Recovery method of waste lithium iron phosphate positive electrode material

Abstract

The invention discloses a waste lithium iron phosphate positive electrode material recovery method, which comprises: S1, taking a waste lithium iron phosphate positive electrode material, carrying outpretreatment to obtain lithium iron phosphate powder, mixing the lithium iron phosphate powder and a solid grinding aid, and carrying out ball milling to obtain mixed powder; and S2, leaching the mixed powder with water to obtain a leaching solution containing valuable metal ions, wherein the grinding aid is an organic acid, and the acid radical ions in the organic acid can form soluble complexeswith iron and lithium respectively. According to the scheme, the problems that in the prior art, the using amount of acid and alkali is too large, the yield of salt-containing wastewater is too large, and secondary pollution is likely to be generated can be well solved.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a method for recycling waste lithium iron phosphate cathode materials. Background technique [0002] Lithium iron phosphate batteries are widely used in portable batteries, electric vehicles and other fields due to their advantages such as environmental friendliness, low price, and long cycle life. However, after the lithium iron phosphate battery reaches its expected life, a large number of waste lithium iron phosphate batteries will be produced on the market. If these waste iron phosphate batteries are not recycled, it will not only cause serious waste of lithium, phosphorus and iron resources, It will also cause very serious environmental pollution problems. [0003] At present, the recycling methods of waste iron phosphate batteries can be divided into two categories: repair and transformation methods and hydrometallurgical methods. The repair method refers...

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Problems solved by technology

Although this method is applicable to the recovery of various lithium iron phosphate positive electrode materials, this method is likely to cause serious environmental pollution problems. On the one hand, when sulfuric acid, hydrochloric acid, nitric acid and other leaching acids are used, SO 3 , Cl 2 , NO x and other toxic gases; on the other hand, due to the excellent structural stability of lithium iron phosphate with olivine structure, the existing technology needs to add excessive, high-concentration (2M ~ 6M) strong acid to fully leach the metal in the positive electrode material This leads to the need to use a large amount of alkaline substances to neutralize the acidic leaching solution in the subsequent purification and separation process. The generation of toxic gases, the use of excessive acid-base solutions and the generation of a large amount of saline wastewater can easily cause secondary pollution to the environment.

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