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{{Short description|Lightweight black carbon residue}}
{{dablink|This article is about the substance consisting of mostly carbon. For the typeface, see [[Charcoal (typeface)]]. For the [[Marvel Comics]] character, see [[Charcoal (comics)]]}}
{{Other uses|Charcoal (disambiguation)}}
'''Charcoal''' is the blackish residue consisting of impure [[carbon]] obtained by removing water and other volatile constituents from [[animal]] and [[vegetation]] substances. It is usually produced by heating [[wood]] in the absence of [[oxygen]] (see [[Charring|char]]), but sugar charcoal, [[bone char]]coal (which contains a great amount of [[calcium phosphate]]), and others can be produced as well. The soft, brittle, light, black, porous material resembles [[coal]] and is 85% to 98% carbon, the remainder consisting of volatile chemicals and ash.
[[File:Charcoal 8.jpg|thumb|Charcoal]]
[[File:Charcoal Packaging - Namibia.jpg|thumb|alt=workers packing charcoal in paper bags | Packaging of charcoal for export in Namibia]]
{{use dmy dates|date=March 2020}}
{{Use American English|date=October 2023}}


'''Charcoal''' is a lightweight black [[carbon]] residue produced by strongly heating [[wood]] (or other [[animal]] and [[plant]] materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this [[pyrolysis]] process, called charcoal burning, often by forming a [[charcoal kiln]], the heat is supplied by burning part of the starting material itself, with a limited supply of [[oxygen]]. The material can also be heated in a closed [[retort]]. Modern charcoal [[briquettes]] used for outdoor cooking may contain many other additives, e.g. [[coal]].
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 must 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 [[wiktionary:collier|collier]], though the term was used later for those who dealt in coal, and the ships that transported it.


The history of wood charcoal production spans ancient times, rooted in the abundance of wood in various regions. The process typically involves stacking wood billets to form a conical pile, allowing air to enter through openings at the bottom, and igniting the pile gradually. Charcoal burners, skilled professionals tasked with managing the delicate operation, often lived in isolation to tend their wood piles. Throughout history, the extensive production of charcoal has been a significant contributor to deforestation, particularly in regions like Central Europe. However, various management practices, such as [[coppicing]], aimed to maintain a steady supply of wood for charcoal production. The scarcity of easily accessible wood resources eventually led to the transition to fossil fuel equivalents like coal.
==Production==


Modern methods of charcoal production involve carbonizing wood in retorts, yielding higher efficiencies compared to traditional kilning methods. The properties of charcoal depend on factors such as the material charred and the temperature of carbonization.
[[Image:Charcoal pile 05.jpg|thumb|200px|Wood pile before covering it by turf or soil, and firing it (around [[1890]])]]
[[Image:Charcoal retorts cm01.jpg|thumb|200px|Modern charcoal retorts]]
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 clay. 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; small scale production on the spot often yields only about 50%, large scale was efficient to about 90% even by the 17th century. The operation is so delicate that it was generally left to professional charcoal burners. These often worked in solitary groups in the woods and had a rather bad social reputation, especially traveling ones who often sold a sack (priced at about a day's wage) with lots of rubbish mixed in to farmers and townsfolk.


Charcoal finds diverse applications, including metallurgical fuel in iron and steel production, industrial fuel, cooking and heating fuel, reducing agent in chemical processes, and as a raw material in pyrotechnics. It is also utilized in cosmetics, horticulture, animal husbandry, medicine, and environmental sustainability efforts, such as carbon sequestration.
Historically the massive production of charcoal (at its height employing hundreds of thousands, mainly in Alpine and neighbouring forests) has been a major cause of [[deforestation]], especially in Central Europe. In England, many woods were managed as [[coppice]]s, which were cut and regrew cyclically, so that a steady supply of charcoal would be available (in principle) for ever; complaints (as early as in Stuart England) about shortages may relate to the results of temporary over-exploitation or the impossibility of increasing production. The increasing scarcity of easily harvested wood was a major factor for the switch to the fossil-fuel equivalents, mainly [[coal]] and [[brown coal]] for industrial use.


However, the production and utilization of charcoal can have adverse environmental impacts, including deforestation and emissions. Illegal and unregulated charcoal production, particularly in regions like South America and Africa, poses significant challenges to environmental conservation efforts.
The modern process of carbonizing wood either in small pieces or as sawdust in [[cast iron]] [[retort]]s 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°.

==History==
{{Further|Fusain|Fossil record of fire}}
{{More citations needed section|date=November 2010}}

=== Charcoal pile ===
{{Main|Charcoal pile}}
[[File:Charcoal Kiln.JPG|thumb|[[Walker Charcoal Kiln|An abandoned charcoal kiln]] near Walker, Arizona, US]]
[[File:Charcoal pile 05.jpg|thumb|Wood pile before covering with [[Sod|turf]] or soil, and firing it ({{circa|1890}})]]The production of wood charcoal in locations where there is an abundance of wood dates back to ancient times. It generally began with piling billets of wood on their ends to form a conical pile. Openings were left at the bottom to admit [[air]], with a central shaft serving as a [[flue]]. The whole pile was covered with turf or moistened [[clay]]. The firing began at the bottom of the flue, and the fire gradually spread outward and upward.

The traditional method in [[Great Britain|Britain]] used a [[Charcoal pile|charcoal pile or clamp]].<ref>{{cite web |date=1999-05-31 |title=Geoarch |url=http://www.geoarch.co.uk/experimental/charcoal.html |url-status=dead |archive-url=https://web.archive.org/web/20040315062219/http://www.geoarch.co.uk/experimental/charcoal.html |archive-date=2004-03-15 |access-date=2012-05-20 |publisher=Geoarch}}</ref> This was essentially a pile of wooden logs (e.g. seasoned oak) leaning in a circle against a chimney. The chimney consisted of 4 wooden stakes held up by some rope. In the clamp too the logs were completely covered with soil and straw allowing no air to enter. It must be lit by introducing some burning fuel into the chimney. The logs burned slowly and transformed into charcoal over a period of 5 days. If the soil covering became torn or cracked by the fire, additional soil was placed on the cracks. Once the burn was complete, the chimney was plugged to prevent air from entering.

==== Charcoal burners ====
{{Main|Charcoal burner}}
The true art of this production method was in managing the sufficient generation of heat, by combusting part of the wood material, and the transfer of the heat to the wood in the process of being carbonized. The operation was so delicate that it was generally left to ''colliers'' (professional charcoal burners). They often lived alone in small huts to tend their wood piles. For example, in the [[Harz Mountains]] of Germany, [[charcoal burner]]s lived in conical [[huts]] called ''[[Köte]]n'' which still exist today.{{when|date=July 2014}}

==== Low efficiency and harmful emissions ====
The success of the operation depends upon the rate of the [[combustion]]. Under average conditions wood yields about 60% charcoal by [[volume]], or 25% by [[weight]];<ref name="EB1911charcoal">{{EB1911|inline=y|wstitle=Charcoal|volume=5|page=856}}</ref> small-scale production methods often yield only about 50% by volume, while large-scale methods enabled higher yields of about 90% by the 17th century. A strong disadvantage of this production method is the huge amount of emissions that are harmful to human health and the environment (emissions of unburnt methane).<ref>{{cite web |title=Roland.V. Siemons, Loek Baaijens, An Innovative Carbonization Retort: Technology and Environmental Impact, TERMOTEHNIKA, 2012, XXXVIII, 2, 131‡138 131 |url=http://www.cleanfuels.nl/Sitepdfs/Siemons_inovativne-posude-za-karbonizaciju-tehnologija-i-uticaj-na-okolinu.pdf}}</ref> As a result of the partial combustion of wood material, the efficiency of the traditional method is low.

=== Peak of production and decline ===

==== Deforestation and scarcity ====
The massive production of charcoal (at its height employing hundreds of thousands, mainly in Alpine and neighbouring forests) was a major cause of [[deforestation]], especially in [[Central Europe]].<ref>{{Cite journal |last=Ray |first=G.F. |date=July 1979 |title=Energy economics — a random walk in history |url=https://linkinghub.elsevier.com/retrieve/pii/0140988379900446 |journal=Energy Economics |language=en |volume=1 |issue=3 |pages=139–143 |bibcode=1979EneEc...1..139R |doi=10.1016/0140-9883(79)90044-6}}</ref>{{when|date=July 2014}} Complaints (as early as the [[Stuart period (England)|Stuart period]]) about shortages may stem from [[over-exploitation]] or the impossibility of increasing production to match growing demand. In [[England]], many woods were managed as [[coppice]]s, which were cut and regrown cyclically, so that a steady supply of charcoal was available. But the increasing scarcity of easily harvested wood was a major factor behind the switch to [[fossil fuel]] equivalents, mainly [[coal]] and [[Lignite|brown coal]] for industrial use.

==== By-product of wood tar production ====
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 residual charcoal was widely used as substitute for [[metallurgy|metallurgical]] [[Coke (fuel)|coke]] in [[blast furnace]]s for [[smelting]]. Tar production led to rapid local deforestation. The end of tar production at the end of the 19th century resulted in rapid re-forestation of affected areas.

