Metallurgical (met) coal (or coking coal) is a naturally occurring sedimentary rock found within the earth’s crust. Categories of met coal include hard coking coal, semi-hard coking-coal, semi-soft coking coal and pulverised coal for injection (PCI). These apply to the different quality grades of met coal, all of which are used to make steel. Met coal typically contains more carbon, less ash and less moisture than thermal coal, which is used for electricity generation.
It is of a higher purity than thermal coal which is used in energy generation. To make steel, metcoal is heated at around 1100 degrees C to remove water and other chemicals. This is done without the presence of oxygen. The result is a lump of near-pure carbon which is called coke.
The coke is fed into a blast furnace along with ‘raw’ iron ore and some other minerals called fluxes. This produces pig iron. Pig iron is the basic ingredient to produce steel. Coal therefore plays three roles in the production of steel: a reducing agent, to turn the pig iron to coke; a source of energy to drive the process by breaking apart molecular bonds; and a source of carbon for the final product (steel is an alloy of carbon and iron).
Major producers: Australia, Canada, United States
Major exporters: Australia, Canada, United States