What is bone char, and what are its primary components and uses?

Bone char, also known by its Latin name *carbo animalis*, is a porous, black, granular material produced by charring animal bones. Its composition typically includes 57–80% tricalcium phosphate (or hydroxyapatite), 6–10% calcium carbonate, and 7–10% carbon. The primary applications for bone char are filtration and decolorization processes.

What are the alternative names and key identifiers for bone char?

Bone char is known by several other names, including bone charcoal, bone black, ivory black, animal charcoal, abaiser, Pigment black 9, and CI 77267. Its CAS Registry Number is 8021-99-6, and its EC Number is 232-421-2. It is also identified by ECHA InfoCard 100.029.470 and the EPA's CompTox Dashboard identifier DTXSID5027693.

Describe the physical and chemical properties of bone char.

Bone char typically appears as a black powder. Its density ranges from 0.7 to 0.8 g/cm³, and it is insoluble in water. The material exhibits an acidity, measured by pKa, between 8.5 and 10.0. These properties are generally reported under standard conditions, specifically at 25°C (77°F) and 100 kPa.

What is the process for producing bone char, including the materials used and critical conditions?

Bone char is produced by charring animal bones, primarily from cattle and pigs, though skulls and spines are now avoided due to disease concerns like Creutzfeldt-Jakob disease. The bones are heated in a sealed vessel to temperatures reaching up to 700°C (1,292°F). Maintaining a low oxygen concentration during this process is crucial for preserving the quality and adsorption capacity of the final product.

What happens to the organic material in bones during bone char production?

During the charring process, most of the organic material present in the animal bones is driven off by the high heat. Historically, this volatile organic material was collected as Dippel's oil. The portion of organic material that remains is transformed into activated carbon, which is an integral part of the final bone char product.

How does the production of bone ash differ from that of bone char?

The key difference lies in the atmospheric conditions during heating. Bone char is produced by heating bones in a low-oxygen environment, which results in a material containing significant amounts of carbon (activated carbon). In contrast, bone ash is produced by calcining bones in an oxygen-rich atmosphere, yielding a material that is primarily calcium phosphate without the substantial carbon content.

How can used bone char be regenerated for reuse?

Used bone char can be regenerated to restore its effectiveness. The process involves washing the material with hot water to remove accumulated impurities. Following the washing, the bone char is heated to approximately 500°C (932°F) in a kiln under controlled air conditions, which reactivates its adsorptive capabilities.

What role does the tricalcium phosphate in bone char play in water treatment?

The tricalcium phosphate component within bone char is key to its effectiveness in water treatment. This mineral compound enables bone char to act as an adsorbent, removing specific contaminants like fluoride and various metal ions from water, thereby making it useful for purifying drinking supplies.

What is the historical significance of bone charcoal in water defluoridation?

Bone charcoal holds historical significance as the earliest known agent used for water defluoridation. It was widely employed in the United States for this purpose from the 1940s through the 1960s, demonstrating its effectiveness in reducing fluoride levels in community water supplies.

In what contexts is bone char still utilized for water treatment today?

Despite the development of modern water treatment technologies, bone char continues to be used in certain applications, particularly in developing countries. Its low cost and the ability to generate it locally make it a viable option for water purification in regions such as Tanzania, often used in conjunction with other filtration methods like nanofiltration.

How does bone char's metal adsorption capacity compare to activated carbon, and for which metals is it particularly effective?

While bone chars generally have lower surface areas compared to activated carbons, they possess high adsorptive capacities for certain metals. Bone char is especially effective at removing metals belonging to Group 12 of the periodic table, which includes copper, zinc, and cadmium.

Besides fluoride and Group 12 metals, what other hazardous metal ions can bone char remove from water?

Bone char demonstrates efficacy in removing other highly toxic metal ions from water. It can be used to adsorb ions associated with arsenic and lead, contributing to the remediation of water sources contaminated with these dangerous heavy metals.

What historical role did bone char play in the sugar refining industry?

Historically, bone char was extensively used in sugar refining, particularly for cane sugar, as a decolorizing and deashing agent. Its function was to remove colored impurities and inorganic substances that could affect the final product's quality and processing.

What specific inorganic impurities does bone char remove during sugar refining, and why is this important?

During sugar refining, bone char effectively removes inorganic impurities such as sulfates, magnesium ions, and calcium ions. Removing these ions is crucial because they can lead to scaling when the sugar solution is concentrated, which can hinder the efficiency of the refining process.

What are the modern alternatives to bone char used in sugar refining?

Modern sugar refineries often utilize alternatives to bone char for decolorization and deashing. These alternatives primarily include activated carbon and ion-exchange resins, which offer different performance characteristics and environmental profiles compared to traditional bone char.

