Phosphogypsum composite cat litter and in-situ solidification preparation method thereof

Abstract

The application discloses phosphogypsum composite cat litter and belongs to the technical field of cat litter. The phosphogypsum composite cat litter comprises components in mass fractions: 70-85 parts of primary raw phosphogypsum base material, 8-18 parts of in-situ composite solidification and activation system, 3-10 parts of porous adsorption modified filler, 0.8-3 parts of biological slow-release deodorization and bacteriostasis component, and 12-22 parts of deionized water. The primary raw phosphogypsum base material is fresh wet-state phosphogypsum by-produced in wet-process phosphoric acid production, which has not been calcined, activated by steam pressure, or pretreated at high temperature, and the water content is controlled to be 18-26%, and the 80-mesh screening passing rate is greater than or equal to 98%. The in-situ composite solidification and activation system is a magnesium-silicon gel composite stabilization system. In the application, the primary uncalcined phosphogypsum can be directly used to prepare high-strength cat litter, the high-temperature calcination and high-temperature long-time drying processes are cancelled, the production energy consumption is greatly reduced, the production cycle is greatly shortened, and high-temperature carbon emission is avoided.

Description

Technical Field

[0001] This invention belongs to the field of cat litter technology, and particularly relates to a phosphogypsum composite cat litter and its in-situ curing preparation method. Background Technology

[0002] Pet litter is an essential consumable for cat owners, with huge market demand. Traditional bentonite cat litter mining is ecologically damaging, generates a lot of dust, and is non-biodegradable; tofu cat litter consumes a large amount of food, is costly, prone to mold and spoilage, and easily clumps and falls apart; existing phosphogypsum-based cat litter relies on industrial solid waste, has the advantages of low cost, large reserves, and green recycling, and represents a new research and development direction for the industry. However, the existing technology system has many fundamental defects and has not yet achieved large-scale industrial application. The specific defects are as follows:

[0003] Traditionally prepared cat litter lacks structural strength, crumbles upon contact with water, severely sticks to claws, and sheds excessive powder, resulting in low product quality. Furthermore, existing technologies generally require multiple pretreatment processes for phosphogypsum, including pre-neutralization, washing to remove impurities, and aging modification, making the process lengthy and complex. Moreover, current phosphogypsum cat litter typically uses single or compound organic / inorganic binders such as CMC, xanthan gum, guar gum, starch, and water glass, relying solely on physical surface coating and bonding to form the litter. Without the formation of a chemical hydration gelling network, the resulting particles have a loose internal structure, poor dry-state wear resistance, and are prone to powdering during transport, leading to unsatisfactory practical applications. To address these issues, a phosphogypsum composite cat litter and its in-situ curing preparation method are urgently needed. Summary of the Invention

[0004] The purpose of this invention is to provide a phosphogypsum composite cat litter and its in-situ curing preparation method in order to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a phosphogypsum composite cat litter, comprising the following components in parts by weight:

[0006] The composition comprises 70-85 parts of raw phosphogypsum base material, 8-18 parts of in-situ composite solidification and activation system, 3-10 parts of porous adsorption modified filler, 0.8-3 parts of biological slow-release deodorizing and antibacterial component, and 12-22 parts of deionized water. The raw phosphogypsum base material is a byproduct of wet-process phosphoric acid production, fresh wet phosphogypsum that has not undergone calcination, autoclaving activation, or high-temperature pretreatment, with a moisture content controlled at 18-26% and an 80-mesh sieve passing rate ≥98%. The in-situ composite solidification and activation system is a magnesium silicate coagulation composite stabilization system, composed of lightly calcined magnesium oxide, silica fume, citric acid complexing stabilizer, and S95 ultrafine slag powder.

[0007] As a further description of the above technical solution:

[0008] The mass percentages of each component in the in-situ composite curing activation system are as follows: 40-50% light-burned magnesium oxide, 25-35% silica fume, 0.5-1.2% citric acid, and the balance being S95 ultrafine slag powder; the light-burned magnesium oxide has an activity ≥60s and a magnesium oxide content ≥85%; the silica fume has a SiO2 content ≥92% and a surface area ≥18000m² / kg; the S95 ultrafine slag powder has a surface area ≥420m² / kg. 2 / kg.

