Bone charcoal, also known as bone char, is a black, granular material produced by charring animal bones. This process removes organic matter, leaving behind a substance primarily composed of calcium phosphate and calcium carbonate, along with a small amount of activated carbon.
Here's a breakdown of bone charcoal:
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Composition:
- Calcium Phosphate (around 70-80%): This is the main component, providing structural integrity.
- Calcium Carbonate (around 10%): This contributes to the overall structure and chemical properties.
- Activated Carbon (around 8-10%): This provides some adsorptive capabilities.
- Trace Minerals: These vary depending on the animal source and processing methods.
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Production: Bone char is made by heating animal bones in a closed container at high temperatures (300-800°C) in the absence of oxygen. This process, called pyrolysis, removes all organic matter (OM).
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Uses:
- Defluoridation: Bone char is used to remove fluoride from water. The fluoride ions replace the carbonate in the bone char's structure.
- Sugar Refining: Bone char was historically used to decolorize and purify raw sugar. While its use has declined in some regions due to concerns about animal products, it remains a viable option.
- Chromatography: Bone char is used as a chromatography medium.
- Pigment: Bone char can be used as a black pigment in art and other applications.
- Fertilizer: It can be used as a slow-release phosphorus fertilizer.
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Advantages:
- Effective at removing certain impurities.
- Relatively inexpensive.
- Can be produced from a waste product (animal bones).
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Disadvantages:
- Animal origin can be a concern for some consumers.
- Can leach phosphate into water, potentially contributing to eutrophication if not properly managed.
- Lower surface area compared to activated carbon from other sources, limiting its adsorptive capacity in some applications.
In summary, bone charcoal is a charred animal bone product primarily composed of calcium phosphate and calcium carbonate, used in various applications such as defluoridation, sugar refining, and as a pigment.
