COREX Process

COREX is one of the methods used for production of hot metal from iron ore. It is a coal-based process. The method was developed by Primetals as a more environmentally friendly alternative to the blast furnace. A corex process eliminates the need to prepare iron ore and coal, and can be used fairly directly in a smelting reduction process. Corex is a two-stage smelting reduction process in which the iron ore is melted in a shaft and purified in a second shaft.

The Method

The COREX process consists of two reactors: a reduction shaft and a melter/gasifier reactor. Iron in the form of lumps, sinter and/or pellets are reduced in the reduction shaft by off-gases coming from the melter/gasifier reactor, resulting in a product consisting of nearly 90% reduced iron. The reduced iron is then discharged into the melter/gasifier reactor. Here the metal undergoes residual reduction and melting by a highly reducing gas obtained from the gasification of coal with oxygen. Hot metal and slag are the end-products of the melter/gasifier reactor.

Advantages

• The process allows direct use of non-coking coal, which is charged inside the melter/gasifier reactor. This reduces cost on coal by 40% in comparison to blast furnaces.
• Though a typical Corex process requires 100% pellets, a stable operation can be maintained by use of iron ore lump fraction of up to 80%.
• Since a Corex process used high-purity oxygen, the resulting top gas or produced gas is nearly nitrogen-free. The high calorific value of the gas allows it to be recycled for reduction work, used for heat/energy generation, or to produce ethanol and acidic acid using the LanzaTech process, developed by Primetals Technologies.