Term: Ferrosilicon
**Production and Reactions:**
– Ferrosilicon is produced by reduction of silica or sand with coke in the presence of iron.
– Typical sources of iron are scrap iron or millscale.
– 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.
**Uses:**
– Ferrosilicon is used as a source of silicon to reduce metals from their oxides and to deoxidize steel and other ferrous alloys.
– It prevents the loss of carbon from the molten steel.
– Ferrosilicon is used for manufacture of silicon, corrosion-resistant and high-temperature-resistant ferrous silicon alloys.
– In the manufacture of cast iron, ferrosilicon is used for inoculation of the iron to accelerate graphitization.
– Ferrosilicon is a basis for manufacture of prealloys like magnesium ferrosilicon.
**Silanes:**
– Treatment of high-silicon ferrosilicon with hydrogen chloride is the basis of the industrial synthesis of trichlorosilane.
– Ferrosilicon is used in the manufacture of sheets for the magnetic circuit of electrical transformers.
**Hydrogen Production:**
– The method of using ferrosilicon for hydrogen production has been in use since World War I.
– Sodium hydroxide, ferrosilicon, and water are key components in the process.
– Ferrosilicon is used by the military to quickly produce hydrogen for balloons.
– The materials used for hydrogen production are stable, not combustible, and do not generate hydrogen until mixed.
– This method of hydrogen production was not thoroughly investigated for about a century.
**Footnotes:**
– The iron is intentionally omitted.
Ferrosilicon is an alloy of iron and silicon with a typical silicon content by weight of 15–90%. It contains a high proportion of iron silicides.
