复杂铝电解质体系固体物相变化过程分析

Analysis of solid-phase transition process in complex aluminum electrolytical system

针对国产电解铝工业所用的铝电解质成分较国外复杂,特别是电解质的摩尔比在2.7～3.1时,电解质熔体的物相结构复杂多变的情况,采用X射线衍射法和全元素化学分析法对工业电解质的固体物相组成、主要组分及电解质的摩尔比进行研究.研究结果表明:钙盐始终以游离的CaF2形式存在.在电解质摩尔比2.7～3.0时,锂盐的酸性相LiNa2AlF6和碱性相LiF同时出现.X射线衍射法分析摩尔比结果较化学法偏高,且差值随摩尔比的增大而减小,当摩尔比大于3时,其测量结果与实际值基本相符.

Compared with foreign countries,the ingredient of aluminum electrolyte is more complicated in aluminium industry in China,and when the molar ratio is between 2.7 and 3.1,the phase constitution of aluminum electrolyte is even more complex and uncertain.The solid phase constitution,main component of industrial electrolyte and electrolyte molar ratio were investigated in two ways,including chemical composition analysis and X-ray diffraction analysis techniques.The investigation result showed that calcium salt always existed in form of free CaF2 all the time.When the molar ratio was between 2.7 and 3.0,the acid phase of lithium salt LiNa2AlF6 and its alkaline phase LiF would occur simultaneously.In addition,the analysis result of molar ratio by using X-ray diffraction techniques was higher than using chemical composition analysis,and their deviation decreased as the molar ratio increased.When the molar ratio was greater than 3,the analysis result was coincident with the practical value.