Purifying agent and purification process for phosphogypsum

Abstract

The present invention belongs to the technical field of phosphogypsum purification. More specifically, it relates to a phosphogypsum purification agent and purification process. The product of the present invention includes spherical hollow graphene oxide particles; the spherical hollow graphene oxide particles are used as a flotation agent in the purification process of phosphogypsum; the preparation steps of the spherical hollow graphene oxide particles include: taking 80-100 parts of graphene oxide, 2-4 parts of non-ionic surfactant, 8-10 parts of dodecylamine, 0.2-0.4 parts of dopamine, and 400-500 parts of ethanol solution by weight; first mixing dodecylamine and non-ionic surfactant with ethanol solution, heating and stirring to dissolve, then adding graphene oxide, ultrasonically dispersing, and then adding dopamine, stirring and reacting in a weakly alkaline environment, spray granulation, and sieving to obtain spherical hollow graphene oxide particles.

Description

Technical Field

[0001] The present invention belongs to the technical field of phosphogypsum purification, and more specifically, relates to a phosphogypsum purification agent and a purification process. Background Art

[0002] Phosphogypsum contains coloring organic and metallic impurities, which limit its processing and application in building materials and chemical fillers, particularly in polymer fillers, plastering, and decorative gypsum products. Therefore, purification is essential to improve the resource utilization of phosphogypsum and expand its applications. Summary of the Invention

[0003] The technical problem addressed by the present invention is the need to address the issues that must be addressed during the resource utilization of phosphogypsum. During their research, the inventors discovered that phosphogypsum contains coloring impurities such as organic impurities and nonferrous metal ions, which affect the light reflectivity of the surface of the phosphogypsum product. Changes in light reflectivity can affect its whiteness. Reflectivity is related to the composition and element types of the phosphogypsum. For example, organic impurities generally appear black, resulting in an off-white or gray-black appearance for the phosphogypsum. Furthermore, impurities such as Fe, Cr, Cu, and Mn in phosphogypsum, present as sulfates, phosphates, oxides, and other metals on the surface of phosphogypsum particles, in their interstices, or encapsulated within calcium sulfate dihydrate crystals, give the phosphogypsum the color of the coloring metal ions. The inventors found that Fe, in particular, is often present in the highest concentration and has the greatest impact on whiteness, typically imparting varying degrees of gray or yellow to the phosphogypsum. To address these technical issues, the present invention provides a phosphogypsum purification agent and purification process.

[0004] The purpose of the present invention is to provide a purifying agent for phosphogypsum.

[0005] Another object of the present invention is to provide a process for purifying phosphogypsum.

[0006] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0007] A purifying agent for phosphogypsum, comprising spherical hollow graphene oxide particles;

[0008] The spherical hollow graphene oxide particles are used as a flotation agent in the purification process of phosphogypsum;

[0009] The preparation steps of the spherical hollow graphene oxide particles include:

[0010] By weight, take 80-100 parts of graphene oxide, 2-4 parts of nonionic surfactant, 8-10 parts of dodecylamine, 0.2-0.4 parts of dopamine, and 400-500 parts of ethanol solution;

[0011] The graphene oxide is transparent graphene oxide with a light transmittance of more than 90%;

[0012] First, dodecylamine and a nonionic surfactant are mixed with an ethanol solution, heated and stirred to dissolve, and then graphene oxide is added. After ultrasonic dispersion, dopamine is added. After stirring and reacting in a weakly alkaline environment, spray granulation is performed and sieved to obtain spherical hollow graphene oxide particles.

[0013] Beneficial effects of the above technical solution:

[0014] In the above technical solution, the spherical hollow graphene oxide particles prepared by themselves are used as a flotation agent in the purification process of phosphogypsum to achieve the purification of phosphogypsum.

[0015] Specifically, first, in the preparation process of spherical hollow graphene oxide particles, dodecylamine is first dissolved in an ethanol solution with the assistance of a non-ionic surfactant. Subsequently, under the action of ultrasound, the lamellar structure of the graphene oxide is gradually peeled off by the cavitation effect of the ultrasound. In particular, under the action of the non-ionic surfactant, the increase in the interlayer spacing of the graphene oxide is further aggravated, thereby facilitating its full peeling. After peeling, dodecylamine can be adsorbed and fixed on the surface of the graphene oxide with the assistance of the non-ionic surfactant and dopamine. During the spray granulation process, thanks to the oxidative self-polymerization reaction of dopamine in a weakly alkaline environment, the graphene oxide lamellar structure forms a spherical structure, and the presence of the non-ionic surfactant and dodecylamine is conducive to the formation of a hollow structure during the spray granulation process.

