A reagent for phosphogypsum reduction conversion and a method for using the same

Abstract

The application discloses a kind of medicament for phosphogypsum reduction conversion and its use method, medicament is made of ammonium carbonate, chitosan and epoxy chloropropane, chitosan is crosslinked with epoxy chloropropane and forms porous microspheres, ammonium carbonate is loaded in ball, and ball surface has negative cation exchange membrane, by the synergistic effect of inorganic salt ammonium carbonate and organic chitosan, phosphogypsum is efficiently treated, realizes the reduction conversion of phosphogypsum and the recovery of calcium, sulfur element.The process can effectively promote the conversion of calcium system at normal temperature and pressure, and small particle solid and nutrient element-rich solution are obtained.The application significantly reduces the storage amount of solid waste, and opens up a wider application way for the large amount of calcium and sulfur elements in phosphogypsum.

Description

Technical Field

[0001] This invention relates to the field of resources and environmental technology, and in particular to a reagent for the reduction and conversion of phosphogypsum and its application method. Background Technology

[0002] Phosphogypsum is a solid waste generated during the production of phosphate fertilizers in the phosphoric acid industry. It is a byproduct of the ammonium phosphate industry and is mainly composed of calcium sulfate. Globally, approximately 150 million tons of phosphogypsum are emitted annually. Due to its harmful components, it is difficult to utilize as a resource, and the current stockpiled amount exceeds 6 billion tons. Phosphogypsum contains impurities such as fluorides, free phosphoric acid, phosphates, and P2O5, which can cause air, water, and soil pollution during stockpiling. However, its overall utilization rate is low, with a global comprehensive utilization rate of only about 10%. The development of harmless treatment and large-scale application solutions for phosphogypsum is urgently needed.

[0003] Currently, phosphogypsum is not only used in building materials and chemical industries, but also has expanded into agricultural applications. From an elemental composition perspective, phosphogypsum contains large amounts of sulfur and calcium, both essential micronutrients for plants. The rational application of sulfur and calcium fertilizers can increase crop yields, improve product quality, and improve soil. However, plants can absorb and utilize only available calcium, not the calcium sulfate in phosphogypsum. Therefore, developing new agents or technologies to promote the conversion of calcium in phosphogypsum and utilizing it to prepare micronutrient fertilizers is of great significance in the treatment and application of phosphogypsum. Summary of the Invention

[0004] The technical problem to be solved: The technical problem to be solved by the present invention is to provide an agent for reducing and converting phosphogypsum, which promotes the reduction of phosphogypsum and calcium conversion, and at the same time obtains a fertilizer.

[0005] Technical solution: An agent for reducing the conversion of phosphogypsum, composed of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, in which ammonium carbonate is loaded and the surface of the microspheres has a negatively charged cation exchange membrane.

[0006] Preferably, the preparation method of the pharmaceutical agent includes the following steps:

[0007] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0008] S12. Epichlorohydrin and alkali were added to the ammonium carbonate-chitosan emulsion, and the mixture was heated and stirred to react. The mixture was then filtered, washed, and freeze-dried to obtain porous microspheres loaded with ammonium carbonate.

[0009] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The microspheres were then removed, dried and washed to obtain the reagent.

[0010] Preferably, in step S11, the mass ratio of chitosan to epichlorohydrin is 1:0.5-0.7, and the heating temperature is 50-70°C. Preferably, in step S13, the mass ratio of sodium lignosulfonate, piperazine, and trimesoyl chloride is 1-2:1-2:1. Preferably, the method of using the agent includes the following steps:

[0011] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0012] S2. Add the treated phosphogypsum to water, add the reagent according to the ratio, and pass in ammonia gas. Stir at room temperature and pressure until the reaction is complete.

[0013] S3. The reacted liquid is subjected to solid-liquid centrifugation to obtain a solution rich in nutrients and solid particles.

[0014] Preferably, the solid-liquid ratio of phosphogypsum to water in step S2 is 1:2 to 4, the molar ratio of ammonia, phosphogypsum and ammonium carbonate in the reagent is 0.5 to 0.9:1:1 to 1.2, and the stirring time is 45 to 50 hours.

[0015] Preferably, the centrifugal separation speed in step S3 is 500-800 r / min.

[0016] Beneficial effects: This invention has the following characteristics:

[0017] The reagent described in this invention is composed of inorganic and organic substances and has a negatively charged cation exchange membrane on its surface. Under the synergistic effect of organic and inorganic substances, it can efficiently adsorb and precipitate calcium ions in phosphogypsum and obtain a solution rich in sulfate ions, and facilitate solid-liquid separation.

