【作者】 柳伟；

【导师】 梁永和；

【作者基本信息】 武汉科技大学 ， 无机非金属材料， 2002， 硕士

【摘要】 本文主要研究了优质镁钙砂的合成和抗水化技术，并以此为基础开发出了具有抗水化性能优良的镁钙质浇注料。全文共分为优质镁钙砂合成技术、镁钙砂抗水化技术和镁钙质浇注料研究三个部分。 在优质镁钙砂合成技术中，本文在前人研究的基础上，结合原料自身的特性，分别研究了机械活化、二步煅烧、消化等制备工艺以及微量添加剂对镁钙砂烧结性能的影响，并对其促烧机理进行了分析和探讨。在以上研究基础之上，提出了一条优质镁钙砂的生产工艺路线。试验证明，采用此工艺路线在1650℃就可以把镁钙砂烧结致密，相对密度达96％以上。 在镁钙砂抗水化技术方面，对目前技术比较先进，抗水化效果良好的碳酸化表面改性方法进行了研究。研究结果表明：该方法在利用CO₂对镁钙砂表面进行处理的过程中，可以使镁钙砂表面生成一层CaCO₃薄膜，从而有效隔绝了外界水分与试样内部CaO的接触。用此方法处理后试样的抗水化性能与未处理试样相比可提高4～5倍。在试验过程中发现，碳酸化改性方法存在反应速度慢，处理时间长等缺点，不利于工业化生产，因此试验提出了在处理气体中引入水蒸气的水化碳酸化改性方法，结果表明：水蒸汽的引入加速了镁钙砂表面CaCO₃的生成，提高了处理效率。与此同时，水化碳酸化方法还进一步提高了镁钙砂的抗水化性能，用其处理后试样的抗水化性能与未处理试样相比可提高7～8倍。试验结果还表明，颗粒粒度和镁钙砂种类对水化碳酸化改性效果有着重要的影响。对粒度而言，由于受到试验设备的限制，较小颗粒的镁钙砂表面改性效果比大颗粒的差，因此对于小颗粒适当延长处理时间是有必要的。镁钙砂种类对改性效果的影响主要与其显微结构有关，对于那些CaO、MgO晶粒发育良好，分布均匀，自身抗水化性能较好的镁钙砂，其改性效果往往更为显著。 在以上研究结果的基础上，成功开发出了以镁钙砂为骨料和镁砂细粉为基质的镁钙质浇注料，并对其抗水化性能，基本性能和抗渣性能进行了研究，结果表明：该浇注料在 110 oC XI Zh烘干并在空气中放置 3个月后未见有任何水化现象的发生，其基本性能和抗渣性与用于对比试验的镁质浇注料相接近，完全可以满足工业实际生产的要求。更多还原

【Abstract】 The synthesis and hydration resistance techniques of high quality magnesia-calcia clinkers are studied in this paper. Furthermore, a kind of magnesia-calcia castable with excellent hydration resistance and application performances based on these techniques is developed.In the view of synthesis technique of high-quality magnesia-calcia clinkers, effects of mechanical activation two step calcining and hydration on the sintering of magnesia-calcia clinkers are researched on the basis of characteristics of raw material used in the experiments. Moreover, the sintering mechanisms of each process are also analyzed and discussed. In addition, experiments have studied and compared the action of different additives on sintering of magnesia-calcia clinkers. According to the results of experiments, a new production process of high quality magnesia-calcia clinkers is designed. The results of experiments show that magnesia-calcia clinkers can be sintered to high density at 1650 by this process and the density of samples can be up to 3.32g/cm3.In regard of hydration resistance technique of magnesia-calcia clinkers, the surface modification method by carbonating is studied. By forming a CaCO3 layer on the surface of magnesia-calcia clinkers treated by CO2, the hydration resistance of these clinkers can be improved effectively. The results show that the hydration resistance of treated samples is improved three or four times as much as that of untreated samples. However, it is found that the surface modification method by carbonating has itself disadvantages that reaction speed is relatively slow and treating time is too long. Therefore , the hydration and carbonation surface modification method is developed. In this method, mixed gas of vapor and CO2 is used and hopes to gain the end of speeding up the form of CaCO3 layer. The experimental results demonstrate that by using this method, the treating time can be reduced to the half and the hydration resistance of magnesia-calcia clinkers can be improved five or six times as much as untreated ones. In addition, the grain size and category have important influence on the effects of surface treatment method by hydrating and carbonating. The results of experiments show that with the decrease of grain size, the hydration resistance of treated samples is reduced. So it is necessary for little clinkers to increase the treating time. In the regard of effects of category of magnesia-calcia clinkers, these that have better microstructure can always have more excellent hydration resistance after treated by the method of the hydration and carbonation surface modification method.According to the results of our experiments, magnesia-calcia castable can be madesuccessfully from the magnesia-calcia clinkers treated by this method. At the same time, its hydration resistance, application performances and corrosion resistance are researched. The results show that this magnesia-calcia castable dried under the condition of 110 X 12h can be placed in the air for 3 months without any hydration phenomena. And its application performances and corrosion resistance are as good as and better than magnesia castable. So it can satisfy the requirements of industry practical application completely.更多还原