Examination of the influence of dissolved halite (NaCl) on the leaching of lead (Pb) from cement-based solidified wastes
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The leaching of lead from cement-based solidified waste forms mixed at different water/cement ratios was studied by conducting equilibrium and semi-dynamic leaching tests using deionized water and sodium chloride solutions. The results suggest that leaching of the primary constituents of the cement (calcium, silicon and sulfate) is controlled by solubility equilibria, with increased leaching into chloride solutions due to ionic strength effects. The original porosity of the waste forms increased with water/cement ratio and chloride solutions further increased it as a result of decalcification. Lead leaching was generally low, and appears to be a transport-controlled process, such that leaching correlates positively with porosity.
KeywordsSolidified waste Leaching Speciation Lead Sodium chloride
This study was supported by Grant 5D43 TW00641 from the Fogarty International Center, National Institutes of Health, USA.
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