Cathode Permeation Mechanism of Lithium in Aluminum Electrolysis

doi:10.12068/j.issn.1005-3026.2021.01.010

Abstract

Abstract: In the process of aluminum electrolysis， the proportion of lithium fluoride in electrolyte increases gradually due to the existence of a small amount of lithium oxide in alumina， and the lithium element permeates the cathode lining. The existent forms of lithium element in electrolyte and cathode carbon blocks were analyzed by X-ray diffraction and scanning electron microscope， and the cathode permeation mechanism of lithium element in aluminum electrolysis was studied. The results show that the lithium element in electrolyte is primarily in the form of LiNa₂AlF₆. Some lithium ions in molten electrolyte are reduced to lithium metal by aluminum and the Mole fraction of lithium in aluminum liquid is positively related to the Mole fraction of lithium fluoride in electrolyte. The lithium in the electrolyte permeating the cathode carbon blocks through the pores and cracks in the cathode carbon blocks is mainly in the form of fluorides. The lithium in the aluminum liquid cannot diffuse into the cathode carbon blocks.

Key words: aluminum electrolysis； lithium fluoride； permeation mechanism； aluminothermic reduction； cathode carbon blocks

CLC Number:

TF131.1

WANG Yao-wu， YOU Jing， PENG Jian-ping， DI Yue-zhong. Cathode Permeation Mechanism of Lithium in Aluminum Electrolysis[J]. Journal of Northeastern University(Natural Science), 2021, 42(1): 62-67.

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