[0009] As a further description of the above technical solution:

[0010] The porous adsorption modified filler is composed of clinoptilolite powder and waste edible fungus residue biochar at a mass ratio of 1:2; the clinoptilolite powder is 100 mesh powder with a porosity ≥45%; the waste edible fungus residue biochar is obtained by carbonizing the fungus residue at 400-450℃ under limited oxygen and crushing it through a 100 mesh sieve, with an iodine adsorption value ≥380mg / g.

[0011] As a further description of the above technical solution:

[0012] The biological slow-release deodorizing and antibacterial component is composed of sodium alginate microcapsules loaded with urease and chitin powder in a mass ratio of 2:1; the sodium alginate microcapsules loaded with urease have a particle size of 200-400 μm and a urease loading of 8-12 wt%, and slowly dissolve and release active enzymes upon contact with water; the chitin powder has a degree of deacetylation ≥85% and a fineness of 100 mesh.

[0013] This invention also discloses an in-situ solidification preparation method for phosphogypsum composite cat litter, the specific steps of which are as follows:

[0014] S1. Perform raw material pretreatment and dry material premixing;

[0015] S2. Perform room temperature spray granulation and simultaneous in-situ hydration and curing;

[0016] S3. Perform low-temperature rapid ripening and shaping;

[0017] S4. Perform surface low-dust modification treatment.

[0018] As a further description of the above technical solution:

[0019] In step S1, raw material pretreatment and dry material premixing are carried out. The specific steps are as follows: fresh raw wet phosphogypsum is screened to remove impurities and debris, ensuring that the 80-mesh pass rate is ≥98%; then, in-situ composite solidification activation system, porous adsorption modified filler, and biological slow-release deodorizing and antibacterial components are added in sequence according to the formula, and put into a horizontal high-power mixer. The mixture is then dry-mixed at room temperature in a closed environment for 6-10 minutes at a stirring speed of 250-300 r / min to obtain a uniform composite dry powder material.

[0020] As a further description of the above technical solution:

[0021] In step S2, simultaneous in-situ hydration and solidification are carried out via room temperature spray granulation. The specific steps are as follows: the composite dry powder obtained in step S1 is fed into a disc granulator, and a quantitative amount of deionized water is continuously sprayed using a high-pressure atomization method under room temperature. The rotation speed of the disc granulator is controlled at 30-40 r / min, and continuous rolling granulation is performed for 8-15 min. The sprayed water simultaneously triggers the hydration and gelation reaction of the in-situ composite solidification activation system. During the granulation and rolling molding process, a symbiotic gelation network of hydrated magnesium silicate, hydrated calcium silicate, and dihydrate gypsum is generated in situ inside the particles, simultaneously completing acid neutralization, soluble phosphorus and fluorine complexation passivation, and heavy metal ion stabilization and solidification, achieving integrated molding, solidification, and impurity removal. After granulation, the particles are screened by a vibrating screen, and qualified intermediate particles of 1.5-4 mm are collected. Fine powder with a particle size <1 mm is all recycled for granulation.

[0022] As a further description of the above technical solution:

[0023] In step S3, a low-temperature rapid curing and shaping process is performed. The specific steps are as follows: the qualified intermediate particles after screening are sent into a low-temperature hot air curing chamber, the curing temperature is controlled at 40-55℃ and the hot air velocity is 1.2-1.8m / s, and the curing is carried out at a constant temperature for 30-90 minutes. Only the free moisture on the surface of the particles is removed, and the final moisture content of the finished product is controlled at 6-9%. The internal gelation and solidification structure, impurity stabilization structure and deodorization function structure of the particles have been fully formed in the granulation stage. The low-temperature curing only plays a role in shaping and dust suppression and does not participate in the structure formation reaction.

