- charcoal
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—charcoaly, adj./chahr"kohl'/, n.1. the carbonaceous material obtained by heating wood or other organic substances in the absence of air.2. a drawing pencil of charcoal.3. a drawing made with charcoal.v.t.4. to blacken, write, or draw with charcoal.5. to cook (food) over charcoal, esp. on a grill.v.i.6. to cook food over charcoal, esp. on a grill.[1300-50; ME charcole, perh. cherre CHAR3 + cole COAL, though literal sense of the compound is unclear]
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Impure form of carbon, obtained as a residue when material containing carbon is partially burned or heated with limited access to air.Coke, carbon black, and soot are forms of charcoal; other forms are named for their source material, such as wood, blood, or bone. Largely replaced by coke in blast furnaces and by natural gas as a raw material, charcoal is still used to make black gunpowder and in case-hardening metals. Activated charcoal is a finely powdered or highly porous form whose surface area is hundreds or thousands of square meters per gram. It has many uses as an adsorbent (see adsorption), including for poison treatment, and as a catalyst or catalyst carrier.* * *
impure form of graphitic carbon (q.v.), obtained as a residue when carbonaceous material is partially burned, or heated with limited access of air. coke, carbon black (qq.v.), and soot may be regarded as forms of charcoal; other forms often are designated by the name of the materials, such as wood, blood, bone, and so on, from which they are derived. Charcoal has been replaced by coke for reducing metal ores in blast furnaces and by natural gas as a source of carbon in making certain chemicals, but it is still employed in making black gunpowder and in case-hardening metals. Formerly, charcoal production from wood was an important source of acetone, methyl alcohol, and acetic acid, all of which are now produced from other raw materials.The use of special manufacturing techniques results in highly porous charcoals that have surface areas of 300–2,000 square metres per gram. These so-called active, or activated, charcoals are widely used to adsorb odorous or coloured substances from gases or liquids, as in the purification of drinking water, sugar, and many other products, in the recovery of solvents and other volatile materials, and in gas masks for the removal of toxic compounds from the air. They also are used as catalysts in making certain chemicals (e.g., phosgene, sulfuryl chloride) or as supports for other catalytic agents.* * *
Universalium. 2010.