Preparation, Pore Structure And Physical Properties Of Porous Sintered Glass-ceramics From Waste Glass

Porous glass-ceramics is a kind of microcrystalline materials, which contain closed or connected pore through the heat treatment of inorganic amorphous materials. The physical properties depend on the pore size, the ratio of crystalline to amorphous phase and structure. They exhibit superior properties such as low density, large specific surface area, low thermal conductivity, high strength and outstanding damping property.The preparation of porous glass-ceramics from waste glass not only lead the large-scale utilization of waste glass, but also significantly reduce the production cost of porous glass-ceramics and simplify the production process, which has significan economic and environmental benefits.In this thesis, porous glass-ceramics with low density, contronable pore size and high strength were prepared by the low temperature sintering-high temperature foaming and favoring the foaming agents and sintering additives. The influences of the sintering parameters and foaming agents on the pore structure, phase composition, apparent density, compressive strength and thermal properties of porous glass-ceramics were investigated in detail. In addition, porous glass-ceramics compound panel was prepared.Researches on the foaming agents show that in the case of calcium carbonate as foaming agent, with the increase of calcium carbonate, the apparent density and compressive strength of porous glass-ceramics decrease first then increases, a change in porosity has the opposite trend, porous glass-ceramics are single wollastonite phase structure and the crystallinity increases. In the case of calcium carbonate/silicon carbide combined powder are used as compound foaming agents, calcium carbonate reduces oxidation temperature and accelerate oxidation rate of silicon carbide. Silicon carbide can improve the porosity of porous glass-ceramics, decrease the apparent density and promote the volume percent of wollastonite. Decreasing the size of SiC particles can reduce the apparent density. However, the nan-SiC can increase the apparent density,reduce the porosity and the pore size. The thermal conductivity of porous glass-ceramics decreases with the increase of CaCO3 in compound foaming agent. The scope of thermal conductivity is 0.096 W/m·K to 0.139 W/m·K. The compressive strength is proportional to the apparent density with the increase of SiC. The compressive strength is 0.7 MPa to 4.7 MPa.Researchs on the sintering parameters show that with CaCO3 as foaming agent theapparent density of porous glass-ceramics decreases and the porosity increases with the increase of sintering temperature and time. Apparent density decreases, the average pore diameter and porosity increase of porous glass-ceramics with the foaming temperature and time increases. The compressive strength is linearly related to the apparent density with the changes of foaming time; the scope of compressive strength is 0.35 MPa to4.98 MPa. The key of the porous glass-ceramics compound panel by one-off sinter lies in regulating the ingredients of glaze layer to make its sintering and recrystallization temperature in the temperature range of the low temperature melting-high temperature foaming.Researchs on the foming mechanism show the waste glass appear dense sintering in 800 °C, bubble nucleates and grows between 800 °C and 900 °C which is in accordance with this article process design. This low temperature sintering-high temperature foaming process is not only suitable for the production of porous glass-ceramics from waste glass but also suitable for the recycle of other slags.