[0024] As a further description of the above technical solution:

[0025] In step S4, a surface low-dust modification treatment is carried out. The specific steps are as follows: prepare a low-viscosity sodium alginate aqueous solution with a mass concentration of 0.3-0.8%, and uniformly spray the matured particles with a low-pressure atomization method to coat them. The spraying amount is 1.5-3% of the total mass of the particles. Let them air dry at room temperature for 15-25 minutes to finally obtain a low-dust, high-strength, long-lasting deodorizing phosphogypsum composite cat litter product.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] This invention enables the direct preparation of high-strength cat litter from uncalcined phosphogypsum, eliminating the need for high-temperature calcination and prolonged high-temperature drying processes. This significantly reduces energy consumption and shortens the production cycle, while eliminating high-temperature carbon emissions. Furthermore, this invention abandons the traditional physical bonding method, generating an inorganic cementitious network in situ through magnesium-silicon hydration reaction. The resulting particles have a dense and stable structure, are wear-resistant and dust-free in the dry state, quickly clump together upon contact with urine, and are resistant to erosion and do not disintegrate. The clumping strength is significantly improved compared to traditional phosphogypsum cat litter, completely solving the problems of powder shedding, clumping, and sticking to paws.

[0028] In this invention, by setting up a triple mechanism of alkalization neutralization, citric acid complexation and gel encapsulation within the process, soluble phosphorus, fluorine and heavy metal ions of phosphogypsum can be fixed in one go, solving the problems of acid reflux, salting out and ion dissolution from the root. The product is safe and non-toxic, meets the safety standards for pet products, and the material does not have the defects of starch and easy mold growth. The deodorization effect is far superior to traditional absorbent cat litter, and there is no odor rebound or mold growth after long-term use.

[0029] In this invention, the material can consume industrial solid waste of phosphogypsum and agricultural solid waste of edible fungi residue. The waste cat litter clumps are non-toxic and harmless, can be naturally degraded, and can be directly used for soil improvement in landscaping, achieving a completely green cycle. Moreover, the raw materials are cheap and readily available, the process is simple, the equipment investment is low, and the production efficiency is high. It can be directly adapted to existing cat litter production lines without major modifications, and has a very strong market promotion prospect. Attached Figure Description

[0030] Figure 1 This is a flowchart of an in-situ solidification preparation method for phosphogypsum composite cat litter. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] Please see Figure 1 This invention provides a technical solution: a phosphogypsum composite cat litter, comprising the following components in the following amounts:

[0034] The composition includes 70 parts of raw phosphogypsum base material, 8 parts of in-situ composite solidification and activation system, 3 parts of porous adsorption modified filler, 0.8 parts of biological slow-release deodorizing and antibacterial component, and 12 parts of deionized water. The raw phosphogypsum base material is a byproduct of wet-process phosphoric acid production, fresh wet phosphogypsum that has not undergone calcination, autoclaving activation, or high-temperature pretreatment, with a moisture content controlled at 18%, and an 80-mesh sieve passing rate ≥98%. The in-situ composite solidification and activation system is a magnesium silicate coagulation composite stabilization system, composed of lightly calcined... The in-situ composite curing and activation system is composed of magnesium oxide, silica fume, citric acid complexing stabilizer, and S95 ultrafine slag powder. The mass percentages of each component in the system are: 40% light-burned magnesium oxide, 25% silica fume, 0.5% citric acid, and the balance being S95 ultrafine slag powder. The light-burned magnesium oxide has an activity ≥60s and a magnesium oxide content ≥85%. The silica fume has a SiO2 content ≥92% and a surface area ≥18000 m² / kg. The S95 ultrafine slag powder has a surface area ≥420 m² / kg. 2 / kg, the porous adsorption modified filler is composed of clinoptilolite powder and waste edible fungus residue biochar in a mass ratio of 1:2; the clinoptilolite powder is 100 mesh powder with a porosity ≥45%; the waste edible fungus residue biochar is obtained by carbonizing the fungus residue at 400℃ under limited oxygen and crushing it through a 100 mesh sieve, with an iodine adsorption value ≥380mg / g; the biological slow-release deodorizing and antibacterial component is composed of urease-loaded sodium alginate microcapsules and chitin powder in a mass ratio of 2:1; the urease-loaded sodium alginate microcapsules have a particle size of 200μm, a urease loading of 8wt%, and slowly dissolve and release active enzymes upon contact with water; the chitin powder has a deacetylation degree ≥85% and a 100 mesh fineness.

