Investigation of the physicochemical properties of alumina produced by sol-gel method

Since alumina (Al2O3), which constitutes about 25% of the earth's crust, is not found in nature as a pure mineral, it is generally obtained as a result of processing bauxite ore with Bayer process. Due to its superior physical and technological characteristics, it finds wide application in many industries. However, impurities such as SiO2 and Fe2O3 from the ore or Na2O included in the structure during synthesis can be found in the structure of the alumina produced by the Bayer process. Nonetheless, bauxite reserves are rapidly decreasing due to high production quantities, resulting in serious increases in alumina production costs. For this reason, recent studies have focused on alumina production from non-bauxite sources. In this study, it was aimed to transform the alumina cryogel synthesized by sol-gel method, which was calcined at 600-1300 °C temperature range, into alumina form, which finds many industrial applications, especially in ceramic industry. In this context, the effects of different aging and drying conditions on the physicochemical properties of the synthesized aerogels were also investigated and characterization of the prepared samples were carried out by using BET, SEM, FT-IR, XRD, TGA / DTA and DSC analyzes. As a result, the effect of calcination temperature on the physicochemical and structural properties of the final product was determined and alumina phase transition was investigated in alumina production which is very important for industrial applications with the use of aerogels as raw material source.