Journal of Nuclear and Related Technology Vol. 4, Special Edition 2007, 87-91 HYDROTHERMAL SYNTHESIS OF ZEOLITES FROM FLY ASH Faizul Che Pa*, Mohd. Zaheruddin Kasmuin*, Suhaina Ismail** & Norlia Baharun** *School of Materials Engineering, Kompleks Pusat Pengajian Jejawi 2, Universiti Malaysia Perlis, 02600 Arau, Perlis **School of Materials & Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang E-mail: faizul@kukum.edu.my ABSTRACT Fly ash (PFA) is a complex material produced after combustion in coal-fired power plants. About half of this fly ash is disposed as solid wastes. A possible alternative to disposal of the fly ash is the synthesis of zeolite. Zeolite Boggsite (Na 3 7Ca 7 4Al 18 5Si 77 5O 192 7H 2 O) was synthesized from fly ash by hydrothermal treatment with NaOH solutions as identified by x-ray diffraction. The zeolite type and degree of crystallization were found to be dependent on the reaction conditions and mineralogy of the raw material, particularly in terms of the relative concentrations of SiO 2 and Al 2 O 3 . Keywords: Fly ash, zeolites, hydrothermal INTRODUCTION PFA has been designated as useful by-products for recycling and extensive studies have been carried out for the alternative utilization (Mimura, 2001; Murayam, 2002; Poole, 2000). The PFA has favourable silicon and aluminium content making their alteration to crystalline zeolitic material possible; the utilization of zeolites synthesized from PFA by hydrothermal treatment seems to be one of the most attractive applications (Mimura, 2001; Murayam, 2002; Poole, 2000). In this study, PFA were used to synthesize zeolites by hydrothermal treatment with NaOH solutions. MATERIALS AND METHOD Raw material The PFA was discharged from coal power plants. After drying, a representative head sample was prepared from each bulk sample by riffling for subsequent chemical, mineralogical and particle size characterisation. Hydrothermal test In each hydrothermal test, a known weight of fly ash was reacted with 2M NaOH in a beaker placed in water bath at a temperature of 80 - 85 0 C. Zeolite was synthesized from slurry under the agitation condition. Solid-liquid ratio was 0.3:1. After an appropriate reaction time (6 – 9 hours), the solids were filtered, washed with distilled water, then dried at 60 0 C and stored in a desiccator prior to SEM, XRD and XRF analysis. 87