Investigation On Floating Bead Thermal Insulation Material Bonded By Aluminum Phosphate

Environmental protection and energy-saving problems are two major issues during economic development in modern society. The thermal insulation and energy saving materials, which possesses the characteristics of the light mass and high strength, have been becoming the focus in the area of thermal insulating and energy-saving technologies. The status of study on thermal insulation materials and the development orientation about their products were discussed based on a large number of literatures come from both at home and abroad.A method of making a new type of light mass and high strength thermal insulation material was investigated. The material was comprised of the floating bead that was extracted from fly ash of power plants, used as thermal insulation aggregate, the aluminum phosphate as binder, the alumina as curing agent. The process parameters for making it and properties of the material were also investigated. The influences of the amount of binder and curing agent, sintering temperature and sintering time on compressive strength, bulk density, thermal shock resistance, and adsorption of water of the material were studied by orthogonal experiment.Experimental results showed that the material which is compose of floating bead, 60% of aluminum phosphate based upon the weight of the floating bead, 20% of curing agent based upon the weight of the aluminum phosphate, made at the 1200℃of sintering temperature and in 1h of sintering time would have good the properties of technologies .The compressive strength could reach 4.346MPa, the bulk density 0.517g/cm~3, the thermal shock 11 times and the ratio of water adsorption 41.7%. It was come to the conclusion that the properties of the material were obviously better than the other types of floating bead thermal insulation materials.It was proved by a lots of experiments that the compressive strength of the material went up with binder. The increasing rate of strength of the material becomes slow, when the content of binder exceeded 60% of floating bead. The highest compressive strength of the material was obtained when 20% of curing agent was added. The strength and high temperature performance of the material were greatly improved with increasing in sintering temperature and amount of the mullite. But the strength was descend when the sintering temperature was higher than 1200℃, in which the floating bead was burnt out and the structure of them was destroyed.The micro-structure and micro-surface of the thermal insulation material were observed by EPMA and the changes of its phases were analyzed by XRD. The binding mechanism, strength mechanism and thermal insulation mechanism about this material were also investigated primarily according to literatures and experiments...