smelter

A smelter is a facility or furnace in which metal is extracted from ore through smelting, a metallurgical process that uses heat and a reducing agent to separate metal from its oxide, sulfide, or other compound. The product is typically crude metal plus a non-metallic slag.

Key steps include ore preparation (crushing and concentration), pre-treatment such as roasting to remove moisture or sulfur, smelting in a furnace with a reducing agent (such as coke or charcoal) and flux, separation of metal from slag, and refining to achieve desired purity before casting.

Common furnace types include blast furnaces for iron production using coke, producing pig iron and slag; reverberatory or electric furnaces for nonferrous metals; electric arc furnaces widely used for steelmaking and recycling; and cupola furnaces in foundries.

Outputs and byproducts include crude metal ingots or pig metal, refined metal, slag, and dross; gaseous emissions such as sulfur dioxide and carbon monoxide; and slag or dust that may be processed for recoveries or require disposal with environmental controls.

Historically smelting enabled the Bronze Age and Iron Age, and today it remains central to primary metal production. Modern operations emphasize energy efficiency, emission controls, and integration with mining, while affected regions balance industrial benefits with environmental and social impacts.