<P> Used bone char can be regenerated by washing with hot water to remove impurities, followed by heating to 500 ° C (932 ° F) in a kiln with a controlled amount of air . </P> <P> 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 in the United States from the 1940s through to the 1960s . As it can be generated cheaply and locally it is still used in certain developing countries, such as Tanzania . Bone chars usually have lower surface areas than activated carbons, but present high adsorptive capacities for certain metals, particularly those from group 12 (copper, zinc, and cadmium). Other highly toxic metal ions, such as those of arsenic and lead may also be removed . </P> <P> Historically, bone char was often used in sugar refining as a decolorising and deashing agent, particularly in cane sugar as this contains more colored impurities . It has largely fallen out of use, particularly in the US and Europe, mainly for economic reasons but also due to the concerns of vegetarians and vegans, as well as various religious groups . </P> <P> Bone char possesses a low decoloration capacity and must be used in large quantities, however, it is also able to remove various inorganic impurities; most importantly sulfates and the ions of magnesium and calcium . The removal of these is beneficial, as it reduces the level of scaling later in the refining process, when the sugar solution is concentrated . Modern alternatives to bone char include activated carbon and ion - exchange resins . </P>

Use of bones in sugar refining in india
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