Charcoal: Difference between revisions
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==Uses== |
==Uses== |
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One of the most important historical applications of wood charcoal was as a constituent of [[gunpowder]]. It was also used in [[metallurgy|metallurgical]] operations as a reducing agent, but its application has been diminished by the introduction of [[coke (fuel)|coke]], [[anthracite]] smalls, etc. A limited quantity is made up into the form of drawing [[crayon]]s; but the greatest amount is used as a [[fuel]], which burns hotter and cleaner than [[wood]]. Charcoal is often used by [[blacksmith]]s, for cooking, and for other industrial applications. |
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===Cooking fuel=== |
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Charcoal [[briquette]]s are widely used for outdoor [[grill]]ing and [[barbeque]]s in backyards and on [[camping]] trips. |
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In many non-industrialized countries, for instance in [[Africa]], charcoal is used for everyday cooking by a large portion of the population. This is potentially a serious health problem when used indoors since [[carbon monoxide]] (CO) is a [[combustion]] product.<ref>[http://www.hc-sc.gc.ca/cps-spc/house-domes/fire-feu/detect/index_e.html Smoke Detectors, Carbon Monoxide Detectors, and Charcoal]</ref> |
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===Industrial fuel=== |
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[[Image:Charcoal bus.jpg|thumb|200px|right|A charcoal powered bus being "fired up" in post war Japan (late 1940's)]]Historically, charcoal was used in great quantities for smelting [[iron]] in [[bloomery|bloomeries]] and later [[blast furnace]]s and [[finery forge]]s. This use was replaced by [[coke (fuel)|coke]] during the [[Industrial Revolution]]. For this purpose, charcoal in [[England]] was measured in dozens (or loads) consisting of 12 sacks or [[shem]]s or seams, each of 8 [[bushel]]s. |
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===Automotive fuel=== |
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In times of scarce petroleum, automobiles and even buses have been converted to burn [[wood gas]] (gas mixture containing primarily [[carbon monoxide]]) released by burning charcoal or wood in a [[wood gas generator]]. In [[occupied France]] during [[World War II]], wood and wood charcoal production for such vehicles (called ''gazogènes'') increased from pre-war figures of approximately fifty thousand tons a year to almost half a million tons in 1943.<ref>[http://www.historycooperative.org/journals/eh/11.4/pearson.html Chris Pearson "'The age of wood': FUEL AND FIGHTING IN FRENCH FORESTS, 1940–1944"]</ref> |
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===Purification/Filtration=== |
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The porosity of [[Activated carbon|activated charcoal]] accounts for its ability to readily [[Adsorbtion|adsorb]] gases and liquids; charcoal is often used to filter water or adsorb [[odor]]s. Its [[pharmacological]] action depends on the same property; it adsorbs the gases of the [[stomach]] and [[intestine]]s, and also liquids and solids (hence its use in the treatment of certain [[toxin|poisonings]]). Charcoal filters are used in some types of [[gas mask]] to remove poisonous gases from inhaled air. Wood charcoal also to some extent removes coloring material from solutions, but animal charcoal is generally more effective. |
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Animal charcoal or bone black is the carbonaceous [[residue]] obtained by the dry distillation of bones; it contains only about 10% carbon, the remainder being calcium and [[magnesium]] phosphates (80%) and other inorganic material originally present in the bones. It is generally manufactured from the residues obtained in the [[Animal glue|glue]] and [[gelatin]] industries. Its decolorizing power was applied in 1812 by Derosne to the clarification of the [[syrup]]s obtained in [[sugar]] refining; but its use in this direction has now greatly diminished, owing to the introduction of more active and easily managed reagents. It is still used to some extent in [[laboratory]] practice. The decolorizing power is not permanent, becoming lost after using for some time; it may be revived, however, by washing and reheating. |
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===Art=== |
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[[Image:Charcoal sticks 051907.jpg|left|thumb|200px|Four sticks of vine charcoal and four sticks of compressed charcoal.]][[Image:Charcoal pencils 051907.jpg|right|thumb|175px|Two charcoal pencils in paper sheaths designed to be unwrapped as the pencil is used and two charcoal pencils in wooden sheaths.]] |
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Charcoal is used in art for [[drawing]], making rough [[sketches]] in [[painting]], and is one of the possible media for making a [[Surrealist techniques#Parsemage|parsemage]]. It must usually be preserved by the application of a [[fixative]]. Artists generally utilize charcoal in three forms: |
