Extractive metallurgy

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Extractive metallurgy is the practice of extracting metal from ore, purifying it, and recycling it. Depending on the methods used to produce the metal, extractive metallurgy is further divided into pyrometallurgy, hydrometallurgy and electrometallurgy. In many cases metals are produced by combinations of these techniques.

The science of extracting metals from their ores is broadly divided into two areas, ferrous metals and non-ferrous metals.

Ferrous metals

Iron is normally produced by reducing the oxide iron ore with coke and additions of slag formers like sand and lime in a blast furnace. The production of iron accounts for more than 90% of the world’s total output of new metals per year. Iron may be refined into steel by oxidizing the impurities, either in an electric arc furnace or in a converter, in which oxygen is blown through the molten iron.

Non-ferrous metals

The metals chromium, nickel, cobalt and manganese are used as alloying elements to improve the properties of steel to obtain stainless steel. The non-ferrous metals produced in greatest quantity include aluminium, copper, nickel, zinc, magnesium, lead, tin, and titanium. The precious metals (gold, silver and platinum) and the “refractory metals” with a very high melting point like tungsten and molybdenum are other important families.

See also

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