feasibility study on synthesis of zeolite from coal wastes of coal washing plants

zeolite was synthesized from coal tailings and coal fly ash sampled from zarand coal washing plant, iran, using h2o2–promoted hydrothermal treatment. samples consisted mainly of sio2 and al2o3 which are the main components for the zeolite synthesis. to perform the experiments, appropriate amount of the starting materials were mixed with 240 ml volume of 30% h2o2 at room temperature with continuous stirring at 480 rpm. then, the temperature was gradually raised to and adjusted at 80oc for 180 min. at the end, the treated mixture was filtered and aged in an oven for 15 h at 95oc to give the zeolitic products. the xrd patterns showed semi-quantitative yields of 21.43% and 8.31% for direct and indirect conversions, respectively. based on xrf analysis, the higher yield of direct conversion could be ascribed to the higher cao content in coal tailings compared to fly ash.