[0035] In this embodiment, high-strength cat litter can be directly prepared from virgin uncalcined phosphogypsum, eliminating the high-temperature calcination and long-term high-temperature drying processes, significantly reducing production energy consumption and shortening the production cycle. There are no high-temperature carbon emissions. Furthermore, this invention abandons the traditional physical bonding mode and generates an inorganic cementitious network in situ through magnesium-silicon hydration reaction. The particle structure is dense and stable, dry, wear-resistant and dust-free, quickly clumps upon contact with urine, and is resistant to erosion and does not collapse. The clumping strength is significantly improved compared to traditional phosphogypsum cat litter, completely solving the problems of powder shedding, clumping, and sticking to paws.

[0036] Example 2

[0037] Please see Figure 1 This invention provides a technical solution: an in-situ solidification preparation method for phosphogypsum composite cat litter, the specific steps of which are as follows:

[0038] S1. Perform raw material pretreatment and dry material premixing. The specific steps are as follows: screen the fresh raw wet phosphogypsum to remove lumpy impurities and debris, ensuring that the 80-mesh passing rate is ≥98%; then add the in-situ composite solidification activation system, porous adsorption modified filler, and biological slow-release deodorizing and antibacterial components in sequence according to the formula, put them into a horizontal high-power mixer, dry mix at room temperature in a closed environment for 6 minutes, and stir at a speed of 250 r / min to obtain a uniform composite dry powder material.

[0039] S2. Perform room temperature spray granulation with simultaneous in-situ hydration and curing. The specific steps are as follows: The composite dry powder obtained in S1 is fed into a disc granulator. Under room temperature, a quantitative amount of deionized water is continuously sprayed using a high-pressure atomization method. The rotation speed of the disc granulator is controlled at 30 r / min, and continuous rolling granulation is performed for 8 minutes. The sprayed water simultaneously triggers the hydration and gelation reaction of the in-situ composite curing system. During the granulation and rolling molding process, a symbiotic gelation network of hydrated magnesium silicate, hydrated calcium silicate, and dihydrate gypsum is generated in-situ inside the particles. Simultaneously, acid neutralization, soluble phosphorus and fluoride complexation passivation, and heavy metal ion stabilization and curing are completed, realizing the integration of molding, curing, and impurity removal. After granulation, the particles are screened by a vibrating screen to collect qualified intermediate particles of 1.5 mm. All fine powder with a particle size <1 mm is recycled for granulation.

[0040] S3. Perform low-temperature rapid curing and shaping. The specific steps are as follows: send the qualified intermediate particles after screening into the low-temperature hot air curing chamber, control the curing temperature at 40℃ and the hot air velocity at 1.2m / s, and cure at a constant temperature for 30 minutes. Only remove the free moisture on the surface of the particles, and control the final moisture content of the finished product to 6%. The internal gelation and solidification structure, impurity stabilization structure and deodorization function structure of the particles have been fully formed in the granulation stage. Low-temperature curing only plays a role in shaping and dust suppression and does not participate in the structure formation reaction.

[0041] S4. Perform surface low-dust modification treatment. The specific steps are as follows: prepare a low-viscosity sodium alginate aqueous solution with a mass concentration of 0.3%, and use a low-pressure atomization method to uniformly spray and coat the matured particles. The spraying amount is 1.5% of the total mass of the particles. Let it air dry at room temperature for 15 minutes to finally obtain a low-dust, high-strength, long-lasting deodorizing phosphogypsum composite cat litter product.

