INALUM environmentally friendly strategy by reusing spent anode (butt) management

Abstract

Abstract To implement vision 2025, INALUM should pay attention to environment aspect and one of the strategies is reusing waste material resulted after the process which in this case reusing spent anode or well known as anode butt. INALUM produces + 40,000-ton butt/year as accounted to production cost that is classified to spend money. Anode butt has contaminated Cryolite (Na3AlF6) during the electrolysis process thus changing the quality. To optimize production cost, those butt materials are reusing as raw material to produce anode. Usage of anode butt as technically lead to deleterious anode quality and electrolysis cell performance. Nevertheless, by internal strategy and well operated by INALUM, not significantly impact gained after using anode butt as anode raw material. Butt cleaning process on the Rodding plant plays an important role in butt quality. By through butt cleaner which has 2 compartment rooms that will be passed through to be cleaned. First room is cleaning room and next room is air blow room are able to produce efficient anode butt to be reused as anode raw material. Butt quality produced by butt cleaning system is highly better than typical range and hence anode quality specifically residual reactivity (RRCO2 and RRO2) still acceptable to INALUM standard. By using 30% butt ratio to produce anode, INALUM can save production cost by + 180 USD/Anode and that is huge saving to average anode production 112,000 anode/year.