Phase Equilibria in the System CaO-MgO

The liquidus, solidus, and subsolidus of the system CaO–MgO have been redetermined. X-ray diffraction and optical techniques show that the maximum solid solution of MgO in the CaO lattice is approximately 17 wt% at 2370°C and the maximum solid solution of CaO in the MgO lattice is approximately 7.8 wt% at 2370°C. The extent of solid solution in each case is substantially greater than previously reported. Magnesium oxide and calcium oxide solid solutions exist at temperatures above 1600°C. The liquidus values closely agree with those previously reported by Rankin and Merwin.