[0042] In this embodiment, by setting up a triple mechanism of alkalization neutralization, citric acid complexation and gel encapsulation in the process, the soluble phosphorus, fluorine and heavy metal ions of phosphogypsum can be fixed in one go, solving the problems of acid reflux, salting out and ion dissolution from the root. The product is safe and non-toxic, meets the safety standards for pet products, and the material does not have the defects of starch and easy mold growth. The deodorization effect is far superior to traditional absorbent cat litter. There is no odor rebound and no mold growth after long-term use.

[0043] Example 3

[0044] Please see Figure 1This invention provides a technical solution: an in-situ solidification preparation method for phosphogypsum composite cat litter, the specific steps of which are as follows:

[0045] S1. Perform raw material pretreatment and dry material premixing. The specific steps are as follows: screen the fresh raw wet phosphogypsum to remove impurities and debris, ensuring that the 80-mesh pass rate is ≥98%; then add the in-situ composite solidification activation system, porous adsorption modified filler, and biological slow-release deodorizing and antibacterial components in sequence according to the formula, put them into a horizontal high-power mixer, dry mix in a sealed environment at room temperature for 10 minutes, and stir at a speed of 300 r / min to obtain a uniform composite dry powder material.

[0046] S2. Perform room temperature spray granulation with simultaneous in-situ hydration and curing. The specific steps are as follows: The composite dry powder obtained in S1 is fed into a disc granulator. Under room temperature, a quantitative amount of deionized water is continuously sprayed using a high-pressure atomization method. The rotation speed of the disc granulator is controlled at 40 r / min, and continuous rolling granulation is performed for 15 min. The sprayed water simultaneously triggers the hydration and gelation reaction of the in-situ composite curing system. During the granulation and rolling molding process, a symbiotic gelation network of hydrated magnesium silicate, hydrated calcium silicate, and dihydrate gypsum is generated in-situ inside the particles. Simultaneously, acid neutralization, soluble phosphorus and fluoride complexation passivation, and heavy metal ion stabilization and curing are completed, realizing the integration of molding, curing, and impurity removal. After granulation, the particles are screened by a vibrating screen, and qualified intermediate particles of 4 mm are collected. Fine powder with a particle size <1 mm is all recycled for granulation.

[0047] S3. Perform low-temperature rapid curing and shaping. The specific steps are as follows: send the qualified intermediate particles after screening into the low-temperature hot air curing chamber, control the curing temperature at 55℃ and the hot air velocity at 1.8m / s, and cure at a constant temperature for 90 minutes. Only remove the free moisture on the surface of the particles, and control the final moisture content of the finished product to 9%. The internal gelation and solidification structure, impurity stabilization structure and deodorization function structure of the particles have been fully formed in the granulation stage. Low-temperature curing only plays a role in shaping and dust suppression and does not participate in the structure formation reaction.

[0048] S4. Perform surface low-dust modification treatment. The specific steps are as follows: prepare a low-viscosity sodium alginate aqueous solution with a mass concentration of 0.8%, and use a low-pressure atomization method to uniformly spray and coat the matured particles. The spraying amount is 3% of the total mass of the particles. Let it air dry at room temperature for 25 minutes to finally obtain a low-dust, high-strength, long-lasting deodorizing phosphogypsum composite cat litter product.

[0049] In this embodiment, the material can consume industrial solid waste of phosphogypsum and agricultural solid waste of edible fungi residue. The waste cat litter clumps are non-toxic and harmless, can be naturally degraded, and can be directly used for soil improvement in landscaping, achieving a completely green cycle. Moreover, the raw materials are cheap and readily available, the process is simple, the equipment investment is low, and the production efficiency is high. It can be directly adapted to existing cat litter production lines without major modifications, and has a very strong market promotion prospect.

[0050] Example 4

[0051] Please see Figure 1 This invention provides a technical solution: an in-situ solidification preparation method for phosphogypsum composite cat litter, the specific steps of which are as follows:

[0052] S1. Perform raw material pretreatment and dry material premixing. The specific steps are as follows: screen the fresh raw wet phosphogypsum to remove impurities and debris, ensuring that the 80-mesh passing rate is ≥98%; then add the in-situ composite solidification activation system, porous adsorption modified filler, and biological slow-release deodorizing and antibacterial components in sequence according to the formula, put them into a horizontal high-power mixer, dry mix at room temperature in a closed environment for 8 minutes, and stir at a speed of 280 r / min to obtain a uniform composite dry powder material.

