Prevention of Trace and Major Element Leaching from Coal Combustion Products by Hydrothermally-Treated Coal Ash

The most important structural components of coal ash obtained by coal combustion in "Nikola Tesla A" power plant located near Belgrade (Serbia) are amorphous alumosilicate, alpha-quartz, and mullite. The phase composition of coal ash can be altered to obtain zeolite type NaA that crystallizes in a narrow crystallization field (SiO(2)/Al(2)O(3); Na(2)O/SiO(2); H(2)O/Na(2)O ratios). Basic properties (crystallization degree, chemical composition, the energy of activation) of obtained zeolites were established. Coal ash extracts treated with obtained ion-exchange material showed that zeolites obtained from coal ash were able to reduce the amounts of iron, chromium, nickel, zinc, copper, lead, and manganese in ash extracts, thus proving its potential in preventing pollution from dump effluent waters