There are two main types of coal: metallurgical (met) and thermal coal, which differ by their fixed carbon, volatile matter, moisture, ash, and sulphur content. Met coal is used for making steel whereas thermal coal is primarily used for generating heat and energy.

 

Further, there are three main categories of metallurgical coal. From highest quality to lowest quality they are: hard coking coal, semi-soft coking coal, and pulverized coal injection (PCI) (or low volatile pulverized coal [LVPCI] injection). Met coal quality can be improved by different washing processes, but only to a certain extent as there is an inherent “coal quality.”