Integral recycling method of lithium iron phosphate positive electrode material

Abstract

The invention provides an integral recycling method of a lithium iron phosphate positive electrode material. The integral recycling method comprises the steps of (1) preparing paste from the lithium iron phosphate positive electrode material, mixing the paste and an acid for leaching reaction, and performing liquid-solid separation to obtain a leaching liquid and residue; (2) adjusting a pH valueof the leaching liquid to 1.5-3, and performing solid-liquid separation to obtain iron phosphate and a deironing acid liquid; (3) adjusting a pH value of the deironing acid liquid to 5-8, and performing solid-liquid separation to obtain a precipitant of aluminum and iron and a lithium-containing purification liquid; and (4) and performing post-treatment on the purification liquid to obtain a lithium product and a precipitation mother liquid. By the method, the recycling rates of lithium, iron and phosphate all are larger than 95wt%, the purity of the obtained lithium carbonate product is larger than 98.5wt%, the impurity content conforms to the requirement of GB / T11075-2013, the iron phosphate product conforms to the quality requirement (HG / T 4701-2014) of battery-level iron phosphate, theresidue discharging quantity is reduced by 85wt%, the flow is simple, and the process is clean.

Description

technical field [0001] The invention belongs to the technical field of resource recovery, and relates to a comprehensive recovery method for positive electrode materials, in particular to a recovery method for lithium, iron and phosphorus in lithium iron phosphate positive electrode materials. Background technique [0002] Lithium iron phosphate material (LFP for short) has attracted much attention because of its abundant raw material sources, low price, non-toxicity, high theoretical capacity, good thermal stability and good cycle performance, and is the development direction of power batteries. With the increase in the use of lithium iron phosphate power batteries, the disposal of waste lithium iron phosphate batteries will become a key link in the field of new energy. If waste batteries are not disposed of safely, it will cause great harm to the environment and public safety. The current conventional practice is to recycle the metal element in the outer skin and the posi...

AI Technical Summary

Problems solved by technology

However, the method first uses alkali and then acid to decompose the lithium iron phosphate positive electrode material, the process is complicated, and the processing cost is high; at the same time, iron is precipitated in the form of iron phosphate and mixed with impurities such as carbon black to be discharged as waste residue, and it has not been commercialized. , resulting in waste of iron and phosphorus resources

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