Preparation And Properties Of Foam Glass

Fly ash as a kind of substantial industy waste residue has many harmful effects on the environment. The preparation of energy saving and environment friendly foam glass with fly ash is a good way of disposing of fly ash efficiently, which has much economics value and environment benefit. The preparation of foam glass not only could dispose large mounts of fly ash preventing the harm of fly ash, but also the foam glass has much economic value. The foam glass has the characteristics of low density, good resistance of acid and good mechanical strengths meeting the demand of actual use. It could be applied in many areas including building industry, chemical industry, defence industry, etc and has good prospects of development.The aim of this paper is to prepare foam glass using fly ash as main constituents, increasing the fly ash content in foam glass as possible. The foam glass with70%fly ash is successfully prepared by powder sinterng method, with adding Na2B4O7as flux agent, sodium silicate and CaCO3as foaming agents, and Na2HPO4as foam stabilizer. The effects of the contents of fly ash, flux agents and foaming agents, sintering temperature and sintering time on preparation, structure and properties of foam glass are researched. The crystalline phases of samples are investigated by X-Ray diffraction(XRD). The distribution and morphology of pores are studied by environmental scanning electron microscopy(SEM). Besides the density, porosity, water absorption, chemical stability and mechanical strengths are analyzed.The results showed that for foam glass with sodium silicate as foaming agent the sample with fly ash content of70%, Na2B4O7content of20%, sodium silicate content of10%and5%of Na2HPO4sintered at800℃for1h has the best comprehensive properties, including the bulk density of0.542g/cm3, the porosity of68.85%, acid-resistance of99.86%and the flexural and compressive strengths of4.59MPa and3.44MPa. For samples with CaCO3as foaming agent the sample with fly ash content of60%, Na2B4O7content of26.7%, CaCO3content of13.3%and5%of Na2HPO4has the best comprehensive properties. The suitable sintering process condition includes the sintering temperature of775℃and sintering time of60min. The density of sample is0.488g/cm3, porosity of72.3%, acid resistance of99.86%and the flexural strength of1.64MPa.