ANODE DESIGN FACTORS FOR PREBAKE ALUMINA REDUCTION CELLS.

As the aluminum industry tends toward the large, mutli-stubbed anodes for low-current density operation, the design factors affecting the mechanical and thermal stresses acting on an in-service anode become increasingly important. The design should be such that the resulting stresses are removed from the mechanical limits of the carbon while they simultaneously provide for minimum stub-to-carbon contact drops. This investigation correlates laboratory and operating data to conclude that thermal stresses are most critical within the first few hours of anode service. Stress levels can be approximated using thermal expansion data together with operational temperature information. From this analysis, near optimum stub hole diameters can be estimated.