May be used as a source of alumina in glazes where it will have the effect of raising the firing temperature and increasing viscosity. Overloading with alumina has a matting effect. The tendency of glazes with high clay content to crawl may be reduced by the introduction of alumina as part replacement of clay. Alumina is also a useful addition to underglaze colours if there is a tendency to crawl.
The high melting point of 2050°C makes alumina useful as a bat wash.
The 100 mesh grade is recommended for use as a bat wash and in refractory bodies. The 300 mesh should be used in glazes and may also be used in bodies.