Determination of trace elements in fly ash samples by FAAS after applying different digestion procedure

Abstract

The fly ash samples obtained from Kangal Power Plant were prepared for FAAS analysis by a new approach. The trace elements of the fly ash samples were leached with appropriate solvents under suitable conditions. The leaching method is known as an effective technique for substances dissolving very hard and refractory materials. The leaching effects of solvents and their mixtures were investigated on fly ash samples that are used largely in analysis of soil and sediment samples. The fly ashes mainly consist of glassy aluminosilicates. The major components of the samples are SiO2, Al2O3, CaO and Fe2O3. Therefore, decomposition of the silicate lattice of the fly ash is required for liberation of trace elements. The dissolution process can be completed by using a mineral acid such as concentrated HCl. This technique has an advantage that the fly ash can be dissolved without any oxidation at room temperature. Maximum element recoveries were obtained by the procedure of 37% HCl leaching after the samples were treated with 2.0 ml of concentrated HE It was also observed that maximum mass loss occurred in this procedure. The effect of the four leaching reagents, which are HCl, HNO3, HClO4 and HNO3 + HClO4. were investigated on fly ash samples that were treated with concentrated HF. An optimum leaching method was determined based on the confidence of analytical results and element recovery rates. (c) 2004 Elsevier B.V. All rights reserved.