Method for recovering phosphorus, iron, and sulfur elements from ferrophosphorus slag while co-producing ammonium phosphate fertilizer

Abstract

This application provides a method for recovering phosphorus, iron, and sulfur elements from a ferrophosphorus slag while co-producing an ammonium phosphate fertilizer, including the following steps: (1) drying, grinding, and sieving the ferrophosphorus slag produced after lithium extraction to produce ferrophosphorus slag particles; (2) mixing the ferrophosphorus slag particles with an ammonium sulfide solution, conducting a hydrometallurgical reaction, and conducting separation to produce an ammonium phosphate solution, a ferrous sulfide solid, and an elemental sulfur solid; (3) subjecting the ammonium phosphate solution to vacuum evaporation for concentration, cooling crystallization, and drying to produce the ammonium phosphate fertilizer; (4) subjecting the ferrous sulfide solid to drying, high-temperature roasting, and purification to produce an iron powder; and (5) recovering the elemental sulfur solid for utilization. This application achieves the efficient separation and gradient recovery of phosphorus, iron, and sulfur elements from a ferrophosphorus slag while co-producing a high-value-added ammonium phosphate fertilizer.

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