AQUEOUS-PHASE EQUILIBRIA IN THE SYSTEM CAO-AL2O3-CACL2-H2O - THE SIGNIFICANCE AND STABILITY OF FRIEDELS SALT

Friedel's Salt is a poorly understood phase in the CaO-Al2O3-CaCl2-H2O system, which is critical in the function and stability of salt-satur ated portland cement-based grouts. Such grouts are required to seal ex ploratory excavations in a radioactive waste repository sited in bedde d salt. The phase equilibria of this system were investigated, and fou r quaternary invariant points were determined to allow construction of a phase diagram. The diagram is constructed using a plotting techniqu e applicable to double-decomposition systems or systems with a recipro cal salt pair. Statistical analysis of solution data was performed to assess the precision and accuracy of the invariant points.