A promising approach for lithium iron phosphate (LFP) battery black mass recycling for fertilizer production

The manufacture of agricultural products has recently gained attention, particularly in the search for practical methods to replace traditional mineral-based raw materials. Therefore, this investigation presents an innovative hydrometallurgical process for producing fertilizers from spent lithium-iron phosphate batteries. Additionally, this work developed a method to produce lithium phosphate as a subproduct. To extract lithium, sodium hydroxide (NaOH) was used; with 2 M NaOH, 20 g/L, 60 min at 25 °C, 98% of lithium was dissolved. Lithium phosphate (purity >98%) was then obtained by precipitation. The solid residue from the alkaline leaching was treated with ethylenediaminetetraacetic acid (EDTA). 98% Fe and ∼96% Cu were extracted (0.3 M EDTA, 60 °C,120 min); therefore, these leachates are promising for fertilizer production. Furthermore, the content of electrolyte solvents and fluoride was analyzed. Electrolyte solvents decomposed in alkaline media, and fluoride concentration was significantly lower than levels found in natural soils, yielding products free of impurities.