STARTUP OF SHUT-DOWN POTS - PROBLEMS AND SOLUTIONS TO IMPROVE RESULTS

摘要

Due to the operational crisis at Votorantim Metais CBA in 2011 (VSS Soderberg technology – 128kA), some anodes were lost, consequently the cathode lifetime and conditions were compromised. With the high amount of shut-down pots, and with the need to resume production (pots in operation), a so-called “recovered cathode pot” was decided to be made, in which the pot side walls (the refractory and ramming paste layers) were cleaned, the refractory and ramp replacement for cold ramming paste was realized and, subsequently, the baking of anodes was carried out. The recovered cathode pots have different lifetimes ranging from 600 to 2700 days. Compared to the normal line pots, these pots showed high amount of leakages, premature failures and lower current efficiency. After several meetings with the technical pot room team, in May 2012 the previous process parameters were altered in order to increase the lifetime, reduce the number of the leakages and improve the current efficiency. This paper will show the implemented changes and the better results of lifetime, leakages and current efficiency to these pots.