Roasting Kinetics of Crude Pyrite as Acid Mine Drainage Remediation Option: A Case Study of Merelani

Abstract

Large-scale production of mine wastes and their secure disposal has been a problem of global concern. In this work, the chemical kinetics of roasting of crude pyrite, a mine waste from Merelani to form sulphur dioxide, a key precursor in the production of sulphuric acid was studied. Conversion of pyrite into sulphur dioxide revealed pseudo first order kinetic with respect of solid reactant in gas-solid system. The activation energy (Ea) value of 15kJ/mol was deduced from Arrhenius equation suggesting that the roasting reaction was controlled by diffusion of oxygen through the ash layer to the reacting surface.  The utilisation of crude pyrite overburden will provide not only social economic development but also proper environmental mitigation of acid mine drainage.