Find the maximum temperature to which the following two magnesia

Find the maximum temperature to which the following two magnesia–alumina refractory materials may be heated before a liquid phase will appear.
(a) A spinel-bonded alumina material of composition 95 wt% Al2O3-5 wt% MgO.
(b) A magnesia-alumina spinel of composition 65 wt% Al2O3-35 wt% MgO.
ConsultFigure.