NH_(3)-(NH_(4))_(2)SO_(4)体系隔膜电解铜电化学研究  

Electrochemical study on membrane electrolysis of cathode copper in NH_(3)-(NH_(4))_(2)SO_(4)system

作　　者：杨建英[1] 唐施阳 杨平 李树超 杨建广 YANG Jianying;TANG Shiyang;YANG Ping;LI Shuchao;YANG Jianguang(Jiangxi Environmental Engineering Vocational College,Ganzhou 341000,China;School of Metallurgy and Environment,Central South University,Changsha 410083,China;Shenzhen Zhongjin Lingnan Nonferrous Metals Co.Ltd.,Shenzhen 518024,China)

机构地区：[1]江西环境工程职业学院,江西赣州341000 [2]中南大学冶金与环境学院,湖南长沙410083 [3]深圳市中金岭南有色金属股份有限公司,广东深圳518024

出　　处：《中国有色冶金》2024年第2期121-128,共8页China Nonferrous Metallurgy

基　　金：湖南省重点研发计划(2022GK2009);湖南省高新技术产业科技创新引领计划(2021GK4004);广西重点研发项目(2021AB26076)。

摘　　要：PCB板(印刷电路板)剪裁铣削渣中含有金属铜和铝,且塑料含量高,采用电化学溶解隔膜电积工艺可以实现铜的剥离并得到高品位阴极铜。该工艺具有流程短、电流效率高、产品纯度高等优点,具有广阔的应用前景,但其电化学机理尚不明确,本文以PCB制造过程中产生的含铜固废作为阳极,采用钛板为阴极,在NH_(3)-(NH_(4))_(2)SO_(4)体系中采用隔膜电解工艺进行了一系列试验,包括不同铵盐体系、氨/硫酸铵体系中不同电极、氨/硫酸铵体系不同电解液组成的电化学行为曲线以及NH_(3)-(NH_(4))_(2)SO_(4)体系电沉积铜的控制步骤、成核机理等。结果表明,氨/硫酸铵体系中电积铜的起始还原电位最低,电积时电耗较低,且该体系中氢的析出电位均较负,可避免因析出氢气降低阴极电流效率的副反应;NH_(3)-(NH_(4))_(2)SO_(4)体系中Cu^(2+)在钛电极表面的电沉积反应为不可逆过程,且为双电子一步转移过程,控制步骤为扩散控制;Cu^(2+)在钛电极上的成核机理接近于瞬时成核。该研究成果可为NH_(3)-(NH_(4))_(2)SO_(4)体系隔膜电解铜工艺提供理论参考。The milling residues from PCB(Printed Circuit Board)cutting typically contain copper and aluminum metals along with a high plastic content.The electrochemical dissolution and electrodeposition process offer an effective method for stripping copper and obtaining highpurity cathode copper from these residues.This process is characterized by its short duration,high current efficiency,and the production of highpurity copper,making it highly promising for various applications.However,the electrochemical mechanism underlying this process remains unclear.In this study,PCBgenerated coppercontaining solid waste was utilized as the anode,with titanium plates serving as the cathode.A series of experiments was carried out using a diaphragm electrolysis process in an NH_(3)-(NH_(4))_(2)SO_(4)system.These experiments included investigations into different ammonium salt systems,various electrodes in the ammonia/ammonium sulfate system,electrochemical behavior curves of different electrolyte compositions in the ammonia/ammonium sulfate system,and control steps and nucleation mechanisms of copper electroplating in the NH_(3)-(NH_(4))_(2)SO_(4)system.The results indicate that the starting reduction potential of copper electroplating in the ammonia/ammonium sulfate system is the lowest,resulting in low energy consumption during electroplating.Additionally,the hydrogen deposition potential in this system is negative,which helps avoid side reactions such as hydrogen evolution and enhances the cathodic current efficiency.The electroplating reaction of Cu^(2+)on the titanium electrode surface in the NH_(3)-(NH_(4))_(2)SO_(4)system is found to be an irreversible process and a twoelectron onestep transfer process,with diffusion control as the controlling step.The nucleation mechanism of Cu^(2+)on the titanium electrode is close to instantaneous nucleation.These findings provide valuable theoretical insights for the NH_(3)-(NH_(4))_(2)SO_(4)system diaphragm electrolysis copper process.

关 键 词：PCB含铜废料 NH_(3)-(NH_(4))_(2)SO_(4)-H_(2)O体系 隔膜电解 电化学机理 成核机理 控制步骤 

分 类 号：TF803.2[冶金工程—有色金属冶金] TF811