==== Charcoal briquette ====
The American form of the [[Briquette|charcoal briquette]] was first invented and patented by Ellsworth B. A. Zwoyer of Pennsylvania in 1897<ref>{{cite web |url=http://inventors.about.com/od/inventionsalphabet/a/barbecue.htm |archive-url=https://archive.today/20120710035824/http://inventors.about.com/od/inventionsalphabet/a/barbecue.htm |url-status=dead |archive-date=10 July 2012 |title=Barbeque – History of Barbecue |publisher=Inventors.about.com |date=2010-06-15 |access-date=2011-12-28 }}</ref> and was produced by the [[Zwoyer Fuel Company]]. The process was further popularized by [[Henry Ford]], who used wood and sawdust byproducts from [[History of Ford Motor Company#Early developments and assembly line|automobile fabrication]] as a [[feedstock]]. Ford Charcoal went on to become the [[Kingsford (charcoal)|Kingsford Company]].

==Production methods==
[[File:Древесный уголь.jpg|thumb|Charcoal under a microscope. Different colors correspond to different relief. Only a charred skeleton remains of the wood cells after charring.]]
The modern process of carbonizing wood, either in small pieces or as [[sawdust]] in [[cast iron]] [[retort]]s, is extensively practiced where wood is scarce, and also for the recovery of valuable byproducts ([[wood spirit]], [[pyroligneous acid]], [[tar|wood tar]]), which the process permits. The question of the [[temperature]] of the [[carbonization]] is important; according to J. Percy, wood becomes brown at {{convert|220|C|sigfig=2}}, a deep brown-black after some time at {{convert|280|C|sigfig=2}}, and an easily powdered mass at {{convert|310|C|sigfig=2}}. Charcoal made at {{convert|300|C|sigfig=2}} is brown, soft and friable, and readily inflames at {{convert|380|C|sigfig=2}}; made at higher temperatures it is hard and brittle, and does not fire until heated to about {{convert|700|C|sigfig=2}}.<ref name="EB1911charcoal" /><ref>{{cite web |title=Carbonisation processes |url=http://www.fao.org/3/x5328e/x5328e05.htm#TopOfPage |access-date=21 May 2021 |publisher=FAO}}</ref>

Modern methods employ retorting technology, in which process heat is recovered from, and solely provided by, the combustion of gas released during carbonization.<ref>{{cite web|url=http://www.cleanfuels.nl/Sitepics/Kilning-principle.png|title=Kilning vs. Retorting: the cause of emissions of unburnt gases.}}</ref> Yields of retorting are considerably higher than those of kilning, and may reach 35%-40%.

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 [[Wood ash|ash]] and other impurities that, together with the structure, determine the properties. The approximate composition of charcoal for [[gunpowder]]s is sometimes empirically described as C<sub>7</sub>H<sub>4</sub>O.{{Citation needed|date=April 2018}} To obtain a coal with high purity, source material should be free of non-volatile compounds.

Wood charcoal is obtained as the residue by [[destructive distillation]] of wood such that the products are:
* Liquid products – [[pyroligneous acid]] and wood tar<ref>{{cite magazine|url=https://www.scientificamerican.com/article/pyroligneous-acid-or-wood-vinegar/ |title=Pyroligneous Acid or Wood Vinegar |date=1857-11-14 |magazine=[[Scientific American]] |access-date=2020-03-14}}</ref>
* Gaseous products – [[wood gas]]
* Residual product – wood charcoal

==Types==
[[File:Japanese Binchōtan (Japanese high-grade charcoal produced from ubame oak).jpg|thumb|''[[Binchōtan]]'', Japanese high grade charcoal made from ''[[Quercus phillyraeoides|ubame oak]]'']]
[[File:Ogatan(JapaneseBriquetteCharcoal).jpg|thumb|''[[Biomass briquettes#Japanese Ogalite|Ogatan]]'', charcoal briquettes made from sawdust]]

*'''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 to remove the last traces of hydrogen.<ref name="EB1911charcoal"/> It was used by [[Henri Moissan]] in his early attempt to create [[synthetic diamond]]s.{{citation needed|date=March 2016}}
*'''[[Activated carbon|Activated charcoal]]''' is similar to common charcoal but is manufactured especially for medical use. To produce activated charcoal, common charcoal is heated to about {{convert|900|C|sigfig=2}} in the presence of an inert gas (usually argon or nitrogen), causing the charcoal to develop many internal spaces, or "pores", which help the activated charcoal to trap chemicals. Impurities on the surface of the charcoal are also removed during this process, greatly increasing its [[adsorption]] capacity.
*'''Lump charcoal''' is a traditional charcoal made directly from [[hardwood]] material. It usually produces far less ash than briquettes.
*'''Japanese charcoal''' has had [[pyroligneous acid]] removed during the charcoal making; it therefore produces almost no smell or smoke when burned. The traditional charcoal of Japan is classified into three types:
**[[Binchōtan|White charcoal]] (''[[Binchōtan]]'') is hard and produces a metallic sound when struck.
**{{illm|Black charcoal|ja|黒炭}}
**[[Biomass briquettes#Japanese Ogalite|Ogatan]] is a more recent type made from hardened sawdust.
*'''Pillow shaped [[briquette]]s''' 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]]. 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.
*'''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. It is used primarily for barbecue as it produces no odor, no smoke, little ash, high heat, and has a long burning time (exceeding 4 hours).
*'''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 [[timber|logs]] are subsequently carbonized.


==Uses==
==Uses==
[[File:Charbon de bois rouge.jpg|thumb|Charcoal burning]]
[[File:Japanese RoundStove Charcoal.JPG|thumb|Grill charcoal made from coconut shell]]
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. Charcoal was also used historically as a source of black [[pigment]] by grinding it up. In this form charcoal was important to early chemists and was a constituent of formulas for mixtures such as [[black powder]]. Due to its high [[surface area]], charcoal can be used as a filter, [[carbocatalysis|catalyst]], or adsorbent.


===Metallurgical fuel===
One of the most important historical applications of wood charcoal is as a constituent of [[gunpowder]]. It is also used in 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.
{{main|Smelting}}
Charcoal burns at temperatures exceeding {{convert|1100|C|abbr=none}}.<ref>{{cite web|author=Updated April 26, 2018 By Gabriella Munoz |url=https://sciencing.com/hot-bonfire-8770.html |title=How Hot Is a Bonfire? |publisher=Sciencing |date=2018-04-26 |access-date=2019-11-13}}</ref> By comparison, the melting point of [[iron]] is approximately {{convert|1200|to|1550|C}}. Due to its porosity, it is sensitive to the flow of air and the heat generated can be moderated by controlling the air flow to the fire. For this reason charcoal is still widely used by blacksmiths. Charcoal has been used for the production of iron and [[steel]] (where it also provided the necessary carbon) since at least 2000 [[BCE]], with artifacts having been found in Proto-Hittite layers at [[Kaman-Kalehöyük]].<ref>{{cite journal |last=Akanuma |first=Hideo |year=2008 |title=The significance of Early Bronze Age iron objects from Kaman-Kalehöyük, Turkey |url=http://www.jiaa-kaman.org/pdfs/aas_17/AAS_17_Akanuma_H_pp_313_320.pdf |journal=Anatolian Archaeological Studies |publisher=Japanese Institute of Anatolian Archaeology |volume=17 |pages=313–320 |place=Tokyo}}</ref> Charcoal briquettes can burn up to approximately {{convert|1260|C}} with a forced air blower forge.<ref>{{Cite journal|date=2016-01-01|title=Characteristics of charcoal combustion and its effects on iron-ore sintering performance|journal=Applied Energy|language=en|volume=161|pages=364–374|doi=10.1016/j.apenergy.2015.09.095|issn=0306-2619|last1=Cheng|first1=Zhilong|last2=Yang|first2=Jian|last3=Zhou|first3=Lang|last4=Liu|first4=Yan|last5=Wang|first5=Qiuwang|bibcode=2016ApEn..161..364C }}</ref>


In the 16th century, England had to pass laws to prevent the country from becoming completely denuded of trees due to production of iron.{{Citation needed|date=January 2017}} In the 19th century charcoal was largely replaced by coke in steel production due to cost, even though coke usually adds sulphur and sometimes other deleterious contaminants to the pig iron. Wooded metallurgical regions devoid of coal like Sweden, the Urals, or Siberia transitioned from charcoal in the early 20th century.
===Industrial Fuel===


===Cooking and heating fuel===
[[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 was replaced for this 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.
Prior to the Industrial Revolution, charcoal was occasionally used as a cooking [[fuel]]. It is counted as a [[smokeless fuel]]; that is, the carbon is sufficiently pure that burning it causes substantially less air pollution than burning the original uncarbonized organic material would. In the 20th century, clean-air legislation mandated smokeless fuels (mostly coke or charcoal) in many areas of Europe. In the 21st century, charcoal has been advocated as a way to improve the health of people burning raw biomass for [[cooking]] and/or heating. Modern "charcoal" briquettes, widely used for outdoor cooking, are made with charcoal but may also include coal as an energy source as well as accelerants, binders and filler.