[0016] The reason for expecting to obtain spherical hollow graphene oxide particles of the above structure is that, on the one hand, their hollow structure can be used to carry various impurities to the surface during the flotation process of phosphogypsum purification by utilizing their lower density, thereby preventing graphene oxide from mixing into the phosphogypsum and affecting the purity of the phosphogypsum; on the other hand, under the action of dodecylamine and the presence of the conjugated region of graphene oxide, it can form adsorption with organic impurities in the phosphogypsum, especially the hydroxyl and carboxyl groups at the edge of the graphene oxide structure and the epoxy groups in the conjugated region, which can effectively adsorb and fix metal ions, such as iron ions, in the phosphogypsum; and, thanks to the structure of the spherical hollow graphene oxide particles after full exfoliation during the preparation process, the conjugated region of graphene oxide can be effectively exposed, so that the conjugated region can be used to further firmly adsorb metal ions, mainly because iron ions, as charge carriers, can form electrostatic attraction or π-π stacking with the π electron cloud of graphene oxide.

[0017] Furthermore, the nonionic surfactant is selected from any one of fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, polysorbate 20, and fatty acid diethanolamide.

[0018] Furthermore, the mass fraction of the ethanol solution is 60-80%.

[0019] Since dodecylamine is a solid at room temperature, if it is directly dissolved in water, its solubility is generally relatively low. However, with the assistance of a certain mass fraction of ethanol solution, it can be dissolved smoothly, which is conducive to the subsequent interaction between the dissolved dodecylamine and graphene oxide.

[0020] Furthermore, the ultrasonic dispersion includes: maintaining the temperature and ultrasonically dispersing for 2-4 hours at a temperature of 60-70° C. and an ultrasonic frequency of 160-180 kHz.

[0021] Under the above-mentioned temperature and ultrasonic frequency, ultrasonic treatment for a sufficient time can be beneficial for fully exfoliating the layered structure of graphene oxide to form a single-layer structure.

[0022] Furthermore, the weakly alkaline environment has a pH of 7.8-8.2.

[0023] Furthermore, the preparation step of the spherical hollow graphene oxide particles further includes:

[0024] By weight, take 80-100 parts of graphene oxide, 2-4 parts of nonionic surfactant, 8-10 parts of dodecylamine, 0.2-0.4 parts of dopamine, 20-30 parts of gelatin solution, and 400-500 parts of ethanol solution;

[0025] First, dodecylamine and a nonionic surfactant are mixed with an ethanol solution, heated and stirred to dissolve, and then graphene oxide is added. After ultrasonic dispersion, dopamine and gelatin solution are added. After stirring and reacting in a weakly alkaline environment, spray granulation and sieving are performed to obtain spherical hollow graphene oxide particles.

[0026] Furthermore, the mass fraction of the gelatin solution is 3-6%; and the gelatin solution includes gelatin and water; the isoelectric point of the gelatin is 7.0.

[0027] Beneficial effects of the above technical solution:

[0028] The above technical solution further introduces gelatin during the preparation of spherical hollow graphene oxide particles. The introduction of gelatin not only facilitates the combination of multiple monolayers of graphene oxide to form spherical particles during the spray granulation process, but also, and most importantly, when added to the purification process of phosphogypsum, the presence of gelatin can to a certain extent improve the strength of the flotation foam, thereby allowing the hollow spherical graphene oxide particles to exist stably in the foam, avoiding foam rupture and resulting in the sedimentation of the graphene oxide particles, which would affect the purity of the phosphogypsum.

