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

您目前所在的位置:首页 - 期刊简介 - 详细页面

中国有色金属学报(英文版)

Transactions of Nonferrous Metals Society of China

Vol. 13    No. 3    June 2003

[PDF Download]        

    

Decomposition of supersaturated 
sodium aluminate solution
CHEN Qi-yuan(陈启元), LI Jie(李 洁),
YIN Zhou-lan(尹周澜), ZHANG Ping-min(张平民)

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

Abstract:The decomposition of supersaturated sodium aluminate solution in the process of alumina production was reviewed. Some fundamental problems, such as the structure of supersaturated sodium aluminate solution and the growth unit of gibbsite precipitation as well as the decomposition mechanism of sodium aluminate solution, were investigated by model analytic technique and theoretical calculation. It is found that the main Al-contained species is S4 symmetric Al(OH)4(H2O)4-. Na↑+
(H2O)4·Al(OH)-4]is found to form in intermediate concentrated solution while[Na+(H2O)2·Al(OH)-4]in highly concentrated solution. Meanwhile, it is proved that
[(H2O)2Al(OH)4- is the basic growth unit of gibbsite and[Al6(OH)18(H2O)6]is a favorable growth unit. Based on above results and ab initio quantum mechanical calculation and transition state theory, a reaction pathway of the decomposition of supersaturated sodium aluminate solution was put forward, in which the transformation of pentacoordinate aluminates ion to hexacoordinate basic growth unit as well as the formation of circled growth unit [Al6(OH)22(H2O)24- are the controlling steps.

 

Key words:  sodium aluminate solution; structural properties; decomposition mechanism; growth unit

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

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

主管:中国科学技术协会 主办:中国有色金属学会 承办:中南大学
湘ICP备09001153号 版权所有:《中国有色金属学报》编辑部
------------------------------------------------------------------------------------------
地 址:湖南省长沙市岳麓山中南大学内 邮编:410083
电 话:0731-88876765,88877197,88830410   传真:0731-88877197   电子邮箱:f_ysxb@163.com