C22B - Definition

Definition statement

This subclass covers:

Metallurgical or chemical processes for producing or recovering metals from metal compounds, ores, metalliferous 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 methods (i.e. pyrometallurgy);
• the extraction of metal compounds from ores or concentrates by wet processes (i.e. hydrometallurgy); apparatus therefor;
• electrothermal treatment of ores or metallurgical products for obtaining metals or alloys; apparatus therefor;
• preliminary treatment of ores or scrap;
• general processes of refining or remelting metals;
• apparatus for electroslag or arc remelting of metals;
• consolidating metalliferous charges or treating agents that are subsequently used in other processes of this subclass, by agglomerating, compacting, indurating or sintering;
• obtaining specific metals, e.g. copper or manganese.

Relationship between large subject matter areas

C22B covers the treatment, e.g. the decarburization, of metalliferous material for purposes of refining. C21C, C21D and C22F provide for decarburization of metal for modifying the physical structure of ferrous and nonferrous metals or alloys, respectively.

C22B also possesses groups for obtaining metals including obtaining metals by chemical processes, and obtaining metal compounds by metallurgical processes. Thus, for example, group C22B 11/00 covers the production of silver by reduction of ammoniacal silver oxide in solution, and group C22B 17/00 covers the production of cadmium oxide by metallurgical process. Furthermore, although compounds of arsenic and antimony are classified in C01G, production of the elements themselves is covered by C22B, as well as the production of their compounds by metallurgical processes.

References relevant to classification in this subclass

This subclass does not cover:

Working metallic powder; manufacture of articles from metallic powder; making metallic powder or suspensions thereof	B22F 9/00
Flotation of ores	B03D
Processing of pig iron, e.g. refining, manufacture of wrought iron or steel; producing sponge iron by direct reduction	C21B, C21C
Electrolytic production or refining of metals	C25C

Informative references

Attention is drawn to the following places, which may be of interest for search:

Casting of metals	B22D
Coating material with metallic material	C23C
Furnaces, retorts, sintering apparatus	F27B
Obtaining metal compounds by non-metallurgical processes	C01G
e.g. purifying zinc oxide e.g. purifying zinc oxide	C01G 9/02
Processes of non-metallurgical separating of materials	B01D
Destroying solid waste or transforming solid waste into something useful or harmless	B09B 3/00

Special rules of classification

When classifying in group C22B 3/00, the nature of any metal which is considered to represent information of interest for search may also be classified in the main groups only of C22B 11/00-C22B 25/00 in group C22B 19/34 or in any of groups C22B 26/00-C22B 61/00. This can, for example, be the case when it is considered of interest to enable searching for extraction of specific metals or their compounds. Such non-obligatory classification should be given as "additional information".

Glossary of terms

In this subclass, the following terms or expressions are used with the meaning indicated:

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 metal (e.g. smelting, roasting of ores, etc.).
Reducing	Changing from a higher to a lower oxidation state such as, for example, from the ferric to the ferrous state, viz.: Fe3+ + e- → Fe2+ 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.