[0018] The main component of phosphogypsum is calcium sulfate, and making full use of this calcium sulfate is key to its resource utilization. Calculations based on the reaction equilibrium constant show a strong tendency for the reaction between calcium sulfate and ammonium carbonate to produce ammonium sulfate and calcium carbonate precipitates. Therefore, using ammonium carbonate as a conversion agent to promote the conversion of phosphogypsum is theoretically feasible, and after the replacement of calcium ions with ammonium ions, the ammonium sulfate in the solution can be used as fertilizer. However, phosphogypsum contains impurities such as iron, copper, and magnesium ions, which can affect the conversion rate of calcium and sulfur. Furthermore, iron ions can react with carbonate ions to form precipitation, easily affecting the purity of calcium carbonate. To improve the selectivity of the conversion agent, a suitable carrier needs to be prepared to reduce the occurrence of side reactions. Chitosan is a natural polysaccharide with abundant hydroxyl and amino groups in its molecular chain, making it easy to chemically modify and an excellent carrier. Using chitosan as a raw material and epichlorohydrin as a cross-linking agent, porous microspheres can be prepared through freeze-drying. These microspheres can serve as carriers for ammonium nitrate. Simultaneously, the abundant hydroxyl and amino functional groups on chitosan can undergo complexation reactions with metal ions, removing impurity metal ions and effectively improving the selectivity of the conversion agent. Besides metal ions, phosphogypsum also contains anions such as phosphate and fluoride. Phosphate can precipitate with calcium ions, affecting the calcium ion conversion rate. Chitosan porous microspheres cannot filter these anions. To reduce the anion content, a cation exchange membrane is prepared on the surface of the chitosan porous microspheres through interfacial polymerization. Sulfonate is added to the reactants of the polymerization reaction to make the membrane negatively charged, thereby repelling anions and selectively allowing cations to pass through, further improving the purity of the generated reactants.

[0019] Compared with the prior art, the present invention has the following advantages and positive effects:

[0020] This invention reduces the amount of solid waste stockpiled and the risk of secondary pollution, and transforms useful elements in solid waste into usable resources, resulting in significant environmental and economic benefits.

[0021] This invention is carried out at normal temperature and pressure, avoiding the energy consumption and equipment costs associated with traditional high-temperature and high-pressure treatments.

[0022] The present invention is simple and easy to operate, with flexible solid-liquid ratio and liquid concentration range, short conversion time, good treatment effect, and strong adaptability. Detailed implementation method:

[0023] To further understand the present invention, preferred embodiments of the present invention will be described below in conjunction with examples.

[0024] Specific examples of preferred choices are as follows:

[0025] Example 1:

[0026] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0027] The preparation method of the pharmaceutical agent includes the following steps:

[0028] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0029] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.5, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0030] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing pyromellitic chloride for polymerization reaction. The microspheres were then removed, dried and washed to obtain the reagent.

[0031] The method of using the medicine includes the following steps:

[0032] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0033] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0034] Example 2:

[0035] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0036] The preparation method of the pharmaceutical agent includes the following steps:

[0037] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0038] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0039] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:1:1. The microspheres were removed, dried and washed to obtain the reagent.

[0040] The method of using the medicine includes the following steps:

[0041] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0042] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0043] Example 3:

[0044] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0045] The preparation method of the pharmaceutical agent includes the following steps:

[0046] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0047] S12. Epichlorohydrin and alkali were added to the ammonium carbonate-chitosan emulsion, and the mixture was heated and stirred at 60°C. The mass ratio of chitosan to epichlorohydrin was 1:0.7. The mixture was filtered, washed, and freeze-dried to obtain porous microspheres loaded with ammonium carbonate.

[0048] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:1:1. The microspheres were removed, dried and washed to obtain the reagent.

[0049] The method of using the medicine includes the following steps:

[0050] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0051] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0052] Example 4:

[0053] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0054] The preparation method of the pharmaceutical agent includes the following steps:

[0055] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0056] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0057] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1.5:1.5:1. The microspheres were removed, dried and washed to obtain the reagent.

