Nano α-Al2O3 powders were successfully prepared from Indonesian local kaolin, kaolin Belitung. Nano α-Al2O3 powders were prepared by alumina extraction processes through liquid polish milling of the calcined kaolin with a H2SO4 solution, thus producing kaolin derived aluminum sulfate. Calcination treatments were conducted at 600 οC and 800 οC. The greatest alumina extracted was about 70.90% for the local kaolin calcined at 800 οC. The aluminum sulfate was neutralized with a NH4OH solution until pH 7-8 to form white sols of Al(OH)3. Sugar was added into the mixture to mask the sols, thus producing gels. The gel was dried at 200 οC and then was calcined at 900 οC for 5 hours, which resulted in the formation of alumina. The calcined alumina was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The alumina phases consisted of a γ- Al2O3 phase of about 47.6% having crystallite sizes of about 4-5 nm and an α-Al2O3 phase of about 52.4% having crystallite sizes of about 19-26 nm. The SEM result shows that the average grain sizes of the alumina powder were less than 250 nm.

Keywords: Nano α-Al2O3, Kaolin belitung, Liquid polish milling, H2SO4, Sugar, Calcination.