高钙镁钙砂的合成及其抗水化性能研究

发布时间：2018-03-20 23:50

  本文选题：高钙镁钙耐火材料　切入点：活性MgO　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着洁净钢、特种钢等高端钢铁产品的生产需要,MgO-Ca O质耐火材料的生产和研究日益受到国内外的重视,该耐火材料具有耐火度高、碱度高、抗渣性好、耐剥落性强等特点,特别是其内部的游离CaO具有良好的净化钢水作用,是冶炼洁净钢、特种钢等不可或缺的优质耐火材料,具有广泛的应用前景。但是MgO-CaO质耐火材料最大的缺点是CaO在空气中极易发生水化反应,造成材料粉化,使其应用受到了极大限制。国内外很多学者对MgO-CaO质耐火材料的抗水化性能做过研究,方法包括二步煅烧法、引入添加剂、表面处理等多种方式,本课题的研究方向主要是通过二步煅烧法和引入Fe2O3+ZrO2复合添加剂两种方式,来提高MgO-CaO质耐火材料的抗水化性能。本课题研究主要包括三步:第一步,以天然白云石矿和天然菱镁矿为原料,破碎磨细至粒度小于100μm,分别在不同温度下轻烧、保温2h,制得MgO、CaO粉料,经过活性测试分别选取活性最高的轻烧温度。第二步,将两种在活性最高温度下轻烧后的粉料分别按照w(CaO)=45%、w(CaO)=50%、w(CaO)=55%进行配比,之后向其中引入不同配比的Fe2O3+ZrO2复合添加剂,复合添加剂中Fe2O3、ZrO2的质量比分别为0.5%Fe2O3+1%ZrO2、0.75%Fe2O3+2%ZrO2、1%Fe2O3+3%ZrO2,最后加入磷酸二氢铝粉末作为结合剂,干混6h,在100MPa压制成Φ50mm×50mm的圆柱试样,分别于1500℃×3h和1600℃×3h烧成。第三步,根据烧后试样的显气孔率、体积密度、水化增重率以及试样的微观结构,确定添加剂的最佳引入量。结果表明:(1)所用白云石矿的最佳轻烧温度为1100℃,菱镁矿的最佳轻烧温度为800℃。(2)加入一定量活性MgO的试样在烧结性能、抗水化性能方面优于不加入活性MgO的试样。(3)Fe2O3+ZrO2复合添加剂在高温下能够促进MgO-西安建筑科技大学硕士学位论文CaO质耐火材料烧结性能的提高,促进晶粒的生长,引入复合添加剂试样的显气孔率、体积密度和抗水化性能都明显优于不加添加剂的空白试样,其中w(CaO)=50%、引入添加剂比例为1%Fe2O3+3%ZrO2的试样,1600℃烧成后水化率从空白试样的10.8%降至4.3%,说明添加剂的引入能够有效改善MgO-CaO质耐火材料的易水化性。(4)1600℃下烧成试样的烧结性能、抗水化性能明显优于1500℃下烧成试样,说明烧成温度越高,对于MgO-CaO质耐火材料烧结性能的提升越明显,有利于抗水化性能的提高。
[Abstract]:In recent years, more and more attention has been paid to the production and research of MgO-CaO refractories for high grade steel products such as clean steel and special steel. The refractories have high fire resistance, high alkalinity and good slag resistance. It has the characteristics of strong peeling resistance, especially its internal free CaO has a good effect on purifying molten steel, and it is an indispensable and high quality refractory material for smelting clean steel and special steel, etc. However, the biggest disadvantage of MgO-CaO refractories is that CaO easily occurs hydration reaction in air, resulting in material pulverization. Many scholars at home and abroad have studied the hydration resistance of MgO-CaO refractories, which include two-step calcinations, additives, surface treatment, etc. The research direction of this subject is mainly to improve the hydration resistance of MgO-CaO refractories by two ways of two-step calcination and the introduction of Fe2O3 ZrO2 compound additive. This research mainly includes three steps: the first step is to improve the hydration resistance of MgO-CaO refractories. Using natural dolomite and natural magnesite as raw materials, the powder of MgO-CaO was prepared by crushing and grinding to less than 100 渭 m at different temperatures for 2 h, respectively. The highest light firing temperature was selected after activity test. The two kinds of powdered materials after light burning at the highest active temperature were mixed with 55% Fe2O3 ZrO2, respectively, according to the composition of 45% of the powder, and then different proportions of Fe2O3 ZrO2 compound additives were introduced into the mixture. The mass ratios of Fe _ 2O _ 3 and ZrO _ 2 in the composite additive were 0.52O3 1and 0.752O3, respectively. Finally, aluminum dihydrogen phosphate powder was added as binder, dried for 6h, compacted into 桅 50mm 脳 50mm cylindrical specimen at 100MPa, and burned at 1500 鈩，

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