Abstract
	Due to their high iron content, fine-grained metal-bearing wastes are potential secondary raw materials whose utilization is restricted because of the contents of heavy metals. One of the conditions of recycling is a complete knowledge of phase and morphological structure of these materials. This paper deals with characterization of the dusts and sludge from metallurgical processes - the dusts from filters of electric arc furnace gas treatment plant, sludge from the filter press of an oxygen converter, and the dust from cast iron electro-filters. The experiments have shown that the steelwork dusts contain iron, mainly trivalent, as hematite, magnetite, franklinite and zincite. The lead is present as a sulphate and chloride. The compounds of cadmium were not detected. They are composed of particles smaller than 10 ?m, mainly spherical in shape. The majority of smaller particles are coagulated into clusters. In the steel work sludge examined, iron is mainly divalent, as wustite and nearly 7 % in metallic form. Contents of trivalent iron is only 3.7 wt. %. Beside wustite and metallic iron, the presence of hematite, franklinite, calcium dizinc hydroxide and calcite was proven. The steelwork sludge consists of unsymmetrical particles of different shape and size. Inhomogeneous, very small particles of Fe, Zn, Pb, Si, Mn, Mg, Al, Ca and O compounds are captured on the larger particles, which are composed of calcium carbonate or magnesium-calcium carbonate, or calcium hydroxide. The sludges from electrostatic filters from the cast iron production (two samples) contain in addition to iron, lead, cadmium and 10 wt. % zinc. The presence hematite, magnetite, franklinite, anglesite, and silica were proven in both samples. Lead chloride was detected only in one sample. Both samples contain ball-shaped, unsymmetrical particles and clusters of very small particles. Electron analyses prove that lead and cadmium compounds are present in smaller particles which are coagulated into clusters or adsorbed on iron or zinc iron oxides particles, or graphite.