[1] Presently, the majority of steel production is through the blast furnace which has to rely on coking coal[2] and requires a sinter plant in order to prepare the iron ore for reduction.
[3] Unlike the blast furnace, smelting reduction processes are typical smaller and use coal and oxygen directly to reduce iron ore into a usable product.
In addition, the Corex process can use iron oxides containing up to 80% lump ore and uses non-coking coal directly as a reducing agent.
After being reduced, the DRI is redirected to the char bed where the iron and slag are melted and then directed to the hearth zone.
Meanwhile, carbon monoxide and hydrogen gas from the original gasification of the coal exit the gasifier while other byproducts are captured in the metallic slag.
For example, at the JSW Steel plant in India it was found that to be viable the Corex process still needed about 15% coke.