General Principles of Metal Extraction

This document explains the fundamental concepts and stages involved in the extraction and refining of metals from their ores, with emphasis on extractive metallurgy. It outlines the main processing steps: concentration of ores (via hydraulic washing, magnetic separation, froth flotation, and leaching), conversion of concentrated ores to oxides by calcination and roasting, and subsequent reduction to free metals through smelting with carbon or alternative reducing agents such as aluminium, magnesium, and hydrogen. Special methods such as alumino-thermic (Goldschmidt) reduction, self-reduction for sulphide ores of Cu, Hg, and Pb, and electrolytic reduction for highly reactive metals (e.g., Na, K, Al) are described. The role of fluxes in forming slag and removing gangue, as well as the basic idea of refining impure metals (e.g., liquation) are also introduced, providing a coherent overview of general principles and processes in metal extraction.