blast furnace

Short definition from Wiktionary

Noun

1. 1
   An industrial furnace in which ore is smelted to metal, the process being intensified by a blast of hot air.
2. 2
   An industrial furnace in which ore is smelted to metal, the process being intensified by a blast of hot air: As above, but specifically such a furnace where the fuel and the ore are intermixed, as for example when coke and iron ore are burned together.