PHYSICAL‐CHEMICAL REACTIONS IN FIRING WHITEWARE*

A bstract The present knowledge concerning reactions which take place during the heat treatment of clay, feldspar, and silica is discussed as well as the relations of these three to the ternary system K 2 O‐Al 2 O 3 ‐SiO 2 . The manner of growth of mullite crystals in feldspar has been studied. Additional experimental data as evidenced by the thermal‐expansion curves of day‐feldspar and clay‐silica mixtures previously fired at high temperatures are presented.