Production and characterization of alumina based aerogel powder use of alumina based raw material and wastes

In the present study, alumina based powder production was aimed using alumina based waste materials (secondary aluminium slag, aluminium anodic waste, chamotte mortar and alumina pot) and raw material (Seydişehir alumina) under atmospheric conditions. Alumina-based materials were dissolved in the prepared base/pure water solution with effect of mixing and temperature and alumina solutions were obtained by filter process. The pH of the solutions was neutralized by using acid/pure water solution and were kept in for aging process. The aging process was continued in percentage by weight %20 pure water/ethanol, ethanol and n-heptane respectively. After aging, solutions were filtered and alumina-based aerogel powder were obtained by drying under atmospheric pressure determined temperature and time. The produced alumina based aerogel powder were characterized with SEM, EDS, FESEM, XRD, DTA, BET, FTIR, thermal conductivity and density analysis. The properties of alumina based aerogel powder produce under different conditions were compared. According to the results of the analysis; produced alumina based aerogel powder are nano-sized (10-120 nm) and have a porous structure thus they have low density values. O-H peaks seen in the FTIR analyzes show that physical water is adsorbed in porous structure. Al-O-H and Al-O peaks show that aerogel powder contain strong alumina bonds. Surface area, particle size and pore volume of alumina based aerogel powder were determined by BET analysis. Endothermic peaks that observed in the thermal analysis results of the alumina based aerogel powder have proven the presence of moisture in the structure. Exothermic peaks caused by oxidation and new phase formation show the reaction of the powder to the temperature change. The low thermal conductivity coeffient as expected was obtained in the thermal conductivity analysis. The density values of alumina based aerogel powder were determined use of a certain container and very low density values were obtained. Keywords: Alumina based aerogel powder, atmospheric drying, sol-gel method.