slurry mixing. The solid produced by the belt filter device is transported to the countercurrent washing device. After being washed by the countercurrent washing device, purified phosphogypsum is obtained.
对比例1Comparative example 1
本对比例中磷石膏的回收方法，具体包括以下步骤：The recovery method of phosphogypsum in this comparative example specifically includes the following steps:
(1)本对比例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
(2)按照m磷石膏：m纯碱：m石灰粉＝9:1:1的质量比称取各物质混合，磷石膏、纯碱和石灰粉的总质量合计为2.2吨；(2) Weigh and mix each substance according to the mass ratio of m phosphogypsum : m soda ash : m lime powder = 9:1:1. The total mass of phosphogypsum, soda ash and lime powder is 2.2 tons;
(3)将步骤(2)称取的物质置于容器内，加5.5吨工艺水后搅拌调成均匀的料浆，工艺水由清水和蒸汽冷凝液混配而成，温度控制在70℃；(3) Place the material weighed in step (2) into a container, add 5.5 tons of process water and stir to form a uniform slurry. The process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
(4)配制质量分数为40％的稀磷酸；(4) Prepare dilute phosphoric acid with a mass fraction of 40%;
(5)酸解脱色：将步骤(3)配制的料浆移入反应容器，并在400r/min的转速下不停地搅拌，将步骤(4)配制的稀硫酸从反应容器底部加入料浆中，稀硫酸的加入量为1310kg，加入时间控制在35min；(5) Acid decolorization: Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 1310kg, and the adding time is controlled at 35min;
(6)反应完全后继续搅拌20min，然后将反应后的料浆排入方形槽静置30min，使石膏料浆与有机浮沫充分分层；(6) After the reaction is complete, continue stirring for 20 minutes, then discharge the reacted slurry into a square tank and let it stand for 30 minutes to fully stratify the gypsum slurry and organic foam;
(7)用刮板机刮去上层浮沫，方形槽底流送至成化槽；(7) Use a scraper to scrape off the upper layer of scum, and send the bottom flow of the square tank to the forming tank;
(8)步骤(7)中刮板机刮出的带沫液体送至压滤机压滤处理，滤饼为脱色渣，压滤后的滤液回收处理后输送至步骤(3)用于调料浆；(8) The foamy liquid scraped out by the scraper in step (7) is sent to the filter press for filtration processing. The filter cake is decolorized residue. The filtrate after filtration is recovered and processed and sent to step (3) for use in seasoning slurry. ;
(9)步骤(7)中方形槽的底流液体送至成化槽，成化槽加蒸汽保温，温度控制在65℃，并不停地对料浆进行搅拌，成化时间控制在2h；(9) The underflow liquid in the square tank in step (7) is sent to the formation tank. Steam is added to the formation tank to keep it warm. The temperature is controlled at 65°C, and the slurry is continuously stirred. The formation time is controlled at 2 hours;
(10)将成化完全后的料浆进行压滤，压滤回收的滤液回收处理后送至磷酸车间作为磷酸生产原料，压滤后的滤饼加工艺水调浆，工艺水的温度、成分及用量同本对比例步骤(3)，获得料浆A；(10) The slurry after complete formation is filtered, and the filtrate recovered by the filter is recycled and processed and sent to the phosphoric acid workshop as a raw material for phosphoric acid production. The filter cake after filtering is added with process water to make slurry. The temperature, composition and The dosage is the same as step (3) of this comparative example to obtain slurry A;
(11)将步骤(10)获得的料浆A进行过滤，过滤后的滤液可以回收并输送至步骤(3)用以调制浆料，过滤后的滤饼经4级逆流洗涤后获得净化磷石膏；(11) Filter the slurry A obtained in step (10). The filtered filtrate can be recovered and transported to step (3) to prepare the slurry. The filtered cake is subjected to 4-stage countercurrent washing to obtain purified phosphogypsum. ;
步骤(11)中4级逆流洗涤时后一级洗涤时的滤液作为上一级洗涤的洗涤液使用，最后 一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本对比例步骤(3)相同。步骤(11)中逆流洗涤最终滤液可以回收并输送至步骤(10)对压滤滤饼进行调浆。In step (11), during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing. The washing liquid in the first-level washing is process water, and the temperature, composition and dosage of the process water are the same as in step (3) of this comparative example. The final filtrate from countercurrent washing in step (11) can be recovered and transported to step (10) to slurry the filter cake.
