%0 Journal Article %T Effect of Na2O/SiO2 mole ratio on the crystal type of zeolite synthesized from coal fly ash %A DUSICA VUCINIC %A IGOR MILJANOVIC %A ALEKSANDRA ROSIC %A PREDRAG LAZIC %J Journal of the Serbian Chemical Society %D 2003 %I Serbian Chemical Society %X Coal fly ash was modified to zeolitic materials by hydrothermal treatment at 90oC. The zeolite synthesis was studied as a function of the mole ratio of Na2O/SiO2 in the reaction mixtures. The results showed that NaP1 zeolite is obtained when the Na2O/SiO2 mole ratio was 0.7. Hydroxysodalite is the dominant zeolite phase in modified fly ash treated with a higher Na2O concentration solution (Na2O/SiO2 = 1.3). The IR and XRD methods were used to determine the phases present in the starting sample and in the zeolitic materials. %K coal fly ash %K hydrothermal treatment %K zeolitic materials %U http://www.shd.org.yu/HtDocs/SHD/Vol68/No6/V68-No6-05.pdf