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为了研究铁铝尖晶石加入量对镁铁铝尖晶石砖的性能影响,本实验以粒度为3~1 mm、1~0 mm、≤0.088 mm的97高纯镁砂和1~0 mm的电熔铁铝尖晶石为原料,讨论了铁铝尖晶石加入量分别为3%、6%、9%、12%和15%时镁铁铝尖晶石砖的性能,利用XRD分析了试样的物相变化,采用SEM分析了烧后试样的微观结构。结果表明:铁铝尖晶石加入量为6%时,镁铁铝尖晶石砖有较高的体积密度和耐压强度以及较低的显气孔率,铁铝尖晶石加入量越多,镁铁铝尖晶石砖的荷重软化温度越低,铁铝尖晶石加入量3%~6%之间为宜。从显微结构照片中可以看出铁铝尖晶石周围生成的尖晶石环和环形裂纹,这是高温过程中部分铁铝尖晶石与方镁石发生离子交换反应所致,这种结构对镁铁铝尖晶石砖的结构柔韧性起着一定的作用。 相似文献
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水泥窑烧成带用镁铁铝尖晶石砖的研制 总被引:3,自引:0,他引:3
为了满足水泥窑烧成带用砖无铬化的要求, 以粒度3.5~1mm、<1mm、<0.088mm的高铁镁 砂和粒度<2mm的铁铝尖晶石为原料,分别讨论了 1500℃、1550℃、1600℃、1650℃的烧成温度和 5%、7%、9%、11%的铁铝尖晶石加入量对镁铁铝尖 晶石砖性能的影响。结果表明:当烧成温度为1600 ℃时,试样已烧结;当铁铝尖晶石加入量为7%时,试 样的耐压强度与粘结强度最高(用粘结强度表征材 料的挂窑皮性)。与直接结合镁铬砖相比,镁铁铝尖 晶石砖在热震稳定性方面更优于直接结合镁铬砖,而 在粘挂窑皮性能方面与其相近。 相似文献
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以铁鳞和特级矾土为原料,分别采用埋石墨和在试样中加入石墨两种方式合成铁铝尖晶石.利用XRD检测了合成试样的物相组成,采用SEM观察和分析了合成试样物相的微观形貌分布.将合成的铁铝尖晶石加入到MgO-MgO·Al2O3系耐火材料中,研究了铁铝尖晶石含量对镁铝铁系耐火材料热震稳定性和挂窑皮性的影响.研究结果表明:采用埋石墨方式更有利于铁铝尖晶石的形成和致密化.当铁铝尖晶石含量为8%时,试样抗折强度剩余率为85%,比没加铁铝尖晶石的试样高,明显提高了热震稳定性;随着铁铝尖晶石含量的增加,挂窑皮效果增强,当铁铝尖晶石含量为8%时,砖与熟料之间结合紧密,而没有加入铁铝尖晶石的试样,砖与熟料之间有明显的缝隙. 相似文献
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方镁石–铁铝尖晶石耐火材料在水泥回转窑烧成带取得良好使用效果,这与其高温下同水泥熟料之间的反应行为密不可分。利用扫描电子显微镜、X射线衍射仪与Factsage模拟等手段研究了镁砂和铁铝尖晶石颗粒以及方镁石–铁铝尖晶石砖高温下与水泥熟料的作用行为。结果表明:镁砂具有优异的抗水泥熟料侵蚀性能,铁铝尖晶石与水泥熟料高温反应生成大量高温液相,并逐渐被蚕蚀。对于方镁石–铁铝尖晶石砖,方镁石物相和铁铝尖晶石颗粒高温下抵抗水泥熟料侵蚀表现出协同作用。以方镁石为主晶相的基质与水泥物料反应生成高熔点物相,在晶界相内形成骨架结构,提高了晶界相的高温粘度,促进了水泥熟料与耐火材料的结合。同时,铁铝尖晶石与方镁石之间的离子交换促进了铁铝尖晶石颗粒与方镁石基质的结合,抑制了高温下与水泥物料反应时长石类低熔点相的产生,提高了铁铝尖晶石的高温稳定性,有利于该类耐火砖在烧成带使用时窑皮的稳定。 相似文献
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以反应烧结铁铝尖晶石和镁砂为原料,研究了添加1%、3%、5%、7%、9%和11%反应烧结铁铝尖晶石对制备镁铁铝尖晶石耐火材料的性能影响。利用XRD分析试样的物相组成,SEM观察试样的微观结构。结果表明:在1%~11%范围内,随着铁铝尖晶石添加量的增加,镁铁铝尖晶石耐火材料的热震稳定性和挂窑皮性能提高,但荷重软化温度降低;铁铝尖晶石加入量为5%时,镁铁铝尖晶石耐火材料有较大的体积密度、较高的常温耐压强度和较小的显气孔率。 相似文献
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分别以烧结铁铝尖晶石、电熔铁铝尖晶石、烧结镁铁砂及电熔镁铁砂为铁的载体,在控制试样化学组成接近前提下,按照镁铁铝尖晶石砖生产工艺制备镁铁铝尖晶石砖试样.检测试样的理化性能并采用XRD和SEM对试样的相组成和显微组织结构进行表征.结果表明:以两种镁铁砂为铁载体的试样体积密度高、显气孔率低、常温耐压强度大及热膨胀率小;以电熔铁铝尖晶石、电熔镁铁砂为铁载体的试样具有较高的荷重软化温度.以铁铝尖晶石为铁载体试样中,形成(Mg,Fe) Al2O4相,铁以Fe2+形式存在;以镁铁砂为铁载体试样中,形成Mg(Fe,Al)2O4相,铁以Fe3+形式存在;以烧结铁铝尖晶石、烧结镁铁砂为铁载体的试样显微结构中存在较多微气孔,以电熔铁铝尖晶石、电熔镁铁砂为铁载体的试样显微结构较为致密. 相似文献
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Synthesis of hercynite by reaction sintering 总被引:1,自引:0,他引:1
Junhong Chen Lingyan YuJialin Sun Yong LiWendong Xue 《Journal of the European Ceramic Society》2011,31(3):259-263
