Description
Calcined kaolin has been produced by the heat treatment of kaolin. Kaolin is alumina and silica and water, and by calcining kaolin we remove both surface and chemically combined water chemically combined, rendering the clay non-plastic.
Spreading a layer of a kaolin in a bisque bowl or platter, then heating the kiln to 1450 degrees 0C is a really good way to calcine kaolin, because that amount of heat does the job without allowing any of the clay to begin to sinter(the first stage of melting).
This means you can likely add the calcined clay directly to a clay or glaze without first having to grind it and screen it.
If it is a deep layer of kaolin, say six inches of clay, it is a good idea to hold the temperature at 1450 0C for one an hour.
