超声波作用下钼酸铵溶液的结晶过程  

Crystallization of ammonium molybdate solution under ultrasonic

作　　者：尹周澜[1] 吴争平[1] 陈启元[1] 张平民[1] 李洁[1] 

机构地区：[1]中南大学化学化工学院,长沙410083

出　　处：《中国有色金属学报》2002年第3期596-601,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目 ( 5 99340 80 )

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 2 1G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H2 Mo7O4 -2 4 ,H8Mo8O4 -3 0 ,[(MoO2 ) (MoO3 ) x -1]2 + (x =1,2 ,3) ,(NH4 ) 4Mo8O2 6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H2 Mo7O4 -2 4 变成 [(MoO2 ) (MoO3 ) x -1]2 + (x=1,2 ,3) 。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 1～2?d to 10～20?min under ultrasonic and the crystalline converts into microcrystal-type under ultrasonic. The total energy and condensation of atoms of H 2Mo 7O 4- 24, H 8Mo 8O 4- 30, [(MoO 2)(MoO 3) x-1] 2+(x=1, 2, 3) and (NH 4)4Mo 8O 26 were computed at the HF/3-21G, STO-3G level. The calculation results show that the transformation from H 2Mo 7O 4- 24 to [(MoO 2)(MoO 3) x-1] 2+(x=1, 2, 3) at pH 2.3～2.5 is the reason of crystallization of microcrystal-type under ultrasonic.

关 键 词：超声波 钼酸铵溶液 结晶 量子化学从头计算 钼粉 

分 类 号：TF123.24[冶金工程—粉末冶金]