Effect of composition and sintering process on mechanical properties of glass ceramics from solid waste

Abstract

Sintered diopside glass ceramics were successfully prepared from mixtures of blast furnace slag, fly ash and mining tailing. Results showed that sample C2 with relatively low iron oxides and mass ratio of CaO/SiO₂ possessed the highest bending strength value among samples. A low content of iron oxide enhanced densification degree because pores were developed by reduction of ferric oxide into ferrous oxide. Moreover, a low CaO/SiO₂ mass ratio also greatly promoted the densification process by prolonging the sintering time and delaying the crystallisation. In addition, sample C1 developed by one-stage sintering had a worse mechanical performance than that obtained by two-stage sintering although they had the same crystals. For all samples, despite of different compositions and sintering processes, the main crystal phases are augite and diopside ferrian.

Keywords:

• Waste
• Sintering
• Diopside
• Glass ceramics
• Mechanical properties

Acknowledgements

This work has been financially supported by the National Natural Science Foundation of China (grant no. 51474028) and the Fundamental Research Funds for the Central Universities of China (grant no. FRF-TP-14-106A2).