Pb elution characteristics of cement bypass dust sludge

Abstract

Cement manufacturing plants use a chlorine bypass system to reduce the contents of chlorine. As bypass system is used, bypassdust is generated which has mainly KCl and small amount of heavy metals. During the KCl elution process, sludge winds upbeing generated and it contains a large amount of Pb which is required high costs for it to be buried. Through this study, wetried to fix the heavy metals by mixing the sludge that came from the bypass dust with the ordinary Portland cement. In orderto fix the Pb, the sludge and OPC were mixed together to manufacture sphere-shaped products that have a diameter of 1cm. The product was put in a thermo-hygrostat for 3 and 7 days at 23 oC with a relative humidity of 80%. After the curing process,all products of Pb contents were analyzed. The amount of Pb elution was different according to the composition of dust whichcame out of the cement factory. The amount of Pb elution went down as the amount of sludge that was less used and withlonger curation periods. In particular, it was confirmed that the Pb content with 7 days of curation satisfies standard valueof 3 mg/L.