【作者】 李金鹏；

【导师】 孙洪巍；

【作者基本信息】 郑州大学 ， 凝聚态物理， 2015， 硕士

【摘要】 耐火材料是具备一定体积稳定性、一定耐高温性能和一定抗腐蚀能力的一类材料。高温设备一般需要耐火材料作为内衬,所以,耐火材料是高温产业不可缺少的一部分。随着冶金技术的发展,对纯净钢、品种钢的需求逐渐增加,连铸比例不断增加,炉外精炼技术日益发展,冶炼洁净钢的钢包在盛放、运送钢水的同时,还要对钢水进行二次的精炼等等,迫使耐火材料发生变革和改进,向高级耐火材料发展。镁钙系耐火材料其强大的优越性慢慢受到人们的关注,包括耐更高的温度,抗渣侵能力良好,还能净化钢液。在诸多氧化物耐火材料中,只有氧化钙不仅耐高温,而且对钢液还有净化作用。所以,镁钙系耐火材料被誉为21世纪我国耐火材料四大发展方向之一。镁钙系耐火材料虽然具有非常多的优良性能,但也存在一些问题,其中最主要的是游离Ca O的水化问题。为了增强镁钙系耐火材料的抗水化性能,常见的方法有以下几种:一是对表面进行处理的方法;二是引入添加剂;三是改变烧结工艺。目前来讲,经研究发现对镁钙系耐火材料抗水化性能有益的添加剂有Ba O、Sr O、Al2O3、Fe2O3、B2O3、Y2O3、Si O2、Cr2O3、Ti O2、Zr O2、Ca F2、稀土氧化物及其复合物等。改善烧结工艺一般包括采用二步烧结法和高温烧结法两种。本次课题以轻烧白云石和轻烧菱镁矿为主要原料,通过采用二步烧结法和调节镁钙系耐火材料中镁钙的比例以及引入石英和锆英石为外加剂,研究其对试样的致密性、抗水化性能、显微结构和物相组成的影响。每组试样都在不同的温度下烧结。以研究不同烧结温度对材料上述性能的影响。研究结果表明:1)镁钙系耐火材料中,Mg O的质量分数为60%时,试样的致密性最好;抗水化性能与Ca O的质量分数密切相关;2)添加石英对镁钙系材料的物相组成影响很大,随着石英含量的增加,试样中产生C3S、C2S和C3MS2,Ca O相的含量逐渐减少直至消失。石英的添加量不宜过多。3)引入锆英石可以大幅度提高试样的抗水化性能,对于不同Mg O含量的试样,最佳的添加量也不同。4)提高烧结温度对试样的各项性能的优化非常明显,可以促使Mg O晶粒明显长大;减少Ca O晶粒内部气孔。更多还原

【Abstract】 Refractory material need have a certain size stability, high temperature resistant performance and corrosion resistance. High temperature equipment generally needs refractory material as lining, so the refractory material is an indispensable part of high temperature industrial. Along with the development of metallurgical technology, the demand for pure steel and high-grade steel, the continuous casting ratio increases gradually. the technology of refining outside the furnace is developing.The ladle of smelting clean steel need refine secondary molten steel, when it was laying up and delivering, which force the refractory material change, improve and develop for high-grade refractory materials. Calcium magnesium series refractory’s powerful superiority is attended gradually by people, which include high temperature resistance, good resistance to slag penetration ability, and also can purify liquid steel. In many oxide refractory materials, Ca O not only has high temperature resistance, but also pury liquid steel. So magnesium calcium series refractory is honoured as one of the four main develop direction of refractory materials in China in the 21 st century.Calcium magnesium series refractory has very many excellent properties, it also exist some problems, one of the most important problem is the free Ca O hydration. In order to enhance the hydration resistance of magnesium calcium series refractory,common methods are divided into the following kinds: the first is surface processing; the second is introduction of additives;the third is change the sintering technology. So far, the study found that the additives which is good for calcium magnesium series refractory hydration resistance include:Ba O,Sr O,Al2O3,Fe2O3,B2O3,Y2O3,Si O2,Cr2O3,Ti O2,Zr O2,Ca F2,rare earth oxides and its composites, etc. The method of improving the sintering technology generally includes two step sintering method and high temperature sintering.This subject uses light burned dolomite, light burned magnesite as main rawmaterials, quartz and zircon as additives. We will study the compactness, hydration resistance, microstructure and phase composition of samples, by using two step sintering method, adjusting the proportion of calcium magnesium and introducing different content additives. Each group of samples were sintered under different temperature.And the influence of properties on different sintering temperature is studied.The results showed that:The compactness of samples is best when w(Mg O) is 60%.The hydration resistance is closely related to w(Ca O).The influence of samples’ phase composition by adding quartz is great. C3S、C2S and C3MS2 emerges with the increase of quartz content.While the content of Ca O is gradually decrease and eventually disappear. Excess quartz is bad for samples.The hydration resistance of samples improve obviously by introduction of zircon.The best contend of zircon is different with w(Mg O).The property improvement is obvious by improving the sintering temperature,which can make grains of Mg O growing up significantly and reduce the inernal porosity of Ca O grain.更多还原