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以棕刚玉(8~1mm)、白刚玉(≤3mm)为骨料,以白刚玉细粉(≤0.045 mm)、-Al2O3微粉(≤5 m,50=2.01 m)、电熔镁砂细粉(≤0.074mm)、硅灰((SiO2)>94%)为基质,以-Al2O3微粉为结合剂,以六偏磷酸钠为减水剂制备铝镁质浇注料,采用废镁铬砖细粉等量代替电熔镁砂细粉,研究了废镁铬砖细粉质量分数(分别为0、1%、2%、3%)对铝镁浇注料性能的影响。试验结果表明:随着废镁铬砖细粉加入量的增大,试样的烘后和烧后强度均提高,体积密度增大,显气孔率减小、线变化率先增大后减小;但抗热震性有所降低、高温抗折强度稍有增大,这主要与高温下废镁铬砖细粉和刚玉细粉生成多种固溶体的量有关。 相似文献
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高炉用Al2O3-SiC-C质铁沟浇注料的高温性能主要与水泥的加入量有关,为了探明水泥与Al2O3-SiC-C铁沟浇注料性能的相关性及如何提高Al2O3-SiC-C铁沟浇注料的高温使用性能,对水泥加入量对材料性能的影响。本文以电熔棕刚玉颗粒、碳化硅颗粒与细粉、硅微粉、α-Al2O3微粉、白刚玉微粉、Secar71水泥、Si粉、球沥青为主要原料,分别加入质量分数为0、0.4%、0.6%、1%、1.5%的水泥等量替代白刚玉微粉,外加质量分数为4.5%的水搅拌均匀,振动浇注成型,研究了水泥加入量对浇注料经各温度热处理后常温物理性能及高温抗折强度的影响。结果表明:随着水泥加入量的增加,试样110℃烘干24 h后的体积密度及抗折耐压强度逐渐增大,1 500℃保温3h后的体积密度及强度逐渐降低。其原因分析水泥的增加会形成更多的钙长石、钙黄长石等低共熔相,水泥加入少,高温下低共熔相形成少,形成较多莫来石晶相,对高温性能有利,但水化产物少,常温性能要求得不到保障。加入水泥质量分数为0.6%时,浇注料的综合性能最好。根据试验实研究结果,添加0.6%水泥的铁沟浇注料在铁沟应用中取得了较好的效果。 相似文献
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研究了α-Al2O3纳米复合高纯刚玉砖基质中的微粉、α-Al2O3纳米粉的加入量对基质流变性的影响,结合试样的烧后性能确定其基质的最佳颗粒组成。结果表明:随着α-Al2O3微粉加入量的增加,泥浆的粘度和剪切应力逐渐减小,当α-Al2O3微粉加入质量分数为14%时,粘度值最低,继续增加α-Al2O3微粉,泥浆的粘度和剪切应力逐渐升高;随着α-Al2O3纳米粉加入量的增加,泥浆的粘度和剪切应力逐渐增大。固定微粉含量,随着α-Al2O3纳米粉加入量的逐渐增加,刚玉砖的体积密度、常温抗折强度及高温抗折强度先增大后减小,当α-Al2O3纳米粉加入量为1%时,三者均达到最大值。综合以上研究,确定基质颗粒组成为:纳米粉含量为1%,微粉含量为8%,细粉为31%。 相似文献
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以镁铝尖晶石为骨料、等摩尔的氧化镁粉和氧化铝微粉为基质料,通过一步固相烧结法合成了水口内层用镁铝尖晶石质耐火材料,考察了原料组成、骨料粒度和成型压力对一步煅烧法制备镁铝尖晶石烧结性能的影响。研究结果表明,随着骨料粒度增大和基质料含量的增加,试样的烧结性变差,烧成试样的烧后线收缩率变小,显气孔率逐渐增大;随着成型压力的增加,烧成试样的显气孔率和烧后线收缩都明显减小。以80目尖晶石为骨料,按尖晶石:氧化镁粉:氧化铝微粉=20:40:40配比(mol%),并以200MPa的压力成型,可以获得结构致密、烧后线收缩率适中的尖晶石质水口内层材料。 相似文献
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《工业加热》2020,(2)
以电熔棕刚玉、97碳化硅、硅微粉、Al_2O_3微粉、白刚玉微粉、Secar71高铝水泥、金属硅粉、高温沥青粉及Carbores P为主要原料,先分别以0、1%、2%、3%的高温沥青粉替代白刚玉粉,外加质量分数为4. 5%的水均匀搅拌,振动成型,探究了高温沥青粉加入量对浇注料流动性、常温物理性能及高温抗折强度的影响,确定了高温沥青粉的最佳加入量;以此为基础,再分别以0、0. 5%、1%、1. 5%的Carbores P等量替代白刚玉粉,外加质量分数为4. 8%的水搅拌均匀,振动浇注成型,进一步研究了Carbores P对浇注料性能的影响。结果表明:随着高温沥青粉加入量的增加,相同加水量浇注料的流动性变差,体积密度减小,显气孔率升高,强度降低,当高温沥青粉加入质量分数为2%时,浇注料的综合性能最佳;在沥青粉确定为2%加入量的前提下,外加1%的Carbores P可以使该浇注料的强度增加,抗氧化性较好,但当Carbores P加入量超过1%后,浇注料流动性显著降低,显气孔率升高,强度降低。根据研究结果,以2%质量分数的高温沥青粉配合1%质量分数的Carbores P作为复合碳源制备的Al_2O_3-SiC-C铁沟浇注料,在现场应用中取得了较好的效果。 相似文献
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由于Al的烧损,炉渣中w(Al2O3)明显增加,w(CaO)明显降低,而w(MgO)降低幅度不大.通过CaO-Al2O3-MgO渣系对钢液洁净度影响的实验表明,钢液中硫含量基本呈先降低后增加的趋势,钢液中氮和氧的含量基本呈降低的趋势,与溶解速率实验的结果基本相符,炉渣成分为50%CaO-45%Al2O3-5%MgO时脱氧速率常数最大. 相似文献
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P. Senthilkumar R. Manimaran Y. Krishna Reddy 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2021,43(2):216-224
ABSTRACT Hybrid nanocomposites are prepared by Al7009 aluminum alloy as base material,graphite and nano magnesium oxide (MgO) as reinforcements. Stir casting processes are used for preparation of hybrid nanocomposite, the percentage of graphite is fixed at 1 wt.% and nano magnesium oxide is varied for 1%, 2%, and 3% by weight and the specimens are named as A (pure), B (1% graphite and 1% MgO), C (1% graphite and 2% MgO), and D (1% graphite and 3% MgO). Evaluation of mechanical properties such as compressive strength, hardness, density, and impact strength behavior of hybrid Al7009 nano aluminum composites are analyzed. From the experimental results, the compressive strength and hardness of hybrid nanocomposite increases up to 2% wt of nano MgO particles and then the value decreases for 3% wt of nano MgO particles. Density increases from the specimens A to C with an increase in percentage of reinforcement in the matrix phase and then it decreases for specimen D. With respect to toughness highest value of 4.4 Jis obtained for sample D and the increase in percentage was 62.9 when compared to sample A, it was 37.5% when compared to specimen B and 12.8% when compared to specimen C. 相似文献
