Method for extracting battery-grade iron phosphate from waste lithium iron phosphate battery

Abstract

The invention relates to a method for extracting battery-grade iron phosphate from a waste lithium iron phosphate battery, which comprises the following steps: mixing crushed and sieved waste lithiumiron phosphate battery powder, sulfuric acid, hydrogen peroxide and water, and stirring for reaction to obtain a mixed solid of iron phosphate and graphite and a filtrate containing lithium sulfate; stirring and dissolving the obtained mixed solid of iron phosphate and graphite by using dilute sulfuric acid, and carrying out solid-liquid separation to obtain filtrate mainly containing iron phosphate and a graphite solid; adding one or more of sodium hydroxide, sodium carbonate, iron powder, ferroferric oxide or ferric oxide into the obtained filtrate to finely adjust the pH value, and carryingout solid-liquid separation to obtain filtrate containing pure iron phosphate; respectively testing the contents of iron and phosphorus in the obtained filtrate, supplementing phosphate radicals, adjusting the pH value of the solution by using sodium hydroxide or ammonia water, and performing filtering and separating to obtain basic iron phosphate and filtrate; washing the obtained basic iron phosphate with pure water, pulping with pure water, adding industrial phosphoric acid, heating for phosphorization, and performing filtering, washing and drying to obtain ferric orthophosphate powder.

Description

technical field [0001] The invention relates to power battery recovery technology, in particular to a method for extracting battery-grade iron phosphate from waste lithium iron phosphate batteries. Background technique [0002] With the popularization and application of lithium battery technology, my country's new energy vehicles have developed rapidly. The large-scale application of power batteries was in 2013, and a large number of lithium batteries were put into the market. Generally, we believe that the life of power batteries is 4-6 years. From the point of view of time, 2018 has entered the retirement period of power batteries. Due to the early development of lithium batteries, some technical barriers have not been overcome. Since 2017, there have been The performance of a large number of batteries has declined, the life of the battery has terminated, and a large number of waste batteries have appeared. Judging from the public reports on the production capacity of ele...

AI Technical Summary

Problems solved by technology

Wherein, method 1 can generally obtain lithium carbonate with higher purity, and the comprehensive recovery rate can generally reach more than 90%, but iron and phosphorus are all wasted, which still pollutes the environment

Although both iron phosphate and lithium carbonate can be recovered in similar method 2, the extracted iron phosphate has high impurities and does not meet the standards for iron phosphate as a raw material for power batteries

Images