Editing Bone char

{{Chembox
| ImageFile = Živočišné_uhlí_(Carbocit).jpg
| ImageSize = 
| ImageAlt = 
| ImageCaption = Pills of bone char

| IUPACName = 
| OtherNames = {{unbulleted list |bone charcoal |bone black |ivory black |animal charcoal |abaiser |Pigment black 9 |CI 77267}}
|Section1={{Chembox Identifiers
| CASNo = 8021-99-6
| PubChem =
| EINECS = 232-421-2
| SMILES = 
| ChemSpiderID = none
}}
|Section2={{Chembox Properties
| Formula =
| MolarMass =
| Appearance = black powder
| Density = 0.7 - 0.8 g/cm<sup>3</sup>
| MeltingPt = 
| BoilingPt =
| pKa = 8.5 - 10.0
| Solubility = insoluble
}}
|Section3={{Chembox Hazards
| MainHazards = 
| FlashPt = 
| AutoignitionPt = 
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}}

'''Bone char''' ({{langx|la| carbo animalis}}) is a porous, black, granular material produced by [[charring]] animal [[bone]]s. Its composition varies depending on how it is made; however, it consists mainly of [[tricalcium phosphate]] (or [[hydroxyapatite]]) 57–80%, [[calcium carbonate]] 6–10% and [[carbon]] 7–10%.<ref>{{cite book |last= Fawell |first=John |title=Fluoride in drinking-water |date=2006 |publisher=WHO |location=Geneva |isbn=9241563192 |page=47 |edition=1st published.}}</ref> It is primarily used for filtration and decolorisation.

==Production==
Bone char is primarily made from cattle and pig bones; however, to prevent the spread of [[variant Creutzfeldt–Jakob disease|Creutzfeldt–Jakob disease]], the [[skull]] and [[Vertebral column|spine]] are no longer used.<ref name="Dirty Jobs: Episode Guide">{{cite web|url=http://dsc.discovery.com/fansites/dirtyjobs/episode/episode.html |title=''Dirty Jobs'' Episode Guide: Season 5 Episode "Bone Black" |archive-url=https://web.archive.org/web/20101113011609/http://dsc.discovery.com/fansites/dirtyjobs/episode/episode.html|archive-date=November 13, 2010}}</ref> The bones are heated in a sealed vessel at up to {{convert|700|C|F}}; the oxygen concentration must be kept low while doing this, as it affects the quality of the product, particularly its [[adsorption]] capacity. Most of the [[organic compound|organic]] material in the bones is driven off by heat, and was historically collected as [[Dippel's oil]]; that which is not driven off remains as [[activated carbon]] in the final product. Heating bones in an oxygen-rich atmosphere gives [[bone ash]], which is chemically quite different.{{Clarify|reason=Calcining bones means burning them in oxygen atmosphere.|date=December 2021}}{{Citation needed|date=December 2021}}

Used bone char can be regenerated by washing with hot water to remove impurities, followed by heating to {{convert|500|C|F}} in a [[kiln]] with a controlled amount of air.

