DETERMINATION OF CHEMICAL-SPECIES IN FLY-ASH COLLECTED AT DIFFERENT SOURCES

Speciation of Cd, Cr, Mn, Ni and Pb in fly ashes derived from iron-sme lter works was carried out. Samples were collected at three technologi cal points and subjected to different treatment by strong acids in ope n vessels and pressurized Teflon bombs. The chemical investigations we re completed by X-ray powder diffraction (XRD) method. Determination o f toxic metals was performed by atomic adsorption spectrometry. Based on the results it was found that the heavy metals were generally bound ed to silicates in the different samples.