Bone ash

Bone ash is a white material produced by the calcination of bones. It is primarily composed of calcium phosphate. It is used in the production of fine china and to make some glazes in pottery.

History

The use of bone ash in ceramics has been traced back to the 18th century. English potter Josiah Spode is credited with the discovery of the formula for fine bone china. He found that by adding bone ash to the mix, he could create a white, translucent, and very durable product.

Production

The production of bone ash involves the burning of animal bones. The bones are first cleaned and degreased, then heated to about 1000 degrees Celsius. This process, known as calcination, reduces the bones to a fine, white ash. The ash is then ground into a fine powder.

Uses

Bone ash is primarily used in the production of bone china. The ash gives the china its characteristic translucency and whiteness. It is also used in some glazes for pottery, and in the production of certain types of glass.

See also

• Bone china
• Calcium phosphate
• Josiah Spode