A blast furnace operates by continuously feeding iron ore, coke, and limestone into the top while blasting preheated air into the bottom. The burning coke produces carbon monoxide, which strips oxygen from the ore as it descends. The resulting liquid iron and molten slag pool at the hearth to be tapped off.
Heard on the job
The number three blast furnace is scheduled for a reline next quarter, so expect a drop in hot metal output.
Related terms
Pig iron
The crude, high-carbon iron tapped directly from a blast furnace.
Hot metal
Liquid metal tapped from a furnace and ready for casting or further processing.
Blow in
The careful, multi-day process of starting up a cold blast furnace.
Forestone
An adjustable cast-iron block used in historic lead smelting hearths.