expanded clay

expanded clay

[ik′spand·əd ′klā] (materials) A material made from common brick clays by grinding, screening, and then feeding through a gas burner at about 2700°F (1482°C), thus changing the ferric oxide to ferrous oxide and causing the formation of bubbles.

expanded clay

Clay which has been heated to a semiplastic condition and expanded to many times its original volume by the formation of internal gas; used as a lightweight aggregate.