[0053] S2. Perform room temperature spray granulation with simultaneous in-situ hydration and curing. The specific steps are as follows: The composite dry powder obtained in S1 is fed into a disc granulator. Under room temperature, a quantitative amount of deionized water is continuously sprayed using a high-pressure atomization method. The rotation speed of the disc granulator is controlled at 35 r / min, and continuous rolling granulation is performed for 12 min. The sprayed water simultaneously triggers the hydration and gelation reaction of the in-situ composite curing system. During the granulation and rolling molding process, a symbiotic gelation network of hydrated magnesium silicate, hydrated calcium silicate, and dihydrate gypsum is generated in-situ inside the particles. Simultaneously, acid neutralization, soluble phosphorus and fluorine complexation passivation, and heavy metal ion stabilization and curing are completed, realizing the integration of molding, curing, and impurity removal. After granulation, the particles are screened by a vibrating screen, and qualified intermediate particles of 3 mm are collected. Fine powder with a particle size <1 mm is all recycled for granulation.

[0054] S3. Perform low-temperature rapid curing and shaping. The specific steps are as follows: send the qualified intermediate particles after screening into the low-temperature hot air curing chamber, control the curing temperature at 45℃ and the hot air velocity at 1.6m / s, and cure at a constant temperature for 60 minutes. Only remove the free moisture on the surface of the particles, and control the final moisture content of the finished product to 7%. The internal gelation and solidification structure, impurity stabilization structure and deodorization function structure of the particles have been fully formed in the granulation stage. Low-temperature curing only plays a role in shaping and dust suppression and does not participate in the structure formation reaction.

[0055] S4. Perform surface low-dust modification treatment. The specific steps are as follows: prepare a 0.5% (w / w) low-viscosity sodium alginate aqueous solution, use low-pressure atomization to uniformly spray and coat the matured particles, the spray amount is 2% of the total mass of the particles, and air dry at room temperature for 20 minutes to finally obtain a low-dust, high-strength, long-lasting deodorizing phosphogypsum composite cat litter product.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A phosphogypsum composite cat litter, characterized in that, The components include the following parts by mass: The composition comprises 70-85 parts of raw phosphogypsum base material, 8-18 parts of in-situ composite solidification and activation system, 3-10 parts of porous adsorption modified filler, 0.8-3 parts of biological slow-release deodorizing and antibacterial component, and 12-22 parts of deionized water. The raw phosphogypsum base material is a byproduct of wet-process phosphoric acid production, fresh wet phosphogypsum that has not undergone calcination, autoclaving activation, or high-temperature pretreatment, with a moisture content controlled at 18-26% and an 80-mesh sieve passing rate ≥98%. The in-situ composite solidification and activation system is a magnesium silicate coagulation composite stabilization system, composed of lightly calcined magnesium oxide, silica fume, citric acid complexing stabilizer, and S95 ultrafine slag powder.

2. The phosphogypsum composite cat litter according to claim 1, characterized in that, The mass percentages of each component in the in-situ composite curing activation system are as follows: 40-50% light-burned magnesium oxide, 25-35% silica fume, 0.5-1.2% citric acid, and the balance being S95 ultrafine slag powder; the light-burned magnesium oxide has an activity ≥60s and a magnesium oxide content ≥85%; the silica fume has a SiO2 content ≥92% and a surface area ≥18000m² / kg; the S95 ultrafine slag powder has a surface area ≥420m² / kg. 2 / kg.

3. The phosphogypsum composite cat litter according to claim 1, characterized in that, The porous adsorption modified filler is composed of clinoptilolite powder and waste edible fungus residue biochar at a mass ratio of 1:2; the clinoptilolite powder is 100 mesh powder with a porosity ≥45%; the waste edible fungus residue biochar is obtained by carbonizing the fungus residue at 400-450℃ under limited oxygen and crushing it through a 100 mesh sieve, with an iodine adsorption value ≥380mg / g.