[0058] The method of using the medicine includes the following steps:

[0059] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0060] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0061] Example 5:

[0062] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0063] The preparation method of the pharmaceutical agent includes the following steps:

[0064] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0065] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0066] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 2:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0067] The method of using the medicine includes the following steps:

[0068] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0069] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0070] Example 6:

[0071] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0072] The preparation method of the pharmaceutical agent includes the following steps:

[0073] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0074] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0075] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:1.5:1. The microspheres were removed, dried and washed to obtain the reagent.

[0076] The method of using the medicine includes the following steps:

[0077] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0078] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0079] Example 7:

[0080] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0081] The preparation method of the pharmaceutical agent includes the following steps:

[0082] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0083] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0084] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0085] The method of using the medicine includes the following steps:

[0086] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0087] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0088] Example 8:

[0089] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0090] The preparation method of the pharmaceutical agent includes the following steps:

[0091] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0092] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0093] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0094] The method of using the medicine includes the following steps:

[0095] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0096] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0097] Example 9:

[0098] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0099] The preparation method of the pharmaceutical agent includes the following steps:

[0100] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0101] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0102] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0103] The method of using the medicine includes the following steps:

[0104] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0105] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0106] S3. The reacted liquid is subjected to solid-liquid centrifugation at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0107] Example 10:

[0108] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0109] The preparation method of the pharmaceutical agent includes the following steps:

[0110] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0111] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0112] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0113] The method of using the medicine includes the following steps:

[0114] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0115] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.7:1:1.1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0116] Example 11:

[0117] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0118] The preparation method of the pharmaceutical agent includes the following steps:

[0119] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0120] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0121] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0122] The method of using the medicine includes the following steps:

[0123] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0124] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.7:1:1.2. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0125] To further illustrate the technical effects of the present invention, a comparative example is also provided, as follows:

[0126] Comparative Example 1:

[0127] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0128] The preparation method of the pharmaceutical agent includes the following steps:

[0129] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0130] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.4, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0131] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:1:1. The microspheres were removed, dried and washed to obtain the reagent.

[0132] The method of using the medicine includes the following steps:

[0133] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0134] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0135] Comparative Example 2:

[0136] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0137] The preparation method of the pharmaceutical agent includes the following steps:

[0138] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0139] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0140] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 0.5:0.5:1. The microspheres were removed, dried and washed to obtain the reagent.

[0141] The method of using the medicine includes the following steps:

[0142] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0143] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:2. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0144] Comparative Example 3:

[0145] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0146] The preparation method of the pharmaceutical agent includes the following steps:

[0147] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0148] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0149] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0150] The method of using the medicine includes the following steps:

[0151] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0152] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:1. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.5:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0153] Comparative Example 4:

[0154] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0155] The preparation method of the pharmaceutical agent includes the following steps:

[0156] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0157] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0158] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0159] The method of using the medicine includes the following steps:

[0160] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0161] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.3:1:1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0162] Comparative Example 5:

[0163] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0164] The preparation method of the pharmaceutical agent includes the following steps:

[0165] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0166] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0167] S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride was 1:2:1. The microspheres were removed, dried and washed to obtain the reagent.

[0168] The method of using the medicine includes the following steps:

[0169] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0170] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.9:1:1.4. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0171] Comparative Example 6:

[0172] An agent for reducing the conversion of phosphogypsum consists of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, and ammonium carbonate is loaded in the microspheres.

[0173] The preparation method of the pharmaceutical agent includes the following steps:

[0174] S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion;

[0175] S12. Add epichlorohydrin and alkali to ammonium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with ammonium carbonate.

[0176] The method of using the medicine includes the following steps:

[0177] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0178] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and ammonium carbonate in the reagent is 0.7:1:1.1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0179] Comparative Example 7:

[0180] An agent for reducing the conversion of phosphogypsum is composed of sodium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with sodium carbonate and have negatively charged cation exchange membranes on their surfaces.

[0181] The preparation method of the pharmaceutical agent includes the following steps:

[0182] S11. Add sodium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain sodium carbonate-chitosan emulsion;

[0183] S12. Add epichlorohydrin and alkali to sodium carbonate-chitosan emulsion, heat and stir at 60°C to react, the mass ratio of chitosan to epichlorohydrin is 1:0.6, filter, wash and freeze dry to obtain porous microspheres loaded with sodium carbonate.

[0184] S13. Sodium carbonate-loaded porous microspheres are immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The mass ratio of sodium lignosulfonate, piperazine and trimesoyl chloride is 1:2:1. The microspheres are then removed, dried and washed to obtain the reagent.

