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CN-117720087-B - Impurity removing device system and method for wet-process phosphoric acid slurry

CN117720087BCN 117720087 BCN117720087 BCN 117720087BCN-117720087-B

Abstract

The invention relates to a system and a method for removing impurities from wet-process phosphoric acid slurry, wherein the system for removing impurities comprises a reaction unit, an impurity removing unit and a flow control unit; and part of slurry after impurity removal is returned to the reaction unit through the flow control unit. According to the impurity removing device system provided by the invention, the continuous production requirement of phosphorite can be met by arranging the reaction unit, the impurity removing unit and the flow control unit, and the reaction of phosphorite and the external circulation extraction of impurities are synchronously carried out, so that the synchronous removal of phosphoric acid and phosphogypsum impurities is realized at the source.

Inventors

  • ZHU GANYU
  • LI HUIQUAN
  • HE LEI
  • ZHENG GUANGMING
  • MENG ZIHENG
  • YANG YUNRUI
  • WANG YONG
  • LI FANG
  • LI SHAOPENG

Assignees

  • 中国科学院过程工程研究所
  • 宜都兴发化工有限公司

Dates

Publication Date
20260508
Application Date
20220908

Claims (20)

  1. 1. The impurity removing device system for the wet-process phosphoric acid slurry is used for synchronously carrying out acidolysis of phosphorite and external circulation extraction of impurities, and is characterized by comprising a reaction unit, an impurity removing unit and a flow control unit; part of slurry of the reaction unit is conveyed to an impurity removal unit through a flow control unit; The part of slurry after impurity removal returns to the reaction unit through the flow control unit; the flow control unit comprises a feeding control unit, a slurry returning device and an organic phase conveying control unit; the impurity removing unit comprises an extraction tower, a pulse device and an organic phase storage device; the feeding control unit is used for conveying part of slurry of the reaction unit to the impurity removal unit; the slurry returning device is used for returning the part of slurry after the impurity removal to the reaction unit.
  2. 2. The system of the impurity removal device according to claim 1, wherein the reaction unit comprises a premixing device, an acidolysis device and a crystallization device which are sequentially connected along the material flow direction, and return acid obtained by separating slurry discharged from the crystallization device is reused in the premixing device.
  3. 3. The system of claim 2, wherein the top of the premixing device is provided with a raw material inlet and a return acid inlet.
  4. 4. The system of claim 2, wherein the top of the acidolysis device is provided with an acid feed.
  5. 5. The system of claim 2, wherein the bottom of the crystallization device is provided with a discharge port.
  6. 6. The system of claim 2, wherein the premixing device, the acidolysis device and the crystallization device are each independently provided with 1-3 reaction tanks, and the reaction tanks are each provided with a stirring device.
  7. 7. The system of claim 6, wherein the reaction tanks are in communication via arches and/or overflow ports.
  8. 8. The system of claim 7, wherein the overflow port has a centroid height from the bottom of the reaction tank that is 50-90% of the height of the reaction tank.
  9. 9. The abatement device system of claim 7, wherein the height of the arch is 50-90% of the height of the reaction tank.
  10. 10. The system according to any one of claims 2 to 9, wherein the organic phase transport control unit is configured to transport the organic phase of the impurity removal unit.
  11. 11. The system of claim 1, wherein the loading control unit comprises a loading device, a slurry pressure stabilizing device, and a first flow monitoring device connected in sequence along a material flow direction.
  12. 12. The system of claim 11, wherein the inlet of the loading device is connected to any one of a reaction tank outlet of the premixing device, a reaction tank outlet of the acidolysis device, or a reaction tank outlet of the crystallization device.
  13. 13. The system of any one of claims 2-9, wherein the organic phase delivery control unit comprises an organic phase delivery device, an organic phase voltage regulator device, and a second flow monitoring device connected in sequence along a material flow direction.
  14. 14. The system of any one of claims 2-9, wherein the top of the extraction column is provided with a slurry inlet and a loaded organic phase outlet, and the bottom of the extraction column is provided with a slurry outlet, an organic phase inlet and a connection port connected with a pulse device; the organic phase storage device is connected with an organic phase inlet through the organic phase conveying control unit; The reaction unit is connected with the slurry inlet through the feeding control unit; the slurry outlet is connected with the reaction unit through the slurry returning device.
  15. 15. The system of any one of claims 6 to 9, wherein the slurry returning device is connected to a next reaction tank adjacent to the inlet of the feeding device, and the next reaction tank comprises any one of a reaction tank of a premixing device, a reaction tank of an acidolysis device, and a reaction tank of a crystallization device.
  16. 16. A method of using the decontamination apparatus system of any one of claims 1-15, the method comprising the steps of: Sequentially carrying out pre-decomposition treatment, acidolysis treatment and crystallization treatment on phosphorite, and separating to obtain return acid after crystallization treatment for pre-decomposition treatment; At least 1 process of the pre-decomposition treatment, the acidolysis treatment or the crystallization treatment is performed, and impurity removal treatment is performed simultaneously; the slurry produced by the impurity removal treatment is returned to any 1 of the processes of the pre-decomposition treatment, the acidolysis treatment or the crystallization treatment.
  17. 17. The method of claim 16, wherein the mass ratio of the return acid to the phosphate rock is (1-5): 1.
  18. 18. The process of claim 16, wherein the acid used in the acidolysis treatment comprises sulfuric acid.
  19. 19. The method of claim 18, wherein the mass ratio of sulfuric acid to phosphorus ore is (1-10): 1.
  20. 20. The method of claim 16, wherein the mass ratio of slurry discharged after the crystallization treatment to the phosphate rock is (0.1-1): 1.