To contain the charcoal and use it for cooking purposes, a [[barbecue grill]] may be used. A small Japanese charcoal grill is known as a ''[[shichirin]]''. A [[brazier]] is a container used to burn charcoal or other solid fuel.
Commercially, charcoal is often found in either lump, [[briquette]] or extruded forms. Lump charcoal is made directly from [[hardwood]] material and usually produces far less ash than briquettes. While some briquettes are made from a combination of charcoal (heat source), [[brown coal]] (heat source), mineral carbon (heat source), [[borax]] (press release agent), [[sodium nitrate]] (ignition aid), limestone (uniform visual ashing), starch (binder), raw sawdust (ignition aid) and possibly additives like [[paraffin]] or lighter fluid to aid in lighting them, other "natural" briquettes are made solely from charcoal and a binder. 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.


To start the charcoal burning is harder than starting a wood fire and [[charcoal lighter fluid]] may be employed. A [[chimney starter]] or [[electric charcoal starter]] are tools to help with starting to light charcoal.
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.


Approximately 75% of fuel burned in [[Haiti]] is charcoal.<ref>{{Cite web|last=Lea|first=John Dale Zach|title=Charcoal Is Not the Cause of Haiti's Deforestation {{!}} Haiti Liberte|date=25 January 2017 |url=https://haitiliberte.com/charcoal-is-not-the-cause-of-haitis-deforestation/|access-date=2021-07-16|language=en-US}}</ref>
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]]. <ref>[http://library.osu.edu/sites/rarebooks/japan/2_1_photos.html Tokyo views of the city; essay contains a small section on Charcoal buses in post-war Japan]]</ref>


===Purification/Filtration===
===Reducing agent===
Certain types of charcoal, such as wood charcoal, are used for reducing heated metallic oxides to their respective metals:{{cn|date=May 2023}}
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 odors. 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 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.
* ZnO + C → Zn + CO
* Fe<sub>2</sub>O<sub>3</sub> + 3C → 2Fe + 3CO


Charcoal can also be used to reduce super heated steam to hydrogen (along with the formation of carbon monoxide):{{cn|date=May 2023}}
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.
* C + H<sub>2</sub>O (1000&nbsp;°C) → H<sub>2</sub> + CO ([[Water gas]])


===Syngas production, automotive fuel===
===Art===
Like many other sources of carbon, charcoal can be used for the production of various [[syngas]] compositions; i.e., various CO + H<sub>2</sub> + CO<sub>2</sub> + N<sub>2</sub> mixtures. The syngas is typically used as fuel, including automotive propulsion, or as a chemical feedstock.
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:
* '''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.


In times of scarce petroleum, automobiles and even buses have been converted to burn wood gas: a gas mixture consisting primarily of diluting [[atmospheric]] [[nitrogen]], but also containing combustible gasses (mostly [[carbon monoxide]]) released by burning charcoal or wood in a [[wood gas generator]]. In 1931, [[Tang Zhongming]] developed an automobile powered by charcoal, and these cars were popular in China until the 1950s, and in [[occupied France]] during [[World War II]], where they were called ''[[:fr:Gazogène|gazogènes]]''.
* '''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 [[pencils]].


===Pyrotechnics===
* '''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.
[[File:Red charcoal.ogv|thumb|Mangrove charcoal burning video]]
Charcoal is used in the production of [[gunpowder|black powder]], which is used extensively in the production of fireworks. It is usually ground into a fine powder, with air float grade being the finest particle size available commercially. When used in black powder compositions, it is often ball-milled with other ingredients so that they are intimately mixed together. Certain charcoals perform better when used to make black powder; these include spruce, willow, paulownia and grapevine among others.{{Citation needed|reason=This is a specific claim that the following source (ref name "sparks") does not back up. If this information is already cited, please include the reference here as well.|date=March 2021}} Charcoal produces fine dark orange/golden [[Spark (fire)|sparks]]. Usually, powder with a mesh size from 10 to 325 is used to obtain showers of golden sparks in pyrotechnic compositions.<ref name=stars>{{citation |url=https://books.google.com/books?id=e4GOAIA8HaEC&pg=PA49 |title=Pyrotechnic Spark Generation |author1=Kenneth L. Kosanke |author2=Bonnie J. Kosanke |pages=49–62 |journal=Journal of Pyrotechnics |isbn=978-1-889526-12-6 |year=1999 |url-status=live |archive-url=https://web.archive.org/web/20171216222210/https://books.google.com/books?id=e4GOAIA8HaEC&pg=PA49 |archive-date=2017-12-16 }}</ref>

===Cosmetic use of bamboo charcoal===
Charcoal is also incorporated in multiple cosmetic products.<ref name="Ahmad-2016">{{Cite journal|last1=Ahmad|first1=N|last2=Isa|first2=S.S.M.|last3=Ramli|first3=M.M.|last4=Hambali|first4=N.A.M.A.|last5=Kasjoo|first5=S.R.|last6=Isa|first6=M.M.|last7=Nor|first7=N.I.M.|last8=Khalid|first8=N.|date=2016|title=Adsorption properties and potential applications of bamboo charcoal: A Review.|url=https://www.matec-conferences.org/articles/matecconf/pdf/2016/41/matecconf_icongdm2016_01097.pdf|journal=MATEC Web of Conferences|volume=78|pages=1–7|via=edp sciences|access-date=3 February 2018|archive-url=https://web.archive.org/web/20180724183931/https://www.matec-conferences.org/articles/matecconf/pdf/2016/41/matecconf_icongdm2016_01097.pdf|archive-date=24 July 2018|url-status=dead}}</ref> It can be produced from regular bamboo cut into small pieces and boiled in water to remove soluble compounds.<ref name="Ahmad-2016" /> Raw [[bamboo charcoal]] is obtained after drying and carbonization in an oven at elevated temperature.<ref name="Ahmad-2016" /> The role of charcoal in cosmetics is based on its highly effective absorbing properties at a microscopic scale.<ref name="Ahmad-2016" />

===Carbon source===
Charcoal may be used as a source of carbon in chemical reactions. One example of this is the production of [[carbon disulphide]] through the reaction of sulfur vapors with hot charcoal. In that case, the wood should be charred at high temperature to reduce the residual amounts of hydrogen and oxygen that lead to side reactions.

===Purification and filtration===
[[File:Activated Carbon.jpg|thumb|right|Activated carbon]]
[[File:-114wiki.jpg|thumb|Charcoal for [[dehumidification]] and [[air purification]] in bathroom]]
Charcoal may be ''activated'' to increase its effectiveness as a filter. [[Activated charcoal]] readily adsorbs a wide range of organic compounds dissolved or suspended in gases and liquids. In certain industrial processes, such as the purification of sucrose from cane sugar, impurities cause an undesirable color, which can be removed with activated charcoal. It is also used to absorb [[odor]]s and toxins in gaseous solutions, as in home air purifiers and some types of [[gas mask]]. The medical use of activated charcoal is mainly the [[Absorption (chemistry)|absorption]] of [[toxin|poisons]].<ref>{{cite journal|last1=Dawson|first1=Andrew|title=Activated charcoal: a spoonful of sugar|journal=Australian Prescriber|volume=20|pages=14–16|doi=10.18773/austprescr.1997.008|year=1997|doi-access=free}}</ref> Activated charcoal is available without a prescription, so it is used for a variety of health-related applications. For example, it is often used to reduce discomfort and embarrassment due to excessive gas ([[flatulence]]) in the digestive tract.<ref>{{cite web|title=Treating flatulence|url=http://www.nhs.uk/Conditions/Flatulence/Pages/Treatment.aspx|work=NHS|publisher=NHS UK|access-date=27 May 2012}}</ref>

Animal charcoal or bone black is the carbonaceous [[residue (chemistry)|residue]] obtained by the dry distillation of bones. It contains only about 10% carbon, the remaining 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 bleaching power was applied in 1812 by Derosne for clarifying [[sugar]] [[syrup]], but its use in this direction has now greatly diminished. Today it is seldom used for this purpose due to the introduction of more active and easily managed reagents, but it is still employed to some extent in [[laboratory]] practice. The bleaching action of the charcoal in solution diminishes as it adsorbs colored contaminants, and it must be reactivated periodically by separate washing and reheating.<ref name="EB1911charcoal"/> While wood charcoal effectively removes some pigments and contaminants from solutions, bone charcoal is generally more effective as an adsorption filter due to its increased porosity and surface area.{{Citation needed|date=April 2023}}

