Preparation, characterization and discussion of glass ceramic foam material: Analysis of glass phase, fractal dimension and self-foaming mechanism

Resource utilization of waste has always been the focus attention due to the increased environmental problems. In this work, glass ceramic foam was prepared using coal gangue, fly ash and silica sand as raw materials without addition agent. The pore morphology, microstructure and some physical properties of the samples with different silica sand contents were investigated. In addition, the fractal dimension was introduced to quantitatively describe the variation in pore morphology. The results illustrated that the addition of silica sand in the samples is beneficial to form a unique close-pore construction which endows the prepared material with good performance for using as a lightweight wall material in the construction field. Discussion indicated that the introduction of silica sand was found to promote the formation of glass phase, which possibly was the Si–Al–O glass system. The variation of fractal dimension inferred that the co-existence of large and small pores formed in samples with high content silica sand may be originated from the interaction of the two glass phases. The analysis of self-foaming mechanism revealed that only the gases released after glass phase formation were effective to build pore structure. This study provides a highly efficient and clean utilization route for recycling solid waste by preparing lightweight glass ceramic foam.