分析本对比例中获得的净化磷石膏的成分，分析结果如下表2所示，所采用的分析方法为磷钼酸喹啉重量法(用以分析磷成分)、ICP-MS(用以分析金属成分)和Q/520122K-002-2020中记载的测试方法(用以分析有机碳成分)，表2中的数据是以净化后的磷石膏除游离水后的干基质量为基准。The components of the purified phosphogypsum obtained in this comparative example were analyzed. The analysis results are shown in Table 2 below. The analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 2 are based on the dry mass of purified phosphogypsum after removing free water.
表2对比例1中回收后的磷石膏成分分析结果
Table 2 Analysis results of recovered phosphogypsum components in Comparative Example 1
由上表2可知，与实施例5相比，对比例1仅对磷石膏进行了一次酸解步骤，所回收的磷石膏中的水溶F、水溶P2O5、Mg、Na等杂质的含量均较高，由此可见，采用两次酸解步骤可以提高回收的磷石膏的纯度。It can be seen from Table 2 above that compared with Example 5, Comparative Example 1 only performed one acidolysis step on phosphogypsum. The content of water-soluble F, water-soluble P 2 O 5 , Mg, Na and other impurities in the recovered phosphogypsum are higher, it can be seen that the purity of the recovered phosphogypsum can be improved by using two acidolysis steps.
对比例2Comparative example 2
本对比例中磷石膏的回收方法，具体包括以下步骤：The recovery method of phosphogypsum in this comparative example specifically includes the following steps:
(1)本对比例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
(2)称取1.8吨该磷石膏并将其置于容器中，加5.5吨工艺水后搅拌调成均匀的料浆，工艺水由清水和蒸汽冷凝液混配而成，温度控制在70℃；(2) Weigh 1.8 tons of phosphogypsum and place it in a container, add 5.5 tons of process water and stir to form a uniform slurry. The process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C. ;
(3)配制质量分数为40％的稀磷酸；(3) Prepare dilute phosphoric acid with a mass fraction of 40%;
(4)一次酸解：将步骤(2)配制的料浆移入反应容器，并在400r/min的转速下不停地搅拌，将步骤(3)配制的稀硫酸从反应容器底部加入料浆中，稀硫酸的加入量为950kg，加 入时间控制在35min；(4) Primary acidolysis: Move the slurry prepared in step (2) into the reaction vessel and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (3) into the slurry from the bottom of the reaction vessel , the amount of dilute sulfuric acid added is 950kg, add The entry time is controlled at 35 minutes;
(5)将酸解完成后的料浆排入方形槽静置30min，使石膏充分沉降，方形槽上方为黑色油状液体；(5) Discharge the slurry after acid hydrolysis into a square tank and let it stand for 30 minutes to allow the gypsum to fully settle, and there will be a black oily liquid above the square tank;
(6)用刮板机刮去步骤(5)中的上层黑色油状液体，分离出上浮的有机物，回收刮板机刮除的油状液体并向其中投入活性炭吸附有机物，吸附完毕后将液体进行压滤，得到的滤饼为脱色渣，压滤后的滤液回收处理后输送至步骤(2)用于调料浆；(6) Use a scraper to scrape off the upper black oily liquid in step (5) to separate the floating organic matter. Recover the oily liquid scraped off by the scraper and put activated carbon into it to absorb the organic matter. After the adsorption is completed, press the liquid Filter, and the obtained filter cake is decolorized residue. The filtrate after pressure filtration is recovered and processed and then transported to step (2) for use in seasoning slurry;
(7)方形槽内的底流浆液送至成化槽，加360kg步骤(3)配制的稀硫酸，成化槽加蒸汽保温，温度控制在65℃，并不停地对料浆进行搅拌，成化时间控制在2h；(7) The underflow slurry in the square tank is sent to the formation tank, and 360kg of dilute sulfuric acid prepared in step (3) is added. Steam is added to the formation tank for insulation, and the temperature is controlled at 65°C. The slurry is continuously stirred to form The melting time is controlled at 2h;
(8)将步骤(7)成化完全后的料浆进行压滤，压滤回收的滤液回收处理后送至磷酸车间作为磷酸生产原料，压滤后的滤饼加工艺水调浆，工艺水的温度、成分及用量同本对比例步骤(2)，获得料浆A；(8) Perform pressure filtration on the complete slurry formed in step (7). The filtrate recovered by the filtration pressure will be recycled and processed and sent to the phosphoric acid workshop as raw material for phosphoric acid production. The filter cake after filtration is added with process water to make slurry. The process water The temperature, composition and dosage are the same as step (2) of this comparative example to obtain slurry A;
(9)将步骤(8)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(2)用以调制浆料A，滤饼经4级逆流洗涤后获得净化磷石膏；(9) Filter the slurry obtained in step (8). The filtered filtrate can be recovered and transported to step (2) to prepare slurry A. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(9)中4级逆流洗涤时后一级洗涤时的滤液作为上一级洗涤的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本对比例步骤(2)相同。步骤(9)中逆流洗涤最终滤液可以回收并输送至步骤(8)对压滤滤饼进行调浆。In step (9), during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing. The washing liquid of the last stage of washing is process water. The temperature, composition and dosage of the process water are the same as those in this comparative example. Same as step (2). The final filtrate from countercurrent washing in step (9) can be recovered and transported to step (8) to slurry the filter cake.
