Coal is a chemical composed of Carbon , Hydrogen , and Oxygen . Carbonization, a chemical process, produces four different varieties of coal: peat, lignite, anthracite, and bituminous coal.
The pressure and temperature applied to coal, as well as the quantity of carbon present in it, determine the kind of coal.
Peat contains 30-50 percent the Carbon.
Lignite has a C content of 50-70 percent.
Anthracite has 95-99 percent C content and is utilized in industry.
Bituminous coal contains 60-80 percent carbon and is utilized as a domestic fuel.
Because of its high carbon content, anthracite is the purest kind of coal.