Utilization of zeolites synthesized from coal fly ash for the purificationof acid mine waters

Two pilot plant products containing 65 and 45% NaP1 zeolite were obtained f rom two Spanish coal fly ashes (Narcea and Teruel Power Station, respective ly). The zeolitic product obtained showed a cation exchange capacity (CEC) of 2.7 and 2.0 mequiv/g, respectively. Decontamination tests of three acid mine waters from southwestern Spain were carried out using the zeolite deri ved from fly ash and commercial synthetic zeolite. The results demonstrate that the zeolitic material could be employed for heavy metal uptake in the water purification process. Doses of 5-30 g of zeolite/L have been applied according on the zeolite species and the heavy metal levels. Moreover, the application of zeolites increases the pH. This causes metal-bearing solid p hases to precipitate and enhances the efficiency of the decontamination pro cess.