In which cases is hydrometallurgy applicable? In such cases, how are the leached out metals recovered from solution? Explain with suitable examples.
Hydrometallurgy is the extraction of metals from ores, concentrates and various waste products. Two distinct processes are involved in hydrometallurgy: leaching and recovering the metal values from solution. The metals or their compounds are precipitated from the solution by electrolysis (copper, zinc, and other metals), by cementation, which is reduction by more electronegative metals (such as copper, silver or gold), by sorption, using ion-exchange resins or carbon, and by liquid extraction of the metal compounds using organic solvents. Burkin, A.R. The Chemistry of Hydrometallurgical Processes. London,1966. Habashi,F. Principles of Extractive Metallurgy. NewYork-London-Paris,1969.