PRODUCTION AND REFINING OF METALS

**Definition:** This place covers:

Metallurgical or chemical processes for producing or recovering metals from metal compounds, ores, waste or scrap metal and for refining metal. Included in this subclass are processes drawn to:

the production of metal by smelting, roasting or furnace method;

the extraction of metal compounds from ore and concentrates by wet processes;

electrochemical treatment of ores and metallurgical products for obtaining metals or alloys; apparatus thereof;

preliminary treatment of ores, concentrates and scrap;

general process for refining or remelting metals;

apparatus for electroslag or arc remelting of metals;

obtaining specific metals;

consolidating metalliferous charges or treating agents that are subsequently used in other processes of this subclass, by agglomerating, compacting, indurating or sintering.

**Limiting references (this place does not cover):** - Flotation of ores -> B03D - Working metallic powder; manufacture of articles from metallic powder; making metallic powder -> B22F9/00 - Silicon -> C01B33/02 - Manufacture of iron and steel -> C21B - Processing of pig-iron, manufacture of wrought iron or steel, treatment in molten state of ferrous alloys -> C21C - Electrolytic production or refining of metals -> C25C

**Glossary:** - Carburizing: Treatment of a metal with an externally supplied source of carbon resulting in the chemical reaction or diffusion of the carbon into the metal. - Decarburization: Treatment of a metal to remove carbon therefrom. - Hydrometallurgy: A generic term for processes involving solution in water or other liquid in which metalliferous material or metal is treated to prepare metal, to purify or to refine metal or to prepare intermediate materials more suitable for use in preparing metal (e.g. extracting, leaching, beneficiating, etc.) - Leaching: Extraction by dissolving soluble constituents from insoluble materials. Either the extracted solution or the insoluble material may contain the desired metalliferous material from which metal is obtained. - Pyrometallurgy: A generic term for processes carried out at relatively high temperatures, usually in furnaces, in which metalliferous material or metal is treated to prepare metal, to purify or to refine free metal, or to prepare intermediate materials more suitable for use in preparing metals (e.g. smelting, roasting, etc) - Reducing: Changing from a higher to a lower oxidation state such as, for example, from ferric to ferrous state or to the elemental state - Refining: Purification of metal by removal of impurities therefrom. - Roasting: The treatment of an ore or concentrate with heat and causing partial or full oxidation of the reactive species present in the ore or concentrate to facilitate metal extraction. - Slag: A vitreous mass that separates from fused metals during smelting or refining of metalliferous material. - Smelting: Treatment of metalliferous material, typically a metal sulfide ore or concentrate, with sufficient heat to cause melting of the sulfide mineral(s) in the ore or concentrate such that a molten metal sulfide phase is formed.