As the free CaO in MgO-GaO refractories is easy to be hydrated, lots of work has been done to solve the problem with useful results having been obtained.

• 镁钙系耐火材料的弱点是其中游离氧化钙易水化的问题，围绕着这一问题，人们做了大量的工作并取得了一些有益的结论。