== Uses ==

===Water treatment===
The [[tricalcium phosphate]] in bone char can be used to remove [[Water fluoridation|fluoride]]<ref>{{cite journal|last=Medellin-Castillo|first=Nahum A. |author2=Leyva-Ramos, Roberto |author3=Ocampo-Perez, Raul |author4=Garcia de la Cruz, Ramon F. |author5=Aragon-Piña, Antonio |author6=Martinez-Rosales, Jose M. |author7=Guerrero-Coronado, Rosa M. |author8=Fuentes-Rubio, Laura |title=Adsorption of Fluoride from Water Solution on Bone Char|journal=Industrial & Engineering Chemistry Research|date=December 2007|volume=46|issue=26|pages=9205–9212|doi=10.1021/ie070023n}}</ref> and metal ions from water, making it useful for the treatment of drinking supplies.
Bone charcoal is the oldest known water defluoridation agent and was widely used in the United States from the 1940s through to the 1960s.<ref>{{cite journal|last=Horowitz|first=HS|author2=Maier, FJ |author3=Law, FE |title=Partial defluoridation of a community water supply and dental fluorosis.|journal=Public Health Reports|date=Nov 1967|volume=82|issue=11|pages=965–72|pmid=4964678|pmc=1920070|doi=10.2307/4593174|jstor=4593174}}</ref> As it can be generated cheaply and locally it is still used in certain developing countries, such as [[Tanzania]].<ref>{{cite journal|last=Mjengera|first=H.|author2=Mkongo, G.|title=Appropriate deflouridation technology for use in flourotic areas in Tanzania|journal=Physics and Chemistry of the Earth, Parts A/B/C|date=January 2003|volume=28|issue=20–27|pages=1097–1104|doi=10.1016/j.pce.2003.08.030|bibcode=2003PCE....28.1097M}}</ref>
Bone chars usually have lower [[surface area]]s than [[activated carbon]]s, but present high adsorptive capacities for certain metals, particularly those from [[Group 12 element|group 12]] ([[copper]], [[zinc]], and [[cadmium]]).<ref>{{cite journal|last=Ko|first=Danny C.K.|author2=Porter, John F. |author3=McKay, Gordon |title=Optimised correlations for the fixed-bed adsorption of metal ions on bone char|journal=Chemical Engineering Science|date=December 2000|volume=55|issue=23|pages=5819–5829|doi=10.1016/S0009-2509(00)00416-4|bibcode=2000ChEnS..55.5819K }}</ref> Other highly toxic metal ions, such as those of [[arsenic]]<ref>{{cite journal|last=Chen|first=Yun-Nen|author2=Chai, Li-Yuan |author3=Shu, Yu-De |title=Study of arsenic(V) adsorption on bone char from aqueous solution|journal=Journal of Hazardous Materials|date=December 2008|volume=160|issue=1|pages=168–172|doi=10.1016/j.jhazmat.2008.02.120|pmid=18417278|bibcode=2008JHzM..160..168C }}</ref> and [[lead]]<ref>{{cite journal|last=Deydier|first=Eric|author2=Guilet, Richard |author3=Sharrock, Patrick |title=Beneficial use of meat and bone meal combustion residue: "an efficient low cost material to remove lead from aqueous effluent"|journal=Journal of Hazardous Materials|date=July 2003|volume=101|issue=1|pages=55–64|doi=10.1016/S0304-3894(03)00137-7|pmid=12850320|bibcode=2003JHzM..101...55D }}</ref> may also be removed.
The practical example of the use of bone char in water purification is demonstrated by use of [[nanofiltration]] in Tanzania.<ref>{{cite web|url=http://gongalimodel.com/Water-Nanofilter.html|title=Water-Nanofilter|website=gongalimodel.com}}</ref>

===Sugar refining===
[[File:Sucre blanc cassonade complet rapadura.jpg|thumb|Sugars (clockwise from top-left): white refined, unrefined, unprocessed cane, brown]]

Historically, bone char was often used in [[White refined sugar#Refining|sugar refining]] as a decolorizing and deashing agent, particularly in cane sugar as this contains more colored impurities.

Bone char possesses a low decoloration capacity and must be used in large quantities,<ref>{{cite book|last1=Asadi|first1=Mosen|title=Beet-Sugar Handbook.|date=2006|publisher=John Wiley & Sons|location=Hoboken|isbn=9780471790983|pages=333}}</ref> however, it is also able to remove various inorganic impurities, most importantly [[sulfate]]s and the ions of magnesium and calcium. The removal of these is beneficial, as it reduces the level of [[Fouling|scaling]] later in the refining process, when the sugar solution is concentrated.<ref>{{cite book|editor=Chung Chi Chou|title=Handbook of sugar refining: a manual for the design and operation of sugar refining facilities|date=2000|publisher=Wiley|location=New York|isbn=9780471183570|pages=368–369}}</ref> Modern alternatives to bone char include [[activated carbon]] and [[ion-exchange resin]]s. However, a small number of companies remain completely or partially dependent on bone char for sugar refinement.