[0029] Furthermore, gelatin with an isoelectric point of 7.0 is selected mainly because, in the preparation process of spherical hollow graphene oxide particles, after the gelatin solution is added, the reaction system is a weakly alkaline environment, that is, the pH is above 7.0. At this time, the hydroxide ions in the solution can react with the carboxyl groups in the gelatin molecular structure, thereby ionizing the carboxyl groups. Due to the electrostatic repulsion with the same negative charge, the gelatin molecular chain is fully stretched, so that multiple monolayer graphene oxide layered structures can be adsorbed and fixed, which is conducive to the stable formation of a spherical structure. In addition, in the purification process of phosphogypsum, an acidic reaction system is often used. At this time, the hydrogen ions in the solution system can be protonated with the amino groups in the gelatin molecular structure, and electrostatic repulsion is generated due to the same positive charge. The generation of this electrostatic repulsion can not only realize the expansion of the spherical structure, so that the monolayer graphene oxide is fully exposed, but also make components such as dodecylamine fully released, so that the product can further effectively adsorb impurities in the system.

[0030] A process for purifying phosphogypsum, using the above-mentioned phosphogypsum purification agent as a flotation agent;

[0031] Furthermore, the purification process of phosphogypsum includes the following purification steps:

[0032] After the phosphogypsum is crushed and finely divided, it is added to the flotation tank, and then water is added, and the pH is adjusted to 2.0-2.2;

[0033] Then, the phosphogypsum purification agent is added to the flotation tank, ultrasonically dispersed, and then a foaming agent is added. After stirring for reaction, the foam is scraped off, and the remaining slurry in the flotation tank is collected, centrifuged, and dried to complete the purification of the phosphogypsum.

[0034] Furthermore, the amount of the purification agent for the phosphogypsum is 1.2-1.5% of the mass of the phosphogypsum.

[0035] Furthermore, the foaming agent is methyl isobutyl carbinol; and the amount of the foaming agent is 0.03-0.05% of the mass of the phosphogypsum. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1: The color state of the refined phosphogypsum before purification in Example 1 of the present application;

[0037] Figure 2 : This is the color state of the purified phosphogypsum in Example 1 of the present application;

[0038] Figure 3 : Comparison of the color state of the refined phosphogypsum before purification and the color state of the phosphogypsum after purification in Example 1 of the present application. DETAILED DESCRIPTION

[0039] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0040] Unless otherwise specified, all reagents and materials used in the following examples were commercially available.

[0041] Example 1

[0042] In parts by weight, 80 parts of graphene oxide, 2 parts of nonionic surfactant, 8 parts of dodecylamine, 0.2 parts of dopamine, 20 parts of 3% gelatin solution, and 400 parts of 60% ethanol solution were taken in sequence;

[0043] Wherein, the graphene oxide is selected to have a D50 of 300 nm;

[0044] Furthermore, the graphene oxide is transparent graphene oxide having a light transmittance of more than 90%;

[0045] The nonionic surfactant is selected from: fatty alcohol polyoxyethylene ether;

[0046] The gelatin solution is obtained by dissolving gelatin and water, wherein the isoelectric point of the gelatin is 7.0;

[0047] First, dodecylamine and a nonionic surfactant were mixed and poured into an ethanol solution, heated and stirred to dissolve for 30 minutes at a temperature of 45°C and a stirring speed of 300 r / min; then graphene oxide was added, and the mixture was ultrasonically dispersed for 2 hours at a temperature of 60°C and an ultrasonic frequency of 160kHz. Then, dopamine was added and the pH was adjusted to 7.8. In the weakly alkaline environment, the mixture was stirred at a speed of 200 r / min for 40 minutes. The material was then transported to a spray dryer with a feed rate of 100 g / min. The main disk speed of the spray dryer was 8000 r / min, the inlet air temperature was 135°C, and the outlet air temperature was 105°C. Spray granulation was performed, and particles with a particle size distribution range of 10-80 μm were sieved to obtain spherical hollow graphene oxide particles.

[0048] The spherical hollow graphene oxide particles obtained above are used as a flotation agent, i.e., a purification agent for phosphogypsum, for use in a purification process for phosphogypsum; specifically, the purification process includes:

[0049] Add phosphogypsum into a grinder, grind it and pass it through an 80-mesh sieve to obtain fine phosphogypsum;

[0050] The refined phosphogypsum is added to a flotation tank, and water in an amount 20 times the mass of the refined phosphogypsum is added to the flotation tank. The mixture is stirred and mixed at a speed of 200 r / min for 30 minutes with an agitator, and the pH value of the material in the flotation tank is adjusted to 2.0. A phosphogypsum purification agent in an amount of 1.2% of the mass of the refined phosphogypsum is added to the flotation tank. After ultrasonic dispersion is carried out at an ultrasonic frequency of 160 kHz for 1 hour, a foaming agent - methyl isobutyl carbinol in an amount of 0.03% of the mass of the refined phosphogypsum is added. The mixture is stirred and reacted at a speed of 600 r / min for 2 hours, and the foam is scraped off. The remaining slurry in the flotation tank is collected, centrifuged, and dried to complete the purification of the phosphogypsum.

