TRACE-METAL ANALYSIS OF COAL FLY-ASH COLLECTED PLAIN AND ON A QUARTZ FIBER FILTER

A simple, uniform procedure has been developed for microwave-based dig estion of fly ash samples collected from the hoppers of an electrostat ic precipitator (ESP), or collected from flue gases on a heat-resistan t quartz fibre filter and for subsequent atomic absorption spectrometr ic analysis of trace metals (Be, Cd, Co, Cr, Cu, Mn, Ni, Pb, V and Zn) . HNO3, HCl, HF and mixtures have been tested as digestion acids. The combination of HNO, and HF has been found to be efficient for the dige stion of fly ash samples with and without quartz fibre filter material . In spite of the complicated matrix, results with satisfactory accura cy and precision (relative standard deviation below 10% for most of th e elements) have been obtained. In the case of analysis of fly ash tog ether with a quartz fibre filter, the calibration curve has to be dete rmined by standard addition to a blank solution containing a dissolved blank quartz fibre filter.