Hexavalent chromium in tricalcium silicate: Part II Effects of CrVI on the hydration of tricalcium silicate

The composition and structure of hydrated tricalcium silicate (C3S)⊛ pastes admixed with CrVI have been studied. The resultant mixture simulates CrVI waste forms stabilized in ordinary Portland cement. Scanning electron microscopy and transmission electron microscopy were used to identify the microstructural changes accompanying the addition of CrVI solutions to C3S. Energy-dispersive X-ray spectroscopy was used to probe the distribution of chromium in the phases within the hazardous waste forms. Elucidation of the molecular structure of the reaction products was accomplished with Fourier transform infrared and nuclear magnetic resonance spectroscopies.