Processing method of ardealite waste
By separating and treating phosphogypsum waste at high temperatures, rare earth elements are extracted and anhydrous phosphogypsum is obtained, which solves the problems of low utilization rate and environmental pollution of phosphogypsum, and realizes efficient utilization of resources and improvement of economic value.
Patent Information
- Application Number
- CN202411247644.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-02-07
AI Technical Summary
Phosphogypsum has a low comprehensive utilization rate and contains harmful heavy metals and impurities, leading to environmental pollution and resource waste.
By adding water and a suspending agent to phosphogypsum waste to form a slurry, separating and adjusting the pH value, and combining solution treatment and high-temperature dehydration and desulfurization, rare earth elements are extracted and anhydrous phosphogypsum is obtained.
It improves the utilization rate of phosphogypsum, reduces environmental pollution, and enhances economic value.
Smart Images
Figure CN119390370A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of phosphorus chemical industry, and in particular to a method for processing phosphogypsum waste. Background Art
[0002] Phosphogypsum is a solid waste of the phosphate fertilizer industry. Generally, about 5-6 tons of phosphogypsum are produced for every ton of phosphoric acid, and 2.5-5 tons of phosphogypsum are discharged for every ton of diammonium phosphate produced. At present, the comprehensive utilization rate of phosphogypsum is relatively low, and it is mainly treated by stockpiling. A large amount of phosphogypsum piled up into mountains not only occupies a large amount of land resources, but also contains soluble phosphorus, fluorine, organic matter and a small amount of cadmium, arsenic, mercury and other harmful heavy metal chemicals that are harmful to organisms. Long-term accumulation of these harmful substances will pollute the surrounding soil, affect vegetation growth, and seriously damage the ecological environment of the area. They will also be washed away by rainwater, analyzed by water, and flow in water bodies, and eventually enter rivers to cause water pollution.
[0003] At present, the output of phosphogypsum is very large, but its utilization rate is very low. There are many reasons for the low utilization rate of phosphogypsum. Since phosphogypsum contains various impurities such as free carbon, hydrochloric acid, and sulfuric acid, it is difficult to fully utilize it, resulting in a relatively single utilization method. The impurity removal method of industrial by-product gypsum is inefficient in removing harmful impurities in phosphogypsum, which affects the reuse of industrial by-product gypsum. Summary of the invention
[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a processing method for phosphogypsum waste.
[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: The invention discloses a processing method for phosphogypsum waste, comprising the steps of adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid viscous slurry, and then standing to separate the slurry into layers, respectively obtaining phosphogypsum backwater and mud; adding a prepared solution A to the mud backwater, stirring and slurrying to obtain a slurry with an acidic pH; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, standing to remove impurities, and obtaining a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, standing to precipitate, and desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0006] As a preferred technical solution of the present invention, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 8-10 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.01-0.06; By adding dilute hydrochloric acid to the mud, a slurry with a pH of 3-6 is obtained.
[0007] As a preferred technical solution of the present invention, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 2-4.
[0008] As a preferred technical solution of the present invention, solution D is an ammonium bicarbonate solution with an ammonium content of 2-5%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 7-8.
[0009] As a preferred technical solution of the present invention, the reducing agent is coal powder and / or coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.01-0.5, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 800-1500°C.
[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. Extract rare earth elements from phosphogypsum waste and recycle them. The whole process is simple to operate, which not only improves the utilization rate of phosphogypsum, but also reduces environmental pollution and improves economic value; 2. Purify the phosphogypsum waste to obtain anhydrous phosphogypsum, thereby improving the utilization rate of phosphogypsum. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a flow chart of the steps of the present invention. DETAILED DESCRIPTION
[0012] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0013] In the drawings, the same reference numerals all refer to the same components.
[0014] Embodiment 1: like Figure 1As shown, the present invention provides a processing method for phosphogypsum waste, which comprises adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid and viscous slurry, and then standing to separate them into layers, respectively obtaining phosphogypsum backwater and mud; adding a modulated solution A to the mud backwater, and obtaining a slurry with an acidic pH after stirring and slurrying; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, and standing to remove impurities to obtain a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and standing to precipitate, and then desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0015] Further, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 8 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.01; By adding dilute hydrochloric acid to the slurry, a slurry with a pH of 3 was obtained.
[0016] Furthermore, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 2.
[0017] Furthermore, solution D is an ammonium bicarbonate solution with an ammonium content of 2%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 7.
[0018] Furthermore, the reducing agent is coal powder, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.01, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 800°C.
[0019] Embodiment 2: like Figure 1 As shown, the present invention provides a processing method for phosphogypsum waste, which comprises adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid and viscous slurry, and then standing to separate them into layers, respectively obtaining phosphogypsum backwater and mud; adding a modulated solution A to the mud backwater, and obtaining a slurry with an acidic pH after stirring and slurrying; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, and standing to remove impurities to obtain a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and standing to precipitate, and then desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0020] Further, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 10 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1: 0.06; By adding dilute hydrochloric acid to the slurry, a slurry with a pH of 6 was obtained.
[0021] Furthermore, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 4.
[0022] Furthermore, solution D is an ammonium bicarbonate solution with an ammonium content of 5%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 8.
[0023] Furthermore, the reducing agent is coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.5, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 1500°C.
