Carborundum or silicon carbide is a chemical compound of silicon and carbon classified in the group of carbides . SiC has great chemical resistance, high hardness, and is used for production of melting crucibles and abrasives. Silicon carbide is obtained through heat-up of quartz sand and coke breeze in an electric furnace (acc. to Eq. 1):

Eq. 1:
SiO_2+3C ightarrow SiC+2CO

Moreover, SiC that is not highly pure is used for deoxidation and added to the charge make-up as primary inoculant (s. Inoculation) during production of cast iron in a melting furnace (preferably a cupola furnace) with high steel rates . In this situation, SiC is calcium and silicon carrier at the same time. The fact that SiC does not melt but slowly dissolves provides greats benefits; i.e. it is available for an extended period and thus contributes to pre-inoculation of the cast iron melt. In cupola furnaces it is added in the form of pellets, in induction crucible furnaces in the form of granular material.

Its composition is approximately 63 % Si, 31 % C, the rest is SiO2.