Reuse of slags containing lead and Zinc as aggregate in a Portland Cement Matrix

Both economic and environmental reasons force research activities to find valid alternatives to the disposal of high quantities of metal containing slags. One of the most promising routes seems to be the exploitation of slags as inert materials for cement conglomerate: to this end a preliminary characterization of slags arising from lead/zinc pyrometallurgical smelting (ISF) and lead batteries recycle (LBR) was made and different slag-Portland cement mixes were prepared with an increasing waste content. Heat evolution has been determined and a series of tests on the final waste forms have been conducted in order to evaluate the mechanical performance and the leaching behaviour. In spite of the acceptable mechanical characteristics for both slag-cement products, a high release of lead represents a serious problem. The conclusion is drawn that if preliminary extraction of the main pollutants from the raw slags is unpractical, just a limited amount of slags can be incorporated in cement. At the same time the adoption of other stabilization techniques should be taken into account. © 2012 Widener University.