Advancements in Metal Concentration Monitoring: Enhanced Copper and Nickel Measurement in Electrometallurgy Processes for Process Control

Current-day electrolysis operations need to adapt to complex ore grades with high impurity levels. The Mipac Metal Concentration Monitor system has undergone significant enhancements to address the evolving challenges in copper (Cu) hydrometallurgy and electrometallurgy, with promising results for the nickel (Ni) sector. The first-generation system uses optical spectroscopy, eliminating the need for online process analyzers that rely on chemical reagents for analysis and specialized laboratory expertise. The upgraded system continues to use optical spectroscopy, with the recent advancements enabling absorbance measurements of the electrolyte solution at two distinct wavelengths for determination of Cu and Ni concentrations. Ni can often present as a dominant impurity in Cu electrorefining, and the ability to measure Ni concentrations online could provide significant production insight for operations. Absorbance spectroscopy measurements showed the characteristic overlapping wavelengths for Cu and Ni, leading to interference during measurement at higher concentrations of Ni. To address this issue, a novel correction algorithm was devised, leveraging the multiple wavelength absorbance data to accurately discern and isolate the contributions between Cu and Ni. The enhanced system retained the previous system’s accuracy, however was still sensitive for some test results. This was likely because of some absorbance of other dissolved species in the Cu electrolyte at the two distinct wavelengths.