Method for recovering positive electrode material of waste lithium iron phosphate battery

Abstract

The invention provides a method for recovering a positive electrode material of a waste lithium iron phosphate battery. The method comprises steps: carrying out discharge treatment of the waste lithium ion battery, and separating positive and negative electrode mixed powder, a battery shell, a copper foil, an aluminum foil and a diaphragm through the physical method; adding the separated positiveand negative electrode mixed powder into NaOH solution for dissolving, removing residual Al elements, putting the residual Al elements into organic acid solution with a certain concentration, leachingLi, Fe and PO4<3->, filtering to remove insoluble graphite, separating a positive electrode material from a negative electrode graphite material, purifying the negative electrode material, and recycling the purified material; then adding a lithium source, an iron source or a phosphorus source according to the determined element ratio of the leachate, making a molar ratio of Li to Fe to PO4<3-> tobe (1-1.05): 1: 1; and carrying out spray pyrolysis under a certain temperature condition and inert gas atmosphere to obtain a carbon-coated lithium iron phosphate material. The method is advantagedin that the disassembling mode is simplified, leaching efficiency is high, impurity elements are not introduced, exhausted waste gas is mainly CO2, and industrial large-scale production is facilitated.

Description

technical field [0001] The invention belongs to the technical field of recycling waste lithium iron phosphate batteries, in particular to a method for recycling positive electrode materials of waste lithium iron phosphate batteries. Background technique [0002] With the advancement of new energy product technology, especially the demand for lithium-ion batteries in the electronic market and electric vehicle market is increasing year by year. As of the end of 2017, my country has promoted more than 1.8 million new energy vehicles and assembled about 86.9GWh of power batteries. Since 2018, lithium-ion batteries will gradually enter a large-scale decommissioning period, and there are a large number of lithium-ion battery disposal problems. However, waste lithium iron phosphate lithium-ion batteries contain reusable resources, such as lithium, aluminum, copper, iron and other valuable metals and graphite and other materials. If these batteries are not handled properly, it will ...

AI Technical Summary

Problems solved by technology

One is to use manual disassembly to separate the positive and negative pole pieces, scrape off the powder, and then recover the lithium compound and iron phosphate respectively through acid leaching and pH adjustment. CN108470952A, CN108461857A, etc., in these disclosed treatment methods, the lithium iron phosphate material is not regenerated in situ, but the lithium element and the iron element are recovered separately, the consumption of acid and alkali is large, the recovery cost is high, and the treatment of the three wastes is difficult

Another method is to directly add lithium source, iron source or phosphorus source to prepare lithium iron phosphate material after calcining, such as the documents CN108550940A, CN108172922A, CN107634222A, CN107275705A, CN106976852A, etc. disclosed by the Chinese Patent Office. High requirements (requires relatively pure positive electrode powder), the uniformity of the newly prepared material particles is difficult to ensure and is prone to impurity, and the electrochemical performance of the positive electrode material cannot be guaranteed

Another method is the document CN106276842A disclosed by the Chinese Patent Office, which is an in-situ synthesis of lithium iron phosphate precursor after leaching with an organic mixed acid, but it needs to be prepared by vacuum distillation and organic solvent precipitation, and the process is complicated, energy consumption is high, and recovery costs High, difficult to achieve industrial production

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