The 13 th Asia Pacific Confederation of APCChE 2010 Chemical Engineering Congress October 5-8, 2010, Taipei 1 Synthesis of Zeolite-A From Coal Bottom Ash: The Influence of Unburned carbon to the Zeolite Quality Hamzah Fansuri a, *, Yuli Yanti a , Everesta Londar and Nurul Widiastuti a a Department of Chemistry, Faculty of Mathematic and Sciences, Institut Teknologi Sepuluh Nopember (ITS), Surabaya 60111 Indonesia. * Corresponding Author’s E-mail: h.fansuri@chem.its.ac.id Keywords: unburned carbon, coal bottom ash, zeolite-A, hydrothermal reaction Abstract This article presents the study of unburned carbon in coal bottom ash influence to the quality of zeolite A that was made of the ash. Synthesis of zeolite A and unburned carbon-containing zeolite A was carried out using two step methods. First, the ash was fused with NaOH at 750 o C in air and inert (N 2 ) atmosphere to retain the unburned carbon content. The fused product was then dissolved in deionized water and aluminate solution was added to adjust SiO 2 /Al 2 O 3 molar ratio to 1.926, which is suitable for zeolit A formation prior to the second step which is a hydrothermal crystallization. Experimental results indicated that product synthesized from extract of the air-fused bottom ash solution contains only zeolite A. On the other hand, when the extract of N 2 -fused bottom ash was used, the zeolite also contains hydroxysodalite and calcite as well as 2.31 % carbon. Study on the variation of carbon addition shows that the crystallinity of zeolite A is lower when higher carbon was added. Pure zeolite A exhibited the highest CEC, ie 347.8 meq/100g, whereas carbon containing- zeolite A showed CEC variation between 93.8 and 221.71 meq/100g.