  bone char () is a porous, black, granular material produced by charring animal bones. its composition varies depending on how it's made, however it consists mainly of tricalcium phosphate (or hydroxylapatite) 57-80%, calcium carbonate 6-10% and activated carbon 7-10%. it is primarily used for filtration and decolourisation. ==production== bone char is primarily made from cow bones, however to prevent the spread of creutzfeldtâjakob disease the skull and spine are never used."dirty jobs: episode guide" the bones are heated in a sealed vessel at up to ; a low concentration of oxygen must be maintained while doing this as it affects the quality of the product, particularly its adsorption capacity. the heat drives off most of the organic material in the bones, which was historically collected as dippel's oil, with the rest being pyrolysed to activated carbon. heating bones in an oxygen-rich atmosphere gives bone ash, which is chemically quite different. used bone char can be regenerated by washing with hot water to remove impurities, followed by heating to  in a kiln with a controlled amount of air. == uses == ===water treatment=== the tricalcium phosphate in bone char can be used to remove fluoride 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 i
Bone_products Charcoal Organic_pigments