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排序方式: 共有71条查询结果,搜索用时 62 毫秒
41.
M. Kaloumenou E. Badogiannis S. Tsivilis G. Kakali 《Journal of Thermal Analysis and Calorimetry》1999,56(2):901-907
This paper reports an investigation of the effect of the particle size of kaolin on its transformation to metakaolinite. Kaolin
from the island of Milos was either crushed or ground in order to produce four samples with different degrees of fineness
(residue at 500 μm: 0–71.8%). The samples were treated thermally under different conditions in order to determine the optimum
treatment conditions. The conversion of kaolinite to metakaolinite and the structural changes in the material during treatment
were investigated by means of TG and XRD, respectively. Each sample was incorporated into a type I cement, at 20% by mass
of cement, and the compressive strengths of the resulting blended cements were measured. It is concluded that the particle
size of the raw kaolin does not affect the thermal conversion or the pozzolanic activity of the material. The use of crushed
kaolin has many benefits since the furnace load can be increased, while the grinding process is needed only to reduce the
size of the metakaolinite particles.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
42.
两种UHMWPE/Kaolin复合材料在干摩擦条件下的滑动摩擦磨损性能研究 总被引:10,自引:2,他引:8
在MM-200型磨损试验机上分别对以釜内聚合和熔融机械混合方法制备的高岭土填充超高分子量聚乙烯基复合材料(UHMWPE/Kaolin)在干摩擦条件下与45^#钢对摩时的摩擦磨损性能进行了研究,并用扫描电子显微镜和立体光学显微镜对其磨损表面进行了观察与分析,对材料的磨损机理进行了探讨。结果表明:引入适量的高岭土能明显降低UHMWPE的摩擦系数和磨损率,用釜内聚合方法制备的UHMWPE/Kaolin复 相似文献
43.
采用LiBO2熔样,X射线荧光光谱仪测定了高岭土的化学组成,结果表明,测定值与化学法及推荐值相符,重复测定高岭土主、次量组分的相对标准偏差小于0.83%,方法简便快捷,分析时间仅为传统湿法化学分析的1/8,应用于高岭土的测定,结果满意。 相似文献
44.
准东煤掺烧高岭土对固钠率及灰熔融特性影响研究 总被引:1,自引:0,他引:1
准东煤掺烧高岭土对固钠率及灰熔融特性影响研究 《燃料化学学报》2015,43(9):1044-1051
选择常见的黏土矿物高岭土作为准东煤添加剂掺烧,研究了不同掺混比例、不同燃烧温度下添加剂的固钠率和煤灰熔融特性的变化,结合XRD谱图和三元相图研究了灰中矿物在高温下的演变过程。结果表明,固钠率随高岭土掺混比例增加逐渐增大,在0~2%时增长较快,2%~5%增长较慢,随燃烧温度升高略微下降;掺混后煤灰熔点随掺混比例先缓慢减小,再快速减小,后快速增加,在3%时达到1 200 ℃左右;XRD和三元相图分析结果表明,煤灰熔融特性变化是由于灰中硅钙石、钙黄长石和钙长石矿物比例的变化引起,发生低温共熔现象是导致掺混比例为3%和4%时煤灰熔点最低的主要原因;当掺混比例为2%时,固钠率在60%以上且灰熔点在1 300 ℃左右,利于固态排渣,当掺混比例为3.0%~4.0%时,灰熔点在1 200 ℃左右,利于液体排渣。 相似文献
45.
