A graded recycling method for lithium, iron, phosphorus and graphite in spent lithium iron phosphate batteries

Abstract

This invention relates to a method for recycling spent lithium iron phosphate batteries, and more particularly to a method for the graded recovery of lithium, iron, phosphorus, and graphite from spent lithium iron phosphate batteries, belonging to the field of lithium-ion battery and resource recycling technology. This method employs a combination of oxidative roasting and selective leaching, effectively improving the leaching rate and selectivity of lithium. Under optimized conditions, the lithium leaching rate approaches 100%, achieving maximum lithium recovery. Simultaneously, addressing the challenge of utilizing iron and phosphorus in the leaching residue, a wet ball milling combined with a secondary acid leaching method is used to separate the phosphorus and iron elements from the negative electrode graphite, achieving graded recovery of iron, phosphorus, and graphite. This method achieves a high lithium recovery rate and efficiently recovers iron phosphate to prepare high-value-added products such as iron oxide and sodium phosphate.

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