Olympic Dam Electric Slag Cleaning Furnace Blister Taphole Optimisation for Increased Copper Production

As we move towards green energy from renewable sources, copper is an essential resource to support decarbonisation of the modern world. The demand for copper is increasing whilst the available copper resources are degrading in quality. One challenge for the future is how we can optimise existing processes to support an increase in copper production. Copper is produced at the BHP Copper SA Smelter based at Olympic Dam. The Electric Slag Cleaning Furnace (EF) blister taphole refractory materials and throughput variables are analysed to enable a safe increase in taphole refractory life. An increase in refractory life results in the potential for more copper throughput of the taphole between planned maintenance periods. Alumina (Al₂O₃) refractory with 30% chromium oxide (Cr₂O₃) (RK30SR) has been trialled in direct comparison to the existing Al₂O₃ refractory with 10% Cr₂O₃ (RK10SR) to determine whether there are advantages for either composition. Mineralogical analysis on very small sample dimensions (i.e. size) has shown a potential advantage due to the higher amount of Cr₂O₃. Further investigation is advised to provide a sufficient sample size required to validate the results. The Al₂O₃ refractory with 30% Cr₂O₃ is 1.4× more expensive than the Al₂O₃ refractory with 10% Cr₂O₃ and therefore should only be implemented once additional throughput will be achieved. The previous 2020 target to increase the throughput of the EF blister tapholes by 40% using a new taphole design (Essack et al. in Blister tapping: increasing production with CFD. Santiago, pp. 655–665) installed in 2021 has been achieved with the existing lower Cr₂O₃ refractory. The maximum allowable copper tonnes tapped through the taphole is the current driver of downtime for refractory replacement. The existing refractory is sufficient to achieve another 20% improvement from the 2020 tonnes limit. At this point, the number of lances used to open the taphole becomes the limitation for copper production. Therefore, the impact of lance usage needs to be addressed as a priority with continuation of the refractory trial once higher lance throughput is achieved, and any benefits expected from the Al₂O₃ refractory with 30% Cr₂O₃ can be realised whilst in use.