Kinetics and Mechanism of Sulfation Reactions during roasting of Sulfides

ROASTING of sulphidic minerals is one of the very important steps in the extraction metallurgical practice of most of the non-ferrous metals from their concentrates. In recent times, the technique of roasting has undergone substantial changes leading to higher production and better products, more suitable for subsequent operations. Some of these processes have developed on the basis of our understanding of the kinetic limitations of the old proc-esses and elimination of such kinetic bottlenecks like diffusion in the roasting processes. These new processes like flash roasting or fluidized roasting are being increasingly utilised in production units. However, our present state of knowledge on the kinetics of roasting reaction lacks certain fundamental understanding of the process which is explained in the following paragraphs.