[0051] Example 2

[0052] In parts by weight, 90 parts of graphene oxide, 3 parts of nonionic surfactant, 9 parts of dodecylamine, 0.3 parts of dopamine, 24 parts of 5% gelatin solution, and 460 parts of 70% ethanol solution were taken in sequence;

[0053] Wherein, the graphene oxide is selected to have a D50 of 310 nm;

[0054] Furthermore, the graphene oxide is transparent graphene oxide having a light transmittance of more than 90%;

[0055] The nonionic surfactant is selected from: nonylphenol polyoxyethylene ether;

[0056] The gelatin solution is obtained by dissolving gelatin and water, wherein the isoelectric point of the gelatin is 7.0;

[0057] First, dodecylamine and a nonionic surfactant were mixed and poured into an ethanol solution, heated and stirred to dissolve for 50 minutes at a temperature of 48°C and a stirring speed of 360 r / min; then graphene oxide was added, and the mixture was ultrasonically dispersed for 3 hours at a temperature of 65°C and an ultrasonic frequency of 170 kHz. Then, dopamine was added and the pH was adjusted to 8.0. In the weakly alkaline environment, the mixture was stirred at a speed of 220 r / min for 50 minutes. The material was then transported to a spray dryer with a feed rate of 110 g / min. The main disk speed of the spray dryer was 8200 r / min, the inlet air temperature was 138°C, and the outlet air temperature was 106°C. Spray granulation was performed, and particles with a particle size distribution range of 10-80 μm were screened to obtain spherical hollow graphene oxide particles.

[0058] The spherical hollow graphene oxide particles obtained above are used as a flotation agent, i.e., a purification agent for phosphogypsum, for use in a purification process for phosphogypsum; specifically, the purification process includes:

[0059] Add phosphogypsum into a grinder, grind it and pass it through a 100-mesh sieve to obtain fine phosphogypsum;

[0060] The refined phosphogypsum is added to a flotation tank, and water 22 times the mass of the refined phosphogypsum is added to the flotation tank. After stirring and mixing with an agitator at a speed of 240 r / min for 30 minutes, the pH of the material in the flotation tank is adjusted to 2.1; then, a phosphogypsum purification agent of 1.3% of the mass of the refined phosphogypsum is added to the flotation tank, and ultrasonic dispersion is carried out at an ultrasonic frequency of 170 kHz for 1.5 hours. Then, a foaming agent - methyl isobutyl carbinol of 0.04% of the mass of the refined phosphogypsum is added, and then the mixture is stirred with an agitator at a speed of 700 r / min for 2.5 hours. The foam is scraped, and the remaining slurry in the flotation tank is collected, centrifuged, and dried to complete the purification of the phosphogypsum.

[0061] Example 3

[0062] In parts by weight, 100 parts of graphene oxide, 4 parts of nonionic surfactant, 10 parts of dodecylamine, 0.4 parts of dopamine, 30 parts of 6% gelatin solution, and 500 parts of 80% ethanol solution were taken in sequence;

[0063] Wherein, the graphene oxide is selected to have a D50 of 320 nm;

[0064] Furthermore, the graphene oxide is transparent graphene oxide having a light transmittance of more than 90%;

[0065] The nonionic surfactant is selected from: octylphenol polyoxyethylene ether;

[0066] The gelatin solution is obtained by dissolving gelatin and water, wherein the isoelectric point of the gelatin is 7.0;

[0067] First, dodecylamine and a nonionic surfactant were mixed and poured into an ethanol solution, heated and stirred to dissolve for 60 minutes at a temperature of 50°C and a stirring speed of 400 r / min; then graphene oxide was added, and the mixture was ultrasonically dispersed at a temperature of 70°C and an ultrasonic frequency of 180 kHz for 4 hours, and then dopamine was added to adjust the pH to 8.2. In the weakly alkaline environment, the mixture was stirred at a speed of 240 r / min for 60 minutes, and then the material was transported to a spray dryer with a feed rate of 120 g / min. The main disk speed of the spray dryer was 8500 r / min, the inlet air temperature was 140°C, and the outlet air temperature was 110°C. Spray granulation was performed, and then particles with a particle size distribution range of 10-80 μm were sieved to obtain spherical hollow graphene oxide particles;

