anthracite

Anthracite is the highest rank of coal, often called hard coal. It has a high carbon content, typically around 86–98%, very low volatile matter, and a high calorific value. The material is hard, dense, and glossy, with a conchoidal fracture. It burns with a clean flame, producing relatively little smoke due to its low sulfur and ash content, and it releases heat slowly and steadily when burned.

Formation and occurrence: Anthracite forms from bituminous coal under prolonged burial and increasing temperature and pressure during metamorphism. This process concentrates carbon and reduces volatiles. It is found in geologic basins and uplifted regions where ancient peat deposits were buried deeply enough to drive coalification. Major producing regions include parts of China, Russia, and Ukraine; the United States, especially Pennsylvania, has long-standing anthracite mines, with other countries also mining it to a lesser extent.

Uses and materials: In places where it is available, anthracite is used for residential heating and for some industrial heating applications due to its high energy density and low sulfur content. It is less common for electricity generation because of cost and handling requirements. Anthracite also serves as a filtration medium in water treatment, where its hardness and porosity help remove particulates in combination with other media.

Environmental and economic notes: Like other coal types, anthracite combustion releases carbon dioxide and other pollutants, though sulfur emissions are typically lower than those of lower-rank coals. Mining can involve surface or underground operations with associated environmental impacts and land disturbance.