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* '''Vine charcoal''' is created by burning sticks of wood (usually [[willow]] or linden/[[Tilia]]) into soft, medium, and hard consistencies. [[Bamboo charcoal]] is the principal tool in Japanese [[Sumi-e]] (炭絵 lit: charcoal drawing) art. |
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* '''Compressed charcoal''' charcoal powder mixed with gum [[Binder (material)|binder]] compressed into round or square sticks. The amount of binder determines the hardness of the stick. Compressed charcoal is used in charcoal [[pencil]]s. |
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* '''Powdered charcoal''' is often used to "tone" or cover large sections of a drawing surface. Drawing over the toned areas will darken it further, but the artist can also lighten (or completely erase) within the toned area to create lighter tones. |
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===Horticulture=== |
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One additional use of charcoal rediscovered recently is in [[horticulture]]. Although [[United States|American]] [[garden]]ers have been using charcoal for a short while, [[research]] on [[Terra preta]] [[soil]]s in the Amazon has found the widespread use of [[biochar]] by [[pre-Columbian]] natives to turn otherwise unproductive [[soil]] into very rich soil. The technique may find modern application, both to improve soils and as a means of [[carbon sequestration]]. |
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== Sources, references and external links == |
== Sources, references and external links == |
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Revision as of 12:09, 19 March 2008
Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by heating wood, sugar, bone char, or others substances in the absence of oxygen (see char). The soft, brittle, lightweight, black, porous material resembles coal and is 85% to 98% carbon with the remainder consisting of volatile chemicals and ash.
The first part of the word is of obscure origin, but the first use of the term "coal" in English was as a reference to charcoal. In this compound term, the prefix "chare-" meant "turn," with the literal meaning being "to turn to coal." The independent use of "char," meaning to scorch, to reduce to carbon, is comparatively recent and is assumed to be a back-formation from the earlier charcoal. It may be a use of the word charren or churn, meaning to turn, i.e. wood changed or turned to coal, or it may be from the French charbon. A person who manufactured charcoal was formerly known as a collier (also as a wood collier). The word "collier" was also used for those who mined or dealt in coal, and for the ships that transported it.
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Types of charcoal
Commercial charcoal is found in either lump, briquette or extruded forms:
- Lump charcoal is made directly from hardwood material and usually produces far less ash than briquettes.
- Briquettes are made by compressing charcoal, typically made from sawdust and other wood by-products, with a binder and other additives. The binder is usually starch. Some briquettes may also include brown coal (heat source), mineral carbon (heat source), borax, sodium nitrate (ignition aid), limestone (ash-whitening agent), raw sawdust (ignition aid) and other additives like paraffin or petroleum solvents to aid in ignition.[1]
- 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.
The characteristics of charcoal products (lump, briquette or extruded forms) vary widely from product to product. Thus it is a common misconception to stereotype any kind of charcoal, saying which burns hotter, etc.
Charcoal is sometimes used to power commercial road vehicles, usually buses - in countries where oil is scarce or completely unavailable. In the years immediately after the second world war, charcoal buses were in regular use in Japan and are still used today in North Korea.[2]
Uses
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Sources, references and external links
- Barbecue Charcoal - The available choices for the backyard barbecue
- On Charcoal
- The Lump Charcoal Database - Information about lump charcoal.
- Photo of traditional charcoal production A forest kiln
- [1] - Charcoal making community for livelihood
- [2] - Traditional charcoal production method, India
- The River Wey and Wey Navigations Community Site — a non-commercial site of over 200,000 words all about the Wey Valley and includes a photo file on charcoal production and information relating to gunpowder manufacture at Chilworth.
- [3] Catoctin Mountain Park, Maryland, USA, includes interpretive features ("Charcoal Trail", etc) on the history of charcoal making in the area.
- Bamboo Charcoal - Properties and Facts
- Coconut Charcoal - Facts
- Simple Home Charcoal Process
- Discovery of new charcoal production process and ARTI, Appropriate Rural Technologies Institute - Making powdered charcoal directly from sugar cane leaves and trash
- The "Adam-retort", or ICPS (Improved Charcoal Production System)
- Flash Carbonization is a pressurised highly efficient charcoal making process.