Why do smelters use graphite crucibles

Why do smelters use graphite ?cruciblesOur crucible are mainly have three types: pure graphite crucible, clay crucible and SiC crucible. Advantages of graphite crucibles as follows:
(1) High thermal conductivity: The melting time is shortened by using a raw material such as graphite having high thermal conductivity;
(2) Good thermal shock resistance: it is not easy to break for rapid cooling and rapid heat;
(3) High temperature resistance: graphite is one of the most  temperature resistant materials currently;
(4) Chemical stability: acid resistance, alkali resistance, organic solvent resistance, etc.

Graphite crucibles are classified into pure graphite crucibles, clay crucibles and silicon carbide crucibles, all of which are used for melting metals. Pure graphite crucibles generally melt gold and silver, jewelry and other products requiring higher purity, the purity requirements can reach the highest carbon content of 99.9%-99.95%; clay crucible and silicon carbide crucible are widely used in smelting copper, aluminum and other large smelters The carbon content is 20-30%, and the melting aluminum temperature is generally 600-1000 ° C. This type of crucible has a fixed type and needs to be opened.