Dissolution Kinetics of Iron from Low-Grade Mn Ore and Optimization Using Response Surface Methodology

In this study an attempt has been made to increase Mn/Fe ratio in dump Manganese ore fines so that it can be used for the production of ferromanganese. For this purpose non-coking coal was used as reductant and dilute hydrochloric acid as leaching medium for the roasted ore. The effects of acid strength, leaching time, leaching temperature, stirring speed, ore particle size and pulp density have been studied. The dissolution of iron follows the kinetic model 1 ? 2x/3 ? (1 ? x)^2/3 = k_dt. Thus product layer diffusion is the controlling mechanism and the activation energy has been determined to be 26.23 kJ/mol at 40–95 °C. Another set of experiments have been conducted according to 2³ full factorial design, and regression equation for iron dissolution has been developed.