共查询到19条相似文献,搜索用时 125 毫秒
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以粉煤灰为原料,采用湿法加碱煅烧法合成了4A分子筛,研究了粉煤灰与烧碱配比、煅烧温度、煅烧时间对合成4A分子筛的影响,结果表明粉煤灰与烧碱配比1.0:0.8,煅烧温度700℃,煅烧时间1 h有利于4A分子筛的合成.利用合成的4A分子筛对水体中六价铬进行了吸附研究,实验确定的最佳吸附条件为:分子筛投加量为0.3 g,溶液pH值为6~7,吸附时间为30 min,吸附温度为10~25℃.最佳吸附条件下分子筛对六价铬有较好的去除效果.吸附以物理吸附为主,符合Freundlich等温吸附式.同时对4A分子筛的再生性进行了研究,2次循环使用后其吸附能力仍能保持初次吸附能力的90.0%以上. 相似文献
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本实验以内蒙古某电厂排放的粉煤灰为原料,根据粉煤灰的结构特点采用酸法-碱法合成A型分子筛,本论文的主要目的是确定利用粉煤灰合成A型分子筛的最佳条件以及负载SiO_2最佳的固化时间。研究用CaO作助溶剂,助溶剂与粉煤灰中SiO_2的摩尔比为0.6,放入马弗炉中温度为850℃下焙烧2h。取一定量改性的粉煤灰,酸法-碱法-合成4A分子筛,先用6mol/L的盐酸,固液比为8:1提取其中的Al(OH)_3,然后将抽滤得到的滤饼中加入8mol/L的氢氧化钠,固液为8:1在95℃的恒温条件下搅拌6h,取滤液,最后将Al(OH)3和含有Na_2SiO_3滤液混合放入高压反应釜中合成4A分子筛,考查了合成分子筛的晶化温度、晶化时间。确定最佳反应条件为:晶化温度T=95℃;晶化时间t=6h。 相似文献
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本试验以内蒙古锡林郭勒盟粉煤灰为原料,采用500℃低温碱融-水热法合成了4A分子筛,并加入了导向剂,有效减少了晶化时间.以4A分子筛的Ca2交换能力为指标,并运用XRD、SEM、FT-IR对生成的4A分子筛进行表征,通过正交试验对合成工艺进行了探究.结果表明:在500℃下碱融活化2h后,粉煤灰中的石英和莫来石晶体结构被完全破坏.原料配比为n(SiO2):n(Al2O3)=2.1,n(Na2O):n(SiO2) =2.2,晶化温度50 ℃,晶化时间30 h,在此条件下生成了纯净的4A分子筛,粒径约为2μm,对Ca2的交换能力为310 mg/g. 相似文献
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《国际聚合物材料杂志》2012,61(1):75-88
This paper deals with the preparation and characterization of poly(ether-ether-ketone) (PEEK) fly ash mica hybrid composites containing filler 5:15, 10:10 and 15:5 fly ash mica combinations loading. The performances and properties of the resulting 20 wt% loading of fly ash mica/PEEK hybrid composites were examined. The resulting hybrid composites of 20 wt% fly ash and mica with varying combinations exhibit the optimum improvement of mechanical properties and dielectric strength. MDSC showed the decrease in the crystallization temperature (Tc) with varying combinations of fly ash and mica. The morphology of fly ash/mica/PEEK hybrid composites was studied by SEM. 相似文献
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Influence of hydration variables on the properties of South African calcium/siliceous-based material
D.O.OGENGA Z.O.SIAGI M.S.ONYANGO M.MBARAWA 《Frontiers of Chemical Engineering in China》2009,3(1):46-51
This study presents findings from experiments on the preparation and characterization of locally available fly ash, quicklime
and the CaO/fly ash sorbent, synthesized using the atmospheric hydration process. The CaO was obtained from calcination of
limestone in a laboratory kiln at a temperature of 900°C. The sorbents were prepared under different hydration conditions:
CaO/fly ash weight ratio (1°1 to 1°3), hydration temperature (55°C–75°C) and hydration period (4–8 h). Results show that the
specific surface area of CaO/ fly ash sorbents (8.8–23.6 m2/g) was higher than that of the CaO (4.78 m2/g) at all preparation conditions. The SEM micrographs show that the prepared sorbent had a more porous structure than either
