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CN-121990540-A - Recycling method of lithium iron phosphate black powder, lithium iron phosphate positive electrode material and application

CN121990540ACN 121990540 ACN121990540 ACN 121990540ACN-121990540-A

Abstract

The embodiment of the application discloses a recycling method of lithium iron phosphate black powder, a lithium iron phosphate anode material and application, wherein the recycling method comprises acid mixing, sintering, acid leaching, solid-liquid separation and separate treatment, the method realizes the omnibearing recovery of three main valuable elements of lithium, iron and phosphorus in the lithium iron phosphate black powder, obtains lithium chloride by treating a liquid phase, has high recovery rate, and obtains the iron phosphate with high added value instead of waste residues by treating a solid phase. In addition, the recycling method adopts acid mixing and preset condition sintering to enable the phase of the lithium iron phosphate to be changed, the occurrence state and leaching behavior of impurity elements are regulated and controlled, after the step of treatment, al, ni, co, mn and other impurities are selectively and efficiently reserved in a liquid phase in subsequent acid leaching, and iron and phosphorus are mainly enriched in a solid phase, so that a foundation is laid for the subsequent preparation of high-purity ferric phosphate.

Inventors

  • WAN YAFENG
  • LI YUNXIA
  • QIU CHENGMING
  • KE JUN

Assignees

  • 湖北金泉新材料有限公司

Dates

Publication Date
20260508
Application Date
20251219

Claims (10)

  1. 1. The recycling method of the lithium iron phosphate black powder is characterized by comprising the following steps of: acid mixing treatment is carried out on the lithium iron phosphate black powder to obtain acid-mixed lithium iron phosphate black powder; sintering the acid-mixed lithium iron phosphate black powder under a preset condition to obtain sintered black powder; acid leaching treatment is carried out on the sintered black powder, and a solid phase and a liquid phase are obtained through filtration; Treating the liquid phase to obtain lithium chloride; Treating the solid phase to obtain iron phosphate; wherein the oxygen content of the preset condition is smaller than the oxygen content in the air.
  2. 2. The recycling method of lithium iron phosphate black powder according to claim 1, characterized in that, The step of acid mixing treatment of lithium iron phosphate black powder comprises the following steps: mixing the lithium iron phosphate black powder with phosphoric acid, and uniformly stirring to obtain the acid-mixed lithium iron phosphate black powder.
  3. 3. The recycling method of lithium iron phosphate black powder according to claim 2, characterized in that, The mass ratio of the lithium iron phosphate black powder to the phosphoric acid is (2-10): 1.
  4. 4. The recycling method of lithium iron phosphate black powder according to claim 1, characterized in that, The preset conditions comprise a low oxygen environment or a reducing atmosphere, the oxygen content of the low oxygen environment is less than 5%, and/or The sintering temperature is in the range of 300 o to 600 o C, and/or The sintering time is within the range of 5min to 120min.
  5. 5. The recycling method of lithium iron phosphate black powder according to claim 1, characterized in that, The step of carrying out acid leaching treatment on the sintered black powder comprises the following steps: Dispersing the sintered black powder in a hydrochloric acid solution, and adding a hydrogen peroxide solution for first acid leaching to obtain a first mixture; Heating the first mixture, and adding hydrogen peroxide solution for second acid leaching to obtain a second mixture; Regulating and controlling the pH value of the second mixture, and filtering to obtain a solid phase and a liquid phase.
  6. 6. The recycling method of lithium iron phosphate black powder according to claim 5, characterized in that, The concentration of the hydrochloric acid solution is in the range of 0.5mol/L to 3mol/L, and/or The temperature of the heating is 40 o to 90 o C, and/or The pH value is in the range of 0.5 to 2.
  7. 7. The recycling method of lithium iron phosphate black powder according to claim 1, characterized in that, A step of treating the liquid phase to obtain lithium chloride, comprising: And adding lithium hydroxide into the liquid phase, regulating the pH to 7-10, and filtering to obtain lithium chloride.
  8. 8. The recycling method of lithium iron phosphate black powder according to claim 1, characterized in that, In the above-mentioned iron phosphate, the iron phosphate, al less than or equal to 100ppm, ni less than or equal to 10ppm, co 10ppm or less and Mn or less than 50ppm.
  9. 9. A lithium iron phosphate anode material is characterized in that, The lithium iron phosphate positive electrode material is recovered by the recovery and utilization method according to any one of claims 1 to 8.
  10. 10. Use of the recycling method of lithium iron phosphate black according to any one of claims 1 to 8 in recycling of electrode materials of lithium ion batteries.

