THE COMING-OF-AGE OF PROCESS ENGINEERING IN EXTRACTIVE METALLURGY

The increasing importance of the application of process engineering principles and techniques in extractive metallurgy is reviewed. Significant developments made in recent years in quantitatively describing metallurgical processes are discussed. Some general approaches and building blocks of process engineering are presented, together with examples related to a number of unit operations and unit processes encountered in extractive metallurgy. A considerable amount of discussion is devoted to the advances made in the engineering analysis of rate processes in metallurgical processes. The importance of the interrelationship between transport phenomena and chemical reactions in metallurgical systems, which are almost always heterogeneous in nature, are emphasized. Quantitative process description is essential for optimally designing process equipment and also for the optimization and control of existing processes. Illustrative examples cited in this article include the analysis and modeling of fluid-solid reactions encountered in pyrometallurgy and hydrometallurgy and the process modeling of flash reaction, solution-mining, and fluidized-bed processes. Examples are also given as to how new process concepts can be developed from the clear understanding of the roles of individual component processes and the interactions among them. The article then takes a brief look at the future of process engineering in extractive metallurgy and presents a proposition for the establishment of a new discipline called "value-addition metallurgy" within the process metallurgy field in response to the rapidly developing demands for value-added materials based on metals.