Abstract

Coal is a source of energy and one type of fossil fuel which is being used worldwide for long time in many applications such as electricity production and industrialised area. Combustion of fossil fuels is and will probably continue to be an important part of the heat and power production systems of many countries. Thus, depending on type and origin of the coal, about 5-15% of the total remains as ash formed from mineral matter. Many elements such as B, Cr, Cu, Ni, Mo, S, V, etc occur in the coal during its formation and condensed to the ash when is burnt. Leaching these hazardous elements from bottom and fly ash will cause environmental problems. Two different types of fly ashes (PEA1, PFA2) were leached with deionised water and nitric acid. The results showed that most of the elements of environmental concern in fly ash are present in small quantities and high leaching rates can be found in acidic conditions (lower pH).