铁离子对铜旋流电沉积的影响研究

    Effect of iron ions on the extraction of copper by cyclone electrowinning

    • 摘要: 含铜的废水及含铜固体废物的酸性浸出液中往往会有大量杂质铁离子,在传统铜电沉积工艺过程中,铜离子需保持较高的浓度,杂质离子需维持较低的水平。旋流电沉积技术可以在较为温和的反应条件下,对低浓度溶液进行高效的选择性回收目标金属离子,并且能够显著提高金属的回收率和纯度。本文针对低浓度铜离子的酸性溶液,采用循环伏安法和计时电流法研究了旋流电沉积过程中不同浓度铁离子就旋流速度对其旋流电沉积铜的影响。研究结果表明,在旋流电沉积过程中Fe3+浓度会影响铜的还原性,Fe3+在浓度0.50 g/L以下时,其对铜的电沉积起到了一定的阴极去极化作用,但进一步增加Fe3+浓度铜还原会受到抑制作用;当Fe3+浓度在0.20~2.00 g/L之间时,电流效率明显随着旋流速度的升高而增加,在Fe3+浓度为0.40 g/L时,其在旋流速度为500 L/h时电流效率最高可达到80%;当旋流速度提高时,电沉积产物铜的微观结构会由附着小颗粒的长条块状转变为六角形或多边形片状、长条块状并存。本实验分析在酸性溶液中铁离子对旋流电沉积铜的影响,为低浓度含铜酸性废水或浸出液固体废物中铜的回收及提纯提供理论基础和实际应用价值。

       

      Abstract: Copper-containing wastewater and acidic leachates of copper-bearing solid wastes are often contaminated with significant amounts of iron ions as impurities. In conventional copper electrodeposition processes, a high concentration of copper ions is required, while impurity ions must be maintained at low levels. Cyclone electrowinning technology has been demonstrated to enable efficient selective recovery of target metal ions from low-concentration solutions under mild reaction conditions, with significantly improved metal recovery rates and purity. In this study, the effects of Fe3+ concentration and cyclone rotational speed on copper electrodeposition in acidic solutions with low-concentration copper ion are investigated using cyclic voltammetry and chronoamperometry. The results reveal that the reducibility of copper during cyclone electrowinning is influenced by Fe3+ concentration. At Fe3+ concentrations below 0.50 g/L, a certain cathodic depolarization effect is observed, promoting copper electrodeposition. However, further increases in Fe3+ concentration are found to inhibit copper reduction. When the Fe3+ concentration ranged in 0.20-2.00 g/L, the current efficiency is significantly enhanced with increasing cyclone speed. The highest current efficiency of 80% is achieved at an Fe3+ concentration of 0.40 g/L and a cyclone speed of 500 L/h. Moreover, the microstructure of the electrodeposited copper is observed to transition from elongated blocks with adhered particles to a mixed morphology of hexagonal/polygonal flakes and elongated blocks as the cyclone speed is increased. This study provides theoretical and practical insights into the recovery and purification of copper from low-concentration acidic copper-containing wastewater or solid waste leachates by analyzing the influence of iron ions on cyclone electrowinning in acidic solutions.

       

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