Bone ash

Bone ash is a white material made when bones are heated at very high temperatures, a process called calcination. It is formed mainly from calcium oxide, phosphorus pentoxide, and a small amount of water. The exact mix can change depending on the type of bones used, but it usually follows the formula Ca₅(OH)(PO₄)₃.

This material is very dense, about 3.10 grams for every milliliter, and it can melt at extremely high temperatures around 1670 °C, which is 3038 °F. Even when heated, most bones keep their shape and structure, making bone ash both interesting and useful in many areas.

History

Antiquity

Burnt bones have been found at many ancient Greek places of worship from the Late Bronze Age to the Hellenistic period. These burnt bones are often white or bluish, which helps scientists recognize them as remains from sacrifices. At a place of worship for Artemis in Eretria, a round altar made of stones filled with soil was discovered from the 8th century BC. Animal bones were burned on top of this altar, then swept away along with other items like pottery. Some believe these altars were used for special rituals, but this idea is debated. A writer named Xenocrates of Aphrodisias mentioned that burnt bones were sometimes used in medicine, though laws in the Roman Empire forbade certain practices.

Uses

Bone ash is an important material used to make bone china, a special kind of pottery. It is mixed with other materials and heated to create strong, beautiful dishes. Before it is used, bones are cleaned, heated to remove natural parts, and ground into a fine powder.

Bone ash can also help plants grow. It can be used directly as a natural plant food or changed with a special liquid to make it even better for plants. In factories, bone ash is used to protect tools and fill small cracks when working with hot metals. It stays strong even at very high temperatures and is easy to use. It is also used to help separate valuable metals like gold and silver from other materials.

Analysis of bone ash

The article looks at bone ash using a special method called X-ray fluorescence. It shows the results for three samples of bone ash used in ceramics.

In culture

Bone ash was used a long time ago in special ways. In old writings from the Book of Amos, it talks about burning bones to make a substance called lime. People also used bone ash in old recipes for white paint and beauty products. It helped in a process called cupellation to separate silver from lead.