石英和锆英石复合镁钙系材料的制备及性能研究

发布时间：2018-04-09 22:09

本文选题：镁钙系耐火材料　切入点：烧结性能　出处：《郑州大学》2015年硕士论文

【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。
[Abstract]:Refractory is a kind of material with certain volume stability, high temperature resistance and corrosion resistance.High-temperature equipment generally needs refractory as lining, so refractories are an indispensable part of high-temperature industry.With the development of metallurgical technology, the demand for pure steel and varieties of steel is increasing gradually, the proportion of continuous casting is increasing, the refining technology is developing day by day, the ladle of smelting clean steel is in full bloom and transporting molten steel at the same time,Second refining of molten steel and so on, forcing refractories to change and improve to the development of high-grade refractories.The strong superiority of magnesia-calcium refractories has been paid more and more attention, including resistance to higher temperature, good slag resistance and purification of molten steel.Among many oxide refractories, only calcium oxide can not only resist high temperature, but also purify molten steel.Therefore, magnesium-calcium-based refractories are regarded as one of the four developing directions of refractories in China in the 21 ~ (st) century.Although the magnesia-calcium refractories have many excellent properties, there are still some problems, the most important of which is the hydration of free Cao.In order to enhance the hydration resistance of magnesia-calcium refractories, the common methods are as follows: first, treating the surface; second, introducing additives; third, changing the sintering process.Two-step sintering and high-temperature sintering are used to improve sintering process.The densification of samples was studied by adopting two-step sintering method, adjusting the proportion of magnesium-calcium in magnesia-calcium series refractories and introducing quartz and zircon as admixtures, using light calcined dolomite and light-burned magnesite as main raw materials.Effects of hydration resistance, microstructure and phase composition.Each sample was sintered at different temperatures.The effect of different sintering temperature on the above properties was studied.The results show that when the mass fraction of MgO in magnesium-calcium refractories is 60, the densification of the samples is the best, and the hydration resistance is closely related to the mass fraction of Cao. The addition of quartz has a great influence on the phase composition of magnesia-calcium refractories.With the increase of quartz content, the contents of C _ 3S _ 2 C _ 2S and C _ 3MS _ 2N _ 2O in the samples gradually decreased and disappeared.The addition amount of quartz should not be too much. 3) the addition of zircon can greatly improve the hydration resistance of the samples. For samples with different MgO content, the optimum addition amount is also different. 4) the optimization of the properties of the samples by increasing the sintering temperature is very obvious.MgO grains can be obviously grown and the internal pores of Cao grains can be reduced.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ175.1

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