[0068] The spherical hollow graphene oxide particles obtained above are used as a flotation agent, i.e., a purification agent for phosphogypsum, for use in a purification process for phosphogypsum; specifically, the purification process includes:

[0069] Add phosphogypsum into a grinder, grind it and pass it through a 120-mesh sieve to obtain fine phosphogypsum;

[0070] The refined phosphogypsum is added to a flotation tank, and water 25 times the mass of the refined phosphogypsum is added to the flotation tank. After stirring and mixing with an agitator at a speed of 300 r / min for 30 minutes, the pH of the material in the flotation tank is adjusted to 2.2; then, a phosphogypsum purification agent of 1.5% of the mass of the refined phosphogypsum is added to the flotation tank, and ultrasonic dispersion is carried out at an ultrasonic frequency of 180 kHz for 2 hours. Then, a foaming agent - methyl isobutyl carbinol of 0.05% of the mass of the refined phosphogypsum is added, and then the mixture is stirred and reacted with an agitator at a speed of 800 r / min for 3 hours. The foam is scraped, and the remaining slurry in the flotation tank is collected, centrifuged, and dried to complete the purification of the phosphogypsum.

[0071] Example 4

[0072] Compared with Example 1, this embodiment differs in that gelatin is not added, and other conditions remain unchanged.

[0073] Example 5

[0074] Compared with Example 1, this example differs in that the isoelectric point of gelatin is 7.8, and other conditions remain unchanged.

[0075] Comparative Example 1

[0076] Compared with Example 1, this comparative example differs in that the preparation method of the purification agent is different, specifically:

[0077] In parts by weight, 80 parts of graphene oxide, 2 parts of nonionic surfactant, 8 parts of dodecylamine, 0.2 parts of dopamine, 20 parts of 3% gelatin solution, and 400 parts of 60% ethanol solution were taken in sequence;

[0078] Wherein, the graphene oxide is selected to have a D50 of 300 nm;

[0079] Furthermore, the graphene oxide is transparent graphene oxide having a light transmittance of more than 90%;

[0080] The nonionic surfactant is selected from: fatty alcohol polyoxyethylene ether;

[0081] The gelatin solution is obtained by dissolving gelatin and water, wherein the isoelectric point of the gelatin is 7.0;

[0082] First, dodecylamine and a nonionic surfactant were mixed and poured into an ethanol solution, heated and stirred for dissolution at a temperature of 45°C and a stirring speed of 300 r / min for 30 minutes; then graphene oxide and dopamine were added, the pH was adjusted to 7.8, and the mixture was stirred and reacted for 40 minutes under the weakly alkaline environment at a stirring speed of 200 r / min. The material was then transported to a spray dryer with a feed rate of 100 g / min, and spray granulation was performed under the conditions of a main disk speed of 8000 r / min, an inlet air temperature of 135°C, and an outlet air temperature of 105°C. Particles with a particle size distribution range of 10-80 μm were subsequently sieved to obtain spherical hollow graphene oxide particles;

[0083] Since ultrasonic treatment was not used, the lamellar structure of graphene oxide was not effectively exfoliated.

[0084] Comparative Example 2

[0085] Compared with Example 1, this comparative example has the following differences:

[0086] The same mass of activated carbon was used to replace graphene oxide, and the other conditions remained unchanged.

[0087] Comparative Example 3

[0088] Compared with Example 1, this comparative example has the following differences:

[0089] No nonionic surfactant and dopamine were added, and the other conditions remained unchanged.

[0090] The performance tests of the products obtained in the above examples and comparative examples were carried out. The specific test methods and test results are as follows:

[0091] Product purity testing:

[0092] The purity of CaSO4·2H2O in the product is determined by measuring the content of crystal water. The method used is based on the GB / T 23456-2018 "Phosphogypsum" standard. The specific test results are shown in Table 1.

