Preparation of Glass Ceramics by Reactive Crystallization with Waste Glass and Spinel

Abstract

Magnesium silicate glass ceramics were prepared by reactive crystallization with mixed powder of waste glass and spinel. The effects of spinel content and sintering temperature and holding time on the crystal phase and morphology of magnesium silicate glass ceramics were investigated. The reactive crystallizing behavior between waste glass powder and spinel was studied using energy dispersive spectrdmeter during the holding process. The result show that the optimum preparation conditions were as follows: the addition of 30 wt% spinel used as crystallization promoting agent, sintering temperature of 900 oC and holding time of 2 h. The magnesium silicate and alumina crystals were formed via an interaction between glass powder and spinel instead of direct precipitation from the parent glass. With increasing of the holding time, the Al and Mg element contents of the glass were increased, on the contrary, that Si element content was decreased in the glass phase. It shows that the Si element is diffused from glass into spinel phase and subsequently magnesium silicate crystals are formed.