Warren E. Haupin

Cathode Voltage Loss in Aluminum Smelting Cells

Components of cathode voltage loss and cathode temperatures in aluminum smelting cells were measured using electrically insulated internal probes and thermocouples. In normal operations, the voltage drop between aluminum and lining was insignificant. Lining voltage loss decreased from 0.35 ±.05 v initially to 0.09 ±.02 v with age as the lining graphitized. The collector bar voltage loss ranged from 0.08 to 0.13 v and changed only slightly with cell age. Collector bar to lining contact voltage was as low as 0.06 v shortly after startup but deteriorated with time to 0.35 +.05 v, becoming the major factor in cathode voltage loss. It is postulated that this deterioration is caused by precipitation of very alkaline bath and β-Al2O3 at the collector bar interface.

Electrical Analog of Multiresistivity Systems Using Single Resistivity Media and Amplifier Circuits

A model is constructed from material of a single electrical conductivity. Current amplifiers, having a low insertion voltage loss, increase or decrease the current flow at boundaries representing changes in conductivity. By making the amplifier gain proportional to the required conductivity change at the boundary, the correct potential field is maintained throughout the model. This new technique overcomes the difficult chore of obtaining graded materials of accurate electrical conductivities.