4. The phosphogypsum composite cat litter according to claim 1, characterized in that, The biological slow-release deodorizing and antibacterial component is composed of sodium alginate microcapsules loaded with urease and chitin powder in a mass ratio of 2:1; the sodium alginate microcapsules loaded with urease have a particle size of 200-400 μm and a urease loading of 8-12 wt%, and slowly dissolve and release active enzymes upon contact with water; the chitin powder has a degree of deacetylation ≥85% and a fineness of 100 mesh.

5. The in-situ solidification preparation method of a phosphogypsum composite cat litter according to any one of claims 1-4, characterized in that, The specific steps are as follows: S1. Perform raw material pretreatment and dry material premixing; S2. Perform room temperature spray granulation and simultaneous in-situ hydration and curing; S3. Perform low-temperature rapid ripening and shaping; S4. Perform surface low-dust modification treatment.

6. The in-situ solidification preparation method of phosphogypsum composite cat litter according to claim 5, characterized in that, In step S1, raw material pretreatment and dry material premixing are carried out. The specific steps are as follows: fresh raw wet phosphogypsum is screened to remove impurities and debris, ensuring that the 80-mesh pass rate is ≥98%; then, in-situ composite solidification activation system, porous adsorption modified filler, and biological slow-release deodorizing and antibacterial components are added in sequence according to the formula, and put into a horizontal high-power mixer. The mixture is then dry-mixed at room temperature in a closed environment for 6-10 minutes at a stirring speed of 250-300 r / min to obtain a uniform composite dry powder material.

7. The in-situ solidification preparation method of phosphogypsum composite cat litter according to claim 5, characterized in that, In step S2, simultaneous in-situ hydration and solidification are carried out via room temperature spray granulation. The specific steps are as follows: the composite dry powder obtained in step S1 is fed into a disc granulator, and a quantitative amount of deionized water is continuously sprayed using a high-pressure atomization method under room temperature. The rotation speed of the disc granulator is controlled at 30-40 r / min, and continuous rolling granulation is performed for 8-15 min. The sprayed water simultaneously triggers the hydration and gelation reaction of the in-situ composite solidification activation system. During the granulation and rolling molding process, a symbiotic gelation network of hydrated magnesium silicate, hydrated calcium silicate, and dihydrate gypsum is generated in situ inside the particles, simultaneously completing acid neutralization, soluble phosphorus and fluorine complexation passivation, and heavy metal ion stabilization and solidification, achieving integrated molding, solidification, and impurity removal. After granulation, the particles are screened by a vibrating screen, and qualified intermediate particles of 1.5-4 mm are collected. Fine powder with a particle size <1 mm is all recycled for granulation.

8. The in-situ solidification preparation method of phosphogypsum composite cat litter according to claim 5, characterized in that, In step S3, a low-temperature rapid curing and shaping process is performed. The specific steps are as follows: the qualified intermediate particles after screening are sent into a low-temperature hot air curing chamber, the curing temperature is controlled at 40-55℃ and the hot air velocity is 1.2-1.8m / s, and the curing is carried out at a constant temperature for 30-90 minutes. Only the free moisture on the surface of the particles is removed, and the final moisture content of the finished product is controlled at 6-9%. The internal gelation and solidification structure, impurity stabilization structure and deodorization function structure of the particles have been fully formed in the granulation stage. The low-temperature curing only plays a role in shaping and dust suppression and does not participate in the structure formation reaction.

9. The in-situ solidification preparation method of phosphogypsum composite cat litter according to claim 5, characterized in that, In step S4, a surface low-dust modification treatment is carried out. The specific steps are as follows: prepare a low-viscosity sodium alginate aqueous solution with a mass concentration of 0.3-0.8%, and uniformly spray the matured particles with a low-pressure atomization method to coat them. The spraying amount is 1.5-3% of the total mass of the particles. Let them air dry at room temperature for 15-25 minutes to finally obtain a low-dust, high-strength, long-lasting deodorizing phosphogypsum composite cat litter product.

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