Recovery of High Value-Added Phosphorus Compounds From Slag Discharged During the Double-Slag Refining Process

In the present study, we developed a technology to produce iron phosphate, which is a cathode material for lithium iron phosphate batteries, by using the slag produced from the double-slag refining process (DRP ○ R slag), that is a by-product of a new resource-saving and environmentally friendly steelmaking process used by JFE Steel Co.We demonstrated that iron phosphate could be obtained from this DRP ○ R slag using the following two methods.First, we treated DRP ○ R slag using our developed wet treatment process, which is a combination of processes consisting of acid-dissolution, alkali-precipitation, a second acid-dissolution, and ion exchange, to obtain an aqueous solution of phosphoric acid.Iron nitrate was then added to this aqueous solution to obtain iron phosphate.We also found that when DRP ○ R slag was treated using our newly developed wettreatment method, the resultant solid was iron phosphate.