Coke, carbon black, and activated carbon are all amorphous carbon, but the composition is the same. They are all composed of graphite microcrystals, but the macroscopic shape is different: coke is made from the coking of coal. , is a black-gray solid containing many impurities; carbon black is a black powder, mainly produced by the incomplete combustion of carbon-containing fuels such as natural gas, liquefied gas, paraffin, benzene and other organic matter; activated carbon is amorphous carbon with a porous structure. Also a black substance. The above is a brief overview, and detailed information can be found to understand their specific properties and uses.

Coke metallurgy utilizes the reducing properties of carbon at high temperatures and the reducing properties of carbon monoxide gas produced by carbon reducing metal oxides (or their incomplete combustion). For example, the reactions that occur during ironmaking are: Fe2O3 + 3C == 2Fe + 3COFe2O3 + 3CO == 2Fe + 3CO2 Total reaction: 2Fe2O3 + 3C == 4Fe + 3CO2