The method of pyrolysis is used in producing wood charcoal. This is done by heating wood or other substances without oxygen. This results in a soft, lightweight, black, porous material resembling coal and is 65% to 87% carbon with the remainder consisting of volatile chemicals and ash. Charcoal can be lumped or extruded.
Lump charcoal is made directly from hardwood material and usually produces far less ash than briquettes while Extruded charcoal is made by extruding either raw ground wood or carbonized wood into logs without the use of a binder. The heat and pressure of the extruding process hold the charcoal together. If the extrusion is made from raw wood material, the extruded logs are then subsequently carbonized.
Wood charcoal is variously used in heating, cooking, purification and filtration, in medicine as dietary supplements and horticulture as a fertilizer. Wood charcoal are mainly produced in the western part of Nigeria essentially Isehin, Igbo-Ora, Igangan, Ilero area of Oyo State.