[0185] The method of using the medicine includes the following steps:

[0186] S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment;

[0187] S2. Add the treated phosphogypsum to water, with a solid-liquid ratio of phosphogypsum to water of 1:3. Add the reagent according to the ratio and introduce ammonia gas. The molar ratio of ammonia gas, phosphogypsum and sodium carbonate in the reagent is 0.7:1:1.1. Stir at room temperature and pressure for 48 hours until the reaction is complete. S3. Centrifuge the reaction liquid at a speed of 600 r / min to obtain a solution rich in nutrients and solid particles.

[0188] The sulfate content of the separated solution was analyzed by barium sulfate gravimetric method to determine the conversion rate of sulfur. The chitosan in the solid particles was dissolved and filtered to obtain calcium carbonate solid. The purity of calcium carbonate was calculated by high-temperature heating and decomposition. The test results of each example and comparative example are shown in Tables 1 to 6.

[0189] Table 1. Effects of different chitosan to epichlorohydrin mass ratios on conversion results

[0190]

[0191] Table 2. Effects of different mass ratios of sodium lignosulfonate, piperazine, and trimesoyl chloride on conversion results.

[0192]

[0193] Table 3. Effects of different solid-liquid ratios of phosphogypsum and water on conversion results

[0194]

[0195] Table 4. Effects of different molar ratios of ammonia, phosphogypsum, and ammonium carbonate on conversion results.

[0196]

[0197]

[0198] Table 5. Effect of the cation membrane on the microsphere surface on the conversion results.

[0199]

[0200] Table 6. Effects of adding different carbonates on conversion results

[0201]

[0202] In summary, the reagent provided by this invention can effectively promote the conversion and recovery of calcium and sulfur elements in phosphogypsum, and the operation can be carried out at room temperature and pressure, with a wide range of applications. It achieves the reduction of phosphogypsum volume and has good economic and environmental benefits.

Claims

1. A reagent for reducing the amount of phosphogypsum converted to a lower concentration, characterized in that: The agent is composed of ammonium carbonate, chitosan and epichlorohydrin. Chitosan and epichlorohydrin are cross-linked to form porous microspheres, which are loaded with ammonium carbonate and have a negatively charged cation exchange membrane on their surface. The preparation method of the pharmaceutical agent includes the following steps: S11. Add ammonium carbonate and chitosan to water, pass carbon dioxide through and stir to dissolve, slowly add liquid paraffin and surfactant and stir to emulsify, to obtain ammonium carbonate-chitosan emulsion; S12. Epichlorohydrin and alkali were added to the ammonium carbonate-chitosan emulsion, and the mixture was heated and stirred to react. The mixture was then filtered, washed, and freeze-dried to obtain porous microspheres loaded with ammonium carbonate. S13. The porous microspheres loaded with ammonium carbonate were immersed in an aqueous solution containing sodium lignosulfonate and piperazine, removed and dried, and then immersed in a hexane solution containing trimesoyl chloride for polymerization. The microspheres were then removed, dried and washed to obtain the reagent.

2. The agent for reducing and converting phosphogypsum according to claim 1, characterized in that: In step S11, the mass ratio of chitosan to epichlorohydrin is 1:0.5~0.7, and the heating temperature is 50~70℃.

3. The agent for reducing and converting phosphogypsum according to claim 1, characterized in that: The mass ratio of sodium lignosulfonate, piperazine, and pyromellitic acid chloride in step S13 is 1~2:1~2:

1.

4. The method of using the agent for reducing and converting phosphogypsum according to claim 1, characterized in that, Includes the following steps: S1. Crush the phosphogypsum, screen out phosphogypsum particles of 200-400 mesh, and carry out harmless treatment; S2. Add the treated phosphogypsum to water, add the reagent according to the ratio, and introduce ammonia gas. Stir at room temperature and pressure until the reaction is complete. S3. The reacted liquid is subjected to solid-liquid centrifugation to obtain a solution rich in nutrients and solid particles.

5. The method of using the agent for reducing and converting phosphogypsum according to claim 4, characterized in that: In step S2, the solid-liquid ratio of phosphogypsum to water is 1:2~4, the molar ratio of ammonia, phosphogypsum and ammonium carbonate in the reagent is 0.5~0.9:1:1~1.2, and the stirring time is 45~50h.

6. The method of using the agent for reducing and converting phosphogypsum according to claim 4, characterized in that: The centrifugation speed in step S3 is 500~800 r / min.

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