Dissolution mechanism of various elements from steelmaking slag into citric acid solution

Abstract

To recycle valuable elements from steelmaking slag, their dissolution mechanism into citric acid solution has been investigated. First, the relationship between dissolution ratio of each element and initial concentration of citric acid (ci) was studied. Then, the concentrations of each species in solution were calculated through mass balance. Based on these results, it can been seen that whenci = 0.00104 mol/L, Ca2+, CaCit−, MgCit−, FeH2PO42+and CaHPO4are the predominant species in solution, and Ca5(PO4)3(OH)(s) precipitate can form easily, which may suppress the dissolution of elements. Whenciincreases to 0.0104 mol/L, dissolution ratio of each element increases significantly, except for iron. And the predominant species correspondingly change to Ca2+, Mg2+, CaCit−, MgCit−, H2Cit−, H3Cit and FeH2PO42+.