分析本对比例中获得的净化磷石膏的成分，分析结果如下表3所示，所采用的分析方法为磷钼酸喹啉重量法(用以分析磷成分)、ICP-MS(用以分析金属成分)和Q/520122K-002-2020中记载的测试方法(用以分析有机碳成分)，表3中的数据是以净化后的磷石膏除游离水后的干基质量为基准。The components of the purified phosphogypsum obtained in this comparative example were analyzed. The analysis results are shown in Table 3 below. The analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 3 are based on the dry mass of purified phosphogypsum after removing free water.
表3对比例2中回收后的磷石膏的成分分析结果

Table 3 Composition analysis results of the recovered phosphogypsum in Comparative Example 2

由上表3可知，与实施例5相比，对比例2在回收磷石膏时未添加碳酸盐，所回收的磷石膏中的水溶F、水溶P2O5、Mg、Na等杂质的含量均较高，其中，有机碳的杂质含量显著增高，白度显著降低，由此可见，在回收磷石膏时，通过在一次酸解步骤中添加碳酸盐可以显著提高回收的磷石膏的纯度和白度，降低有机碳的杂质含量。It can be seen from Table 3 above that compared with Example 5, Comparative Example 2 did not add carbonate when recovering phosphogypsum, and the content of water-soluble F, water-soluble P 2 O 5 , Mg, Na and other impurities in the recovered phosphogypsum are all relatively high. Among them, the impurity content of organic carbon is significantly increased and the whiteness is significantly reduced. It can be seen that when recycling phosphogypsum, the purity and purity of the recovered phosphogypsum can be significantly improved by adding carbonate in an acidolysis step. Whiteness, reducing the impurity content of organic carbon.
对比例3：Comparative example 3:
本对比例中磷石膏的回收方法，具体包括以下步骤：The recovery method of phosphogypsum in this comparative example specifically includes the following steps:
(1)本对比例选用湖北省某磷复肥厂的磷石膏，该磷石膏颜色呈灰黑色，白度为22.71，游离水含量为25.71％，石膏的水溶磷含量为0.4986％，总磷为1.524％，浸出液pH在1～2之间；(1) This comparative example uses phosphogypsum from a phosphate compound fertilizer factory in Hubei Province. The phosphogypsum is gray-black in color, has a whiteness of 22.71, a free water content of 25.71%, a water-soluble phosphorus content of gypsum of 0.4986%, and a total phosphorus of 1.524%, the pH of the leach solution is between 1 and 2;
(2)按照m磷石膏：m纯碱：m石灰粉＝9:0.4:1.6的质量比称取各物质混合，共计称取2.2吨；(2) Weigh and mix each substance according to the mass ratio of m phosphogypsum : m soda ash : m lime powder = 9:0.4:1.6, weighing a total of 2.2 tons;
(3)将步骤(2)称取的物料置于容器中，加5.5吨工艺水后搅拌调成均匀的料浆，工艺水由清水和蒸汽冷凝液混配而成，温度控制在70℃；(3) Place the material weighed in step (2) into a container, add 5.5 tons of process water and stir to form a uniform slurry. The process water is a mixture of clean water and steam condensate, and the temperature is controlled at 70°C;
(4)配制质量分数为40％的稀磷酸；(4) Prepare dilute phosphoric acid with a mass fraction of 40%;
(5)酸解脱色：将步骤(3)配制的料浆移入反应容器，并在400r/min的转速下不停地搅拌，将步骤(4)配制的稀硫酸从反应容器底部加入料浆中，稀硫酸的加入量为950kg，加入时间控制在35min；(5) Acid decolorization: Move the slurry prepared in step (3) into the reaction vessel, and stir continuously at a rotation speed of 400r/min. Add the dilute sulfuric acid prepared in step (4) into the slurry from the bottom of the reaction vessel. , the adding amount of dilute sulfuric acid is 950kg, and the adding time is controlled at 35min;
