Application of response surface methodology for roasting optimization in composite roasting—Acid leaching vanadium extraction process

Abstract

Composite roasting with CaO/MgO and leaching process is an environmentally friendly and simple technique in the treatment of vanadium slag which has been practiced using CaO and MgO as composite roasting additives. The recovery of vanadium is significantly influenced by the roasting parameters, viz., CaO/V2O5 mole ratio (x1), MgO/V2O5 mole ratio (x2), roasting temperature (x3), and holding time (x4). Therefore, the response surface method (RSM) and central composite design (CCD) were performed to model and optimize the roasting factors in this research. The results shown that the models for the dissolution of vanadium, phosphorus, and manganese show good concordance with the experimental data. Additionally, a multiple response simultaneous optimization using the desirability function was used to find the optimum roasting conditions for the leaching efficiency of vanadium, phosphorus, and manganese. The optimal results were obtained at x1 = 0.84, x2 = 0.40, x3 = 900 °C, and x4 = 1.89 h. Under these conditions, 90.87% vanadium, 13.64% phosphorus, and 48.61% manganese were leached, which were beneficial not only to the recovery of vanadium but also to the minimization of impurity element of phosphorus and the maximum recovery of manganese.