Charcoal is the lightweight black carbon and ash residue hydrocarbon produced by removing water and other volatile constituents from animal and vegetation substances. This section needs additional citations for verification. Historically, the production of wood charcoal in locations where there is an abundance of wood dates back to a very ancient period, and generally consists of piling billets of wood on their ends so as to form a charcoal mask clay pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue.
An abandoned charcoal kiln near Walker, Arizona, USA. In Finland and Scandinavia, the charcoal was considered the by-product of wood tar production. The best tar came from pine, thus pinewoods were cut down for tar pyrolysis. The charcoal briquette was first invented and patented by Ellsworth B.
Zwoyer of Pennsylvania in 1897 and was produced by the Zwoyer Fuel Company. Charcoal has been made by various methods. The traditional method in Britain used a clamp. The chimney consists of 4 wooden stakes held up by some rope. The logs are completely covered with soil and straw allowing no air to enter.
Modern methods employ retorting technology, in which process heat is recovered from, and solely provided by, the combustion of gas released during carbonisation. The properties of the charcoal produced depend on the material charred. The charring temperature is also important. Charcoal contains varying amounts of hydrogen and oxygen as well as ash and other impurities that, together with the structure, determine the properties. The approximate composition of charcoal for gunpowders is sometimes empirically described as C7H4O. Common charcoal is made from peat, coal, wood, coconut shell, or petroleum.
Sugar charcoal is obtained from the carbonization of sugar and is particularly pure. It is purified by boiling with acids to remove any mineral matter and is then burned for a long time in a current of chlorine in order to remove the last traces of hydrogen. Activated charcoal is similar to common charcoal but is made especially for medical use. To produce activated charcoal, manufacturers heat common charcoal in the presence of a gas that causes the charcoal to develop many internal spaces or «pores». These pores help activated charcoal trap chemicals.
Lump charcoal is a traditional charcoal made directly from hardwood material. It usually produces far less ash than briquettes. Ogatan is a more recent type made from hardened sawdust. Pillow shaped briquettes are made by compressing charcoal, typically made from sawdust and other wood by-products, with a binder and other additives. Sawdust briquette charcoal is made by compressing sawdust without binders or additives.
It is the preferred charcoal in Taiwan, Korea, Greece, and the Middle East. It has a round hole through the center, with a hexagonal intersection. 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 subsequently carbonized. Charcoal has been used since earliest times for a large range of purposes including art and medicine, but by far its most important use has been as a metallurgical fuel. Charcoal is the traditional fuel of a blacksmith’s forge and other applications where an intense heat is required.