Mechanisms of metal stabilization in cementitious matrix: Interaction of dicalcium silicate (C 2 S) paste and copper oxide
Journal
Toxicological & Environmental Chemistry
Journal Volume
43
Journal Issue
1-2
Pages
51-62
Date Issued
1994
Author(s)
Abstract
There are relatively few published studies describing the microstructural and microchemical interactions of metal-containing wastes and solidifying agents in solidification systems. An understanding of such interactions would be useful to predict the ability of fixation systems to retard the solubility and/or mobilitty of the incorporated metal species. Thus, solidification systems could be designed to exert a minimal environmental impact. For the present study, the interactions between dicalcium silicate (C2S) paste and CuO were characterized using X-ray diffractometer (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray analysis (EDAX). The results of XRD analysis indicated that the C2S paste/CuO fixation system provided a mild alkaline environment during hydration reaction. The interfacial microanalysis by SEM/EDAX of C2S paste and CuO showed a significant difference between hydrated β- and non-hydrated y-C2S systems. The interfacal zone is in about 1 pm thickness and the concentration gradient of calcium and silicon observed in the CuO region is due to the interaction of hydrated β-C2S and CuO. It is suggested that the CuO was stabilized in the C2S paste by two major mechanisms; Ca and Si from hydrated β-C2S diffuse and form a solid solution in the CuO region, and CuO is in well contact with C2 S paste. © 1994, Taylor & Francis Group, LLC. All rights reserved.
SDGs
Type
journal article