Study On Preparation Of Foaming Material With Tuff

Foaming materials generally refer to a new kind of lightweight functional materials with a large number of evenly distributed pores in the matrix. This kind of materials has high porosity which can meet the designed requirement for practical applications. Compared to compact materials, the foaming materials have adjustable size and evenly distributed porous structure, which result in the features such as high porosity, light weight, heat insulation, sound insulation, large specific surface area, higher absorbed impact energy rat, ect.In this thesis, we investigated the preparation of forming materials via calcinations at certain temperature, using tuff, perlite tailings and waste glass were used as primary starting materials, and with addition of foaming agent, foam stabilizer and fluxing agent. The research works include the following topics:(1) We investigated the properties of basic materials and auxiliary additives. The mechanism of SiC as foaming agent was explored.(2) The effects of preparation conditions on the properties of products. Such as the content of foaming agent content, foaming temperature, tuff content, accelerator (foam stabilizer and fluxing agent) content, heating rate, the forming pressure of green body and holding time, we investigated by single-factor test method. The parameters of these factors have been optimized preliminary, which was0.5%～1.0% of foaming agent content,950℃～990℃of foaming temperature,45%～55% of tuff content,2.5% of foam stabilizer content,2.5% of fluxing agent content,20℃/min of heating rate,4MPa of forming pressure of green body and30min of holding time, respectively.(3) Based on the results of single-factor test, orthogonal experiment was carried out to optimize the best combination of parameters. The interaction effects of foaming agent content, foaming temperature and tuff content was explored. The results of variance analysis and significance test showed that the properties of foaming materials are primarily determined by foaming agent content and the foaming temperature.(4) Characterizations have been performed including mechanical property (compressive strength) and physical properties including apparent density, water absorption and thermal conductivity, and microstructure of the foaming materials. (5) Large-size tests of foaming materials have been made.Favorable performance of the foaming materials can be achieved through the optimized preparation conditions, including the foaming agent content of0.75%, foaming temperature of975℃, tuff content of50%, foam stabilizer content of2.5%, fluxing agent content of2.5%, heating rate of20℃/min, the forming pressure of green body of4MPa and holding time of30min, respectively. For this product, the apparent density was0.55g/cm3, the compressive strength was8.39MPa, the thermal conductivity was0.094W/m·K and the water absorption was0.54%. The results of large-size tests showed that products with steady performance and high reproducibility have been made.The utilization of tuff, perlite tailings and waste glass in the preparation of foaming material, not only opens up a new approach of tuff utilizing, but also achieve the comprehensive utilization of perlite tailings and waste glass. In addition, the products are the advanced energy saving and thermal insulation materials. It has positive significance in the comprehensive utilization of resources, environmental protection and economic development.