BOF slag glass-ceramics prepared in different atmospheres from parents glasses with various reduction degree

Abstract

As a special material with better mechanical properties than that of traditional glasses and ceramics, glass-ceramics which can be made from the bulk of industrial solid wastes from the perspective of protecting the environment, could be applied into the fields of construction and industry. For BOF slag, its residual iron element contained inside also can be recovered by a reduction process when it was melted to prepare parent-glass. This is an effective way to resolve the problems of how to utilize such metallurgical slags in large scale and recover the remaining metal component. In this study, the parents glass with different reduction degree were made from BOF slag, fly ash and varied amounts of coal powders, and glass-ceramics were obtained by respectively heating the various parents glass in air or in nitrogen. Results have shown that crystallization is occurred in all parents glasses heated in air, but is suppressed in samples heated in N2 except for the parent glass with TFe content of about 4.5%. Since the TFe content of parents glass is above 7.5%, the shape of crystalline exothermic peak is high and sharp, and the main crystal phases are diopside(-ferrian) and augit. A maximum bending strength of glass-ceramics heated in different atmospheres is obtained for samples with 8% coal powders mixed. The N2 atmosphere could promote the optimal bending strength and decrease its heating temperature.