Use of spent pot linings from primary aluminium production as raw materials for the production of opal glasses

摘要

The use of the carbonaceous fraction of spent pot linings (SPL) from primary aluminium electrolytic cells as a raw material for the production of opal glasses is evaluated. The SPL was heat treated and mixed with limestone to eliminate carbon and to minimise fluorine volatilisation. This material was then mixed with other glass formers, melted, and quenched to produce a glass. The cyanide which forms part of the SPL was thermally decomposed and some of the fluorine is incorporated into the glass matrix. The final material contains small crystals of fluorspar, which are responsible for light scattering and the opacity of the material, dispersed in an amorphous phase. The crystalline phase was identified by x-ray diffraction and its morphology was observed by scanning electron microscopy.