As crucial as understanding the refractory material itself is how it is formed. The modern foundryman needs to select the right refractory - both material and shape - for the right job to ensure an optimal process.
Most powdered glass is sourced from used glass and then ground down. This makes it a more cost-effective resource. There are however milled glass products which are sourced from new glass or reject glass containers for specialised applications.
Porcelain, whose origin can be traced back to China, can be described as a ceramic material formed by heating various materials together. These materials, including Kaolin which is heated in a kiln to high range temperatures between 1200 and 1400ºC.