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MARCH 2026 I I-CONNECT007 MAGAZINE 55 column size is fixed, the inlet copper mass flow rate determined by the feed concentration and volumetric flow rate, governs removal efficiency. Because feed concentration in practice depends on etcher usage, volumetric flow rate is the pri- mary controllable parameter. Data correlated best when copper removal was plotted against specific inlet mass flow rate, confirming predictable, con- trollable system behavior. Effluent pH was also analyzed as a potential control parameter. It depended on both throughput (in bed volumes) and feed copper concentration. Predicting pH required determining processed bed volumes and then accounting for feed concentra- tion, indicating that real-time monitoring could sup- port process control. Desorption behavior was simpler. In all tests, copper concentration in the electrolyte increased as copper was stripped from the resin. The time required for complete desorption decreased with increasing flow rate. An empirical correlation showed that desorption time was strongly depen- dent on volumetric flow rate (R² = 0.9883) and largely independent of copper or acid concentra- tion. As expected, higher flow rates significantly reduced regeneration time, a critical factor for practical implementation. Waste generation was primarily associated with discarding diluted effluent at the start of adsorption and desorption. Some electrolyte dilution persisted, suggesting that actual waste volumes may be slight- ly higher than measured. In a full-scale system, this waste stream must be considered, especially for facilities operating with zero liquid discharge. Summary and Conclusion Overall, the data demonstrates that ion-exchange resin can effectively remove significant quanti- ties of copper from acidic cupric etchant without organic solvents. Copper removal is governed by column size and inlet copper mass flow rate, while desorption time depends primarily on elec- trolyte flow rate. Compared with LLE systems, ion exchange eliminates hazardous solvents, reduces chemical inventory, minimizes footprint, and lowers cross-contamination risk. Although further scale-up testing and optimization are required, solvent-free copper recovery using ion-exchange resin is tech- nically feasible and offers substantial environmen- tal and operational advantages. Comparing Figures 1, 2, and 3 & 2 demonstrates our concepts, providing stress-tested technical op- tions to the market. This technology development is now being applied in a production-scale process at Green- Source Fabrication LLC in New Hampshire. This Novel Copper Extraction has been coupled with the latest generation of GreenSource Engineer- ing's acidic copper etchers, utilizing "soft touch" and "puddle-free technology" as part of the up- dated and improved DES system. Acknowledgements Thank you to Derek Lovejoy, who won the Best Student Paper Award at IPC APEX EXPO 2023, for his commit- ment to thoroughly testing and applying his findings, and to Mark Girard for making things happen despite the doubters. I-CONNECT007 Richard Nichols is technical marketing director at Green- Source Engineering. Figure 3: A production-ready alternative to copper control for a solvent extraction system on cupric chloride acidic etch.