Effect of CaO on Atmospheric Pressure Desilication of Sodium Aluminate Solution
Received:August 01, 2022   Revised:August 16, 2022   Accepted:August 30, 2022      Published Online:November 14, 2022
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DOI:doi:10.3969/j.issn.1007-7545.2022.12.009
KeyWord:lime; desilication; reaction mechanism; sodium aluminate solution; Bayer process
           
AuthorInstitution
YANG Zai-ming 东北大学设计研究院有限公司
WU Hong-fei 东北大学 冶金学院
PAN Xiao-lin 东北大学 冶金学院
YU Hai-yan 东北大学 冶金学院
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Abstract:
      The reaction behavior of CaO during desilication process of sodium aluminate solution was systematically investigated by analyzing the producing quantity, phase composition and morphology of desilication products with XRD and SEM-EDS methods. The results show that the amount of desilication products rise gradually with the increase of calcium ratio and reaction time. The desilication products mainly include four phases, i.e., tricalcium aluminate hexahydrate, hydrogarnet, zeolite-A and zeolite. The increasing of calcium ratio and reaction time is beneficial to the conversion of desilication products tricalcium aluminate hexahydrate to hydrogarnet, and the corresponding lattice constant and unit cell volume of desilication products increase continuously. The morphology of different types of desilication products is quite different, and the precipitation sequence of desilication products is as follows: tricalcium aluminate hexahydrate, hydrogarnet, zeolite-A, and zeolite.
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