(6)反应完全后继续搅拌20min，然后将反应后的料浆排入方形槽静置30min，使石膏料浆与有机浮沫充分分层；(6) After the reaction is complete, continue stirring for 20 minutes, then discharge the reacted slurry into a square tank and let it stand for 30 minutes to fully stratify the gypsum slurry and organic foam;
(7)用刮板机刮去步骤(6)中方形槽上层浮沫，方形槽的底流送至成化槽；(7) Use a scraper to scrape off the scum on the upper layer of the square tank in step (6), and send the bottom flow of the square tank to the forming tank;
(8)将步骤(7)中刮板机刮除的带沫液体送至压滤机压滤处理，滤饼为脱色渣，压滤后的滤液回收处理后输送至步骤(3)用于调制料浆；(8) Send the foamy liquid scraped by the scraper in step (7) to the filter press for filtration processing. The filter cake is decolorized residue. The filtrate after filtration is recovered and processed and sent to step (3) for preparation. slurry;
(9)步骤(7)中方形槽的底流液体送至成化槽，加360kg步骤(4)配制的稀硫酸，成化槽加蒸汽保温，温度控制在65℃，并不停地对料浆进行搅拌，成化时间控制在2h；(9) The underflow liquid in the square tank in step (7) is sent to the forming tank, and 360kg of the dilute sulfuric acid prepared in step (4) is added. Steam is added to the forming tank for heat preservation. The temperature is controlled at 65°C, and the slurry is continuously heated Stir and control the formation time to 2 hours;
(10)将成化完全后的料浆进行压滤，压滤回收的滤液回收处理后送至磷酸车间作为磷酸生产原料，压滤后的滤饼加工艺水调浆，工艺水的温度、成分及用量同本对比例步骤(3)，获得料浆A；(10) The slurry after complete formation is filtered, and the filtrate recovered by the filter is recycled and processed and sent to the phosphoric acid workshop as a raw material for phosphoric acid production. The filter cake after filtering is added with process water to make slurry. The temperature, composition and The dosage is the same as step (3) of this comparative example to obtain slurry A;
(11)将步骤(10)获得的料浆进行过滤，过滤后的滤液可以回收并输送至步骤(3)用以调制浆料，滤饼经4级逆流洗涤后获得净化磷石膏； (11) Filter the slurry obtained in step (10). The filtered filtrate can be recovered and transported to step (3) to prepare the slurry. The filter cake is washed with four levels of countercurrent to obtain purified phosphogypsum;
步骤(11)中4级逆流洗涤时后一级洗涤时的滤液作为上一级洗涤的洗涤液使用，最后一级洗涤的洗液为工艺水，工艺水的温度、成分及用量与本对比例步骤(3)相同。步骤(11)中逆流洗涤最终滤液可以回收并输送至步骤(10)对压滤滤饼进行调浆。In step (11), during the 4-stage countercurrent washing, the filtrate from the last stage of washing is used as the washing liquid of the previous stage of washing. The washing liquid of the last stage of washing is process water. The temperature, composition and dosage of the process water are the same as those in this comparative example. Step (3) is the same. The final filtrate from countercurrent washing in step (11) can be recovered and transported to step (10) to slurry the filter cake.
分析本对比例中获得的净化磷石膏的成分，分析结果如下表4所示，所采用的分析方法为磷钼酸喹啉重量法(用以分析磷成分)、ICP-MS(用以分析金属成分)和Q/520122K-002-2020中记载的测试方法(用以分析有机碳成分)，表4中的数据是以净化后的磷石膏除游离水后的干基质量为基准。The components of the purified phosphogypsum obtained in this comparative example were analyzed. The analysis results are shown in Table 4 below. The analysis methods used were quinoline phosphomolybdate gravimetric method (for analyzing phosphorus components) and ICP-MS (for analyzing metals). Composition) and the test method recorded in Q/520122K-002-2020 (for analyzing organic carbon composition), the data in Table 4 are based on the dry mass of purified phosphogypsum after removing free water.
