Cathode Inspection and Repair Procedure Improvements in ALBRAS

In February 2022, a power outage in Potline 2 in ALBRAS shut down 223 cells. As part of the restarting process, a methodology for the evaluation and classification of cathodes was developed to support the decision on which ones to restart or not. As inspections proceeded, some cells presented damage to the rammed slope that required repairs. A methodology for patching was standardized, aiming to avoid potential future iron contamination. 211 cells were inspected, 186 were restarted, and 108 were repaired according to the new methodology. This group performed better in the subsequent year: only 10% had to be relined, against 32% in the not-repaired group; 9% of the cells were restarted due to failure, against 14% in the other group. The same group also performs better in terms of iron contamination of operating cells. ALBRAS extended the new method to all four potlines after the end of the restart.