where does the bone ash for bone china come from
Bone china The production of bone china is similar to porcelain, except that more care is needed because of its lower plasticity and a narrower vitrification range. The traditional formulation for bone china is about 25% kaolin, 25% Cornish stone and 50% bone ash.[11] The bone ash that is used in bone china is made from cattle bones that have a lower iron content. These bones are crushed before being degelatinised and then calcined at up to 1250 °C to produce bone ash.[12] The ash is milled to a fine particle size.[13] The kaolin component of the body is needed to give the unfired body plasticity which allows articles to be shaped.[2] This mixture is then fired at around 1200 °C.[13] The raw materials for bone china are comparatively expensive, and the production is labour-intensive, which is why bone china maintains a luxury status and high pricing.[5]
Bone Bone tissue (osseous tissue) is a hard tissue, a type of dense connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralization of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mineralised matrix of bone tissue has an organic component of mainly collagen called ossein and an inorganic component of bone mineral made up of various salts. Bone tissue is a mineralized tissue of two types, cortical bone and cancellous bone. Other types of tissue found in bones include bone marrow, endosteum, periosteum, nerves, blood vessels and cartilage.