Leaching Characteristics of Solidification System of C₃A/CuO

Abstract

This study was to evaluate the leaching characteristics of a solidification/stabilization system, using a static-renewal leaching test in which the leachant was renewed periodically after intervals of static leaching. Tricalcium aluminate was selected as a solidification agent and CuO as a contaminant to simplify the solidified waste. The model solidified waste matrix was vulnerable to the renewable acetic acid (1 N) solutions. The release of Ca was rapid; in about 10 extractions, the amount of Ca released had reached the maximum. Similarly, the leaching of Al was significant; about 90% of the total Al solidified was transferred to the acetic acid solution after 10 extractions. The proton promoted surface reaction is hypothesized to be the controlling process in dissolving the calcium compounds. The dissolution reactions would enlarge the capillary pores and produce new voids in the matrix that enhance solute leaching. Since both Ca and Al hydration compounds were rapidly leached out of the solid matrix, C