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Utilization of solid waste can be a preferable waste management solution. In this study, a type of self-foamed glass ceramic material was prepared using lead zinc mine tailings, red mud, and silica sand tailings through in-situ decomposition foaming. The effect of silica sand tailings content on the pore morphology, microstructure, and basic performances of the prepared specimen was analyzed. Meanwhile, the differences in the pore morphology and self-foaming behavior of the foamed glass ceramics were discussed. The obtained results indicated that the addition of silica sand tailings facilitated the formation of the glass phase in samples, and the composition, content, and viscosity of the glass phase could be changed by adjusting the content of silica sand tailings, resulting in a uniform distribution of the formed pores. Owing to their well-distributed pore structure, foamed glass ceramics exhibit excellent comprehensive properties (light weight and high strength), making them a potential non-load-bearing material. In this study, the comprehensive properties of the sample prepared with 40 wt% silica sand tailings were determined to be the best: exhibiting the lowest bulk density (0.63 g/cm3), highest porosity (72.6%), and an applicable mechanical strength (9.7 MPa). This study utilized three solid wastes through a reasonable combination based on their chemical composition, and proposed a novel technique for the preparation of self-foaming glass ceramics via the cooperative treatment of various wastes. [ABSTRACT FROM AUTHOR]

Abstract In this contribution, we presented a systematical investigation and prepared partially vitrified ceramic foam materials using polymetallic ore tailings (POTs) and other waste as raw materials. More importantly, six different POTs were evaluated in terms of bloating behavior, besides, the effects of sintering temperature and fly ash (FA) content on the structure, physical-mechanical properties and chemical stability were investigated. Our results revealed that among all selected POTs, the BT2 sample exhibits the best bloating ability due to the formation of appropriate liquid content, which is favorable for forming stable pore structure. Increased sintering temperature can accelerate the liquid phase formation and the increase in pore size, resulting in higher porosity and lower bulk density. And the pore structure varies with the addition of FA relatively uniform pore size distribution, high porosity and high compressive strength can be well achieved in this way. Besides, the partial vitrification of ceramic foam materials contributes to an increase in chemical stability while also reducing the risk of environmental pollutions. Here, an excellent performance combination (low bulk density at 0.63 g/cm3, high porosity at 73.6%, high compressive strength at 9.1 MPa) can be obtained in an optimized condition (15 wt% FA additions, sintering temperature at 1120 °C). The finding in this work, we believe, would provide guidance for rational utilization industrial wastes, which based on the synergistic complementarity effect between chemical components. Highlights • Partially vitrified ceramic material was prepared by rational composition design. • The bloating behavior and foaming mechanism of samples were analyzed. • A new glass ceramic foam with high porosity and high strength was prepared. [ABSTRACT FROM AUTHOR]

In the direction of dealing with solid hazards, preparing glass ceramic foam materials has become a practicable technique due to its environmental-friendly and economical characteristic. Here, we have successfully prepared glass ceramic foams with excellent combination of properties by utilizing lead-zinc mine tailings (LZMT), fly ash (FA) and red mud (RM) as the major component. The influence of sintering temperature on phase evolution, pore morphology, microstructure, physical properties and chemical stability of glass ceramic foam was investigated. The results reveal all above performances exhibit temperature-dependent character, with increasing sintering temperature, the performances enhance first and then deteriorate, the optimal porosity and compressive strength value for the prepared sample can be well achieved at the temperature of 980 °C. Liquid phase was formed during the heat treatment process and resulted in the variation of pore structure. According to SEM image and EDS spectra, the liquid phase may be the Ca-Al-Si-O system glass with less network modifier. The experiment results indicated that glass ceramic foams can be obtained by using solid wastes with different chemical compositions, better yet, it features with economic efficiency to solve the industrial solid wastes problems. [ABSTRACT FROM AUTHOR]

The here described investigation was essentially aimed at exploring the chemical stabilization and reutilization of iron-rich slag from copper metallurgy, by the manufacturing of glass-ceramic foams. The foams were developed according to a new method, recently reported for pure recycled soda-lime glass. Mixtures of soda-lime glass/slag powders (with slag content ranging from 10 to 30 wt%), suspended in alkaline aqueous solution, underwent progressive low temperature (80 °C) hardening, owing to the formation of hydrated calcium silicate compounds (C S H). Before complete setting, an extensive foaming could be achieved by vigorous mechanical stirring, with the help of a surfactant. After foaming, glass/slag mixtures could be sintered at 800–1000 °C; the mutual interaction caused an extensive crystallization, with precipitation of Ca Fe silicates and iron oxides (hematite and magnetite), promoting the mechanical properties (up to 4.4 MPa, with a porosity of about 80%). Leaching test confirmed the stabilization of pollutants, from the slag, in the final ceramics. Owing to the separation of iron oxides, particularly magnetite, the newly obtained foams exhibited a ferrimagnetic behavior, that could be exploited in electromagnetic shielding applications. [ABSTRACT FROM AUTHOR]

Glass ceramic foams were prepared by direct foaming method, using coal fly ash and waste glass as the main materials, borax and calcium carbonate as fluxing agent and foaming agent, respectively. The effects of coal fly ash additions, foaming time, heating rate and sintering temperature on the bulk density, porosity, mechanical properties and thermal conductivity were systematically investigated. The optimum parameters to prepare the glass ceramic foams were obtained at 800 °C for 45 min with 40 wt.% coal fly ash, 60 wt.% waste glass, 30 wt.% borax and 0.5 wt.% calcium carbonate. The specimens prepared this way have a low bulk density (as low as 0.46 g/cm 3 ), exhibiting considerable compressive strength (exceeding 5 MPa) and low thermal conductivity (about 0.36 (W/m K)). The energy saving effect using glass ceramic foams was evaluated by EnergyPlus software, indicating that the prepared glass ceramic foams show good energy conservation effect for building thermal insulation materials. The preparation of glass ceramic foams using solid wastes may provide a promising way to prepare thermal insulation material, considering the advantages in both economic and environmental aspects. [ABSTRACT FROM AUTHOR]