Optimization of dissolution of metals from Waelz sintering waste (WSW) by hydrochloric acid solutions

In this study Taguchi method was applied to determine the optimum conditions of dissolution of metals in Waelz sintering waste (WSW) in HCl solutions. The effects of solid-to-liquid ratio, reaction temperature, stirring speed, acid concentration, and reaction time on extraction efficiency were investigated. The optimum conditions were determined as follows: solid-to-liquid ratio, 0.1; reaction temperature, 65 °C; stirring speed, 700 rpm; acid concentration, 3 M and the reaction time, 48 min. Under these conditions, extraction efficiencies of zinc, cadmium and lead from waste were 97%, 91% and 0.052%, respectively.