Coal composition

Coal is a mineral in which the chemical element of carbon is prevalent. Carbon content (the so-called coalification) depends foremost on the time during which the conversion from plant matter to the final mineral took place. The older the coal, the higher the carbon percentage and the less apparent the original vegetable component, i.e. the fossil, remains of plant tissues, resin, etc. And, in particular, such coal is of higher quality and is in greater demand.

However, besides that coalification and representation of impurities is dependent on other circumstances, in particular on species composition of plants from which the coal was formed, on the character of the deposit, geological history thereof, etc.

Other components represented to various extents according to the types of coal are the following:

• water
• clay rocks
• silicate rocks
• sulphur compounds

The rank of coalification and content of other components is important for the possibility of coal utilization. Coal with high carbon content and low impurities serves for coking, chemical industry etc. Raw material of lesser quality is used for combustion and production of electricity in power-plants.