[0093] Whiteness was measured using a YQ-Z-48A whiteness meter. A certain amount of powdered sample was placed in a sample press and pressed into a sample plate with a smooth surface, no texture, no defects, and no stains. Five sample plates were pressed under the same conditions for each concentrate, and the whiteness was measured separately. The average value was taken. The specific test results are shown in Table 1.

[0094] Table 1: Product performance test results

[0095]

[0096] The same method was used to test the purity and whiteness of the phosphogypsum raw material. The purity and whiteness of the product were 67.88% and 29.76% respectively.

[0097] As can be seen from the test results in Table 1, the product obtained by the present invention can effectively remove impurities in phosphogypsum, thereby significantly improving its purity and whiteness.

[0098] Moreover, combined with the Figure 1-3 It can be seen that the phosphogypsum is treated with the purification method of the embodiment of the present application. Due to the removal of colored impurities in the phosphogypsum, such as metal ions such as iron ions, it can be purified and the color whiteness is improved.

[0099] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A purifying agent for phosphogypsum, characterized in that: including spherical hollow graphene oxide particles; The spherical hollow graphene oxide particles are used as a flotation agent in the purification process of phosphogypsum; The preparation steps of the spherical hollow graphene oxide particles include: By weight, take 80-100 parts of graphene oxide, 2-4 parts of nonionic surfactant, 8-10 parts of dodecylamine, 0.2-0.4 parts of dopamine, and 400-500 parts of ethanol solution; The graphene oxide is transparent graphene oxide with a light transmittance of more than 90%; First, dodecylamine and a nonionic surfactant are mixed with an ethanol solution, heated and stirred to dissolve, and then graphene oxide is added. After ultrasonic dispersion, dopamine is added. After stirring and reacting in a weakly alkaline environment, spray granulation is performed and sieved to obtain spherical hollow graphene oxide particles.

2. A phosphogypsum purification agent according to claim 1, characterized in that: The nonionic surfactant is selected from any one of fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, polysorbate 20, and fatty acid diethanolamide.

3. The purifying agent for phosphogypsum according to claim 1, characterized in that: The mass fraction of the ethanol solution is 60-80%.

4. The purifying agent for phosphogypsum according to claim 1, characterized in that: The ultrasonic dispersion comprises: maintaining the temperature at 60-70° C. and ultrasonic frequency at 160-180 kHz for 2-4 hours.

5. The purifying agent for phosphogypsum according to claim 1, characterized in that: The weakly alkaline environment has a pH of 7.8-8.

2.

6. The purifying agent for phosphogypsum according to claim 1, characterized in that: The preparation step of the spherical hollow graphene oxide particles further includes: By weight, take 80-100 parts of graphene oxide, 2-4 parts of nonionic surfactant, 8-10 parts of dodecylamine, 0.2-0.4 parts of dopamine, 20-30 parts of gelatin solution, and 400-500 parts of ethanol solution; First, dodecylamine and a nonionic surfactant are mixed with an ethanol solution, heated and stirred to dissolve, and then graphene oxide is added. After ultrasonic dispersion, dopamine and gelatin solution are added. After stirring and reacting in a weakly alkaline environment, spray granulation and sieving are performed to obtain spherical hollow graphene oxide particles.

7. A phosphogypsum purification agent according to claim 6, characterized in that: The mass fraction of the gelatin solution is 3-6%; and the gelatin solution includes gelatin and water; the isoelectric point of the gelatin is 7.

0.

8. A purification process for phosphogypsum, characterized in that: Using the phosphogypsum purification agent according to any one of claims 1 to 7 as a flotation agent; Furthermore, the purification process of phosphogypsum includes the following purification steps: After the phosphogypsum is crushed and finely divided, it is added to the flotation tank, and then water is added, and the pH is adjusted to 2.0-2.2; Then, the phosphogypsum purification agent is added to the flotation tank, ultrasonically dispersed, and then a foaming agent is added. After stirring for reaction, the foam is scraped off, and the remaining slurry in the flotation tank is collected, centrifuged, and dried to complete the purification of the phosphogypsum.

9. A purification process for phosphogypsum according to claim 8, characterized in that: The amount of the purifying agent for the phosphogypsum is 1.2-1.5% of the mass of the phosphogypsum.

10. The process for purifying phosphogypsum according to claim 8, characterized in that: The foaming agent is methyl isobutyl carbinol; and the amount of the foaming agent is 0.03-0.05% of the mass of the phosphogypsum.

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