Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第12卷    第3期    总第48期    2002年6月

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文章编号:1004-0609(2002)03-0596-06
超声波作用下钼酸铵溶液的结晶过程
尹周澜,吴争平,陈启元,张平民,李  洁

(中南大学 化学化工学院, 长沙 410083)

摘 要: 研究了超声波作用下钼酸铵溶液的结晶过程,揭示了超声波对四钼酸铵晶型的影响规律。研究表明,在无超声波作用下生成β型四钼酸铵的反应需1~2d,在超声波作用下只需十几分钟即可完成,并且发生晶型改变,生成了微粉型四钼酸铵。在实验基础上提出了钼酸铵溶液结晶的可能途径,并在RHF/3-21G和STO-3G水平上,对超声波作用下钼酸铵溶液结晶过程中所涉及到的H2Mo7O4-24, H8Mo8O4-30,(MoO2)(MoO3)x-12+(x=1,2,3),(NH4)4Mo8O26等进行量子化学从头计算,得到各研究体系的总能量和集居数。计算结果表明,当pH值为2.3~2.5时,超声波产生的特殊的“超声效应”可能使钼酸铵溶液中的H2Mo7O4-24变成[(MoO2)(MoO3)x-12+(x=1,2,3),从而生成微粉型四钼酸铵。

 

关键词: 超声波;钼酸铵溶液;结晶;量子化学从头计算

Crystallazition of ammonium
 molybdate solution under ultrasonic
YIN Zhou-lan,WU Zheng-ping,CHEN Qi-yuan,
ZHANG Ping-min,LI Jie

College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China

Abstract:The crystallization process of ammonium molybdate solution under ultrasonic was studied. The crystalline under ultrasonic were detected. It is indicated that ultrasonic has a great effect on the process of preparation β-type ammonium tetramolybdate. The crystallization time is shortened from 1~2d to 10~20min under ultrasonic and the crystalline converts into microcrystal-type under ultrasonic. The total energy and condensation of atoms of H2Mo7O4-24, H8Mo8O4-30, [MoO2)(MoO3)x-12+(x=1,2,3) and (NH4)4Mo8O26 were computed at the HF/3-21G, STO-3G level. The calculation results show that the transformation from H2Mo7O4-24 to [(MoO2)(MoO3)x-12+(x=1,2,3) at pH 2.3~2.5 is the reason of crystallization of microcrystal-type under ultrasonic.

 

Key words: ultrasonic; ammonium molybdate solution; crystallization; abinitio

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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