===Art===
[[File:Charcoal sticks 051907.jpg|right|thumb|Four sticks of vine charcoal and four sticks of compressed charcoal]]
[[File:Charcoal pencils 051907.jpg|right|thumb|Two charcoal pencils in paper sheaths that are unwrapped as the pencil is used, and two charcoal pencils in wooden sheaths]]
{{Main|Charcoal (art)}}
[[Charcoal (art)|Charcoal]] is used for [[drawing]], making rough [[Sketch (drawing)|sketches]] in [[painting]], and is one of the possible media used for making a [[Surrealist techniques#Parsemage|parsemage]]. It usually must be preserved by the application of a [[Fixative (drawing)|fixative]]. Artists generally utilize charcoal in four forms:
* '''Vine charcoal''' is created by burning grape vines.
* '''Willow charcoal''' is created by burning willow sticks.
* '''Powdered charcoal''' is often used to "tone" or cover large sections of a drawing surface. Drawing over the toned areas darkens it further, but the artist can also lighten (or completely erase) within the toned area to create lighter tones.
* '''Compressed charcoal''' is charcoal powder mixed with gum [[Binder (material)|binder]] and compressed into sticks. The amount of binder determines the hardness of the stick.<ref>{{cite web|title=charcoal: powdered, compressed, willow and vine|url=http://museartanddesign.com/2011/09/charcoal-powdered-compressed-willow-and-vine/|work=Muse Art and Design|access-date=27 May 2012|date=7 September 2011|archive-url=https://web.archive.org/web/20120831055917/http://museartanddesign.com/2011/09/charcoal-powdered-compressed-willow-and-vine/|archive-date=31 August 2012|url-status=dead}}</ref> Compressed charcoal is used in charcoal [[pencil]]s.


===Horticulture===
===Horticulture===
{{main|Biochar}}
One additional use of charcoal rediscovered recently is in horticulture. Although American gardeners have been using charcoal for a short while, research on [[Terra preta]] soils 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]].
One additional use of charcoal was rediscovered recently{{When|date=April 2024}} for [[horticulture]]. Although American gardeners have used charcoal for a short time, [[research]] on [[Terra preta]] soils in [[Amazonia]] has discovered the widespread use of [[biochar]] by [[pre-Columbian]] natives to ameliorate unproductive [[soil]] into soil rich in [[carbon]]. The technique may find modern application, both to improve soils and as a means of [[carbon sequestration]].<ref>{{cite book|editor=Johannes Lehmann|others=Stephen Joseph|title=Biochar for Environmental Management: Science and Technology|url=http://www.biochar-international.org/projects/book|access-date=30 Dec 2013|year=2009|publisher=[[Earthscan]]|isbn=978-1-84407-658-1|archive-date=11 December 2017|archive-url=https://web.archive.org/web/20171211102426/http://www.biochar-international.org/projects/book|url-status=dead}}</ref>


===Animal husbandry ===
== Sources, references and external links ==
Charcoal is mixed with feed, added to [[poultry litter|litter]], or used in the treatment of [[manure]].<ref>{{citation |last1=Gerlach |first1=Achim |last2=Schmidt |first2=Hans-Peter |title=The use of biochar in cattle farming |journal=The Biochar Journal |date=2014 |location=Arbaz, Switzerland |issn=2297-1114 |url=https://www.biochar-journal.org/en/ct/9}}</ref> Poultry benefits from using charcoal in this manner.<ref>{{cite web |title=Biochar: Helping Everything from Soil Fertility to Odor Reduction |first=David |last=Yarrow |date=March 2015 |publisher=Acres U.S.A. |url=http://www.ecofarmingdaily.com/biochar-poultry-farming-unexpected-uses-biocarbon/ |access-date=7 March 2019 |archive-url=https://web.archive.org/web/20190609181128/http://www.ecofarmingdaily.com/biochar-poultry-farming-unexpected-uses-biocarbon/ |archive-date=9 June 2019 |url-status=dead }}</ref><ref>{{cite web |date=2011-03-10 |title=Charcoal supplemented diet reduces ammonia in chickens' litter |first=Stephanie |last=Schupska Site=CAES News |url=http://www.caes.uga.edu/news-events/news/story.html?storyid=4067 |access-date=7 March 2019 |archive-date=30 July 2020 |archive-url=https://web.archive.org/web/20200730124219/https://www.caes.uga.edu/news-events/news/story.html?storyid=4067 |url-status=dead }}</ref>
* Natural History of Europe - 2005 TV co-production including BBC and ZDF
* [http://www.personal.rdg.ac.uk/~scsharip/Charcoal.htm On Charcoal]
* The Valley - BBC TV - one year of life on a 17th century farm reenacted by archaeologists and historians
* [http://www.lump-charcoal.com The Lump Charcoal Database] - Information about lump charcoal.
* [http://www.holzpellet.com/index_en.htm H E Z Organisation] - Information about charcoal in Germany.
* [http://www.madehow.com/Volume-4/Charcoal-Briquette.html How charcoal briquettes are made.]
* [http://www.nutritional-herbal-supplements.com/herbal-supplements/charcoal.html] - Information about charcoal.
* [http://www.phogle.com/en/photos/1.html Photo of traditional charcoal production] A forest kiln
* [http://www.weyriver.co.uk/theriver The River Wey and Wey Navigations Community Site] &mdash; 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.
* [http://www.nps.gov/cato/historyculture/charcoal.htm] Catoctin Mountain Park, Maryland, USA, includes interpretive features ("Charcoal Trail", etc) on the history of charcoal making in the area.
* [http://www.blacktonature.com/abtbc.shtml Bamboo Charcoal] - Properties and Facts


A concern that activated charcoal might be used unscrupulously to allow livestock to tolerate low quality feed contaminated with [[aflatoxin]]s resulted in the Association of American Feed Control Officials banning it in 2012 from use in commercial livestock feeds.<ref>{{cite book|isbn=978-1612120133|title=The Chicken Health Handbook, 2nd Edition: A Complete Guide to Maximizing Flock Health and Dealing with Disease|first=Gail |last=Damerow |author-link=Gail Damerow |page=391 |date=2015 |publisher=Storey }}</ref>
[[Category:Art materials]]
[[Category:Fuels]]
[[Category:Carbon forms]]
[[Category:Pyrotechnic compositions]]


===Medicine===
[[ca:Carbó vegetal]]
{{see also|Activated charcoal (medication)}}
[[cs:Dřevěné uhlí]]
[[File:Meule charbon bois.jpg|thumb|right|[[Charcoal pile]]]]
[[da:Trækul]]
Charcoal in the form of [[charcoal biscuit]]s was consumed in the past for gastric problems. Now it can be consumed in tablet, capsule, or powder form for digestive effects.<ref name="stearn2007">
[[de:Holzkohle]]
{{cite book
[[es:Carbón vegetal]]
|title=Warts and all: straight talking advice on life's embarrassing problems
[[eo:Lignokarbo]]
|last=Stearn
[[fr:Charbon de bois]]
|first=Margaret
[[ko:숯]]
|year=2007
[[hr:Ugljen (crtački)]]
|publisher=Murdoch Books
[[id:Pensil arang]]
|location=London
[[he:פחם עץ]]
|isbn=978-1-921259-84-5
[[nl:Houtskool]]
|page=333
[[ja:炭]]
|url=https://books.google.com/books?id=aSRmxC47VNMC
[[pl:Węgiel drzewny]]
|access-date=2009-05-03
[[pt:Carvão vegetal]]
}}
[[ru:Древесный уголь]]
</ref> Research regarding its effectiveness is controversial.<ref>Am J Gastroenterology 2005 Feb 100(2)397–400 and 1999 Jan 94(1) 208–12</ref>
[[sl:Oglje]]

[[fi:Puuhiili]]
Charcoal has been used in combination with [[saccharin]] in research to measure [[Mucociliary clearance|mucociliary]] transport time.<ref name=PubMed.gov>{{cite journal|last1=Passali|first1=Desiderio|title=Experiences in the determination of nasal mucociliary transport time.|journal=Acta Otolaryngol|date=1984|volume=97|issue=3–4|pages=319–23|pmid=6539042|doi=10.3109/00016488409130995}}</ref>
[[sv:Träkol]]

[[vi:Than gỗ]]
Charcoal has also been incorporated into [[toothpaste]] formulas; however, there is no evidence to determine its safety and effectiveness.<ref>{{Cite journal|last1=Brooks|first1=John K.|last2=Bashirelahi|first2=Nasir|last3=Reynolds|first3=Mark A.|date=2017-06-07|title=Charcoal and charcoal-based dentifrices: A literature review|journal=Journal of the American Dental Association|volume=148|issue=9|pages=661–670|doi=10.1016/j.adaj.2017.05.001|issn=1943-4723|pmid=28599961}}</ref>

[[Red colobus]] monkeys in Africa have been observed eating charcoal for self-medication. Because their leafy diets contain high levels of [[cyanide]], which may lead to indigestion, they learned to consume charcoal, which absorbs the cyanide and relieves discomfort. This knowledge is transmitted from mother to infant.<ref>{{cite web|url=https://www.pbs.org/wnet/nature/episodes/clever-monkeys/monkeys-and-medicinal-plants/3957/ |title=Clever Monkeys: Monkeys and Medicinal Plants |publisher=PBS |date= 2011-09-13|access-date=2012-05-20}}</ref>

==Environmental sustainability==
[[File:Bagged Charcoal.webm|thumb|Bagged Charcoal in Bole [[Bamboi]], Ghana]]
Production and utilization of charcoal, like any use of woody biomass as fuel, typically results in emissions and can contribute to deforestation.

