含银铜基电触头复合材料废料中铜分离回收研究

Separation and recovery of copper from waste materials of silver-containing copper-based electrical contact composites

  • 摘要: 针对生产上硫硝法回收含银铜基电触头复合材料废料造成的铜资源浪费和氨氮废水问题,文中提出一种短流程、高收率、无污染的直接电解法,选用H2SO4-CuSO4体系,将废料直接作为阳极,钛板作阴极进行电解。研究结果表明:在恒压0.6 V、Cu2+浓度为40 g/L、H2SO4浓度为160 g/L、温度为60 ℃、电解时间为10 h条件下,铜溶解率达到99.9%以上,并得到99.9%以上的高纯铜。此外,通过相关电化学测试探明Ni2+浓度对铜溶解/沉积动力学的影响规律,研究结果表明:当Ni2+浓度小于10 g/L时,更有利于阳极铜的溶解,且能够促进Cu的电结晶过程;当有Ni2+存在时,Cu2+还原过程是受扩散控制的准可逆反应,溶液中的Ni2+浓度为10 g/L时,最有利于Cu2+的扩散;Ni2+浓度不影响Cu沉积形核模型,其均以混合模型为主,在Ni2+浓度为10 g/L条件下,当电位低于0.5 V时,阴极铜稀疏多孔,粒子堆叠较为严重,而当电位为0.6 V时,能得到致密平整的铜层。

     

    Abstract: The conventional sulfur-nitration process for recycling silver-containing copper-based electrical contact composites suffers from copper resource loss and generates ammonia-nitrogen wastewater. To address these issues, this study proposed a short-process, high-yield, and pollution-free direct electrolysis method using the H₂SO₄-CuSO₄ system, where the waste material served as the soluble anode and a titanium plate as the cathode. The results showed that under constant pressure of 0.6 V, Cu2+ concentration of 40 g/L, H2SO4 concentration of 160 g/L, temperature of 60 ℃, and electrolysis time of 10 h, the copper solubility rate reached more than 99.9%, producing high-purity copper of more than 99.9%. In addition, relevant electrochemical tests were carried out to find out the influence of Ni2+ concentration on the kinetics of copper dissolution/deposition. The results showed that Ni2+ concentration less than 10 g/L was more conducive to the dissolution of anode copper and could promote the electrocrystallization process of copper. In the presence of Ni2+, the reduction process of Cu2+ was a quasi-reversible reaction controlled by diffusion. A Ni²⁺ concentration of 10 g/L in the solution was found to be the most conducive to the diffusion of Cu2+. The Ni²⁺ concentration did not affect the nucleation model of Cu deposition, which was predominantly a mixed model. Under the condition of 10 g/L Ni²⁺, the cathodic copper was sparse and porous with severe particle stacking when the potential was below 0.5 V, whereas a dense and smooth copper layer was obtained at a potential of 0.6 V.

     

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