Anthracite coal, also known as hard coal, is a naturally occurring carbonaceous material that represents the highest level of non-metamorphic coalification. Anthracite coal forms when the geologically preserved organic residue of primordial swamps is compressed and re-worked by the Earths crust. The result is a low ash, low volatile, homogenous coal with a high BTU content.Anthracite coal is used in products and processes where non-conductive, low cost, black mineral filler is required. It can also be used in foundries as a carbon raiser, refractory coating component, or other hot metal application. Anthracite coal also performs well as filler in rubber compounds, and as a pigment.
Electrically Calcined Anthracite Coal
Electrically calcined anthracite (ECA) is manufactured by heat treating high grade anthracite coal in an electrically “fired” calcining furnace. ECA is heated to temperatures as high as 2000 C, which results in some development of graphitic structure in the finished product.
When compared to conventional anthracite coal, ECA has high carbon content and relatively high thermal and electrical conductivity compared to un-calcined anthracite. As a result of the unique processing used to manufacture this material it has low moisture, volatile, and sulfur content.
Electrically calcined anthracite can be used in the manufacture of Prebake electrodes, Soderberg and tamping pastes, and carbon blocks. ECA is also an excellent smelting additive due to its high purity and consistency.
Gas Calcined Anthracite Coal
Similar to the ECA material, this material differs as it is calcined with gas-fired furnaces instead of electricity.
Bituminous Coal / Sea Coal
Bituminous coal, also know as soft coal, is a naturally occurring substance that forms from the coalified remains of plant life deposited in swamps, deltas, and other primordial environments. Because it has been subjected to less intense re-working by the Earths crust, bituminous coal is non-homogeneous. This form of coal is relatively high in volatile content and may contain 30-60% volatile content.Due to its high level of inherent hydrocarbon content, bituminous coal is extremely low in electrical conductivity. Bituminous coal is used as a filler, additive, or component in any application that requires a highly volatile coal. Finely divided bituminous coal will form explosive mixtures with air, so care must be taken in processing this material.