I. PRINCIPLES OF EXTRACTIVE METALLURGY（采掘冶金原理）.PDF

I. PRINCIPLES OF EXTRACTIVE METALLURGY RAKES H KUMAR Email : rakesh@ninlindia.org Extractive metallurgy as a discipline deals with the extraction of metals from naturally occurring and man made resources. Separation is the essence of metal extraction. Development of efficient separation schemes calls for a through understanding of extractive metallurgy principles in terms of physical chemistry (thermodynamics kinetics); materials and energy flow/balance, transport phenomena, reactor and reactor engineering, instrumentation and process control, and environment and waste management. (Slide 1-4) In general, metallurgical separation processes involves chemical reactions, and classified as pyrometallurgical, hydrometallurgical, and electrometallurgical. The processes are also classified as ferrous [dealing with iron and steel] and nonferrous [dealing with all other metals, e.g. base metals (like Cu, Pb, Zn, Ni, ...), light metals (Al, Mg, Ti), precious metals (Au, Ag, Pt, Pd, ...), rare earth (Ce, Nd, Sm, ...), nuclear metals (U, Th, ...), rare metals (Os, Ru, ...) etc]. (Slide 6) Various pyrometallurgical unit processes are: calcination, roasting, smelting, converting, refining, distillation etc. Each of these processes serves a specific purpose from the point of view of separation. They require specialized reactor depending upon the phases (solid/liquid/ gases) involved, mode of contact, temperature, environmental measures etc Calcination and roasting are used as pre-treatment prior to other pyro- and hydro- metallurgical operations. (Slide 7, 8) Smelting is the most common of pyrometallurgical operations. Reduction smelting is carried out for oxides. During the smelting, metal compound (e.g. oxide of metal) is reduced to metallic form, and the undesirable impurities (gangue) combine with flux to form slag. Immiscibility of metal and slag together with density difference fo