The first development of what would come to be known as bone china was once made by Thomas Frye at his Bow porcelain factory close to East London in 1748. His factory was once located very close to the cattle markets and slaughterhouses of Essex, and hence convenient access to animal bones.
Frye used up to 45% bone ash in his method to create what he referred to as “fine porcelain”. Later, Josiah Spode in Stoke-on-Trent further developed the idea between 1789 and 1793, introducing his “Stoke China” in 1796. He died unexpectedly 12 months later, and his son Josiah II shortly rechristened the ware “Bone china”.
Among his developments was to abandon Frye’s system of calcining the bone collectively with some of the different uncooked body materials, alternatively calcining just the bone.
Bone china swiftly proved to be rather popular, leading to its manufacturing through other English pottery manufacturers. Both Spode’s method and his business had been successful: his system of 6 components bone ash, 4 components china stone and 3.5 components china clay, stays the groundwork for all bone china, and it was solely in 2009 that his company, Spode, went into receivership before, in the end, being offered by means of skill of Portmeirion.
The production of bone china is comparable to porcelain, except that greater care is needed due to the fact of its lower plasticity and a narrower vitrification range. The ordinary formulation for bone china is about 25% kaolin, 25% Cornish stone and 50% bone ash.
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.
The ash is milled to a fine particle size. The kaolin element of the body is needed to give the unfired body plasticity which permits articles to be shaped. This mixture is then fired at around 1200 °C. The raw materials for bone china are comparatively expensive, and the production is labour-intensive, which is why bone china keeps a luxurious repute and excessive pricing.