What is refractory clay?
Refractory clay is that which will withstand high heat. Not all clays will do this – porcelain turns to a glassy substance and low fire clays may swell and fall apart at higher temps. Refractory clay is used to do things like line pouring spouts or entire furnaces for molten iron and steel. With a proper selection of materials it can be used to fire bricks and will hold molten glass and not contaminate it. The color is not specified – fire brick is yellow or nearly white. Some of the clay is man-made while fire brick clay sources tend to be focused – Missouri supplies a lot.