Tarek S. Jamil Hany H. Abdel Ghafar Hanan S. Ibrahim Islam H. Abd El-Maksoud 《Solid State Sciences》2011,13(10):1844-1851
The optimum condition as well as adsorption behavior of two zeolite types prepared from Egyptian kaolin (namely, zeolite A and zeolite X) with methylene blue (MB) are demonstrated in this study. This will be a step to remove such dyes from textile as well as dying industries.MB removal was investigated using synthetic solutions at initial concentrations 15 mg/L of MB at constant temperature and pH (25 ± 0.1 °C and 7.5 ± 0.2) respectively. The removal efficiency was determined at different contact times and different zeolite doses.The optimum contact times for the removal of MB were 60 min and 75 min for zeolite X and zeolite A, respectively. 0.6 g was the optimum dose for removal of MB with both zeolite types.The batch method has been employed, using MB concentration in solution ranging from 2 to 25 mg/L. The percentage removal and distribution coefficients (Kd) were determined for the adsorption system as a function of sorbate concentration. The isothermal models investigated in this study show that adsorption ratios of MB on both zeolites match to Langmuir and Freundlich equation adding to that every equation constant has been calculated. According to the equilibrium studies, adsorption of zeolite X in higher concentrations is much better than that of zeolite A. Dublin–Kaganer–Radushkevich (DKR) shows physisorption endothermic adsorption process for both zeolites and also linear correlation of Redlich–Peterson and Tekman isothermal models were proved.These results show that zeolites prepared from naturally abundant Egyptian kaolin hold great potential to remove dying materials such as MB from wastewater. This will encourage using such low cost technique in removal of dyes from industrial wastewater. 相似文献
46.
47.
Hartati Didik Prasetyoko Mardi Santoso Imroatul Qoniah Wai L. Leaw Putri B. D. Firda Hadi Nur 《中国化学会会志》2020,67(6):911-936
Zeolite is extensively synthesized for the application in a large variety of catalysis processes such as ion exchange, hydrocarbon cracking, and organic synthesis. In order to satisfy the serious terms of sustainability that denotes to the reduction of costs and chemical waste, kaolinite-based zeolites were produced from cheap natural resources as against to the conventional process that employs pure sodium silicate and sodium aluminate. This review paper is to highlight the current trends in the synthesis of zeolite. Prior to previous reviews, great concern is focused on the impurities effect on the catalytic performance of kaolinite-based zeolites. This study reveals that the impact of impurities in a catalytic reaction was in fact, underestimated or neglected. For instance, it was found that Fe ion concentration as small as 60 ppm gives significant catalytic output. Hence, a new practice to report the concentration of impurities in the research publication is suggested. This undoubtedly will generate a better interpretation of the catalytic activity from the zeolite framework. 相似文献
48.
G. Srihari 《合成通讯》2013,43(5):896-906
Michael addition of various active methylene compounds to β-nitrostyrenes is efficiently catalyzed by using Kaolin preloaded with KOH in acetonitrile at room temperature with moderate to good yields. 相似文献
49.
50.
Maria F. Gazulla M. Jesús Ventura Marta Rodrigo Jéssica Gilabert 《Analytical letters》2018,51(12):1956-1972
Water may be present in clayey materials in different forms (hydration water and structural water), providing different properties to the materials such as reactivity and plasticity, and affecting the industrial processes in which they are involved, resulting in the importance of the determination these types of water. In addition, some clayey materials such as bentonites or sepiolites, present very high avidity for water, which must be considered in the characterization of the materials, and especially in the structural water content determination. In the literature, no rapid and accurate methods for the determination of structural water content in this type of clayey materials are described and validated, so to fill the lack of a methodology for determining structural water, a method by combustion and infrared detection has been established. In the development of the methodology, the sample preparation was the most important step, in which the drying process of the samples had particular relevance. The time and temperature of drying and the maximum time that the samples can be stored in the desiccator before the analysis were evaluated. The development of the measurement method was performed optimizing the conditions and constructing calibration curves. The developed methodology was validated using reference materials. Finally, several clayey materials (sepiolites, bentonites, and kaolin) were analyzed using the developed methodology. The results were compared with those obtained by differential thermal analysis-thermogravimetry (DTA-TG), concluding that the DTA-TG analysis is only useful for the determination of structural water when the materials do not contain carbonates (e.g., calcite, dolomite). 相似文献