Experimental Study Of Foamed Glass Preparation By Hydrothermal Hot Pressing-calcination Method

As a new type of porous glass material,foamed glass was prepared using solid waste rich in glass phase as starting materials.Because of its unique combination of properties,foam glass is widely used in construction and many other fields such as insulation materials,sound insulation materials and so on.Foamed glass materials are currently manufactured via a combination of solid state sintering and decomposition of organic compounds or calcium carbonate during the foaming process with various additives,which is high energy consumption,long time and low compressive strength.Recently,new routes hydrothermal hot-pressing-calcination method for preparing porous glass have been implemented by Yoshikawa et al.involving only water as blowing agent with no other additives,which is economic and environmental protection.This process was applied to common glass but researches on the utilization of waste beer bottle glass and industrial solid waste such as fly ash were rare.Meanwhile,there are only a simple study on the whole process and the impact of the processing parameters on product performance are rarely involved.Our research was therefore motivated to study the feasibility of preparing foamed glass with beer bottle glass and coal fly ash as the raw materials.Additionally,the whole process of HHP-calcination and related principles were investigated.The main research contents and conclusions are as follows:(1)Study on foam glass prepared with waste beer bottle glass by hydrothermal hot pressing-calcination.Through single factor experiment and orthogonal experiment of different experimental conditions on the morphology and properties of foam glass,the optimal experimental conditions were determined and the basic principles of the process under optimum conditions were also investigated.The(HHP)-treated glass compacts with water content of 20% prepared at 200? for 25 min at a constant loading pressure of 8.5 MPa exhibited a marked expansion after heat treatment conducted at 800? for 1 h with heating rate of 5?/min in an air atmosphere.These foamed glasses exhibited the lowest apparent densities that varied from 0.24 to 0.25g/cm3 and a high compressive strength about 1.5~1.6MPa.(2)Study on foamed glass prepared with waste glass and fly ash by hydrothermal hot pressing-calcination.The influence of fly ash content and two main parameters with the heating rate and sintering temperature on foamed glass properties(density,compressive strength,porosity)were analyzed,the process principle was also discussed.The(HHP)-treated compacts with heating rate of 5?/min showed the best performance after heat treatment conducted at 800? in an air atmosphere.These foamed glass exhibited a low apparent densities of 0.27g/cm3,a high compressive strength about 1.75 MPa and and the excellent porosity about 75%.The results investigated by XRD and FT-IR showed that the formation of Sodium Calcium Silicate(Na6Ca3Si6O18),Quartz(SiO2),and the gel product were present in the foamed glass which contributed to the excellent compressive strength.(3)Study on thermal conductivity model of foamed glass.The thermal conductivity is affected by porosity,stomatal size,stomatal shape,and pore distribution.The relationship between the thermal conductivity of foamed glass and the related factors was studied.Finally,the thermal conductivity model of foam glass was established,which provided reference for the preparation and research of foamed glass materials.