Regular Article

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

¹ School of Metallurgical Engineering, Anhui University of Technology, Maanshan 243032, PR China
² Key Laboratory of Metallurgical Emission Reduction & Resources Recycling (Anhui University of Technology), Ministry of Education, Maanshan 243002, PR China

^* e-mail: suchang8195@163.com

Received: 2 September 2018
Accepted: 13 November 2018

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 (c_i) was studied. Then, the concentrations of each species in solution were calculated through mass balance. Based on these results, it can been seen that when c_i = 0.00104 mol/L, Ca²⁺, CaCit⁻, MgCit⁻, FeH₂PO₄²⁺ and CaHPO₄ are the predominant species in solution, and Ca₅(PO₄)₃(OH)(s) precipitate can form easily, which may suppress the dissolution of elements. When c_i increases 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⁺.