Effect of CaF2 on viscosity, structure and properties of CaO-Al2O3-MgO-SiO2 slag glass ceramics

• Published in: Journal of non-crystalline solids Vol. 500; pp. 310 - 316
• Main Authors: Deng, Leibo, Zhang, Xuefeng, Zhang, Mingxing, Jia, Xiaolin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2018
• Subjects: Bayan Obo tailings; Fly ash; Glass ceramics; Stainless-steel slag; Viscosity; Viscosity; Stainless-steel slag; Fly ash; Bayan Obo tailings; Glass ceramics
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2018.08.018

Bayan Obo tailings (BOTs), fly ash (FAS), and stainless-steel slag (SSS) are industrial wastes that require reasonable, clean, and effective utilization for environment protection. The paper focuses on the structure and properties of glass-ceramics that were prepared by melting BOT, FAS, and SSS raw materials. The effect of CaF2 on the viscosity, structure, and performance of CaO-Al2O3-MgO-SiO2 (CAMS) slag glass-ceramics is determined by viscometer, differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and physicochemical properties measurements. The results show that moderate amounts of CaF2 facilitates depolymerization of the silicate networks, which leads to a decrease in the melting temperature, viscosity and viscous activation energy of glass. However, the content of more than 3% CaF2 results in a dramatic decreases in the chemical stability of the glass-ceramics because of the transformations of the main crystalline phase from diopside to anorthite, which is accompanied by fluorite precipitation. •Glass and glass-ceramics has been obtained by Bayan Obo tailings, fly ash and stainless-steel slag.•Moderate amounts of CaF2 contributed to reduce the degree of polymerization of the silicate networks.•Excess CaF2 content resulted in a dramatic decrease of the chemical stability of the glass ceramics.