Description

Recycling method of lithium iron phosphate black powder, lithium iron phosphate positive electrode material and application Technical Field The application relates to the technical field of battery anode material recovery, in particular to a recycling method of lithium iron phosphate black powder, a lithium iron phosphate anode material and application. Background Along with the wide application of lithium ion batteries, particularly lithium iron phosphate batteries and the coming of retired tides, the recycling of the lithium iron phosphate black powder which is the positive electrode material of the waste batteries is increasingly important. Meanwhile, in the production process of the lithium iron phosphate anode material, a large amount of lithium iron phosphate black powder caused by ternary doping (introducing Ni, co and Mn elements) and crushing and mixing can be generated, and the black powder contains valuable lithium, iron and phosphorus elements, but also metal impurities such as Al, ni, co, mn and the like are introduced. At present, the recycling method of lithium iron phosphate black powder mainly adopts hydrochloric acid or sulfuric acid for direct acid leaching, and aims to recycle lithium salt in the form of lithium chloride or lithium carbonate. However, the method has less attention on the recovery of the iron element and the phosphorus element, the comprehensive utilization rate of resources is low, and even if the recovery of the iron element and the phosphorus element is tried to prepare the ferric phosphate, the obtained ferric phosphate has higher Al, ni, co, mn and other impurities. Disclosure of Invention The application provides a recycling method of lithium iron phosphate black powder, a lithium iron phosphate anode material and application, and aims to solve the problems that the lithium iron phosphate black powder cannot effectively recycle iron and phosphorus and the content of impurities in a recycled product is high. The application provides a recycling method of lithium iron phosphate black powder, which comprises the following steps: acid mixing treatment is carried out on the lithium iron phosphate black powder to obtain acid-mixed lithium iron phosphate black powder; sintering the acid-mixed lithium iron phosphate black powder under a preset condition to obtain sintered black powder; acid leaching treatment is carried out on the sintered black powder, and a solid phase and a liquid phase are obtained through filtration; Treating the liquid phase to obtain lithium chloride; the solid phase is treated to obtain iron phosphate. Optionally, in some embodiments of the present application, the step of acid-mixing the lithium iron phosphate black includes: mixing the lithium iron phosphate black powder with phosphoric acid, and uniformly stirring to obtain the acid-mixed lithium iron phosphate black powder. Optionally, in some embodiments of the present application, the mass ratio of the lithium iron phosphate black powder to the phosphoric acid ranges from (2-10): 1. Optionally, in some embodiments of the present application, the step of acid leaching the sintered black powder includes: Dispersing the sintered black powder in a hydrochloric acid solution, and adding a hydrogen peroxide solution for first acid leaching to obtain a first mixture; Heating the first mixture, and adding hydrogen peroxide solution for second acid leaching to obtain a second mixture; Regulating and controlling the pH value of the second mixture, and filtering to obtain a solid phase and a liquid phase. Optionally, in some embodiments of the application, the concentration of the hydrochloric acid solution may range from 0.5mol/L to 3mol/L, and/or The temperature of the heating is 40 o to 90 o C, and/or The pH value is in the range of 0.5 to 2. Optionally, in some embodiments of the application, the step of treating the liquid phase to obtain lithium chloride comprises: And adding lithium hydroxide into the liquid phase, regulating the pH to 7-10, and filtering to obtain lithium chloride. Optionally, in some embodiments of the application, the step of treating the solid phase to obtain iron phosphate comprises: Washing and acid leaching the solid phase, and filtering to obtain filtrate; adjusting the iron-phosphorus ratio in the filtrate, and adding titanium salt to obtain an iron-phosphorus-titanium-containing solution; Adding a precipitant into the solution, adjusting the pH to 1.5-2.5, and washing and sintering to obtain the ferric phosphate. In a second aspect, an embodiment of the present application provides a lithium iron phosphate positive electrode material, where the lithium iron phosphate positive electrode material is recovered by the aforementioned recovery method. In a third aspect, an embodiment of the present application provides an application of a recycling method of lithium iron phosphate black in recycling an electrode material of a lithium ion battery. The recycling method of the li