Description

Impurity removing device system and method for wet-process phosphoric acid slurry Technical Field The invention belongs to the technical field of phosphorus chemical industry, relates to a system and a method for removing impurities, and in particular relates to a system and a method for removing impurities from wet-process phosphoric acid slurry. Background Wet phosphoric acid is a process for preparing phosphoric acid by decomposing phosphorite with inorganic acid. After the phosphorite is treated by the wet process, metal impurities such as iron, magnesium, aluminum, sodium, potassium, silicon and the like in the phosphorite enter phosphoric acid and phosphogypsum as byproducts, and the quality of the phosphoric acid and the resource utilization of the phosphogypsum can be seriously influenced. The existing impurity removal methods for phosphoric acid comprise a crystallization method, a chemical precipitation method, an ion exchange method, a solvent extraction method and the like, and the impurity removal treatment for phosphogypsum comprises a water washing method, a lime neutralization heat treatment method, a screening method, a calcination method, an organic solvent extraction method and the like, but the methods have the problems of high energy consumption, high cost, environmental pollution, equipment corrosion and the like. CN 204873847U discloses a wet-process phosphoric acid purifying system, which comprises an extracting system, a desulfurizing and defluorinating device, a sedimentation washing device and a back extraction system which are sequentially connected in series, wherein the wet-process phosphoric acid purifying system of the utility model adjusts the connection relation in the traditional wet-process phosphoric acid purifying system, adjusts the traditional four-tank one-tower five-stage extraction and one-stage back extraction into four-tank four-stage extraction and two-stage back extraction, and improves the extraction rate by more than 10% under the conditions of not changing the structure of an extracting tower and not adding new equipment. However, the purification system only aims at phosphoric acid treatment, the purification effect is achieved by adopting a multi-stage extraction mode, the problem of phosphogypsum impurity residue is not considered, and the recycling of phosphogypsum is not facilitated. CN 111943156A discloses a process for optimizing phosphoric acid reaction and separation by using active silicon dioxide, which comprises the steps of S1, mixing the active silicon dioxide, S2, reslurrying the active silicon dioxide and dilute phosphoric acid, S3, mixing and ageing a digestion tank, S4, filtering by a vacuum rotary drum filter, and S5, cleaning a dilute phosphoric acid pipe system. The process can realize harmless treatment of fluorine-containing silicon dioxide, improve the recovery rate of fluosilicic acid in phosphorite, and realize efficient separation of phosphogypsum and dilute phosphoric acid after the auxiliary agent is mixed into a phosphoric acid digestion tank. However, the invention only solves the problems of separation and purification of phosphoric acid and innocent treatment of fluorine-containing raw materials, and does not consider impurities remained in phosphogypsum and phosphoric acid after acidolysis of phosphorite, thereby being not beneficial to purifying phosphoric acid and recycling phosphogypsum. CN 204675835U discloses a wet-process phosphoric acid impurity removing device, which can effectively remove magnesium ions and sulfate radicals in the wet-process phosphoric acid production, and the phosphoric acid after impurity removal meets the requirements of industrial production industrial grade, feed grade and other phosphates, wherein the sulfate radical removing rate is more than 85%, the magnesium ion removing rate is more than 50%, and the phosphoric acid loss rate is 1.2-1.5%. However, the impurity removing device can remove part of impurities in phosphoric acid in a targeted manner, is low in removal rate and has certain limitation. In view of the shortcomings of the prior art, there is a need to provide a system of an impurity removal device that is efficient in impurity removal, simple in equipment and low in cost. Disclosure of Invention The invention aims to provide a system and a method for removing impurities from wet-process phosphoric acid slurry, wherein the system for removing impurities can synchronously perform acidolysis of phosphorite and external circulation extraction of impurities, so that synchronous removal of phosphoric acid and phosphogypsum impurities is realized, the production efficiency is high, and the system and the method are suitable for a wet-process phosphoric acid production process. In order to achieve the aim of the invention, the invention adopts the following technical scheme: in a first aspect, the invention provides a system of a wet-process phosphoric acid slurry impurity removal device