Effect of additives on the hydration resistance of materials synthesized from the magnesia-calcia system

The effect of a variety of doping additives on the hydration resistance of calcined materials in the MgO-CaO system was investigated. Samples were pre pared from lightly calcined flotation magnesite that was mixed with dolomit e, as well as from analytically pure CaO and MgO; then, the samples were do ped with additives that contained cations with various valences (monvalent to tetravalent). Both the hydration rate and the powdering rate were measur ed. The important role of the higher-valence cations in improving the hydra tion resistance of the MgO-CaO materials was revealed, This behavior is bel ieved to be due to the formation of vacancies in solid solutions of CaO or MgO with higher-valence cations, The Ti4+ cation forms a solid solution wit h CaO, which reduces the Ca2+ concentration and leads to the improved hydra tion resistance of calcined materials from the MgO-CaO system.