Burning temperature of a Persian-period pottery kiln at Tel Michal, Israel, estimated from the composition of slag-like material formed in its wall

The maximum burning temperature of a Persian-period pottery kiln excavated at Tel Michal (Makmish), on the Mediterranean coast north of Tel Aviv, is estimated from the composition of slag-like material which was formed is its wall, using X-ray diffraction and Ir spectroscopy methods. The kiln was built with two chambers: a lower one for the burning, and an upper one where the vessels were fired. The slag-like material, which contains mainly quartz and high temperature cristobalite in porous glassy material, was formed in the wall of the lower chamber by partial melting of its noncalcareous sandy clay matter. Thermal simulation indicates that its composition is compatible with a heating temperature between 1100° and 120°C, which represents the maximum burning temperature in the lower chamber of the kiln. An elevated burning temperature was needed to obtain the firing temperatures of the pottery in its upper chamber.