Preparation of porous glass-ceramics from coal fly ash and asbestos tailings by high-temperature pore-forming

Abstract

This paper presented a new method of preparing porous glass-ceramics by high-temperature pore-forming using coal fly ash and asbestos tailings as raw materials. The effects of the content of asbestos tailings and sintering temperature on the phase composition, microstructure and properties of the porous glass-ceramics had been systematically discussed, furthermore, the pore formation mechanism was also expounded. Compared with T0, porous glass-ceramics from T1, T2 and T3 experienced more violent self-expansion during the sintering process due to the addition of asbestos tailings. The porosity of porous glass-ceramics from T3 was 51%, the bulk density was 1.42 g/cm³, the flexure strength was 19 MPa, the main crystal phase was indialite, along with several secondary phases such as anorthite, enstatite, and forsterite. Due to the high strength, the material was expected to be used as a porous construction material with load-bearing function. This work provided a convenient and promising method for the utilization of coal fly ash and asbestos tailings to prepare porous glass-ceramics without adding foaming agents.

Keywords: Asbestos tailings; Coal fly ash; Porous glass-ceramics; Self-expansion.