材料期刊网

为了研究合成温度对含镁铝尖晶石的铝酸盐水泥晶粒尺寸和凝结性能的影响，以白云石、工业氧化铝和轻烧镁砂为原料，按 Al2 O3、MgO、CaO 质量比为71920配料后混合均匀，并在高温炉中分别经1100、1200、1300、1400和1500℃保温3 h 煅烧并破粉碎至50μm 以下，制备了含 MA 的铝酸盐水泥，对水泥试样进行了XRD 和 SEM分析，并检测了凝结时间。研究结果表明：含 MA 的铝酸盐水泥中的 CA、MA 和 CA2相分别在900、1100和1200℃生成。当合成温度从1100℃升高至1500℃时，水泥中 MA 的晶粒尺寸从纳米到微米级可控，CA 或 CA2的粒径从2～3μm 逐渐长大至5μm 以上，并烧结在一起形成骨架，MA 包裹在 CA 或 CA2相周围。随着合成温度的升高，水泥的凝结时间延长，其原因一方面在于 CA 或 CA2晶粒的长大，致使水化活性较低；另一方面在于 MA 晶粒的长大阻碍了水与内部 CA 或 CA2的反应，对水泥的水化过程有明显的阻碍作用。

Dolomite,industrial alumina and caustic magnesite were used as starting materials to study the in-fluence of temperature on the crystal size and setting properties of aluminate cement with magnesium alu-minate spinel.The starting materials were mixed homogeneously according to the mass ratio of 71 9 20 of Al2 O3 MgO CaO,heated to 1 100,1 200,1 300,1 400,1 500 ℃,respectively,in a high temperature furnace and soaked for 3 h.After that,the cement bulk was crushed to below 50 μm.The MA bearing aluminate ce-ment was characterized by XRD and SEM,and the setting time was tested.The results show that the phases of CA,MA and CA2 can be formed at 900,1 100 and 1 200 ℃,respectively.The crystal size of spinel could be controlled from nanometer to micrometer as the synthesis temperature rises from 1 100 to 1 500 ℃,and CA as well as CA2 grows from 2 -3 μm to 5 μm,and then sinter together forming skeleton,CA and CA2 crystals are surrounded by MA crystals.Meanwhile,the setting time delays with the synthesis temperature rising due to the growth of CA or CA2 crystals,decreasing the hydration activity;and the growth of MA crystals,hindering the reactions between water and CA or CA2 ,thus obviously hindering the hydration of the cement.