Hercynite was synthesized by a reaction sintering method using industrial alumina, mill scale, and carbon black as starting materials in the presence of nitrogen and solid carbon at high temperatures. Phase and microstructure changes during the synthesis were investigated. The specimen sintered at 1450 °C consisted of hercynite (FeO·Al2O3), Al2O3, Fe2O3, Fe3O4 and others. In contrast, the specimens sintered at 1550 and 1650 °C only showed hercynite phase, which exhibited typical octahedral or cubic structures. The results showed that by controlling the atmosphere and the addition of reactants, the transformation from Fe3O4 to FeO was controlled, and the reduction of FeO by carbon was restrained, which extended the temperature range at which FeO could exist stably, thus making it feasible to prepare high-purity hercynite by a reaction sintering method. The firing temperature of high-purity hercynite should be above 1550 °C. 相似文献
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以氧化铁粉、α-Al2O3粉、石墨为主要原料,分别外加质量分数为0、2%、5%和8%的钛白粉,以亚硫酸纸浆废液为结合剂混练均匀后,压制成型为50 mm×50 mm的试样,于100℃干燥24 h,在氮气气氛中分别于1400、1450、1500和1550℃保温4 h煅烧,然后检测烧后试样的体积密度,并分析其物相组成和显微结构。结果表明:在氮气气氛下,TiO2的引入能降低铁铝尖晶石的合成温度,1450℃煅烧后铁源几乎完全转化为铁铝尖晶石;TiO2的引入能明显促进铁铝尖晶石的烧结,引入2%质量分数的钛白粉的试样体积密度最高,物相组成最好;引入多于2%质量分数的钛白粉的试样中有一定量的Fe2TiO5-Al2TiO5固溶相生成,试样体积密度下降,而且随着温度升高,Ti4+更容易被还原而抑制Fe3+还原,从而阻碍铁铝尖晶石的合成。 相似文献
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《Carbon》2013
A multiwall carbon nanotube (MWCNT)/hercynite (FeAl2O4) hybrid nanomaterial was synthesized by one-step chemical vapor deposition (CVD) using acetylene as precursor and FeOx–AlOOH xerogel as catalyst. The hybrid material was composing by hercynite nanoparticles (diameter 10–50 nm) intimately attached to the walls of the MWCNTs. The diameter of the MWCNTs was related to particle size of the catalyst. The hybrid nanomaterial exhibited a characteristic magnetic behavior that can be considered as a combination of superparamagnetism and ferromagnetism, with a saturation magnetization of 5.7 emu/g at an applied field of 18 kOe and a coercivity of 520 Oe. The hybrid displayed a relatively low pHZPC (approx. 3.2) and formed very stable aqueous suspensions at pH 5.5. Controlled oxidation of the hybrid generated oxidized functional groups, as –OH and –COOH, and promoted the transformation of hercynite to hematite. Due to the high dispersibility of the hybrid in water, it presents an interesting potential as nanofiller for hydrophilic polymers. 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献