Calcined Anthracite

Heat treated anthracite will have virtually no volitile matter resulting in an almost pure carbon.

Black Diamond is capable of generating over 3MW of electricity per annum from methane drainage. Alternatively, the gas generated will be used as a heat source to produce gas calcined anthracite (GCA).  

Electrically calcined anthracite (ECA) is manufactured by heat treating high grade anthracite in an electrically “fired” calcining furnace at temperatures in excess of 2000 °C. High grade anthracite is heated to high temperatures, which results in the development of a graphitic structure. The electrical resistance of ECA is normally between 500-700 µwm, our ECA has a significantly lower resistance at 330 µwm leading to better electrical conductivity. Similar to the ECA material, GCA differs as it is calcined within a gas-fired rotary kiln instead of electricity leading to an increased real density and reduced ash content. The product should have a low ash content, moisture, volatile, and sulphur content to which the Black Diamond antracite is well suited. The high grade anthracite should have a volitile of between 4-10% before being calcinated.

Calcined anthracite is used as a carbon source in the manufacture of pre-bake electrodes, soderberg and tamping pastes, and carbon paste electrodes and blocks. Calcined antharcite is also an excellent smelting additive due to its high purity. It can be used to make synthetic graphite through high-temperature treatment (graphitization). Most synthetic graphite is used in electrodes (including batteries), with the predicted increase in the use of electric vehicles, demand will increase significantly.



Fixed carbon is 99% representing the solid combustible residue that remains after a coal particle is heated and the volatile matter is expelled. The fixed-carbon content is over 98% determined by subtracting the percentages of moisture, volatile matter, and ash from the coal.




Ash, avr %



Volatiles, daf %


0-25 mm

Fixed carbon content %