Preparation And Study On Slag Glass-ceramics

Along with the booming of metallurgy industry in our country, the amount of blast slag is increasing rapidly, which caused a serious imbalance between man and nature. The blast slag can be used to produce cement, but it is not the most effective way to solve the environment problems caused by this kind of solid waste.The blast slag is mostly composed of silicate and aluminum silicate, which are closed to the compositions of glass-ceramics materials. Furthermore, Fe2O3(FeO) in the blast slag is an effective nucleation agent in the glass-ceramics system. So it is a promising method to prepare glass-ceramics materials by using the blast slag.In this paper, a kind of blast slag produced by a certain steel corporation in Hunan province was used as raw materials together with mineral materials such as quartz, feldspar, fluorite, dolomite, calcite and other chemical reagents such as sodium hexametaphosphate and Cr2O3, to prepare glass-ceramics by melting method. The major crystalline of the glass-ceramics was augite(CaSiO3)and diopside(Ca·Mg(SiO3)2). DSC was used to ascertain the heat-treatment temperature system, and XRD together with SEM to characterize the phase composition and microstructure of the glass-ceramics, and some other physical properties of this material were also examined. The effect of nucleation agent, heat-treatment parameters and the content of the blast slag in raw material were discussed.Along with the increase of the content of the blast slag, the content of the crystal phase in the glass-ceramics was decreased, which caused the decline of its mechanical properties. When the content of the blast slag was 20~45wt%, the glass melted equably. A separated phase appeared in the slag glass after molding which turned the color of the glass into white and is propitious to the nucleating and crystallization of the slag glass. When the content of the blast slag was more than 50wt%, there would be scruff on the surface of the melted glass, and there would be no phase separation in the molding glass which made the nucleating and crystallization more difficult. This problem can be solved by optimizing the nucleation agent and heat-treatment parameters.In order to promote the properties of blast slag glass-ceramics, proper nucleation agent should be correctly selected. In this paper they are used as complex nucleation agent to prepare optimized glass-ceramics.