Possibility of Secondary Lead Slag Stabilization in Concrete with Presence of Selected Additives

A comparative technical and environmental evaluation of products arising from the stabilization/solidification of secondary lead metallurgical slag into a cement matrix was performed. Provided samples of an industrial slag generated in the process of recovery of lead from automotive batteries (Engitec CX process), were used in experimental work. Characterization of slag by X-ray Diffraction (XRD), Atomic Absorption Spectrometry (AAS) and Optical Microscopy (OM) revealed that slag contains a certain percentage of sodium and lead, in the form of oxides and sulphides, as well as unreacted coke and iron compounds. Dissolving of the slag components causes migration of ions into water what can induce a significant pollution of environment. Processing options for stabilization/solidification of secondary lead metallurgical slag into cement matrix with barium hydroxide and gypsum as selected additives due to possibility of forming insoluble forms of slag compounds were determined. The influence of concrete composition on the compressive strength, in the presence of selected additives, was also studied. Toxicity characteristics leaching procedure (TCLP) was conducted to evaluate the leaching behaviour. The results revealed that with careful control of the solidification process in presence of selected additives, slag could be used as a partial aggregate replacement in the concrete production.