Acheson method

The Acheson process is a graphitization process used to manufacture silicon carbide in carbide furnaces . It was invented by Edward Goodrich Acheson and named after him.

execution

In the Acheson process, a 20 m long board made of synthetic carbon moldings is embedded in powdered coke and then covered with sand . The shaped bodies are connected to electrodes and an electric current is applied.

The carbide furnace is now heated to 2200-2400 ° C with the aid of an electric current, so there is enough energy available to produce hexagonal α-silicon carbide from silicon dioxide in an endothermic reaction :

{\ displaystyle \ mathrm {SiO_ {2} +3 \, C + 625.1kJ \ longrightarrow \ alpha \! - \! SiC + 2 \, CO}}

Purity of carbide

The resulting silicon carbide is of varying purity . Highly pure silicon carbide is colorless, technical silicon carbide is often dark in color due to the presence of impurities.

Degree of purity (in%)	colour
99.8	light green
99.5	dark green
99	black
<99	Gray

literature

^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 866.
^ ^A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 984.

[1] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 866.

[HoWi984-2] A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 984.