Abstract
	While pyrometallurgy is most suitable for treating high grade oxide ores, hydrometallurgy is suitable for low grade oxide ores and for sulfide concentrates.  Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc.  It has been also successful in the electrowinning of copper from solution obtained by leaching-solvent extraction.  However, if the copper industry shifts from smelting to pressure leaching then electrowinning will dominate the area of aqueous electrometallurgy.  At present all data point out to pressure leaching as the eminent route for treating copper sulfide concentrates in the twenty first century.  This technology now used for treating zinc sulfide and refractory gold concentrates, alleviates pollution problems by SO2.