The use of charcoal as a smelting fuel has been experiencing a resurgence in [[South America]] resulting in severe environmental, social and medical problems.<ref>{{cite news |url=http://www.corpwatch.org/article.php?id=14328 |title=Brazil: Enslaved workers make charcoal used to make basic steel ingredient |author1=Michael Smith |author2=David Voreacos |newspaper=Seattle Times |date=January 21, 2007 |access-date=16 September 2012 |archive-date=16 September 2012 |archive-url=https://web.archive.org/web/20120916015009/http://www.corpwatch.org/article.php?id=14328 |url-status=dead }}</ref><ref>{{cite journal |url= http://oem.bmj.com/content/62/2/128.full|title=World at work: Charcoal producing industries in northeastern Brazil |journal=Occupational and Environmental Medicine |volume=62 |issue=2 |pages=128–132 |author=M. Kato1, D. M. DeMarini, A. B. Carvalho, M. A. V. Rego, A. V. Andrade1, A. S. V. Bonfim and D. Loomis |year=2004 |doi=10.1136/oem.2004.015172 |pmid=15657196 |pmc=1740946 |archive-url=https://web.archive.org/web/20121122205209/http://oem.bmj.com/content/62/2/128.full |archive-date=22 November 2012 |url-status=dead }}</ref> Charcoal production at a sub-industrial level is one of the causes of deforestation. Charcoal production is now usually illegal and nearly always unregulated, as in [[Brazil]], where charcoal production is a large illegal industry for making [[pig iron]].<ref>{{cite web|url=http://news.mongabay.com/2012/0514-hance-pig-iron-amazon.html# |title=U.S. car manufacturers linked to Amazon destruction, slave labor |publisher=News.mongabay.com |date= 2012-05-14|access-date=2012-05-20}}</ref><ref>{{cite web|url=http://www.greenpeace.org/international/driving-destruction/ |title=Driving Destruction in the Amazon: How steel production is throwing the forest into the furnace |work=[[Greenpeace]] |date=2012-05-11 |access-date=2012-05-20 |archive-url=https://web.archive.org/web/20120520033806/http://www.greenpeace.org/international/driving-destruction/ |archive-date=2012-05-20 |url-status=dead}}</ref><ref>The documentary film ''The Charcoal People'' (2000) [https://www.imdb.com/title/tt0245034/reviews?ref_=tt_urv] shows in detail the [[deforestation in Brazil]], the poverty of the laborers and their families, and the method of constructing and using a clamp for burning the wood.</ref>

Massive forest destruction has been documented in areas such as [[Virunga National Park]] in the [[Democratic Republic of Congo]], where it is considered a primary threat to the survival of the mountain gorillas.<ref>{{cite web |url=http://gorilla.cd |title=Virunga National Park |publisher=Gorilla.cd |access-date=2012-05-20 |url-status=dead |archive-url=https://web.archive.org/web/20081003023434/http://gorilla.cd/ |archive-date=2008-10-03 }}</ref> Similar threats are found in [[Zambia]].<ref>{{cite web|url=http://www.loe.org/shows/segments.html?programID=94-P13-00009&segmentID=3 |title=Living on Earth: Zambia's Vanishing Forests |publisher=Loe.org |date=1994-03-04 |access-date=2011-12-28}}</ref> In [[Malawi]], illegal charcoal trade employs 92,800 workers and is the main source of heat and cooking fuel for 90 percent of the nation's population.<ref name="Malawi">{{cite web|title=Is charcoal the key to sustainable energy consumption in Malawi? |work=UNEARTH News |date=July 2013 |access-date=10 August 2013 |url=http://unearthnews.org/is-charcoal-the-key-to-sustainable-energy-consumption-in-malawi/ |archive-url=https://archive.today/20130811103023/http://unearthnews.org/is-charcoal-the-key-to-sustainable-energy-consumption-in-malawi/ |url-status=dead |archive-date=2013-08-11 }}</ref> Some experts, such as Duncan MacQueen, Principal Researcher–Forest Team, [[International Institute for Environment and Development|International Institute for Environment and Development (IIED)]], argue that while illegal charcoal production causes deforestation, a regulated charcoal industry that required replanting and sustainable use of the forests "would give their people clean efficient energy – and their energy industries a strong competitive advantage".<ref name="Malawi"/>

Recent assessments of charcoal imported to Europe have shown that many charcoal products are produced from tropical wood, often of undeclared origin. In an analysis of barbecue charcoal marketed in Germany, the [[World Wildlife Fund]] found that most products contain tropical wood. As a notable exception, reference is made to barbecue charcoal imports from [[Namibia]], where charcoal is typically produced from surplus biomass resulting from [[woody plant encroachment]].<ref>{{Cite web|title=Market Analysis Barbecue Charcoal 2018 - The Dirty Business of Barbecue Charcoal|url=https://mobil.wwf.de/fileadmin/fm-wwf/Publikationen-PDF/WWF_Market_analysis_barbecue_charcoal_2018.pdf|last=Zahnen|first=Johannes|website=WWF|access-date=2020-05-27}}</ref><ref>{{Cite web|title=From Bush to Charcoal: the Greenest Charcoal Comes from Namibia|url=https://fsc.org/en/newsfeed/from-bush-to-charcoal-the-greenest-charcoal-comes-from-namibia|date=2020-03-17|website=Forest Stewardship Council|access-date=2020-05-27|archive-date=27 July 2020|archive-url=https://web.archive.org/web/20200727194351/https://fsc.org/en/newsfeed/from-bush-to-charcoal-the-greenest-charcoal-comes-from-namibia|url-status=dead}}</ref><ref>{{Cite journal |last=Haag |first=Volker |last2=Zemke |first2=Valentina Theresia |last3=Lewandrowski |first3=Tim |last4=Zahnen |first4=Johannes |last5=Hirschberger |first5=Peter |last6=Bick |first6=Ulrich |last7=Koch |first7=Gerald |date=2020-09-11 |title=The European charcoal trade |url=https://brill.com/view/journals/iawa/41/4/article-p463_4.xml |journal=IAWA Journal |volume=41 |issue=4 |pages=463–477 |doi=10.1163/22941932-bja10017 |issn=0928-1541}}</ref> [[Charcoal trafficking in Somalia]] is an economic and environmental issue with significant regional-security implications.<ref>{{Cite book |last=Gridneff |first=Ilya |title=Environmental Politics in the Middle East |publisher=Oxford University Press |year=2018 |isbn=9780190916688 |editor-last=Verhoeven |editor-first=Harry |location=Oxford |pages=121–148 |chapter=Burning Somalia's Future: The Illegal Charcoal Trade Between the Horn of Africa and the Gulf}}</ref>

==In popular culture==
The last section of the film ''[[Le Quattro Volte]]'' (2010) gives a good and long, if poetic, documentation of the traditional method of making charcoal.<ref>{{cite web |url=https://www.imdb.com/title/tt1646975/ |title= Le quattro volte (2010) |website= [[IMDb]] |access-date=16 September 2012}}</ref> The [[Arthur Ransome]] children's series ''[[Swallows and Amazons series|Swallows and Amazons]]'' (particularly the second book, ''[[Swallowdale]]'') features carefully drawn vignettes of the lives and the techniques of charcoal burners at the start of the 20th century, in the [[Lake District]] of the UK. [[Antonín Dvořák|Antonín Dvořák's]] opera ''[[King and Charcoal Burner]]'' is based on a Czech legend about a king who gets lost in a forest and is rescued by a charcoal burner.

