Clay impregnation with metallic ions - to produce low melting binders in the clay

摘要

In a method of treating clay or any clay based ceramic compsn. metallic ions whic form oxides at the firing temp. of the clay are distributed throughout the clay by mixing the dry clay with solid crystals of a cpd. esp. a salt of the metal, then contacting the mixt. with a liq. phase which may dissolve the ions at least partly and thoroughly mixing, or which may be the crystals in the molten state, to diffuse the ions into the clay. Clay so treated is calcined, moulded and fixed. Preferred ions are alkali(ne earth) and transition metal ions. The ions are chosen so that they form low wetting silicates which produce a low wetting ceramic bond with the clay particles, hence the clay mouldings can be fixed at a comparatively low temp. and have the same or better mechanical properties than those fixed at normal firing temps.