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 werecompromised. With the high amount of shut-down pots, and withthe need to resume production (pots in operation), a so-called“recovered cathode pot” was decided to be made, in which the potside walls (the refractory and ramming paste layers) were cleaned,the refractory and ramp replacement for cold ramming paste wasrealized and, subsequently, the baking of anodes was carried out.The recovered cathode pots have different lifetimes ranging from600 to 2700 days. Compared to the normal line pots, these potsshowed high amount of leakages, premature failures and lowercurrent efficiency. After several meetings with the technical potroom team, in May 2012 the previous process parameters werealtered in order to increase the lifetime, reduce the number of theleakages and improve the current efficiency.This paper will show the implemented changes and the betterresults of lifetime, leakages and current efficiency to these pots.