Foamed Glass-ceramics Prepared By Using Titania-Bearing Blast Furnace Slag

With the gradual and further view of scientific development, developing circular economy and raising the availability of resources become a research hotpot in scientific research field recently. In this paper, foamed glass and foamed glass-ceramics were made by using titania-bearing blast furnace slags. Material was analyzed and characterized by modern test technique suchas XRD,SEM and FT-IR. The research not only has effect on resources, environment and ecoligy, but also finds utilization ways which can solve the utilization problem of titania-bearing blast furnace slag, improves technical content and adding value of Material.Foamed glass-ceramics which was prepared in the research is divided into two parts, that is, preparation of foamed glass and sitallization of foamed glass.In the first part, insulation materials of foamed glass were made by using titania-bearing blast furnace slag. Properties foamed glass were researched by the amount of additive and heat treatment. First, amount of additive and heat treatment process parameters were determined preliminarily by single factor experiment. Second the optimal amount of additive and optimum process parameters of heat treatment were obtained by the optimization of orthogonalization. The results show that the optimal content of blister calcium carbonate, stabilizing agent sodium phosphate and lacquer solvent borax were 1.5%,6% and 6% respectively. Heat treating regime foamed glass fired was the best when heating rate was 12℃/min,foaming temperature was 900℃and foaming time was 15min.Excellent performance of foamed glass is homogeneous aperture, low thermal coefficient of conduction and low bulk density low by preheating, sintering, foaming,foam stabilizing and annealing and soon. The additions of blister, foaming time, and foaming temperature have great influence on aperture size and homogeneity of foamed glass. The additions of foam stabilizer limit generation of bulk to some extent. Production cost of foamed glass was decreased by using solid waste as basic material. In addition, due to smaller particle size of micro silicon powder, process in grinding of part raw omitted, thus material production cost was decreased to some extent.In the second part, foamed glass-ceramics as wall materials were made by using optimization of foamed glass with second heating treating. Microcrystallization behavior was controlled by controlling heat treatment. First, heat treatment process was preliminary ascertained using the single factor method. The best heat treatment processing parameters were obtained by using optimization treatment of orthogonalizatio. The results show that effect of nucleation temperature on microcrystallization behavior is the most influential factor. The second factor is crystallization temperature, and the third factor is nucleation time and crystallization time. Long nucleation time caused uneven crystallization while short nucleation time caused inadequacy of nucleation. Crystallization time mainly effect on Grain Size. Nucleation time and crystallization time are not suitable for long time, or they can produce harmful effects on microcrystallization behavior. The optimal processing parameters of heat treatment are showed as follows:nucleation temperature is 740℃, nucleation time is 80 min, crystallization temperature is 890℃, and crystallization time is 100 min. It produced a lot of nanocrystalline in the internal of foamed glass after heat treatment. By using modern test technique suchas XRD,SEM and FT-IR, main crystal phase of foamed glass-ceramics is hedenbergite, and anorthite was the minor crystallization phase, such as spherical magnesium titanate minor one e.g. Compressive strength of foamed glass significantly increased and thermal conductivity increased slightly to meet the standard of thermal insulation material for building wall.In a word, foamed glass has preferable heat-insulating propeily and simple technology by using titania-bearing blast furnace slag. When utilization ratio of titania-bearing blast furnace slag is over 30%,excellent properties of products were obtained with the lower sintering temperature and lower cost without the adding of nucleating agent.