Thermo-mechanical Studies of Thimble Geometry and Stub Materials for Voltage Drop Across the Anode-Rod Connection in Aluminum Electrolysis Cell

This study gets across the underlying problem of voltage drop within the anode of an aluminum reduction cell and presents a thermo-electro-mechanical (TEM) model of this phenomenon. The literature review shows that the carbon–cast iron interface is responsible for a considerable amount of the total voltage drop within the anode. Relations for the electric contact resistance at this interface as a function of pressure and temperature are deduced from onsite measured data from the plant. In the first approach, the main physical properties of the thimble material were investigated. A TEM finite element modeling was developed for the geometrical effect approach of the stub hole and the thimble designs. Results show that the structure of the cast iron to carbon connector decreases the air gap. At the same time, the contact pressure occurs on the stub-hole bottom, and the contact area on the stub-hole wall increases proportionally. Consequently, the current density diminishes with an improved current distribution. Graphical Abstract