[0024] Embodiment 3: like Figure 1 As shown, the present invention provides a processing method for phosphogypsum waste, which comprises adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid and viscous slurry, and then standing to separate them into layers, respectively obtaining phosphogypsum backwater and mud; adding a modulated solution A to the mud backwater, and obtaining a slurry with an acidic pH after stirring and slurrying; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, and standing to remove impurities to obtain a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and standing to precipitate, and then desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0025] Further, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 9 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.04; By adding dilute hydrochloric acid to the slurry, a slurry with a pH of 5 was obtained.
[0026] Furthermore, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 3.
[0027] Furthermore, solution D is an ammonium bicarbonate solution having an ammonium content of 3%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 7.5.
[0028] Furthermore, the reducing agent is coal powder and coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.3, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 1000°C.
[0029] Embodiment 4: like Figure 1 As shown, the present invention provides a processing method for phosphogypsum waste, which comprises adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid and viscous slurry, and then standing to separate them into layers, respectively obtaining phosphogypsum backwater and mud; adding a modulated solution A to the mud backwater, and obtaining a slurry with an acidic pH after stirring and slurrying; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, and standing to remove impurities to obtain a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and standing to precipitate, and then desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0030] Further, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 8.5 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.025; By adding dilute hydrochloric acid to the slurry, a slurry with a pH of 4 was obtained.
[0031] Furthermore, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 2.5.
[0032] Furthermore, solution D is an ammonium bicarbonate solution having an ammonium content of 2.5%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 7.5.
[0033] Furthermore, the reducing agent is coal powder and coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.3, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 1000°C.
[0034] Embodiment 5: like Figure 1 As shown, the present invention provides a processing method for phosphogypsum waste, which comprises adding water and a suspending agent to the phosphogypsum waste, fully heating and stirring, mixing the materials to form a uniform turbid and viscous slurry, and then standing to separate them into layers, respectively obtaining phosphogypsum backwater and mud; adding a modulated solution A to the mud backwater, and obtaining a slurry with an acidic pH after stirring and slurrying; performing liquid-solid separation on the slurry to obtain a slag and a liquid, adding a solution B to the liquid to keep the pH of the liquid acidic, and standing to remove impurities to obtain a liquid C; filtering the liquid C to obtain a filter residue and a filtrate, adding a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and standing to precipitate, and then desalting and drying the obtained precipitate to obtain a rare earth carbonate enrichment; The material residue and the filter residue are mixed with the phosphogypsum return water, quicklime or lime milk is added thereto, stirred and re-slurried to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
[0035] Further, solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 9.5 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.045; By adding dilute hydrochloric acid to the slurry, a slurry with a pH of 5.5 was obtained.
[0036] Furthermore, solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 3.
[0037] Furthermore, solution D is an ammonium bicarbonate solution having an ammonium content of 4.5%, and solution D is added to the filtrate to adjust the pH value of the filtrate to 7.5.
[0038] Furthermore, the reducing agent is coal powder and / or coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.4, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 1400°C.
[0039] The present invention discloses a method for processing phosphogypsum waste, which extracts rare earth elements from the phosphogypsum waste and recycles them. The whole process is simple to operate, which not only improves the utilization rate of phosphogypsum, but also reduces pollution to the environment and improves the economic value. The phosphogypsum waste is purified to obtain anhydrous phosphogypsum, thereby improving the utilization rate of the phosphogypsum.
[0040] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for processing phosphogypsum waste, characterized in that: The following steps are involved: Add water and a suspending agent to the phosphogypsum waste, fully heat and stir, mix the materials to form a uniform turbid viscous slurry, and then stand to separate the layers to obtain phosphogypsum backwater and mud respectively; add the prepared solution A to the mud backwater, and obtain a slurry with an acidic pH after stirring and slurry adjustment; perform liquid-solid separation on the slurry to obtain a slag and a liquid, add a solution B to the liquid to keep the pH of the liquid acidic, and stand to remove impurities to obtain a liquid C; filter the liquid C to obtain a filter residue and a filtrate, add a solution D to the filtrate to adjust the pH of the filtrate to alkaline, and stand to precipitate, then desalt and dry the obtained precipitate to obtain a rare earth carbonate enriched product; The material residue and the filter residue are mixed with the phosphogypsum return water, and quicklime or lime milk is added thereto and stirred to obtain phosphogypsum slurry; A reducing agent is added to the anhydrous phosphogypsum, and the phosphogypsum slurry is subjected to high-temperature dehydration and desulfurization, and anhydrous phosphogypsum is obtained after cooling.
2. The method for processing phosphogypsum waste according to claim 1, characterized in that: Solution A is prepared by adding a small amount of sodium silicate to an ammonium-containing solution, adjusting the pH value of the solution to 8-10 with sodium hydroxide; and adding sodium phosphate to the solution at a liquid-to-solid ratio of 1:0.01-0.06; By adding dilute hydrochloric acid to the mud, a slurry with a pH of 3-6 is obtained.
3. The method for processing phosphogypsum waste according to claim 1, characterized in that: Solution B is a saturated oxalic acid solution, and solution B is added to the feed liquid to adjust the pH value of the feed liquid to 2-4.
4. The method for processing phosphogypsum waste according to claim 1, characterized in that: Solution D is an ammonium bicarbonate solution with an ammonium content of 2-5%. Solution D is added to the filtrate to adjust the pH value of the filtrate to 7-8.
5. The method for processing phosphogypsum waste according to claim 1, characterized in that: The reducing agent is coal powder and / or coke, the weight ratio of anhydrous phosphogypsum to the reducing agent is 1:0.01-0.5, and the temperature for high-temperature dehydration and desulfurization of the phosphogypsum slurry is 800-1500°C.