Does the sugar industry still use bone char, and if so, why?

Yes, a small number of companies in the sugar industry continue to use bone char, either completely or partially, for their refining processes. This continued reliance suggests that bone char still offers specific advantages or cost-effectiveness for certain operations, despite the availability of modern alternatives.

Why is bone char valued as a black pigment in artistic applications?

Bone char is highly regarded as a black pigment for artistic uses, such as paints, inks, and printmaking, due to its deep, intense black color and excellent tinting strength. These qualities allow artists to achieve rich tones and subtle gradations in their work.

What are the historical and current names for bone char used as an artist's pigment, and what is the status of ivory black?

Bone char used as a pigment is historically known as 'bone black' or 'ivory black.' While 'ivory black' was once derived from charred ivory, it is now generally considered a synonym for bone black. The use of actual ivory has ceased due to its high cost and international regulations protecting endangered species.

Which famous artists are noted for using bone black or ivory black pigments?

The use of bone black and ivory black pigments dates back centuries, with notable artists employing them. Old Masters like Rembrandt and Velázquez utilized these pigments, as did more modern painters such as Édouard Manet and Pablo Picasso. Manet, for instance, used ivory black to depict the black attire in his painting 'Music in the Tuileries'.

What niche applications exist for bone char?

Bone char serves in several specialized applications. It is used in refining crude oil to produce petroleum jelly. Historically, it was mixed with tallow or wax by soldiers to treat leather equipment, acting as both a preservative and a black pigment known as 'black ball.' More recently, a refined form coats the heat shield of the ESA-NASA Solar Orbiter satellite for thermal protection.

How was bone char utilized in the 18th and 19th centuries for military purposes?

In the 18th and 19th centuries, soldiers used bone char mixed with tallow or wax to treat military leather equipment. This mixture served a dual purpose: it helped preserve the leather, extending its lifespan, and provided a simple method for achieving a black color, commonly referred to as 'black ball,' for leather goods like shoes.

What role does bone char play in the Solar Orbiter satellite?

A refined form of bone char is applied to the titanium heatshield of the ESA-NASA Solar Orbiter satellite. This specialized coating is essential for protecting the spacecraft from the extreme glare and intense heat emanating from the sun during its mission.

In which television series and episode was the production of bone char featured?

The production process of bone char was showcased on the Discovery Channel's television series *Dirty Jobs*. Specifically, it was featured in Season 5, Episode 19, titled 'Bone Black,' which originally aired on February 9, 2010.

How is human bone char referenced in Thomas Pynchon's novel *The Crying of Lot 49*?

In Thomas Pynchon's novel *The Crying of Lot 49*, human bone char, referred to as 'bone charcoal,' is mentioned as being used for filters in cigarettes. The source of the bones is described as US soldiers who died during World War II and were buried in a lake in Italy.

What is the context of human bone char in Jaroslav Hašek's *The Good Soldier Švejk*?

Jaroslav Hašek's novel *The Good Soldier Švejk* includes a reference to human bone char, termed 'spodium,' being used in sugar refineries. The narrative humorously touches upon the idea of soldiers not dying in vain, as their bones could be used for industrial purposes, with the protagonist questioning if officers' bones fetched a higher price than those of ordinary soldiers.

What related materials are listed alongside bone char in the 'See also' section?

The 'See also' section lists related materials such as activated carbon, carbon black, and potash. These substances share some properties or applications with bone char, particularly concerning carbon-based materials and their uses in various industrial and chemical processes.

What is the standard state reference for the properties of bone char listed in the infobox?

The properties listed for bone char, such as density and pKa, are typically provided for the material in its standard state. This standard state is defined as being at a temperature of 25 degrees Celsius (77 degrees Fahrenheit) and a pressure of 100 kilopascals.

What is Dippel's oil, and how is it related to bone char production?

Dippel's oil was a historical byproduct collected during the production of bone char. It was derived from the organic material in animal bones that was driven off by heat during the charring process. This oil was historically used for various purposes.

What is the significance of the 'activated carbon' component within bone char?

The activated carbon present in bone char is a result of the organic material within the bones that is not completely driven off during the charring process. This activated carbon contributes to the material's adsorptive properties, which are crucial for its use in filtration and decolorization.

What is the role of heat in the production of bone char?

Heat is essential in the production of bone char, as it is used to char the animal bones at temperatures up to 700°C (1,292°F). This high temperature drives off the organic components of the bones and transforms the remaining mineral structure into a porous, carbon-rich material.

What specific historical period saw widespread use of bone charcoal for water defluoridation in the United States?

Bone charcoal was extensively utilized in the United States for the purpose of defluoridating water during the mid-20th century, specifically from the 1940s through the 1960s. This period highlights its significance as an early and effective method for removing excess fluoride from drinking water supplies.

