低分子比铝电解质的槽电阻-Al_2O_3浓度曲线

RELATIONSHIP CURVES OF PSEUDO-RESISTANCE VS ALUMINA CONCENTRATION FOR LOW CRYOLITE RATIO ALUMININM ELECTROLYTES

低分子比铝电解质的槽电阻－Ａｌ２Ｏ３浓度曲线是实现低分子比铝电解而进行Ａｌ２Ｏ３下料自动控制的基础。本文在实验室铝电解槽上使用低分子比电解质，应用Ｌｅ－ＢｌａｎｃｅＩ－Ｕ曲线法测定了槽电阻计算式Ｒ＝（Ｕ－Ｖｅｘｔ）／Ｉ中的常数值Ｖｅｘｔ，并通过测定槽电压Ｕ，槽电流Ｉ和Ａｌ２Ｏ３浓度，研制了槽电阻－Ａｌ２Ｏ３浓度曲线。结果表明：Ｖｅｘｔ的值的范围为１６２～１６８Ｖ，平均值为１６５Ｖ，槽电阻－Ａｌ２Ｏ３浓度曲线上都存在槽电阻极小值，并且随电解质分子比减小，槽电阻极小值增大，而槽电阻极小值所对应的Ａｌ２Ｏ３浓度减小。对使用分子比为２０～２６电解质的工业电解槽，Ａｌ２Ｏ３浓度可控制在槽电阻－Ａｌ２Ｏ３浓度曲线极小值左侧的２％～３％范围内，槽内既不会产生沉淀又不会发生阳极效应，节省电能并取得良好指标。

The auto control of Al 2O 3 feed to realize low cryolite ratio aluminium electrolysis is based on the relationship curves of pseudo-resistance vs alumina concentration in low cryolite ratio electrolytes In a bench-scale aluminium electrolysis cell the authors measured the value of Vext in the expression of pseudo-resistanceR=(U-Vext)/I]by Le-Blance I-U curve method,cell voltage V,cell current Iand Al 2O 3 concentration in low cryolite ratio electrolysis The relationship curves of pseudo-resistance vs alumina concentration at various ratios were plotted The study results were as follows:the range of Vext was from 1 62V to 1 68V,the average value was1 65V ,there were minima of pseudo-resistance on the curves of pseudo-resistance vs Al 2O 3 concentration;with decreasing of the cryolite ratio of bath the minima of pseudo-resistance increased and the corresponding alumina concentration values to the minima of pseudo-reistance decreased The industrial electrolysis cells with 2 0-2 6 cryolite ratio electrolytes may be operated and controlled at 2%-3 wt% range of alumina concenration on the left-hand side of the minimum point,the sludge and the anode effect do not occur,a good production performance can be obtained and energy-saving can also be achieved