Fundamental insights into gallium leaching for sustainable electronic waste recovery
摘要
This study systematically concerns the leaching behavior and dissolution kinetics of gallium (Ga). The objective was to identify sustainable leaching agents by incorporating organic acid reagents. Using a novel approach involving pH-adjusted experiments, the findings elucidated the dissolution behavior, delineating acidolysis and complexolysis. The screening results demonstrated the efficacy of oxalic acid (10 mM), which extracted 1105.2 ± 61.4 mg/L of Ga at pH 1.2. Dissolution kinetics based on the shrinking core model (SCM) revealed a synergistic mechanism governed by film diffusion and surface chemical reaction control, with chemical reaction control dominating at higher temperatures. One-factor-at-a-time (OFAT) experiments clarified the influence of experimental parameters on Ga leaching yield. In addition, the Box-Behnken design (BBD) was employed to evaluate parameter interactions, confirming the significance of the process parameters, including interaction terms, while characterizing the model in terms of a quadratic expression. Under optimized conditions: 710.55 mM acid concentration, a reaction temperature of