表4对比例3中回收后的磷石膏成分分析结果
Table 4 Analysis results of recovered phosphogypsum components in Comparative Example 3
由上表4可知，与实施例5相比，对比例3在回收磷石膏时减少了碳酸盐中可溶性碳酸盐的用量，所回收的磷石膏中的水溶F、水溶P2O5、Mg、Na等杂质的含量均相对增高，特别是总P2O5的含量显著增高，由此可见，在回收磷石膏时，通过在一次酸解步骤中添加碳酸盐可以显著提高回收的磷石膏的纯度，降低有机碳的杂质含量，且当可溶性碳酸盐的含量大于40％时，有利于释放磷石膏包裹的各类杂质，使回收的磷石膏的纯度更高。It can be seen from Table 4 above that compared with Example 5, Comparative Example 3 reduced the amount of soluble carbonate in carbonate when recovering phosphogypsum. The water-soluble F, water-soluble P 2 O 5 , and water-soluble carbonate in the recovered phosphogypsum were The contents of impurities such as Mg and Na increased relatively, especially the total P 2 O 5 content increased significantly. It can be seen that when recovering phosphogypsum, adding carbonate in the first acidolysis step can significantly increase the recovered phosphorus. The purity of gypsum reduces the impurity content of organic carbon, and when the content of soluble carbonate is greater than 40%, it is beneficial to release various impurities wrapped in phosphogypsum, making the recovered phosphogypsum higher in purity.
上面对本发明实施例作了详细说明，但是本发明不限于上述实施例，在所属技术领域普通技术人员所具备的知识范围内，还可以在不脱离本发明宗旨的前提下做出各种变化。此外，在不冲突的情况下，本发明的实施例及实施例中的特征可以相互组合。 The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those of ordinary skill in the art without departing from the gist of the present invention. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

Claims (10)

  1. 一种磷石膏的回收方法，其特征在于：该回收方法包括以下步骤：A method for recycling phosphogypsum, characterized in that: the method includes the following steps:
    将磷石膏与碳酸盐混合进行一次酸解，去除浮沫，再进行二次酸解，然后压滤并洗涤，得到纯化后的磷石膏。Mix phosphogypsum and carbonate for primary acidolysis to remove scum, then perform secondary acidolysis, and then filter and wash to obtain purified phosphogypsum.
  2. 根据权利要求1所述的磷石膏的回收方法，其特征在于：所述磷石膏与碳酸盐的质量比为(4～9)：1。The method for recovering phosphogypsum according to claim 1, characterized in that: the mass ratio of the phosphogypsum to carbonate is (4-9):1.
  3. 根据权利要求1所述的磷石膏的回收方法，其特征在于：所述一次酸解步骤和/或二次酸解步骤所用的酸液为硫酸。The method for recovering phosphogypsum according to claim 1, characterized in that: the acid liquid used in the primary acidolysis step and/or the secondary acidolysis step is sulfuric acid.
  4. 根据权利要求1～3任一项所述的磷石膏的回收方法，其特征在于：所述将磷石膏与碳酸盐混合进行一次酸解步骤具体为：将磷石膏、碳酸盐和水混合制得浆液A，然后从浆液A底部通入酸液并搅拌，得到含沫料浆。The method for recovering phosphogypsum according to any one of claims 1 to 3, characterized in that: the step of mixing phosphogypsum and carbonate to perform primary acidolysis is specifically: mixing phosphogypsum, carbonate and water. Slurry A is prepared, and then acid solution is introduced from the bottom of slurry A and stirred to obtain a foam-containing slurry.
  5. 根据权利要求1所述的磷石膏的回收方法，其特征在于：所述洗涤采用逆流洗涤的方法；优选地，所述逆流洗涤的级数为2～6级；优选地，所述下一级逆流洗涤的排出液用作上一级逆流洗涤的洗液。The method for recovering phosphogypsum according to claim 1, characterized in that: the washing adopts a countercurrent washing method; preferably, the number of stages of the countercurrent washing is 2 to 6; preferably, the next stage The discharge liquid from the counter-current washing is used as the washing liquid for the upper-stage counter-current washing.
