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首页> 外文期刊>Journal of Materials Science >Formation process of Na-X zeolites from coal fly ash
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Formation process of Na-X zeolites from coal fly ash

机译：粉煤灰形成Na-X沸石的过程

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摘要

In order to synthesize Na-X zeolite from coal fly ash (Fa), Fa was pretreated under stirring condition at various temperatures of 20–50°C for 72 h and then aged at 85°C for a given period with NaOH solutions. The resulting materials were characterized by various means. When Fa was aged for 72 h without pretreatment, species P were formed. As the pretreating temperature raised from 20 to 50°C, the degree of crystallinity of faujasite increased, while that of species P decreased. The faujasite species formed was identified as Na-X zeolite with molar ratio SiO2/Al2O3 = 2.4. When Fa was pretreated at 50°C and aged for 60 h, the only species formed was Na-X zeolite. Increasing the pretreating temperature up to 50°C results in the increase of Si4+ and Al3+ concentrations in the treating solution by dissolution of amorphous material in Fa. With the conditions used, the crystalline phase, such as α-quartz and mullite, was poorly dissolved during the treatment. Hence, the higher pretreating temperature would give the uniform nucleation and crystal growth of Na-X zeolite during the aging.
机译：为了由粉煤灰（Fa）合成Na-X沸石，在搅拌条件下于20–50°C的各种温度下对Fa进行了72 h的预处理，然后在NaOH溶液中于85°C的条件下老化了一定的时间。所得材料通过各种手段表征。当Fa进行72 h老化而没有进行预处理时，形成了P物种。随着预处理温度从20升高到50°C，八面沸石的结晶度增加，而P物种的结晶度下降。形成的八面沸石种类为Na-X沸石，摩尔比为SiO2 / Al2 O3 。当Fa在50°C预处理并老化60小时时，形成的唯一物种是Na-X沸石。将预处理温度提高到50°C，会导致非晶态材料溶解在Fa中而导致处理液中Si4 +和Al3 +的浓度增加。在所使用的条件下，诸如α-石英和莫来石的结晶相在处理期间几乎不溶解。因此，较高的预处理温度将在老化过程中使Na-X沸石具有均匀的形核和晶体生长。

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  • 来源
    《Journal of Materials Science》 |2004年第5期|1677-1682|共6页
  • 作者

    H. Tanaka; S. Matsumura; R. Hino;

  • 作者单位

    Department of Material Science Faculty of Science and Engineering Shimane University;

    Department of Material Science Faculty of Science and Engineering Shimane University;

    Department of Material Science Faculty of Science and Engineering Shimane University;

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