Experimental Research On The Preparation Of Thermal-insulating Coating Using Fly Ash Zeolite

Building Energy Saving is imperative as it is of great importance to the energy security of our country. Research of a kind of coating with thermal insulation and heat preservation function for the wall is an effective way of the development of building energy saving. As common solid waste of China, fly ash utilization is the basic way to solve the pollution problem of it. Zeolite, which was made from raw material of fly ash, was as the functional filler of heat preservation coating packing for the outer wall. It not only makes recycling use of the fly ash, but also finds a new way of building energy saving.In this paper, zeolite was prepared by two steps synthesis method using fly ash as raw material, and then zeolite was used to prepare coatings of building outer wall with heat insulation. The aims of the present work are the synthesis the fly ash zeolite of low coefficient thermal conductivity, and determination of the optimum technological conditions through the single factor experiment. Moreover, the sunlight defending ability of fly ash zeolite was also tested. The main research contents and conclusions are as follows:(1) The fly ash zeolite was synthesized by two steps synthesis method using fly ash as raw material. Single factor experiments are conducted, concentration of sodium hydroxide, solid-liquid ratio, silica alumina ratio and temperature were involved. The best process conditions were as follows: 3mol/L sodium hydroxide concentration, solid-liquid ratio 10:1, silica alumina ratio is 2:1, the crystallization temperature of 120℃. The largest of pore volume of the fly ash zeolite was obtained with a quantity of 0.148 m3/g, and the minimum thermal conductivity was 0.153W/(m-k). It can meet the requirements of thermal insulation material.(2) Based on coating-based formulation, the basis of fly ash floating beads were took as the functional filler, and then the best preparation of architectural heat insulation coating formula was determined:the basis of the styrene acrylic emulsion 30g, water 25g,0.3g fiber, titanium dioxide 25 g, 0.1 ml dispersant, wetting agent,0.1 ml, functional filler 10g. At the same time, the doze of the PVC was determined, it turned out that when PVC was 40%, the coating of heat insulation performance is best, absolute temperature can reduce 5 ℃. As a result, the preparation of the coating is in line with national standards under the condition mentioned above.(3) In order to eliminate the influence of coating thickness on the result of the experiment in the follow-up experiments, the influence of the thickness of the coating on the thermal insulation performance was considered. Experimental results showed that there is no significant difference among these samples of vary thickness, that is to say, heat insulation effect is basically the same after increasing the coating thickness.(4) In order to verify the sunlight defending ability of fly ash zeolite, the fly ash zeolite, fly ash floating bead and diatomite materials were took as the function packing of the preparation of heat insulation coating, it is found out that with 9% the fly ash zeolite, fly ash floating bead and diatomite, the equilibrium temperatures were reduced 5℃,7℃ and 12℃ respectively. The experimental results showed that the zeolite can make good performance on defending sunlight and owns good heat preservation efficiency.(5) In order to further verify the insulation performance of the fly ash zeolite, the sunlight simulation experiment was performed. The experimental results showed that the maximum temperature difference of fly ash floating bead was 12℃, diatomite’s was 12.8℃ and the fly ash zeolite’s was 14.7℃. It is further demonstrate that heat insulation performance of the fly ash zeolite coating is better than fly ash floating bead and diatomite coating.