  6. 根据权利要求1所述的磷石膏的回收方法，其特征在于：所述压滤步骤具体为：将压滤步骤得到的液体作为磷酸生产原料输送至磷酸生产车间，并将压滤步骤得到的固体调制成浆液B后过滤。The phosphogypsum recovery method according to claim 1, characterized in that: the filtration step specifically includes: transporting the liquid obtained in the filtration step as a raw material for phosphoric acid production to the phosphoric acid production workshop, and using the solid obtained in the filtration step to Prepare slurry B and filter.
  7. 一种磷石膏，其特征在于：采用权利要求1～6任一项所述的方法制得。A kind of phosphogypsum, characterized in that: it is prepared by the method described in any one of claims 1 to 6.
  8. 权利要求7所述的磷石膏在建筑材料中的应用。Application of the phosphogypsum described in claim 7 in building materials.
  9. 一种磷石膏的回收***，其特征在于：所述回收***用于实施权利要求1～6任一项所述的回收方法，所述回收***包括酸解装置、方形槽、成化槽、过滤***及逆流洗涤装置，所述酸解装置底部设有第一酸液入口，酸解装置与方形槽连接，方形槽上设有刮板机，方形槽与成化槽连接，成化槽上设有第二酸液入口，成化槽与过滤***连接，过滤***的固体出口与逆流洗涤装置连接。A phosphogypsum recovery system, characterized in that: the recovery system is used to implement the recovery method according to any one of claims 1 to 6, and the recovery system includes an acidolysis device, a square tank, a formation tank, a filter system and countercurrent washing device. The bottom of the acidolysis device is provided with a first acid liquid inlet. The acidolysis device is connected to a square tank. A scraper is provided on the square tank. The square tank is connected to a forming tank. There is a scraper on the forming tank. There is a second acid liquid inlet, the formation tank is connected to the filtration system, and the solid outlet of the filtration system is connected to the countercurrent washing device.
  10. 根据权利要求9所述的磷石膏的回收***，其特征在于：所述过滤***包括压滤装置、调浆装置及过滤装置，所述压滤装置与成化槽连接，压滤装置的液体出口与磷酸生产***连接，压滤装置的固体出口与调浆装置连接，调浆装置与过滤装置连接，过滤装置的固体出口与逆流洗涤装置连接。 The phosphogypsum recovery system according to claim 9, characterized in that: the filtration system includes a filter press device, a slurry adjusting device and a filter device, the filter press device is connected to the formation tank, and the liquid outlet of the filter press device It is connected to the phosphoric acid production system, the solid outlet of the filter press device is connected to the slurry adjusting device, the slurry adjusting device is connected to the filtering device, and the solid outlet of the filtering device is connected to the countercurrent washing device.
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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3951675A (en) * 1972-10-02 1976-04-20 Centre D'etudes Et De Recherches Des Phosphates Mineraux Cerphos Method for the treatment of phosphogypsum
US4301130A (en) * 1978-05-06 1981-11-17 Politechnika Wroclawska Method of washing waste phosphogypsum
CN103288118A (en) * 2013-05-24 2013-09-11 东莞上海大学纳米技术研究院 Method for dissociating industrial by-product gypsum and crystallizing to grow calcium sulphate crystal whiskers
US20140044619A1 (en) * 2012-08-10 2014-02-13 Sparstane Technologies LLC Process for converting fgd gypsum to ammonium sulfate and calcium carbonate
CN206502610U (en) * 2017-02-16 2017-09-19 内江师范学院 A kind of system of use desulfurated plaster coproduction nano-calcium carbonate, ammonium sulfate and sodium chloride
CN108796612A (en) * 2018-06-06 2018-11-13 湖北三宁化工股份有限公司 A kind of method of ardealite Cycle-decomposition Sulphuric acid calcium pyroborate coproduction of ammonia sulfate
CN111072054A (en) * 2019-12-31 2020-04-28 安徽六国化工股份有限公司 Preparation of high-purity gypsum powder and byproduct NH from phosphogypsum4Cl process
CN112808736A (en) * 2020-12-21 2021-05-18 贵州昊华工程技术有限公司 Purification and harmless treatment method of phosphogypsum
CN115504695A (en) * 2022-09-06 2022-12-23 宜昌邦普循环科技有限公司 Phosphogypsum recycling method

