Ceramics-Silikáty 50, (1) 22 - 26 (2006)

Easily filtrated alumina-oxides spherical precursors were prepared by homogenous precipitation from aluminium(III) sulphate with urea. Urea was employed as precipitation agent. X-Ray powder diffraction (XRD) spectra identified three different phases, namely: α-boehmite, boehmite and hydrobasaluminite. The morphology of prepared samples was observing by SEM (scanning electron microscopy) equipped with EDX (energy dispersive analysis by X-rays). The spherical clusters were examined at small concentration and the hydrobasaluminite islands were observed at the largest concentration of reagents. The microstructure characteristics were obtained by BET (Brunauer-Emmett-Teller) and BJH (Barret-Joyner-Halanda) methods. BET in wide range from 6 to 142 m²/g and the all kinds of porous distribution were acquired, respectively. These methods showed that relationship between phase structures and microstructure exists.