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《International Journal of Hydrogen Energy》2022,47(58):24358-24373
Ni–Co/Mg(Al)O alloy catalysts with different Co/Ni molar ratios have been prepared from Ni- and Co-substituted Mg–Al hydrotalcite-like compounds (HTlcs) as precursors and tested for dry reforming of methane. The XRD characterization shows that Ni–Co–Mg–Al HTlcs are decomposed by calcination into Mg(Ni,Co,Al)O solid solution, and by reduction finely dispersed alloy particles are formed. H2-TPR indicates a strong interaction between nickel/cobalt oxides and magnesia, and the presence of cobalt in Mg(Ni,Co,Al)O enhances the metal-support interaction. STEM-EDX analysis reveals that nickel and cobalt cations are homogeneously distributed in the HTlcs precursor and in the derived solid solution, and by reduction the resulting Ni–Co alloy particles are composition-uniform. The Ni–Co/Mg(Al)O alloy catalysts exhibit relatively high activity and stability at severe conditions, i.e., a medium temperature of 600 °C and a high space velocity of 120000 mL g?1 h?1. In comparison to monometallic Ni catalyst, Ni–Co alloying effectively inhibits methane decomposition and coke deposition, leading to a marked enhancement of catalytic stability. From CO2-TPD and TPSR, it is suggested that alloying Ni with Co favors the CO2 adsorption/activation and promotes the elimination of carbon species, thus improving the coke resistance. Furthermore, a high and stable activity with low coking is demonstrated at 750 °C. The hydrotalcite-derived Ni–Co/Mg(Al)O catalysts show better catalytic performance than many of the reported Ni–Co catalysts, which can be attributed to the formation of Ni–Co alloy with uniform composition, proper size, and strong metal-support interaction as well as the presence of basic Mg(Al)O as support. 相似文献
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A.S. Fedotov D.O. Antonov O.V. Bukhtenko V.I. Uvarov V.V. Kriventsov M.V. Tsodikov 《International Journal of Hydrogen Energy》2017,42(38):24131-24141
The role of aluminum in the formation of Ni–Al–Co-containing porous ceramic membrane-catalytic converters (MCC) obtained by SHS method, which are high-active in dry and steam reforming of methane, ethanol and fusel alcohols into synthesis gas, was discovered. It was shown that the aluminum introduced into the charge through mechanical alloying leads to a significant increase in the catalytic activity of the converter in the studied processes, as compared to aluminum introduced by mechanical mixing. In this case, the addition of 5% aluminum to the initial nickel charge allows achieving of maximum productivity for syngas against other studied concentrations of Al. The Al content increase above the optimum leads to a significant formation of the catalytically inactive phase of Ni3Al intermetallide. TEM and X-ray diffraction methods show that due to oxidation-reduction phase transformations involving aluminum there occurs the formation of metal oxides on the basis of γ-Al2O3 with the structure of spinel having nanosized Ni–Co alloy particles formed on its surface during the reductive activation stage. 相似文献
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介绍了炼钢厂使用后废弃的镁碳砖的回收利用,将其制备成为w(MgO)> 40%的镁球,用于转炉炼钢,替代部分白云石作为造渣辅料,起到优化转炉冶炼造渣工艺、改善炼钢垃圾对环境污染的作用,实现了废弃镁碳砖在炼钢工艺中的全量利用. 相似文献
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南雄市百顺地区花岗岩体地质特征 总被引:1,自引:0,他引:1
初步研究了百顺地区花岗岩体的地质特征,主要以印支期和燕山期的花岗岩为主。该2期花岗岩体的SiO2和Al2O3质量分数较高,分别为63.60%~75.37%和12.12%~18.78%;SiO2与Al2O3、CaO、MgO、FeO、MnO、K2O、TiO2之间的负相关,以及与Na2O、P2O5之间的正相关都不是很明显。全碱(Na2O+K2O)质量分数均较高,为7.17%~13.77%,为过碱性花岗岩。铝饱和指数(ACNK)在0.92%~1.65%之间,碱度指数(A/NK)为1.06%~1.80%,为过铝质。 相似文献