Pyroprocessing includes such terms as ore-roasting, calcination and sintering. Magnesium oxide is produced by the calcination of magnesium carbonate or magnesium hydroxide. Cerium(IV) oxide is formed by the calcination of cerium oxalate or cerium hydroxide. This aluminium hydroxide can be converted to aluminium oxide or alumina by calcination. The step of the high temperature calcination transforms it into alumina. In some cases, calcination of a metal results in oxidation of the metal. Magnesium oxide from calcination is used as an electrical insulator in fire-resistant cables. Usually a high temperature calcination step is required to eliminate organics remnants. After calcination the flint pebbles were milled to a fine particle size. Bone ash is a white material produced by the calcination of bones. It was a side product of calcination of copper ore. The precious metals are separated from the metal salt by calcination. The template could be further removed by calcination and left a pore structure behind. Bhasma in "Ayurveda" has been defined as a substance obtained by calcination. Alchemists distinguished two kinds of calcination, "actual" and "potential".