==See also==
* [[Biomass briquettes]]
* [[Char cloth]]
* [[Charcoal in food]]
* [[Ember]]
* [[Slash-and-char]]
* [[Thomas Britton]] (1644 – 1714), small coal merchant of London, noted for his singing voice.
* [[Tortillon]]

==References==
{{Reflist}}

==External links==
{{Wiktionary|charcoal}}
*{{Commons category-inline|Charcoal}}
*{{cite EB1911|wstitle=Charcoal |volume=5 |page=856 |short=x}}
*[http://www.fao.org/docrep/X5328e/x5328e00.htm Simple technologies for charcoal making]
*[https://www.tandfonline.com/doi/abs/10.1179/030801899678966 "On Charcoal" by Peter J F Harris]
*[https://www.youtube.com/watch?v=wtIr0FI4vbo Charcoal Making at Hopewell Furnace National Historic Site in Pennsylvania - U.S. National Park Service] (YouTube video)
*[https://web.archive.org/web/20170809141714/http://www.worldwidehelpers.org/wwhweb/uploads/files/Fuel%20from%20the%20Fields-%20Charcoal%20from%20Agricultural%20Waste.pdf Illustrated how-to]
*[https://web.archive.org/web/20150911103902/https://wiki.duke.edu/display/engineerswithoutborders/Biomass+Charcoal Experiments with varied techniques, illustrated]
*[https://www.dw.com/en/charcoal-an-environmental-disaster/av-50155336 "Charcoal - An Environmental Disaster"] {{Webarchive|url=https://web.archive.org/web/20190829051400/https://www.dw.com/en/charcoal-an-environmental-disaster/av-50155336 |date=29 August 2019 }}, a 2019 [[DW-TV|Deutsche Welle television program]] documenting the charcoal production industry in [[Africa]] and [[Europe]] and related industries, environmental consequences of the use and production of charcoal, and efforts toward sustainability; narrated in English

{{Wood products}}
{{Allotropes of carbon}}

{{Authority control}}

[[Category:Charcoal| ]]
[[Category:Biologically based therapies]]
[[Category:Fuels]]
[[Category:Allotropes of carbon]]
[[Category:Soil improvers]]
[[Category:Barbecue]]
[[Category:Pyrotechnic fuels]]

Latest revision as of 08:33, 22 December 2024

Charcoal
workers packing charcoal in paper bags
Packaging of charcoal for export in Namibia

Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln, the heat is supplied by burning part of the starting material itself, with a limited supply of oxygen. The material can also be heated in a closed retort. Modern charcoal briquettes used for outdoor cooking may contain many other additives, e.g. coal.

The history of wood charcoal production spans ancient times, rooted in the abundance of wood in various regions. The process typically involves stacking wood billets to form a conical pile, allowing air to enter through openings at the bottom, and igniting the pile gradually. Charcoal burners, skilled professionals tasked with managing the delicate operation, often lived in isolation to tend their wood piles. Throughout history, the extensive production of charcoal has been a significant contributor to deforestation, particularly in regions like Central Europe. However, various management practices, such as coppicing, aimed to maintain a steady supply of wood for charcoal production. The scarcity of easily accessible wood resources eventually led to the transition to fossil fuel equivalents like coal.

Modern methods of charcoal production involve carbonizing wood in retorts, yielding higher efficiencies compared to traditional kilning methods. The properties of charcoal depend on factors such as the material charred and the temperature of carbonization.

Charcoal finds diverse applications, including metallurgical fuel in iron and steel production, industrial fuel, cooking and heating fuel, reducing agent in chemical processes, and as a raw material in pyrotechnics. It is also utilized in cosmetics, horticulture, animal husbandry, medicine, and environmental sustainability efforts, such as carbon sequestration.

However, the production and utilization of charcoal can have adverse environmental impacts, including deforestation and emissions. Illegal and unregulated charcoal production, particularly in regions like South America and Africa, poses significant challenges to environmental conservation efforts.

History

[edit]

Charcoal pile

[edit]
An abandoned charcoal kiln near Walker, Arizona, US
Wood pile before covering with turf or soil, and firing it (c. 1890)

The production of wood charcoal in locations where there is an abundance of wood dates back to ancient times. It generally began with piling billets of wood on their ends to form a conical pile. Openings were left at the bottom to admit air, with a central shaft serving as a flue. The whole pile was covered with turf or moistened clay. The firing began at the bottom of the flue, and the fire gradually spread outward and upward.

The traditional method in Britain used a charcoal pile or clamp.[1] This was essentially a pile of wooden logs (e.g. seasoned oak) leaning in a circle against a chimney. The chimney consisted of 4 wooden stakes held up by some rope. In the clamp too the logs were completely covered with soil and straw allowing no air to enter. It must be lit by introducing some burning fuel into the chimney. The logs burned slowly and transformed into charcoal over a period of 5 days. If the soil covering became torn or cracked by the fire, additional soil was placed on the cracks. Once the burn was complete, the chimney was plugged to prevent air from entering.

Charcoal burners

[edit]

The true art of this production method was in managing the sufficient generation of heat, by combusting part of the wood material, and the transfer of the heat to the wood in the process of being carbonized. The operation was so delicate that it was generally left to colliers (professional charcoal burners). They often lived alone in small huts to tend their wood piles. For example, in the Harz Mountains of Germany, charcoal burners lived in conical huts called Köten which still exist today.[when?]

Low efficiency and harmful emissions

[edit]

The success of the operation depends upon the rate of the combustion. Under average conditions wood yields about 60% charcoal by volume, or 25% by weight;[2] small-scale production methods often yield only about 50% by volume, while large-scale methods enabled higher yields of about 90% by the 17th century. A strong disadvantage of this production method is the huge amount of emissions that are harmful to human health and the environment (emissions of unburnt methane).[3] As a result of the partial combustion of wood material, the efficiency of the traditional method is low.

Peak of production and decline

[edit]

Deforestation and scarcity

[edit]

The massive production of charcoal (at its height employing hundreds of thousands, mainly in Alpine and neighbouring forests) was a major cause of deforestation, especially in Central Europe.[4][when?] Complaints (as early as the Stuart period) about shortages may stem from over-exploitation or the impossibility of increasing production to match growing demand. In England, many woods were managed as coppices, which were cut and regrown cyclically, so that a steady supply of charcoal was available. But the increasing scarcity of easily harvested wood was a major factor behind the switch to fossil fuel equivalents, mainly coal and brown coal for industrial use.

By-product of wood tar production

[edit]

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 residual charcoal was widely used as substitute for metallurgical coke in blast furnaces for smelting. Tar production led to rapid local deforestation. The end of tar production at the end of the 19th century resulted in rapid re-forestation of affected areas.

Charcoal briquette

[edit]

The American form of the charcoal briquette was first invented and patented by Ellsworth B. A. Zwoyer of Pennsylvania in 1897[5] and was produced by the Zwoyer Fuel Company. The process was further popularized by Henry Ford, who used wood and sawdust byproducts from automobile fabrication as a feedstock. Ford Charcoal went on to become the Kingsford Company.

Production methods

[edit]
Charcoal under a microscope. Different colors correspond to different relief. Only a charred skeleton remains of the wood cells after charring.

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 for 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 (430 °F), a deep brown-black after some time at 280 °C (540 °F), and an easily powdered mass at 310 °C (590 °F). Charcoal made at 300 °C (570 °F) is brown, soft and friable, and readily inflames at 380 °C (720 °F); made at higher temperatures it is hard and brittle, and does not fire until heated to about 700 °C (1,300 °F).[2][6]

Modern methods employ retorting technology, in which process heat is recovered from, and solely provided by, the combustion of gas released during carbonization.[7] Yields of retorting are considerably higher than those of kilning, and may reach 35%-40%.

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.[citation needed] To obtain a coal with high purity, source material should be free of non-volatile compounds.

Wood charcoal is obtained as the residue by destructive distillation of wood such that the products are:

Types

[edit]
Binchōtan, Japanese high grade charcoal made from ubame oak
Ogatan, charcoal briquettes made from sawdust
  • 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 to remove the last traces of hydrogen.[2] It was used by Henri Moissan in his early attempt to create synthetic diamonds.[citation needed]
  • Activated charcoal is similar to common charcoal but is manufactured especially for medical use. To produce activated charcoal, common charcoal is heated to about 900 °C (1,700 °F) in the presence of an inert gas (usually argon or nitrogen), causing the charcoal to develop many internal spaces, or "pores", which help the activated charcoal to trap chemicals. Impurities on the surface of the charcoal are also removed during this process, greatly increasing its adsorption capacity.
  • Lump charcoal is a traditional charcoal made directly from hardwood material. It usually produces far less ash than briquettes.
  • Japanese charcoal has had pyroligneous acid removed during the charcoal making; it therefore produces almost no smell or smoke when burned. The traditional charcoal of Japan is classified into three types:
  • Pillow shaped 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. 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.
  • 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. It is used primarily for barbecue as it produces no odor, no smoke, little ash, high heat, and has a long burning time (exceeding 4 hours).
  • 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.

Uses

[edit]
Charcoal burning
Grill charcoal made from coconut shell

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. Charcoal was also used historically as a source of black pigment by grinding it up. In this form charcoal was important to early chemists and was a constituent of formulas for mixtures such as black powder. Due to its high surface area, charcoal can be used as a filter, catalyst, or adsorbent.

Metallurgical fuel

[edit]

Charcoal burns at temperatures exceeding 1,100 degrees Celsius (2,010 degrees Fahrenheit).[9] By comparison, the melting point of iron is approximately 1,200 to 1,550 °C (2,190 to 2,820 °F). Due to its porosity, it is sensitive to the flow of air and the heat generated can be moderated by controlling the air flow to the fire. For this reason charcoal is still widely used by blacksmiths. Charcoal has been used for the production of iron and steel (where it also provided the necessary carbon) since at least 2000 BCE, with artifacts having been found in Proto-Hittite layers at Kaman-Kalehöyük.[10] Charcoal briquettes can burn up to approximately 1,260 °C (2,300 °F) with a forced air blower forge.[11]

In the 16th century, England had to pass laws to prevent the country from becoming completely denuded of trees due to production of iron.[citation needed] In the 19th century charcoal was largely replaced by coke in steel production due to cost, even though coke usually adds sulphur and sometimes other deleterious contaminants to the pig iron. Wooded metallurgical regions devoid of coal like Sweden, the Urals, or Siberia transitioned from charcoal in the early 20th century.

