The Preparation Of Porous Ceramic By Construction Waste

Construction waste is produced from the process of new construction, demolition,decoration and reconstruction etc. At present, the characteristic of construction waste is hugequantity and under-utilization. The treatment of accumulation and landfill has brought seriousenvironmental problems to the society. The purpose of this thesis is to study the utilization ofconstruction waste in the preparation of porous ceramic,this work will this work will providea new approach of the utilization of construction waste, and has a very important social valueand economic value.The construction waste was analyzed in detail, the results showed that the main mineralsof construction waste are quartz, burntochre and calcite. there are a certain amount of organicmatter, carbonate and quartz, and organic matter, calcium carbonate and iron oxide willproduced gas at different high temperature.Effects of organic matter, calcium carbonate and iron oxide on foaming of ceramicduring sintering were examined in this work.. The origin offoaming come form iron oxidechemical reaction during sintering,rather than the burning of organic matter anddecomposition of calcium carbonate.The effect of Calcium carbonate, calcium oxide andmagnesium oxide on the high temperature foaming of ferric oxide was researched in detial.The experimental results showed that: the effect of calcium carbonate on iron oxide is mainlyfrom calcium oxide,which was produced by decomposition of calcium carbonate.the effect ofcalcium oxide on iron oxide is mainly due to reduce liquid viscosity of the high temperatureand produce anorthite during ceramic sintering. the effect of magnesium oxide on iron oxideis mainly due to reduce liquid viscosity of the high temperature,and influences the process ofbubbles swelling. The liquid viscosity of2wt%magnesium oxide additive is more suitablefor bubbles swelling and running out hardly. Thus the sintering density of the ceramic isminimum compared with the other content of magnesium oxide.The porous ceramics was prepared from construction waste, potassium sand, ball clayand the super white sand. The basic formulation for preparation of the porous ceramicmaterial was determined through a large number of exploratory experiments as following:construction waste30wt%, ball clay20wt%, potassium sand40wt%， the super whitesand10wt%and carborundum0.4wt%. The effect of the four raw materials connect and the four processing parameters on the water absorption and sintered density was discussed indetail,and was explained by some rational reasons.The processing parameters such as millingtime, molding pressure, sintering temperature and sintering time were optimized with theorthogonal experiments, the optimized condition were the sintering temperature1215℃,molding pressure10Mpa, milling time36minutes and sintering time1minute.Porous ceramic was prepared in these optimized conditions, water absorbing capacity reached9.30%, the sintered density reached0.78g/cm3, compressive strength13.44MPa, thermalconductivitycoefficient0.42W/m K.