چكيده به لاتين
Insulating bricks and aluminum bodies are of great interest because of application in refractory, catalysts, biomaterials, membranes and others. One of the ways to provide these bodies can be to create a suspension containing alumina particles and various additives, then casting them in a metal or wooden frame and tightening them in the mold, and finally the process of drying and sintering them. In this study, slurries containing 75 wt% Alumina, 25 wt% water were prepared with sodium hexametaphosphate lubricant and then added to various silicasol additives, high alumina cement, starch, carboxymethyl cellulose and internal foam agent (fire foam) Added. After stirring and foaming the slurry, they were poured into a metal mold and, after stiffening and drying, sintered them at a temperature of 1510 ℃. Some of the samples were sintered at a temperature above 1650 ℃, and some samples also contained Al(OH) 3.Flow examinations of different slurry slurries showed that all of them had a pseudoplastic and shear-thinning behavior, and all of them, except for carboxymethyl cellulose slurries, had a thixotropic behavior. The viscosity number of the slurry contains only alumina, alumina- foam, alumina - foam -cement, alumina - silica sol- carboxymethyl cellulose which showed an increase in the viscosity of the slurry with different additives.Suitable physical and mechanical results for insulating bricks with a working temperature of about 1500 ℃ to samples containing silica- starch- foam and high alumina -foam - silica sol- carboxymethyl cellulose- fire foam. The results of microstructure and x-ray analysis of different samples showed that in samples containing even silica, the effect was not the formation of mullite, and in samples containing high alumina cement, calcium aluminate was also present in sampels. Medium and porosity in samples containing silica soll, foam and saturation of about 8 μm, in samples containing high alumina foam and cement, about 10 μm, and in samples containing foam, silica sol and carboxymethyl cellulose, about 12 μm after sintering in The temperature was 1510-1650° C.The shape of the porosity indicates that the applied shear stresses have not been able to change the form of a quasi-spherical porosity.
Keywords: Alumina insulation bricks, fire foam, flow properties, flexural strength, total porosity.
