Influence of particle size on sinterability, crystallisation kinetics and flexural strength of wollastonite glass-ceramics from waste glass and fly ash

Wollastonite glass-ceramics were prepared from waste glass and fly ash by using the primary powder sintering. The sinterability, crystallisation kinetics and mechanical property of glass-ceramics have been investigated systematically with respect to the influence of particle size of raw materials. As compared to coarse powders (44 μm), fine powders (6 μm) exhibited fast sintering rate, high densification and high degree of crystallinity. The sintering kinetic analysis showed that the sintering activation energies were 229 and 157 kJ mol−1 for coarse and fine powders respectively, in well agreement with those from the linear shrinkage analysis. The activation energies of crystallisation were 245 and 317 kJ mol−1 for coarse and fine powders, respectively, suggesting high energy barrier of crystallisation for fine powders. The flexural strengths of wollastonite glass-ceramics from fine powders were increased by more than 50% as compared to that from coarse powders, resulting from the improved densification, high degree of crystallinity and crystal shape anisotropy as well as crystal refinement.