Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years.
The composition of coal is reported either as a proximate analysis (moisture, volatile matter, fixed carbon, and ash) or an ultimate analysis (ash, carbon, hydrogen, nitrogen, oxygen, and sulfur).
There are four major types/ranks of coal. Rank refers to steps in a slow, natural process called “coalification,” during which buried plant matter changes into an ever denser, drier, more carbon rich, and harder material. The four ranks are :
Anthracite : The highest rank of coal. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter.
Bituminous : Bituminous coal is a middle rank coal between subbituminous and anthracite. Bituminous usually has a high heating (Btu) value and is the most common type of coal used in electricity generation in the United States. Bituminous coal appears shiny and smooth when you first see it, but look closer and you may see it has layers.
Subbituminous : Subbituminous coal is black in color and dull (not shiny), and has a higher heating value than lignite.
Lignite : Lignite coal, aka brown coal, is the lowest grade coal with the least concentration of carbon.
Also, there is peat. Peat is not actually coal, but rather the precursor to coal. Peat is a soft organic material consisting of partly decayed plant and, in some cases, deposited mineral matter. When peat is placed under high pressure and heat, it becomes coal.
Coal is primarily used as fuel to generate electric power in the United States. The coal is burned and the heat given off is used to convert water into steam, which drives a turbine. Certain types of coal can also be used for metallurgical processes, like forging steel, smelting metals, or even in smelting sands, which are used to cast metal. Finally, coal can be burned to provide heat for individual homes.
The most significant uses of coal are in electricity generation, steel production, cement manufacturing and as a liquid fuel. Different types of coal have different uses. Steam coal – also known as thermal coal – is mainly used in power generation.
Coking coal, also known as metallurgical coal, is used to create coke, one of the key irreplaceable inputs for the production of steel. There are many varieties of coal in the world, ranging from brown coal or lignite to anthracite.
Steam coal, also known as thermal coal, is suitable for electric power production. Steam coal is ground into a fine powder that burns quickly at high heats and is used in power plants to heat water in boilers that run steam turbines.
We also trade in imported coal from South Africa & United States of America.