700 PCBs, which exhibit significantly higher gold and silver contents than mixed electronic boards. This approach isolates the effect of material composition on carbon intensity while maintaining identical energy and transport inputs. 4. RESULTS 4.1. GHG Emission Hotspots In R&R-Based Recovery Systems (Cradle-To-Gate) This subsection presents a cradle-to-gate GHG emission hotspot analysis for the recovery and reuse (R&R) system, identifying the life cycle stages that contribute most significantly to total emissions. Figure 1 shows the relative contribution of transport, electricity consumption, thermal treatments, and direct emissions to the overall carbon footprint of the R&R system. The total carbon footprint of the R&R process amounts to 28.69 tCO₂eq for 20.39 tons of electronic boards, with metal treatment and recovery at the EMCR facility being the dominant contributor (27.07 tCO₂eq; 94.34%). Maritime transport of WEEE from Peru to Europe represents a secondary hotspot (1.47 tCO₂eq; 5.13%), while upstream activities such as mobile combustion during collection and loading (0.10 tCO₂eq; 0.36%) and electricity consumption at the Comimtel plant (0.05 tCO₂eq; 0.17%) contribute marginally to total emissions. The process configuration and associated emissions remain constant between the R&R and R&RMP scenarios, as both involve similar collection, transport, and treatment of electronic boards; therefore, the identified hotspots are representative of both cases. For the BAU model, a comparable stage-level disaggregation of emissions is not available within the scope of this study. Nevertheless, it is well established in the literature that energy use, particularly fuel consumption associated with material transport and extraction activities, constitutes the dominant source of GHG emissions in conventional mining systems. Consequently, differences in carbon footprint per kilogram of recovered metal between BAU and R&Rbased scenarios are primarily driven by structural differences in energy intensity and allocation effects rather than by changes in the processing stages themselves.
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