This comprehensive book covers both the principles and practice of each unit process. Starting with an introduction to extraction of metals, hydrometallurgy in particular, the text goes on to discuss roasting processes followed by chapters on leaching of materials under atmospheric pressure and elevated pressures, microbial leaching and electrochemical processes. Concentration-cum-purification of leach liquor by ion-exchange and solvent extraction, metal recovery from leach solutions by chemical and reductive precipitation and electrolytic processes are then considered. A number of solved and unsolved problems are given at the end of each chapter. Computer programs for the construction of stability diagrams and potential-pH diagrams form a part of the Appendix.