Method for recovering lithium from waste lithium iron phosphate batteries

Abstract

The present invention provides a method for recovering lithium from a spent lithium iron phosphate battery, comprising: carrying out a calcination reaction of the positive electrode black powder of the spent lithium iron phosphate battery in a calcination furnace filled with a protective gas; adjusting the flow rate of introduced chlorine gas to control the calcination reaction temperature to 50-300°C based on the mixture in the calcination furnace; immersing the calcination product after the calcination reaction in water to obtain a calcination product solution; suction filtering the calcination product solution to obtain a filtrate; and evaporating and concentrating the filtrate, followed by drying to produce lithium chloride crystals. The present invention allows for one-step calcination at a low temperature and controls the calcination reaction temperature by adjusting the flow rate of introduced chlorine gas, thereby converting the lithium element in the spent lithium iron phosphate battery into water-soluble lithium chloride and further producing lithium chloride crystals. This method is simple in process, has high reaction efficiency, low energy consumption, and a high lithium element recovery rate of 95%, making it of great value for industrial applications.

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