Bone char

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.

Uses

Bone char is used to remove fluoride from water and to filter aquarium water. It has been used in the sugar refining industry for decolorizing (a process patented by Louis Constant in 1812 which is no longer commonly used).

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 artistic pigment formerly made by grinding charred ivory in oil. Today it is considered a synonym for bone char. Ivory is no longer much used because of the expense and endangered species issues.

External links

• History of bone black pigment