the fly ash or the CaO. The X-ray diffraction (XRD) analysis shows the presence of complex compounds containing calcium silicate
hydrate in the synthesized sorbents. This contributed to the high BET specific surface area. The Brunauer-Emmett-Teller (BET)
specific surface area was found to decrease with increase in the amount of fly ash with the ratio of 1:1 (CaO/Fly ash) giving
the highest value. It was also found that an increase in the hydration time resulted in an increased BET specific surface
area, although there was only a slight effect on the same by an increase in temperature. 相似文献
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《Ceramics International》2023,49(10):15655-15664
Recycling fly ash for ceramic membrane fabrication not only reduces solid waste discharge, but also decreases the membrane cost. Now, fly ash is becoming a promising substitute material for ceramic membrane preparation. A significant difference between fly ashes from different plants is the particle size, which makes performances of fly ash membranes unpredictable. The novelty of this work is to clarify the effects of the particle size of fly ash on ceramic membranes, thereby giving practical suggestions on fly ash selection for ceramic membrane preparation. Ceramic membranes were fabricated with different sizes of fly ashes. Effects of particle size on porosity, pore size, microstructure, mechanical strength and gas permeability of the membrane were investigated. Results indicate that a broader particle size distribution of fly ash leads to a denser structure of membrane with a lower porosity. Pore size and gas permeability of membrane increase while bending strength decreases with the particle size increasing. Bending strength of a fly ash membrane is largely determined by large particles in the fly ash because the large particles lead to cracks in the membrane. This work provides experimental bases for developing high performance ceramic membranes from fly ash. 相似文献
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在工程实践中,作为装配式建筑的墙体材料,既要有较好的保温隔热性能,又要满足一定的力学性能。轻质泡沫混凝土是一种很好的选择,但普通的泡沫混凝土材料在满足热工性能时其力学性能往往表现较差。本文提出一种高强度低导热泡沫混凝土制备方法,研究了水胶比、泡沫掺量、粉煤灰掺量和聚丙烯(PP)纤维掺量对泡沫混凝土的抗压强度和导热系数的影响,并采用扫描电镜(SEM)探究了粉煤灰和PP纤维对泡沫混凝土微观形貌的影响。结果表明:当水胶比为0.6、泡沫掺量为4%(质量分数,下同)、粉煤灰掺量为25%以及PP纤维掺量为0.2%时,泡沫混凝土的抗压强度较高且导热系数较低。 相似文献
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针对粉煤灰粒度细小带来的分离困难等问题,研究了一种粉煤灰制备多孔水处理材料的方法。对成型过程中石灰添加量、铝粉添加量、粉煤灰粒度以及搅拌速度等影响因素进行了研究。分别考察了成型试件的吸水率、COD去除率、氨氮去除率、抗压强度、干体积密度以及抗冻性能。结果表明最佳制备条件为:粉煤灰:石灰:石膏:水泥:铝粉:水:十二烷基苯磺酸钠为34.5:10.5:2:4:0.056:35:0.15,粉煤灰、石灰、石膏、水泥粒度为O.075mm,搅拌速度为400r/min。制得的多孔试件各项指标为:于体积密度约为540-590kg/m^3,抗压强度为0.7~0.9MPa,吸水率为70%-80%,COD去除率为22%左右,氨氮去除率为38%左右,冻融后质量损失为2.5%左右,冻后抗压强度为0.5MPa,均达到较优水平,是一种很好的水处理材料。 相似文献
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粉煤灰制备氧化铝的研究进展 总被引:1,自引:0,他引:1
目前国内外由粉煤灰制备氧化铝的方法主要为酸浸法和碱熔法。分别从各制备工艺的特点、优点及其存在的问题等方面进行评述,并对其发展趋势进行了阐述。指出采用新工艺和新技术提高粉煤灰中的氧化铝的活化程度,碱熔法具有较好的工业应用前景。 相似文献