Abstract Calcined dolomite containing free-CaO cannot be directly applied in magnesium phosphate cement (MPC) as magnesia raw materials. To chemically combine with CaO and replace magnesite, dolomite-bauxite-gypsum (DBG) powders were calcined to produce MPC containing ye'elimite. The properties of the calcined DBG powders obtained at calcination temperatures no higher than 1300 °C were studied. The performance of these MPC pastes prepared with calcined DBG powders and the hydration process of the new system were also investigated. Results showed that the calcined DBG powders were mainly composed of magnesia, ye'elimite and belite. MPC pastes with calcined DBG powders exhibited high early compressive strength and good volume stability. Ye'elimite was confirmed to participate in the hydration reactions and would also improve the water resistance of the MPC pastes. Some new amorphous hydration products containing Al-P in mesh-like structures were observed during water curing and might be beneficial for the compressive strength development.

中文翻译：

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白云石磷酸镁水泥的制备及性能

摘要 含游离CaO的煅烧白云石不能直接应用于磷酸镁水泥（MPC）作为氧化镁原料。为了与 CaO 进行化学结合并取代菱镁矿，煅烧白云石-铝土矿-石膏 (DBG) 粉末以生产含有 ye'elimite 的 MPC。研究了在不高于 1300 °C 的煅烧温度下获得的煅烧 DBG 粉末的性能。还研究了用煅烧 DBG 粉末制备的这些 MPC 糊剂的性能和新系统的水化过程。结果表明，煅烧后的DBG粉体主要由氧化镁、ye'elimite和belite组成。具有煅烧 DBG 粉末的 MPC 糊剂表现出高早期压缩强度和良好的体积稳定性。耶' elimite 被证实参与了水合反应，并且还会提高 MPC 糊剂的耐水性。在水固化过程中观察到一些新的含有 Al-P 网状结构的无定形水化产物，可能有利于抗压强度的发展。