Ferro Silicon

Ferrosilicon is produced by the reduction of silica or sand with coke in the presence of iron. Typical sources of iron are scrap iron or mill scale. Ferrosilicons with silicon content up to about 15% are made in blast furnaces lined with acid fire bricks.

Ferrosilicons with higher silicon content are made in electric arc furnaces. The usual formulations on the market are ferrosilicons with 15%, 45%, 75%, and 90% silicon. The remainder is iron, with about 2% consisting of other elements like aluminum and calcium. An overabundance of silica is used to prevent the formation of silicon carbide. Microsilica is a useful byproduct.