HIGH‐TEMPERATURE PREPARATION AND THE OPTICAL PROPERTIES OF SODIUM ALUMINATE*

ABSTRACT Crystalline sodium aluminate was prepared by heating monomolecular and other mixtures of Na 2 CO 3 and Al 2 O 3 3H 2 O for varying periods to temperatures up to 1700°C. The constituents produced were identified by petrographic‐microscopic methods, and new optical data on sodium aluminate was obtained. Sodium aluminate was found to exist from temperatures below 1100 to above 1700°C, its melting point being above 1700°C. Small amounts of iron oxide aid the formation of sodium aluminate, especially at the lower temperatures.