Study On Preparation Of Light-Weight High Strength Heat-Insulation Materials Using Fly Ash Floating Beads

At present our country pays more attention to resource conservation and energy conservation and environmental protection.In the field of heat preservation and heat insulation,fly ash floating beads originated from waste of power plants has been used as main raw material instead of the traditional materials used for the production of the light-weight heat-insulation materials,but the total applying amount of fly ash floating beads accounts for 60-80%and compressive strength is not high when volume density is low.This paper prepared creatively to a kind of light-weight high strength heat-preservation and heat-insulation material through the technological formula optimization and traditional extrusion molding process with high content of fly ash floating beads(80-95%)to introduce voids,parts of bentonite and magnesia clay as binder,a small amount of PVA solution as plasticizer.The large introduction of fly ash floating beads in the formula not only finds substitute for the natural raw material for preparation of light-weight heat-insulation materials,but also explores a new pathway for the utilization of fly ash.The results showed that the green body with the volume density 0.433?0.619 g/cm3,compressive strength 5.35?15.8 MPa when sintering temperature range 1200??1300?;the volume density 0.75 g/Cm3,compressive strength 24.3 MPa after plus 5%magnesia clay(1300?);super light volume density 0.38 g/cm3,compressive strength 3.2 MPa(1150?).The control of fly ash floating beads by different particle sizes has great influence on the sample of various performances.The volume density and compressive strength changes insignificant with the decreasing of particle size of floating beads when adding 95%fly ash floating beads;The volume density and compressive strength changes greatly with the decreasing of particle size of floating beads when adding 80%fly ash floating beads,after the first increases gradually decreases.The volume density and compressive strength of the sample are maximum when floating beads of 120-160 particle size,and the volume density 0.601?1.038 g/cm 3,compressive strength 10.65?39.5 MPa when sintering temperature range 1200??1300?.In the control of floating beads by different particle sizes are also found that samples of thermal conductivity shows the tendency of decrease at first and then increase with the decreasing of particle size of floating beads.The heat conduction performance(?')of the sample is minimum and heat preservation and heat insulation performance is best when floating beads of 160-200 particle size.The heat conduction performance of the sample by different particle sizes of floating beads significantly rise when the sintering temperature from 1200? to 1300?.Compared with the original formula not plus magnesia clay,the sintering shrinkage,volume density and compressive strength of the sample have a certain degree of increase with the rising of magnesia clay content in the sample.The improvement of compressive strength of the sample by plusing 5%magnesia clay is more obvious with bentonite clay content builds up in the formula.The introduction of magnesia clay can promote the dissolution of quartz and mullite formation,it also helps the melt and reduces the sintering temperature,increases the strength of body.Different content of PVA solution has great influence on the green strength,volume density and compressive strength.The green strength increases with the rising of content of PVA solution.The volume density decreases with the rising of content of PVA solution.