Coke (fuel)

Cokeis afuelused mainly inblast furnacesto reduceiron oxideto produceiron.It containscarbon,and is similar tocoal.It is made from coal by cooking out things that are not carbon. Coke is a product of destructive distillation of coal. This is done in an airlessfurnaceor oven (kiln) at temperatures as high as 2,000 °C (3,600 °F) but usually around 1,000–1,100 °C (1,800–2,000 °F).This baking drives offvolatileparts of the coal, such aswater,gas,andtar.

Coke is an almost pure form of carbon. Thecalorific value(heat energy produced when a fuel is burnt) of coke is about 56,000 kilojoules/kilogram.

Coke oven atsmokeless fuelplant,Abercwmboi,SouthWales,1976

Coke is used as a fuel and as areducing agentinsmeltingiron orein ablast furnace.Thecarbon monoxideproduced by its combustion reduces iron oxide (hematite) to the iron product.

Although coke is more expensive than coal, it can be used in households as a clean fuel, relatively free of smoke and impurities. At the present day its use in domestic heating has been less than oil or gas, but in the 20th century it was often used in kitchenstoves.