Preparation and properties of diopside-based CaO-MgO-Al2O3-SiO2 glass-ceramic using biomass fly ash.

• Glass-ceramic was prepared from biomass fly ash by using a powder sintering method. • The crystallization behavior was dominated by surface crystallization. • Fine diopside grains (0.2–1 μm) were observed in the glass-ceramic. • The highest bending strength of glass-ceramic reached 212 MPa when sintered at 920 ℃ for 1 h. In this work, diopside-based CaO-MgO-Al 2 O 3 -SiO 2 glass-ceramic was prepared from biomass fly ash (BFA) by powder sintering method. The parent glass powder was prepared by melting 76%BFA-9%CaO-6%Al 2 O 3 –9%MgO (in mass) at 1450 ℃ followed by water quenching and ball milling. The glass powder was sintered at 830, 850 and 920 ℃ for 1–16 h to obtain the glass-ceramic. It was found that the crystallization behavior was controlled by surface crystallization, and diopside was the major crystalline phase. The mechanical properties of glass-ceramic were improved by prolonging the sintering time from 4 to 16 h at 830 ℃. However, the sizes of pores in glass-ceramic increased as increasing the sintering time at 850 ℃, which deteriorated the properties of the glass-ceramic. The glass-ceramic sintered at 920 ℃ for 1 h has a high crystallinity and fine grains, and showed the highest bending strength of 212 MPa. [ABSTRACT FROM AUTHOR]