Aqueous Phase Equilibria in the System CaO‐Al 2 O 3 ‐CaCl 2 ‐H 2 O: The Significance and Stability of Friedel's Salt

Friedel's Salt is a poorly understood phase in the CaO‐Al 2 O 3 ‐CaCl 2 ‐H 2 O system, which is critical in the function and stability of salt‐saturated portland cement‐based grouts. Such grouts are required to seal exploratory excavations in a radioactive waste repository sited in bedded salt. The phase equilibria of this system were investigated, and four quaternary invariant points were determined to allow construction of a phase diagram. The diagram is constructed using a plotting technique applicable to double‐decomposition systems or systems with a reciprocal salt pair. Statistical analysis of solution data was performed to assess the precision and accuracy of the invariant points.