Charcoal

Charcoal is the blackish residue consisting of impure carbon obtained by

Production

Production of wood charcoal in districts where there is an abundance of wood dates back to a very remote period, and generally consists of piling billets of wood on their ends so as to form a conical pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue. The whole pile is covered with turf or moistened soil. The firing is begun at the bottom of the flue, and gradually spreads outwards and upwards. The success of the operation depends upon the rate of the combustion. Under average conditions, 100 parts of wood yield about 60 parts by volume, or 25 parts by weight, of charcoal.

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Historically the massive production of charcoal (at its height employing hundreds of thousands, mainly in Alpine and neighbouring forrests) has been a major cause of deforestation, especially in Central Europe. The increasing scarcity of easily harvested wood was a major factor for the switch to the fossil equivalents, mainly coal and brown coal for industrial use.

Related Topics:
Deforestation - Coal - Brown coal

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The modern process of carbonizing wood either in small pieces or as sawdust in cast iron retorts is extensively practiced where wood is scarce, and also by reason of the recovery of valuable byproducts (wood spirit, pyroligneous acid, wood tar), which the process permits. The question of the temperature of the carbonization is important; according to J. Percy, wood becomes brown at 220°C., a deep brown-black after some time at 280°, and an easily powdered mass at 310°. Charcoal made at 300° is brown, soft and friable, and readily inflames at 380°; made at higher temperatures it is hard and brittle, and does not fire until heated to about 700°.

Related Topics:
Cast iron - Retort - Wood spirit - Pyroligneous acid - Wood tar

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