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CN-121990535-A - Process for producing phosphoric acid

CN121990535ACN 121990535 ACN121990535 ACN 121990535ACN-121990535-A

Abstract

The application provides a preparation method of phosphoric acid, which belongs to the technical field of wet-process phosphoric acid, and comprises the steps of mixing phosphate rock powder and iron lithium tailings powder to obtain a composite phosphorus source, mixing the composite phosphorus source and sulfuric acid, heating and stirring to obtain reaction slurry, and carrying out solid-liquid separation on the reaction slurry to obtain phosphoric acid and a calcium sulfate filter cake. The application aims to solve the technical problem of high production cost caused by excessive dependence on phosphorite in the existing phosphoric acid preparation process.

Inventors

  • HE LEI
  • YU BINGRONG
  • ZHU CHONGJI

Assignees

  • 湖北万润新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20260204

Claims (10)

  1. 1. A method for preparing phosphoric acid, comprising the steps of: Mixing phosphate rock powder and lithium iron tailings powder to obtain a composite phosphorus source; mixing the composite phosphorus source with sulfuric acid, heating and stirring to obtain reaction slurry; and (3) carrying out solid-liquid separation on the reaction slurry to obtain phosphoric acid and a calcium sulfate filter cake.
  2. 2. The preparation method of claim 1, wherein the mass percentage of the iron lithium tailings in the composite phosphorus source is 10-40% based on dry product.
  3. 3. The preparation method of claim 1, wherein the mass percentage of the iron lithium tailings in the composite phosphorus source is 10-30% based on dry product.
  4. 4. The preparation method according to claim 1, wherein the mass percentage of sulfate ions in the reaction slurry is controlled within a range of 35-47%.
  5. 5. The method according to claim 4, wherein the mass ratio of the composite phosphorus source to the sulfuric acid is 1 (2-3), or And (3) mixing the composite phosphorus source with sulfuric acid, heating and stirring to obtain reaction slurry, wherein a part of phosphoric acid is used as circulating mother liquor to be refluxed to be mixed with the composite phosphorus source and sulfuric acid, and the mass ratio of the composite phosphorus source to the sulfuric acid to the circulating mother liquor is 1 (1.95-2.8) (0.2-0.25).
  6. 6. The preparation method according to claim 1, wherein the temperature of the heating and stirring is 80-95 ℃, and the time of the heating and stirring is 2-4 hours.
  7. 7. The preparation method of claim 1, wherein the stirring speed during heating and stirring is 200-350 r/min.
  8. 8. The method according to claim 1, wherein the sulfuric acid has a mass concentration of 70 to 98%, and/or, In the phosphoric acid, the mass percentage of P 2 O 5 is 5-12.6%.
  9. 9. The method of claim 1, wherein prior to the step of mixing the ground phosphate rock with the lithium iron tailings to obtain the composite phosphorus source, further comprising: drying phosphorite until the water content is less than or equal to 2%, grinding and sieving with a 80-100 mesh sieve to obtain phosphorite powder; And (3) drying the iron lithium tailings until the water content is less than or equal to 2% by mass, and grinding and sieving the iron lithium tailings with a 80-100 mesh sieve to obtain iron lithium tailings powder.
  10. 10. The process according to claim 9, wherein the phosphorite is dried at a temperature of 80 to 110 ℃ and/or, And drying the lithium iron tailings at the temperature of 80-110 ℃.

Description

Process for producing phosphoric acid Technical Field The application belongs to the technical field of wet-process phosphoric acid, and particularly relates to a preparation method of phosphoric acid. Background The wet phosphoric acid is usually obtained by acidolysis reaction by using inorganic acid and phosphorite as reaction raw materials. Taking concentrated sulfuric acid as an example, the wet process phosphoric acid reaction is: Ca5(PO4)3F+5H2SO4+10H2O→3H3PO4+5CaSO4·2H2O+HF. the method is extremely dependent on high-quality natural phosphorite, and has larger demand. However, as the exploitation of phosphate resources increases, phosphate becomes increasingly smaller, which may lead to an increasing production cost of phosphoric acid. Disclosure of Invention In view of the technical problems in the background art, the application provides a preparation method of phosphoric acid, which aims to solve the technical problem of high production cost caused by excessive dependence on phosphorite in the existing phosphoric acid preparation process. The embodiment of the application provides a preparation method of phosphoric acid, which comprises the following steps: Mixing phosphate rock powder and lithium iron tailings powder to obtain a composite phosphorus source; mixing the composite phosphorus source with sulfuric acid, heating and stirring to obtain reaction slurry; and (3) carrying out solid-liquid separation on the reaction slurry to obtain phosphoric acid and a calcium sulfate filter cake. According to the technical scheme, the iron lithium tailings powder and the phosphate rock powder are mixed to be used as a composite phosphorus source and acidolysis is carried out, so that on one hand, the consumption of phosphate rock in the phosphorus source can be reduced, the excessive dependence of phosphoric acid production on natural phosphate rock is reduced, on the other hand, the iron lithium tailings is rich in phosphorus elements, and the process method can realize the efficient recovery of the phosphorus elements in the iron lithium tailings (in some embodiments, the recovery rate of the phosphorus elements can reach more than 95 percent), thereby being beneficial to solving the problems of resource waste and environmental pollution caused by accumulation of the iron lithium tailings, changing waste into valuables, improving the resource utilization rate, and integrally reducing the raw material purchase cost and the solid waste treatment cost. In addition, the process method is in seamless connection with the existing wet phosphoric acid production process, no major equipment transformation is needed, and the applicability is high. In some embodiments, the step of mixing the ground phosphate rock with the lithium iron tailings powder to obtain a composite phosphorus source further comprises, prior to: drying phosphorite until the water content is less than or equal to 2%, grinding and sieving with a 80-100 mesh sieve to obtain phosphorite powder; And (3) drying the iron lithium tailings until the water content is less than or equal to 2% by mass, and grinding and sieving the iron lithium tailings with a 80-100 mesh sieve to obtain iron lithium tailings powder. In the embodiment, phosphorite and lithium iron tailings are firstly dried and ground, the moisture content of the phosphorite and the lithium iron tailings is reduced, and the particle size is regulated and controlled within a proper range, so that the phosphorite and the lithium iron tailings are mixed to serve as a composite phosphorus source to participate in acidolysis reaction, and the reactivity is improved. In some embodiments, the phosphorite is dried at a temperature of 80-110 ℃. In this embodiment, drying is performed under the above temperature conditions, so that high-temperature damage to the phosphorite can be avoided while improving drying efficiency and effect. In some embodiments, the lithium iron tailings are dried at a temperature of 80-110 ℃. In this embodiment, drying is performed under the above temperature conditions, so that high-temperature damage to components in the iron lithium tailings can be avoided while improving drying efficiency and effect. In some embodiments, the mass percentage of the iron-lithium tailings in the composite phosphorus source is 10-40%, preferably 10-30%, based on dry products. In the embodiment, the doping amount of the iron lithium tailings in the composite phosphorus source is controlled within the range, so that the phosphorus ore consumption can be reduced, the optimal balance between the total phosphorus yield and the impurity reduction can be achieved, and the high phosphorus yield and the low iron impurity can be realized. In some embodiments, the mass percentage of sulfate ions in the reaction slurry is controlled within a range of 35-47%. In this example, the concentration of sulfate ions in the reaction system is controlled within the above range, so that an appropriate acid-ba