Study On Synthetic Process Of Porous Mulute Sound-absorbing Material

In this paper, the high porosity mullite sound-absorbing material whose main crystallinephase was mulltite was produced by using low-cost coal gangue as the main raw materials,asmall quantity of bauxite acting as auxiliary raw material, clay as anchoring agent, MgO andCaCO3as sintering aid, adding composite pore former materials, and forming by extrusionmolding.Temperature parameters were determined by sintering on different sintering temperatureand holding time. According to TG-DTA, Archimedes principle,XRD and SEM，apparentporosity, volume density, mechanical property and microstructure were measured andanalysized. The best sintering temperature was1400℃, and the best holding time was120min.The effects of the additive amount of sawdust starch and graphite.coal gangue with differentpore-forming materials on the performance of Porous mullite synthetized were researched.The experiment results show that apparent porosity is increased, volume density and flexualstrength are decreased with the increasing of the adding amount of pore-forming material. Thestructure of porous mullite was strengthened according to reaction sintering and fiberreinforcing. The results show that the samples produced by reaction sintering in-situ wasimproveed three times than the reference sample, and it also improved structure strength ofporous mullite highly through fiber reinforced.Starch used as binder and pore-forming aids, the process of plastic making was improvedto prepare the high porosity mullite sound-absorbing material according to the principle ofstrarch consolidation forming. The best adding content of starch was5%, prepareing poroussound-absorbing mullite material with density of0.87g.cm-3, apparent porosity of64.2%,compressive strength of3MPa. The sound absorption coefficient of the material was testedby standing wave tube method. The results show that the low-frequency sound absorptionperformance of the materials increased and the high-frequency of the materials changed little.With the improvement of the apparent porosity of the materials, it was benefit of theimprovement of high-frequency sound absorption performance Porous mullitesound-absorbing materials were prepared by adding different content of mullite fiber. The test results show that adding suitable content mullite fiber was beneficial to the improvement ofthe mechanical properties of materials, and it also could increase the sound absorptioncoefficient of the materials. When the adding content of mullite fiber was6%, the strengthwas the highest, about5.2MPa. When the adding content of mullite fiber was4%，the soundabsorption performance of the material was the best, the average sound absorption coefficientwas0.48.