Extractive metallurgy

Extractive metallurgy is the practice of extracting metal from ore, purifying it, and recycling it.

Pyrometallurgy

Pyrometallurgy involves the treatment of ores at high temperature to convert ore minerals to raw metals, or intermediate compounds for further refining.

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Roasting, smelting and converting are the most common pyrometallurgical processes.

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A roasting process is used to extract metals from sulfide ores: in this process the ore is heated in the presence of oxygen and the sulfur is oxidised and driven off as sulfur dioxide. Some metals in this process remain in the sulfide form, while other metals are turned into an oxide form. The desired metal may be in either product.

Related Topics:
Oxygen - Sulfur - Oxidised - Sulfur dioxide

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Oxidative smelting and converting are similar to the roasting process, but differ slightly in the way that the processes' temperatures are high enough to promote melting of materials. Some mineral are more reluctant to oxidation, so they remain in the sulfide form, while other minerals are completely oxidized and form compounds with additives, often called flux. Molten sulfides and oxide compounds split in two layers because of the different specific weights.

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The created in these operations sulfur dioxide and carbon dioxide are major pollutants.

Related Topics:
Sulfur dioxide - Carbon dioxide - Pollutants

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