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1876204B (en) * 2006-07-06 2010-07-07 上海南化水处理技术工程有限公司 Ardealite innocent treatment method
CN101850992A (en) * 2010-02-11 2010-10-06 汪晋强 Method for preparing calcium carbonate and co-producing sodium sulfate by using phosphorus gypsum and soda ash
CN102352535B (en) * 2011-09-22 2014-01-29 东莞上海大学纳米技术研究院 Method for preparing calcium sulfate crystal whiskers from desulfurized gypsum under normal pressure
CN104495774A (en) * 2014-12-08 2015-04-08 宜昌市三峡天润纳米材料工程技术研究中心有限公司 Method for co-production of nanometer hydroxyapatite and calcium sulfate whisker from phosphogypsum
CN105220233A (en) * 2015-10-22 2016-01-06 昆明理工大学 A kind of take phosphogypsum as the method that high-purity sulphuric acid calcium pyroborate prepared by raw material
CN206244428U (en) * 2016-12-02 2017-06-13 钱程 A kind of removal of impurities device for improving quality of industry by-product gypsum
CN107473775B (en) * 2017-09-07 2020-04-10 中化云龙有限公司 Method for recovering phosphorus and fluorine in phosphoric acid concentrated slag acid and co-producing low-fluorine water-soluble fertilizer
RU2680589C1 (en) * 2018-05-24 2019-02-22 Общество с ограниченной ответственностью "Гибридные удобрения" Method of processing phosphogypsum for phosphorous fertilizer
CN210030481U (en) * 2019-03-08 2020-02-07 安徽六国化工股份有限公司 Phosphogypsum stacking and collecting device
CN110316708A (en) * 2019-06-06 2019-10-11 贵州川恒化工股份有限公司 The method that phosphorus ore produces half water phosphoric acid coproduction alpha type high-strength gypsum
RU2703644C1 (en) * 2019-06-13 2019-10-21 Федеральное государственное бюджетное образовательное учреждение высшего образования "Челябинский государственный университет" Method of producing gypsum binder from gypsum-containing slurry
CN112897529A (en) * 2021-02-01 2021-06-04 江苏一夫科技股份有限公司 Method for extracting silicon dioxide from phosphogypsum
CN112978781A (en) * 2021-04-13 2021-06-18 中国五环工程有限公司 Phosphogypsum harmless treatment method
CN113120875B (en) * 2021-04-25 2022-12-30 云南云天化股份有限公司 Production method of low-impurity wet-process phosphoric acid and high-quality alpha-hemihydrate gypsum
CN114572951B (en) * 2022-01-28 2023-09-12 宜昌邦普循环科技有限公司 Doped ferric phosphate and preparation method and application thereof
CN114703368A (en) * 2022-02-21 2022-07-05 云锡文山锌铟冶炼有限公司 Method for treating zinc-indium-containing gypsum slag

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3951675A (en) * 1972-10-02 1976-04-20 Centre D'etudes Et De Recherches Des Phosphates Mineraux Cerphos Method for the treatment of phosphogypsum
US4301130A (en) * 1978-05-06 1981-11-17 Politechnika Wroclawska Method of washing waste phosphogypsum
US20140044619A1 (en) * 2012-08-10 2014-02-13 Sparstane Technologies LLC Process for converting fgd gypsum to ammonium sulfate and calcium carbonate
CN103288118A (en) * 2013-05-24 2013-09-11 东莞上海大学纳米技术研究院 Method for dissociating industrial by-product gypsum and crystallizing to grow calcium sulphate crystal whiskers
CN206502610U (en) * 2017-02-16 2017-09-19 内江师范学院 A kind of system of use desulfurated plaster coproduction nano-calcium carbonate, ammonium sulfate and sodium chloride
CN108796612A (en) * 2018-06-06 2018-11-13 湖北三宁化工股份有限公司 A kind of method of ardealite Cycle-decomposition Sulphuric acid calcium pyroborate coproduction of ammonia sulfate
CN111072054A (en) * 2019-12-31 2020-04-28 安徽六国化工股份有限公司 Preparation of high-purity gypsum powder and byproduct NH from phosphogypsum4Cl process
CN112808736A (en) * 2020-12-21 2021-05-18 贵州昊华工程技术有限公司 Purification and harmless treatment method of phosphogypsum
CN115504695A (en) * 2022-09-06 2022-12-23 宜昌邦普循环科技有限公司 Phosphogypsum recycling method

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