===Black pigment===
[[File:MANET - Música en las Tullerías (National Gallery, Londres, 1862).jpg|thumbnail|Édouard Manet, ''Music in the Tuileries'', 1862]]

Bone char is also used as a black [[pigment]] for [[paint|artist's paint]], printmaking, calligraphic and drawing inks as well as other artistic applications because of its deepness of color and excellent tinting strength.  [[Bone Black (pigment)|Bone black]] and ivory black are artists' pigments which have been in use since historic times—by both old masters like [[Rembrandt]] and [[Diego Velázquez|Velázquez]] and more modern painters such as [[Édouard Manet|Manet]] and [[Pablo Picasso|Picasso]]. The black dresses and high hats of the gentlemen in Manet's ''[[Music in the Tuileries]]'' are painted in ivory black.<ref>Bomford D, Kirby J, Leighton, J., Roy A., ''Art in the Making: Impressionism''.  National Gallery Publications, London, 1990, pp. 112-119</ref><ref>[http://colourlex.com/project/manet-music-in-the-tuileries/ Édouard Manet, 'Music in the Tuileries Gardens'], ColourLex</ref>

Ivory black was formerly made by grinding charred [[ivory]] in [[oil]]. Nowadays  ivory black is considered a synonym for bone black. Actual ivory is no longer used because of the expense and because animals that are natural sources of ivory are subject to international control as [[endangered species]].

===Niche uses===
*It is used to refine [[petroleum|crude oil]] in the production of [[petroleum jelly]].
*In the 18th and 19th centuries, bone char mixed with tallow or wax (or both) was used by soldiers in the field to impregnate military leather equipment, both to increase its lifespan and as the simplest way to obtain pigment for black leatherware.  Military and civilians used it as shoe polish and preservative, including on shoes with the "rough" side out.  In period reference materials, it is referred to as "black ball".
*The ESA-NASA [[Solar Orbiter]] satellite uses a refined form of bone char applied to its titanium heatshield. This protects it against the glare and heat of the sun. Irish company Embio developed the coating and uses its 'CoBlast' technique, originally developed to coat titanium medical implants.<ref>{{cite web|url=http://m.esa.int/Our_Activities/Space_Engineering_Technology/Prehistoric_cave_pigment_to_shield_ESA_s_Solar_Orbiter|title=Prehistoric cave pigment to shield ESA's Solar Orbiter|website=[[ESA.int]]}}</ref>
[[File:Solar Orbiter Structural Thermal Model.jpg|thumb|This photo shows the Solar Orbiter with its black, bone char coated heatshield.]]

==In popular culture==
* The production of bone char was featured on the [[Discovery Channel]]'s TV series ''[[Dirty Jobs]]'', on episode 19 of season 5, "Bone Black", originally broadcast on 9 February 2010.<ref name="Dirty Jobs: Episode Guide"/>
* Human bone char, referred to as "bone charcoal", is mentioned in [[Thomas Pynchon]]'s novel ''[[The Crying of Lot 49]]''. The bones come from US soldiers who died in combat during WWII and were buried in a lake in Italy, and the char is used for filters in cigarettes.
* Human bone char is mentioned in [[Jaroslav Hašek]]'s novel ''[[The Good Soldier Švejk]]''. The work contains a reference to soldiers not dying in vain because their bones will be used to make bone charcoal ("[[spodium]]") for sugar refineries, the protagonist getting disciplined by his commander for wondering whether the coal from officers' bones is sold to the refineries at a higher price than that made from ordinary privates' bones.

==See also==
* [[Activated carbon]]
* [[Carbon black]]
* [[Potash]]

== References ==
{{Reflist}}

== External links ==
* {{Cite Americana|wstitle=Blacks |short=x}}
* [http://colourlex.com/project/ivory-black/ Ivory black], ColourLex
* [http://colourlex.com/project/bone-black/ Bone black], ColourLex

{{DEFAULTSORT:Bone Char}}
[[Category:Organic pigments]]
[[Category:Bone products|Char]]
[[Category:Charcoal]]