ALUMINE HYDRATEE

HYDRATED ALUMINA

Ref : ALHY

Hydrated alumina

 

Molar formula

Al2O3              

Molar mass = 102

Main sources of aluminium in glazes.

It is a neutral oxide that increases the viscosity of the glaze and modifies its melting temperature.

Feldspars also contribute aluminum to the glaze, but in lesser proportion.

Hydrated alumina: Al2O3: 65.2%.

Becomes identical to calcined alumina by losing its water of hydration (calcination).

Used primarily to promote 'stiffness' of glazes (6-10% of silica content).

Increasing firing temperature and resistance to chemical attack.

In larger quantities (15% of glaze) however, produces opaque and matt effects.

Also used on kiln shelves as protection against glaze sticking..