Cooking and heating fuel

[edit]

Prior to the Industrial Revolution, charcoal was occasionally used as a cooking fuel. It is counted as a smokeless fuel; that is, the carbon is sufficiently pure that burning it causes substantially less air pollution than burning the original uncarbonized organic material would. In the 20th century, clean-air legislation mandated smokeless fuels (mostly coke or charcoal) in many areas of Europe. In the 21st century, charcoal has been advocated as a way to improve the health of people burning raw biomass for cooking and/or heating. Modern "charcoal" briquettes, widely used for outdoor cooking, are made with charcoal but may also include coal as an energy source as well as accelerants, binders and filler.

To contain the charcoal and use it for cooking purposes, a barbecue grill may be used. A small Japanese charcoal grill is known as a shichirin. A brazier is a container used to burn charcoal or other solid fuel.

To start the charcoal burning is harder than starting a wood fire and charcoal lighter fluid may be employed. A chimney starter or electric charcoal starter are tools to help with starting to light charcoal.

Approximately 75% of fuel burned in Haiti is charcoal.[12]

Reducing agent

[edit]

Certain types of charcoal, such as wood charcoal, are used for reducing heated metallic oxides to their respective metals:[citation needed]

  • ZnO + C → Zn + CO
  • Fe2O3 + 3C → 2Fe + 3CO

Charcoal can also be used to reduce super heated steam to hydrogen (along with the formation of carbon monoxide):[citation needed]

Syngas production, automotive fuel

[edit]

Like many other sources of carbon, charcoal can be used for the production of various syngas compositions; i.e., various CO + H2 + CO2 + N2 mixtures. The syngas is typically used as fuel, including automotive propulsion, or as a chemical feedstock.

In times of scarce petroleum, automobiles and even buses have been converted to burn wood gas: a gas mixture consisting primarily of diluting atmospheric nitrogen, but also containing combustible gasses (mostly carbon monoxide) released by burning charcoal or wood in a wood gas generator. In 1931, Tang Zhongming developed an automobile powered by charcoal, and these cars were popular in China until the 1950s, and in occupied France during World War II, where they were called gazogènes.

Pyrotechnics

[edit]
Mangrove charcoal burning video

Charcoal is used in the production of black powder, which is used extensively in the production of fireworks. It is usually ground into a fine powder, with air float grade being the finest particle size available commercially. When used in black powder compositions, it is often ball-milled with other ingredients so that they are intimately mixed together. Certain charcoals perform better when used to make black powder; these include spruce, willow, paulownia and grapevine among others.[citation needed] Charcoal produces fine dark orange/golden sparks. Usually, powder with a mesh size from 10 to 325 is used to obtain showers of golden sparks in pyrotechnic compositions.[13]

Cosmetic use of bamboo charcoal

[edit]

Charcoal is also incorporated in multiple cosmetic products.[14] It can be produced from regular bamboo cut into small pieces and boiled in water to remove soluble compounds.[14] Raw bamboo charcoal is obtained after drying and carbonization in an oven at elevated temperature.[14] The role of charcoal in cosmetics is based on its highly effective absorbing properties at a microscopic scale.[14]

Carbon source

[edit]

Charcoal may be used as a source of carbon in chemical reactions. One example of this is the production of carbon disulphide through the reaction of sulfur vapors with hot charcoal. In that case, the wood should be charred at high temperature to reduce the residual amounts of hydrogen and oxygen that lead to side reactions.

Purification and filtration

[edit]
Activated carbon
Charcoal for dehumidification and air purification in bathroom

Charcoal may be activated to increase its effectiveness as a filter. Activated charcoal readily adsorbs a wide range of organic compounds dissolved or suspended in gases and liquids. In certain industrial processes, such as the purification of sucrose from cane sugar, impurities cause an undesirable color, which can be removed with activated charcoal. It is also used to absorb odors and toxins in gaseous solutions, as in home air purifiers and some types of gas mask. The medical use of activated charcoal is mainly the absorption of poisons.[15] Activated charcoal is available without a prescription, so it is used for a variety of health-related applications. For example, it is often used to reduce discomfort and embarrassment due to excessive gas (flatulence) in the digestive tract.[16]

Animal charcoal or bone black is the carbonaceous residue obtained by the dry distillation of bones. It contains only about 10% carbon, the remaining 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 glue and gelatin industries. Its bleaching power was applied in 1812 by Derosne for clarifying sugar syrup, but its use in this direction has now greatly diminished. Today it is seldom used for this purpose due to the introduction of more active and easily managed reagents, but it is still employed to some extent in laboratory practice. The bleaching action of the charcoal in solution diminishes as it adsorbs colored contaminants, and it must be reactivated periodically by separate washing and reheating.[2] While wood charcoal effectively removes some pigments and contaminants from solutions, bone charcoal is generally more effective as an adsorption filter due to its increased porosity and surface area.[citation needed]

Art

[edit]
Four sticks of vine charcoal and four sticks of compressed charcoal
Two charcoal pencils in paper sheaths that are unwrapped as the pencil is used, and two charcoal pencils in wooden sheaths

Charcoal is used for drawing, making rough sketches in painting, and is one of the possible media used for making a parsemage. It usually must be preserved by the application of a fixative. Artists generally utilize charcoal in four forms:

  • Vine charcoal is created by burning grape vines.
  • Willow charcoal is created by burning willow sticks.
  • Powdered charcoal is often used to "tone" or cover large sections of a drawing surface. Drawing over the toned areas darkens it further, but the artist can also lighten (or completely erase) within the toned area to create lighter tones.
  • Compressed charcoal is charcoal powder mixed with gum binder and compressed into sticks. The amount of binder determines the hardness of the stick.[17] Compressed charcoal is used in charcoal pencils.

Horticulture

[edit]

One additional use of charcoal was rediscovered recently[when?] for horticulture. Although American gardeners have used charcoal for a short time, research on Terra preta soils in Amazonia has discovered the widespread use of biochar by pre-Columbian natives to ameliorate unproductive soil into soil rich in carbon. The technique may find modern application, both to improve soils and as a means of carbon sequestration.[18]

Animal husbandry

[edit]

Charcoal is mixed with feed, added to litter, or used in the treatment of manure.[19] Poultry benefits from using charcoal in this manner.[20][21]

A concern that activated charcoal might be used unscrupulously to allow livestock to tolerate low quality feed contaminated with aflatoxins resulted in the Association of American Feed Control Officials banning it in 2012 from use in commercial livestock feeds.[22]

Medicine

[edit]
Charcoal pile

Charcoal in the form of charcoal biscuits was consumed in the past for gastric problems. Now it can be consumed in tablet, capsule, or powder form for digestive effects.[23] Research regarding its effectiveness is controversial.[24]

Charcoal has been used in combination with saccharin in research to measure mucociliary transport time.[25]

Charcoal has also been incorporated into toothpaste formulas; however, there is no evidence to determine its safety and effectiveness.[26]

Red colobus monkeys in Africa have been observed eating charcoal for self-medication. Because their leafy diets contain high levels of cyanide, which may lead to indigestion, they learned to consume charcoal, which absorbs the cyanide and relieves discomfort. This knowledge is transmitted from mother to infant.[27]

Environmental sustainability

[edit]
Bagged Charcoal in Bole Bamboi, Ghana

Production and utilization of charcoal, like any use of woody biomass as fuel, typically results in emissions and can contribute to deforestation.

The use of charcoal as a smelting fuel has been experiencing a resurgence in South America resulting in severe environmental, social and medical problems.[28][29] Charcoal production at a sub-industrial level is one of the causes of deforestation. Charcoal production is now usually illegal and nearly always unregulated, as in Brazil, where charcoal production is a large illegal industry for making pig iron.[30][31][32]

Massive forest destruction has been documented in areas such as Virunga National Park in the Democratic Republic of Congo, where it is considered a primary threat to the survival of the mountain gorillas.[33] Similar threats are found in Zambia.[34] In Malawi, illegal charcoal trade employs 92,800 workers and is the main source of heat and cooking fuel for 90 percent of the nation's population.[35] Some experts, such as Duncan MacQueen, Principal Researcher–Forest Team, International Institute for Environment and Development (IIED), argue that while illegal charcoal production causes deforestation, a regulated charcoal industry that required replanting and sustainable use of the forests "would give their people clean efficient energy – and their energy industries a strong competitive advantage".[35]

Recent assessments of charcoal imported to Europe have shown that many charcoal products are produced from tropical wood, often of undeclared origin. In an analysis of barbecue charcoal marketed in Germany, the World Wildlife Fund found that most products contain tropical wood. As a notable exception, reference is made to barbecue charcoal imports from Namibia, where charcoal is typically produced from surplus biomass resulting from woody plant encroachment.[36][37][38] Charcoal trafficking in Somalia is an economic and environmental issue with significant regional-security implications.[39]

[edit]

The last section of the film Le Quattro Volte (2010) gives a good and long, if poetic, documentation of the traditional method of making charcoal.[40] The Arthur Ransome children's series Swallows and Amazons (particularly the second book, Swallowdale) features carefully drawn vignettes of the lives and the techniques of charcoal burners at the start of the 20th century, in the Lake District of the UK. Antonín Dvořák's opera King and Charcoal Burner is based on a Czech legend about a king who gets lost in a forest and is rescued by a charcoal burner.

