An important source of calcium phosphate made from calcined cattle bones. Real bone ash is chemically inert and free of organic matters. Calcium acts as a flux, and phosphorous as a glass former.
Melting point 1670c
|20 mesh||40 mesh||80 mesh||100 mesh||200 mesh||325 mesh|
|Percentage retained on screen||2.3%||3.5%||22.6%||42.8%||24.0%||3.4%|
Commonly used in commercial porcelains known as bone china, where it lowers the maturing temperature and adds translucency. Used in iron red glazes where it brightens the colour, and is used to give texture in low fire glazes.