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Bone char
From Wikipedia, the free encyclopedia
Bone char, also known as bone black or animal charcoal, is a granular black material produced by calcinating animal bones: the bones are heated to high temperatures in the absence of air to drive off volatile substances. It consists mainly of calcium phosphate and a small amount of carbon. Bone char has a very high surface area and a high absorptive capacity for lead, mercury, and arsenic.
Bone char is used to remove fluoride from water and to filter aquarium water.
It is often used in the sugar refining industry for decolorizing (a process patented by Louis Constant in 1812). This is a concern for vegans and vegetarians, since about a quarter of the sugar in the US is processed using bone char as a filter (about half of all sugar from sugar cane is processed with bone char, the rest with activated carbon). As bone char does not get into the sugar, sugar processed this way is considered parve/Kosher.
It is used to refine crude oil in the production of Vaseline.
Bone char is also used as a black pigment. It is sometimes used for artistic painting because it is the deepest available black, though charcoal black is often satisfactory and is more often used. Ivory black is an artists' pigment formerly made by grinding charred ivory in oil. Today it is considered a synonym for bone char. 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.