See also

[edit]

References

[edit]
  1. ^ "Geoarch". Geoarch. 31 May 1999. Archived from the original on 15 March 2004. Retrieved 20 May 2012.
  2. ^ a b c d  One or more of the preceding sentences incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Charcoal". Encyclopædia Britannica. Vol. 5 (11th ed.). Cambridge University Press. p. 856.
  3. ^ "Roland.V. Siemons, Loek Baaijens, An Innovative Carbonization Retort: Technology and Environmental Impact, TERMOTEHNIKA, 2012, XXXVIII, 2, 131‡138 131" (PDF).
  4. ^ Ray, G.F. (July 1979). "Energy economics — a random walk in history". Energy Economics. 1 (3): 139–143. Bibcode:1979EneEc...1..139R. doi:10.1016/0140-9883(79)90044-6.
  5. ^ "Barbeque – History of Barbecue". Inventors.about.com. 15 June 2010. Archived from the original on 10 July 2012. Retrieved 28 December 2011.
  6. ^ "Carbonisation processes". FAO. Retrieved 21 May 2021.
  7. ^ "Kilning vs. Retorting: the cause of emissions of unburnt gases".
  8. ^ "Pyroligneous Acid or Wood Vinegar". Scientific American. 14 November 1857. Retrieved 14 March 2020.
  9. ^ Updated April 26, 2018 By Gabriella Munoz (26 April 2018). "How Hot Is a Bonfire?". Sciencing. Retrieved 13 November 2019.{{cite web}}: CS1 maint: numeric names: authors list (link)
  10. ^ Akanuma, Hideo (2008). "The significance of Early Bronze Age iron objects from Kaman-Kalehöyük, Turkey" (PDF). Anatolian Archaeological Studies. 17. Tokyo: Japanese Institute of Anatolian Archaeology: 313–320.
  11. ^ Cheng, Zhilong; Yang, Jian; Zhou, Lang; Liu, Yan; Wang, Qiuwang (1 January 2016). "Characteristics of charcoal combustion and its effects on iron-ore sintering performance". Applied Energy. 161: 364–374. Bibcode:2016ApEn..161..364C. doi:10.1016/j.apenergy.2015.09.095. ISSN 0306-2619.
  12. ^ Lea, John Dale Zach (25 January 2017). "Charcoal Is Not the Cause of Haiti's Deforestation | Haiti Liberte". Retrieved 16 July 2021.
  13. ^ Kenneth L. Kosanke; Bonnie J. Kosanke (1999), "Pyrotechnic Spark Generation", Journal of Pyrotechnics: 49–62, ISBN 978-1-889526-12-6, archived from the original on 16 December 2017
  14. ^ a b c d Ahmad, N; Isa, S.S.M.; Ramli, M.M.; Hambali, N.A.M.A.; Kasjoo, S.R.; Isa, M.M.; Nor, N.I.M.; Khalid, N. (2016). "Adsorption properties and potential applications of bamboo charcoal: A Review" (PDF). MATEC Web of Conferences. 78: 1–7. Archived from the original (PDF) on 24 July 2018. Retrieved 3 February 2018 – via edp sciences.
  15. ^ Dawson, Andrew (1997). "Activated charcoal: a spoonful of sugar". Australian Prescriber. 20: 14–16. doi:10.18773/austprescr.1997.008.
  16. ^ "Treating flatulence". NHS. NHS UK. Retrieved 27 May 2012.
  17. ^ "charcoal: powdered, compressed, willow and vine". Muse Art and Design. 7 September 2011. Archived from the original on 31 August 2012. Retrieved 27 May 2012.
  18. ^ Johannes Lehmann, ed. (2009). Biochar for Environmental Management: Science and Technology. Stephen Joseph. Earthscan. ISBN 978-1-84407-658-1. Archived from the original on 11 December 2017. Retrieved 30 December 2013.
  19. ^ Gerlach, Achim; Schmidt, Hans-Peter (2014), "The use of biochar in cattle farming", The Biochar Journal, Arbaz, Switzerland, ISSN 2297-1114
  20. ^ Yarrow, David (March 2015). "Biochar: Helping Everything from Soil Fertility to Odor Reduction". Acres U.S.A. Archived from the original on 9 June 2019. Retrieved 7 March 2019.
  21. ^ Schupska Site=CAES News, Stephanie (10 March 2011). "Charcoal supplemented diet reduces ammonia in chickens' litter". Archived from the original on 30 July 2020. Retrieved 7 March 2019.
  22. ^ Damerow, Gail (2015). The Chicken Health Handbook, 2nd Edition: A Complete Guide to Maximizing Flock Health and Dealing with Disease. Storey. p. 391. ISBN 978-1612120133.
  23. ^ Stearn, Margaret (2007). Warts and all: straight talking advice on life's embarrassing problems. London: Murdoch Books. p. 333. ISBN 978-1-921259-84-5. Retrieved 3 May 2009.
  24. ^ Am J Gastroenterology 2005 Feb 100(2)397–400 and 1999 Jan 94(1) 208–12
  25. ^ Passali, Desiderio (1984). "Experiences in the determination of nasal mucociliary transport time". Acta Otolaryngol. 97 (3–4): 319–23. doi:10.3109/00016488409130995. PMID 6539042.
  26. ^ Brooks, John K.; Bashirelahi, Nasir; Reynolds, Mark A. (7 June 2017). "Charcoal and charcoal-based dentifrices: A literature review". Journal of the American Dental Association. 148 (9): 661–670. doi:10.1016/j.adaj.2017.05.001. ISSN 1943-4723. PMID 28599961.
  27. ^ "Clever Monkeys: Monkeys and Medicinal Plants". PBS. 13 September 2011. Retrieved 20 May 2012.
  28. ^ Michael Smith; David Voreacos (21 January 2007). "Brazil: Enslaved workers make charcoal used to make basic steel ingredient". Seattle Times. Archived from the original on 16 September 2012. Retrieved 16 September 2012.
  29. ^ M. Kato1, D. M. DeMarini, A. B. Carvalho, M. A. V. Rego, A. V. Andrade1, A. S. V. Bonfim and D. Loomis (2004). "World at work: Charcoal producing industries in northeastern Brazil". Occupational and Environmental Medicine. 62 (2): 128–132. doi:10.1136/oem.2004.015172. PMC 1740946. PMID 15657196. Archived from the original on 22 November 2012.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  30. ^ "U.S. car manufacturers linked to Amazon destruction, slave labor". News.mongabay.com. 14 May 2012. Retrieved 20 May 2012.
  31. ^ "Driving Destruction in the Amazon: How steel production is throwing the forest into the furnace". Greenpeace. 11 May 2012. Archived from the original on 20 May 2012. Retrieved 20 May 2012.
  32. ^ The documentary film The Charcoal People (2000) [1] shows in detail the deforestation in Brazil, the poverty of the laborers and their families, and the method of constructing and using a clamp for burning the wood.
  33. ^ "Virunga National Park". Gorilla.cd. Archived from the original on 3 October 2008. Retrieved 20 May 2012.
  34. ^ "Living on Earth: Zambia's Vanishing Forests". Loe.org. 4 March 1994. Retrieved 28 December 2011.
  35. ^ a b "Is charcoal the key to sustainable energy consumption in Malawi?". UNEARTH News. July 2013. Archived from the original on 11 August 2013. Retrieved 10 August 2013.
  36. ^ Zahnen, Johannes. "Market Analysis Barbecue Charcoal 2018 - The Dirty Business of Barbecue Charcoal" (PDF). WWF. Retrieved 27 May 2020.
  37. ^ "From Bush to Charcoal: the Greenest Charcoal Comes from Namibia". Forest Stewardship Council. 17 March 2020. Archived from the original on 27 July 2020. Retrieved 27 May 2020.
  38. ^ Haag, Volker; Zemke, Valentina Theresia; Lewandrowski, Tim; Zahnen, Johannes; Hirschberger, Peter; Bick, Ulrich; Koch, Gerald (11 September 2020). "The European charcoal trade". IAWA Journal. 41 (4): 463–477. doi:10.1163/22941932-bja10017. ISSN 0928-1541.
  39. ^ Gridneff, Ilya (2018). "Burning Somalia's Future: The Illegal Charcoal Trade Between the Horn of Africa and the Gulf". In Verhoeven, Harry (ed.). Environmental Politics in the Middle East. Oxford: Oxford University Press. pp. 121–148. ISBN 9780190916688.
  40. ^ "Le quattro volte (2010)". IMDb. Retrieved 16 September 2012.
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