Method for the high efficiency recycling of iron phosphate black powder slag

Abstract

This method recycles iron phosphate slag, which is produced as waste during lithium iron phosphate battery recycling processes that contain leaching or crushing for the sole extraction of lithium. This method extracts aluminum phosphate, iron phosphate, and lithium phosphate from the waste slag. The recycling process comprises these steps: (a) extraction of aluminum phosphate through addition of sodium hydroxide; (b) removal of carbon additives, graphite and other organic compounds through solvation of solely lithium, iron, and phosphate compounds through addition of sulfuric acid; (c) precipitation of iron phosphate by addition of hydrogen peroxide; (d) extraction of lithium phosphate from the mother liquor; (e) recycling of mother liquor into water and sodium sulfate. This process wastes few chemicals while still having a high reclamation efficiency in terms of purity and quantity. Furthermore, due to its relatively low costs, the profit margin of this process is very good.