Why is bone char particularly useful for refining cane sugar compared to beet sugar?

Bone char is especially beneficial for refining cane sugar because cane sugar inherently contains a higher concentration of colored impurities. Its decolorizing properties are therefore more critical and effective in processing cane sugar to achieve a refined white product.

How does the bone char coating on the Solar Orbiter satellite function?

The refined bone char coating on the Solar Orbiter satellite's titanium heatshield serves a critical thermal protection role. It is designed to shield the spacecraft from the intense glare and extreme heat generated by the sun, preventing damage to sensitive components.

Bone Char Wiki: Bone Char: From Byproduct to Essential Material

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What is Bone Char?

Bone Char
Names
Other names bone charcoal bone black ivory black animal charcoal abaiser Pigment black 9 CI 77267
Identifiers
CAS Number	8021-99-6
ChemSpider	none
ECHA InfoCard	100.029.470
EC Number	232-421-2
CompTox Dashboard (EPA)	DTXSID5027693
Properties
Appearance	black powder
Density	0.7 - 0.8 g/cm³
Solubility in water	insoluble
Acidity (pK_a)	8.5 - 10.0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Definition and Composition

Bone char, also known by its Latin name carbo animalis, is a porous, black, granular material derived from the charring of animal bones. Its precise composition is variable, but it predominantly consists of approximately 57–80% tricalcium phosphate (or hydroxyapatite), 6–10% calcium carbonate, and 7–10% carbon. Its primary utility lies in its exceptional capabilities for filtration and decolorization.

Production Process

Charring Bones

The manufacturing of bone char involves heating animal bones, primarily from cattle and pigs, in a sealed vessel at temperatures reaching up to 700 °C (1,292 °F). To ensure the quality and adsorption capacity of the final product, the oxygen concentration during this process must be carefully controlled and kept minimal. This controlled heating drives off most of the organic material, historically collected as Dippel's oil, while the remaining carbonaceous material forms the activated carbon component of the bone char. It is important to distinguish this process from the creation of bone ash, which results from heating bones in an oxygen-rich atmosphere and yields a chemically distinct substance.

Regeneration

Used bone char, having lost its efficacy through adsorption, can be regenerated. This process typically involves washing with hot water to remove accumulated impurities, followed by a controlled heating phase in a kiln at approximately 500 °C (932 °F) with a regulated air supply. This regeneration allows for the reuse of the material, enhancing its economic and environmental viability.

Diverse Applications

Water Purification

The tricalcium phosphate component of bone char exhibits a significant affinity for fluoride ions and various metal cations. This property makes it an effective agent for treating drinking water, particularly for the removal of fluoride. Historically, bone char was a primary agent for water defluoridation in the United States from the 1940s to the 1960s. It continues to be employed in certain developing nations, such as Tanzania, due to its local availability and cost-effectiveness. Furthermore, bone char demonstrates high adsorptive capacities for toxic heavy metal ions like copper, zinc, cadmium, arsenic, and lead, making it valuable for industrial wastewater treatment.

Sugar Refining

Historically, bone char played a crucial role in the refining of cane sugar. Its primary function was as a decolorizing and deashing agent, effectively removing colored impurities from the raw sugar liquor. Beyond color removal, bone char is also effective at eliminating inorganic impurities, notably sulfates, and ions of magnesium and calcium. The reduction of these scaling ions is beneficial, preventing fouling during the subsequent concentration stages of the refining process. While modern alternatives like activated carbon and ion-exchange resins are now prevalent, a segment of the sugar industry still relies on bone char for its unique efficacy.

Black Pigment

Artistic Applications

Bone char is highly valued as a black pigment in various artistic mediums, including paints, printmaking inks, and calligraphy inks. Its granular structure and carbonaceous nature impart a deep, rich black color with exceptional tinting strength. Renowned artists throughout history, such as Rembrandt, Velázquez, Manet, and Picasso, utilized pigments derived from charred bone. The term "ivory black" is often used synonymously with bone black, though historically it referred to pigment made from charred ivory. Due to cost and conservation concerns regarding ivory, modern "ivory black" pigments are typically derived from bone char.

Historical Masters

The profound depth and permanence of bone black pigment made it a staple for Old Masters. Its use is evident in the subtle gradations of shadow and the striking contrasts seen in works by artists like Rembrandt and Velázquez. In the 19th century, painters such as Édouard Manet employed ivory black to render the dark attire in iconic pieces like Music in the Tuileries, showcasing its enduring appeal in capturing form and volume.

