Recycling method of waste lithium iron phosphate positive electrode powder

Abstract

The invention relates to a recycling method of waste lithium iron phosphate positive electrode powder. The recycling method comprises the following steps: S1, mixing the lithium iron phosphate positive electrode powder with a first inorganic acid, a metal complexing agent and water for aluminum removal treatment, and conducting filtering to obtain an aluminum-removed lithium iron phosphate material; S2, subjecting the aluminum-removed lithium iron phosphate material and a second inorganic acid to mixing and pulping, adding hydrogen peroxide for an oxidation reaction, and conducting filtering to obtain iron-containing phosphorus filter residues; S3, subjecting the iron-phosphorus-containing filter residues and a third inorganic acid to mixing, pulping and dissolving, and conducting filtering to remove graphite so as to obtain an iron-phosphorus-containing filtrate; and S4, adjusting the pH value of the iron-containing phosphorus filtrate by adopting alkali, conducting reacting, separating out a precipitate, carrying out filtering, and taking filter residues so as to obtain iron phosphate. According to the recycling method, the waste lithium iron phosphate positive electrode powder can be used as a raw material to prepare iron phosphate with relatively high purity and relatively few impurities, and the yield of the method is high.

Description

Technical field[0001]The present invention relates to the field of battery technology, and more particularly to recovery methods of waste phosphate positive electrode powder.Background technique[0002]Lithium iron phosphate batteries due to its high operating voltage, large energy density, long cycle life, good safety performance, self-discharge rate, and no memory effect, its market share increases year by year. In the next 10 years, the lithium iron phosphate battery will substituted a nickel-watery-based ternary battery (NMC) battery as a major fixed electrical energy storage tool. Although the cycle of lithium iron phosphate batteries is long, the battery capacity will appear larger attenuation after 5 to 8 years, so that it cannot be used normally. Limited to the recycling technology of existing battery materials, the current recycling enterprises only recover lithium accounting for about 4% of the main content, however, the primary components of the lithium iron phosphate catho...

AI Technical Summary

Problems solved by technology

Although the cycle life of lithium iron phosphate batteries is long, the battery capacity will be greatly attenuated after 5 to 8 years of normal use, so that it cannot be used normally and is scrapped.

Limited to the recycling technology of existing battery materials, the current recycling companies only recycle about 4% of the main content of lithium. However, the main components of iron and phosphorus in the positive electrode powder of lithium iron phosphate batteries cannot be recycled due to the high content of aluminum impurities. This will not only increase the environmental burden, but also restrict the popularization and application of lithium iron phosphate batteries

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