††††A blast furnace is a furnace used for extracting metals from their ores by the injection of a hot air blast.
Blast furnaces for making cast iron were built in Scandinavia around 800 AD. Modern blast furnaces, used to extract iron from iron ore, are up to 60 metres high, produce 10,000 tonnes of iron a day, and work non-stop for up to 10 years. Iron ore, limestone and coke are fed into the top of the furnace. Hot air is pumped into the bottom. Molten iron collects at the bottom of the furnace, from where it can be removed. The waste material, called slag, is removed separately.