Specialized Uses

Industrial & Technological Roles

Beyond its primary applications, bone char finds utility in several specialized areas:

Petroleum Refining: It is employed in the refinement of crude oil for the production of petroleum jelly.
Military Equipment: Historically, bone char mixed with tallow or wax was used to treat military leather goods, providing preservation and a black pigment, often referred to as "black ball".
Aerospace Technology: A refined form of bone char is applied to the titanium heat shield of the ESA-NASA Solar Orbiter satellite. Developed using a 'CoBlast' technique, this coating protects the spacecraft from the intense glare and heat of the sun.

In Popular Culture

Media and Literature

The production and nature of bone char have captured attention in various cultural contexts:

The Discovery Channel's television series Dirty Jobs featured the production of bone char in its Season 5 episode titled "Bone Black".
Thomas Pynchon's novel The Crying of Lot 49 references human bone char, derived from fallen soldiers, used in cigarette filters.
Jaroslav Hašek's satirical novel The Good Soldier Švejk includes a passage where soldiers contemplate the use of bone char ("spodium") from fallen comrades for sugar refineries, questioning the pricing based on rank.

References

Fawell, John (2006). Fluoride in drinking-water. WHO. ISBN 9241563192.
Discovery Channel. (n.d.). Dirty Jobs Episode Guide: Season 5 Episode "Bone Black". Archived from the original on November 13, 2010.
Medellin-Castillo, Nahum A., et al. (2007). Adsorption of Fluoride from Water Solution on Bone Char. Industrial & Engineering Chemistry Research, 46(26), 9205–9212. doi:10.1021/ie070023n
Horowitz, HS; Maier, FJ; Law, FE (1967). Partial defluoridation of a community water supply and dental fluorosis. Public Health Reports, 82(11), 965–72. doi:10.2307/4593174
Mjengera, H.; Mkongo, G. (2003). Appropriate deflouridation technology for use in flourotic areas in Tanzania. Physics and Chemistry of the Earth, Parts A/B/C, 28(20–27), 1097–1104. doi:10.1016/j.pce.2003.08.030
Ko, Danny C.K.; Porter, John F.; McKay, Gordon (2000). Optimised correlations for the fixed-bed adsorption of metal ions on bone char. Chemical Engineering Science, 55(23), 5819–5829. doi:10.1016/S0009-2509(00)00416-4
Chen, Yun-Nen; Chai, Li-Yuan; Shu, Yu-De (2008). Study of arsenic(V) adsorption on bone char from aqueous solution. Journal of Hazardous Materials, 160(1), 168–172. doi:10.1016/j.jhazmat.2008.02.120
Deydier, Eric; Guilet, Richard; Sharrock, Patrick (2003). Beneficial use of meat and bone meal combustion residue: "an efficient low cost material to remove lead from aqueous effluent". Journal of Hazardous Materials, 101(1), 55–64. doi:10.1016/S0304-3894(03)00137-7
Gongali Model. (n.d.). Water-Nanofilter. gongalimodel.com.
Asadi, Mosen (2006). Beet-Sugar Handbook. John Wiley & Sons. ISBN 9780471790983.
Chou, Chung Chi (Ed.). (2000). Handbook of sugar refining: a manual for the design and operation of sugar refining facilities. Wiley. ISBN 9780471183570.
Bomford D, Kirby J, Leighton J., Roy A. (1990). Art in the Making: Impressionism. National Gallery Publications.
ColourLex. (n.d.). Édouard Manet, 'Music in the Tuileries Gardens'. colourlex.com.
European Space Agency. (n.d.). Prehistoric cave pigment to shield ESA's Solar Orbiter. ESA.int.
Encyclopedia Americana. (1920). Blacks.

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References

Bomford D, Kirby J, Leighton, J., Roy A., Art in the Making: Impressionism. National Gallery Publications, London, 1990, pp. 112-119

Ãdouard Manet, 'Music in the Tuileries Gardens', ColourLex

A full list of references for this article are available at the Bone char Wikipedia page

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Bone Char: From Byproduct to Essential Material

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What is Bone Char? ℹ️

🦴 Definition and Composition

Production Process 🔥

⚙️ Charring Bones

🔄 Regeneration

Diverse Applications 🌍

💧 Water Purification

🍬 Sugar Refining

Black Pigment 🎨

🖌️ Artistic Applications

🖼️ Historical Masters

Specialized Uses 🚀

⚗️ Industrial & Technological Roles

In Popular Culture 📺

🎬 Media and Literature

References 📚

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Dive in with Flashcard Learning!

What is Bone Char?

Definition and Composition

Production Process

Charring Bones

Regeneration

Diverse Applications

Water Purification

Sugar Refining

Black Pigment

Artistic Applications

Historical Masters

Specialized Uses

Industrial & Technological Roles

In Popular Culture

Media and Literature

References

Teacher's Corner

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Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice