Enhanced Zinc Electrodeposition by Multi-Component Low-Concentration Organic Additives and Synergistic Mechanism

During hydrometallurgical zinc production, tannic acid (DNS) for germanium recovery, polyacrylamide (PAM) for accelerated slag separation, and gelatin (MJ) added during electrodeposition enter the electrolyte and accumulate during cycling, negatively affecting the quality of zinc deposition when their concentration exceeds a threshold value. This study compares the effects of adding DNS, MJ, and PAM in a mixture with those of adding them alone during zinc electrodeposition. The results showed that the mixed addition significantly increased the current efficiency (CE) and reduced the energy consumption (EC) compared to the addition of DNS alone. At 5 mg/L DNS + 5 mg/L PAM, the CE reached 97.29%, an improvement of 5.42%, and the EC was reduced by 121.2 kWh/t Zn. XRD analysis showed that the additive blend had a complete (002) surface preference orientation. SEM and roughness analysis showed a reduction in roughness and an increase in surface smoothness and uniformity. Electrochemical analyses showed that the hybrid additives enhanced Zn2+ mass transfer, suppressed polarization, and reduced the overpotential for zinc deposition. This study contributes to the optimization of the zinc electrodeposition process and improves industrial efficiency.