Lead and chromium leaching from portland cement. Physical and chemical aspects

Portland cement samples containing lead and chromium have been investigated in efforts to study the physical and chemical aspects of the toxic metal leaching process. Fourier transform infrared spectroscopy (FTIR) results of leached samples indicate the disappearance of calcium hydroxide, the decrease of carbonate, and changes in the sulfate molecular vibrations. Scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) reveal the spatial elemental distribution and morphology changes of the leached samples, while mercury intrusion porosimetry reveals the pore size distribution. The chemical interaction of lead and chromium with the cementitious components and the subsequent morphological changes is studied. Alsom leaching behavior as described by models using physical chemical effects is compared.

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