物理化学学报 >> 2010, Vol. 26 >> Issue (09): 2369-2374.doi: 10.3866/PKU.WHXB20100935

电化学 上一篇    下一篇

电流密度对锌电积用Pb-Ag平板阳极电化学行为的影响

蒋良兴1, 衷水平2, 赖延清1,  吕晓军1, 洪波1,  彭红建1,  周向阳1, 李劼1, 刘业翔1   

  1. 1. 中南大学冶金科学与工程学院,长沙410083;
    2. 紫金矿业集团股份有限公司, 福建上杭364200
  • 收稿日期:2010-04-12 修回日期:2010-05-31 发布日期:2010-09-02
  • 通讯作者: 赖延清 E-mail:csulightmetals@126.com
  • 基金资助:

    国家自然科学基金(50954006)资助项目

Effect of Current Densities on the Electrochemical Behavior of a Flat Plate Pb-Ag Anode for Zinc Electrowinning

JIANG Liang-Xing1, ZHONG Shui-Ping2, LAI Yan-Qing1, LV Xiao-Jun1, HONG Bo1, PENG Hong-Jian1, ZHOU Xiang-Yang1, LI Jie1, LIU Ye-Xiang1   

  1. 1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, P. R. China;
    2. Zijin Mining Group Co., Ltd., Shanghang 364200, Fujian Province, P. R. China
  • Received:2010-04-12 Revised:2010-05-31 Published:2010-09-02
  • Contact: LAI Yan-Qing E-mail:csulightmetals@126.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50954006).

摘要:

研究了在不同电流密度下进行长时间极化后Pb-Ag(0.8%(质量分数, w))平板阳极的阳极电位、腐蚀率及阳极钝化膜. 同时, 也研究了该阳极在ZnSO4-MnSO4-H2SO4电解液中的阴极电流效率和阴极锌品质.阳极钝化膜的表面形貌用扫描电镜(SEM)进行观测.实验结果表明, 不管电解液中是否存在Mn2+, 电流密度对阳极和阴极的电化学行为都产生了显著的影响. 随着电流密度的升高, 阳极电位、腐蚀率、阴极电流效率和阳极泥生成量也增加, 而阴极锌中的Pb 含量则减少. 当电流密度从500 A·m-2 降到200 A·m-2 时, 阳极在ZnSO4-MnSO4-H2SO4 电解液中的稳定电位和腐蚀率分别减少64 mV 和40%. 此外, 在比较低的电流密度下, 阳极电位更容易稳定, 阳极表面生成的钝化膜更加致密并与基体结合牢固, 这些都有利于降低阳极腐蚀率. 为了降低阳极电位、减小阳极腐蚀率及阳极泥生成量并提高阴极电流效率和阳极锌品质,锌电积的理想工作条件是较低的阳极电流密度和较高的阴极电流密度.

关键词: 锌电积, 电流密度, Pb-Ag 阳极, 阳极电位, 腐蚀率

Abstract:

We studied the anodic potential, corrosion rate, and anodic passive layer of a flat plate Pb-Ag (0.8% (mass fraction, w) anode over a long period of polarization under different current densities. Additionally, the cathode current efficiency and quality of the zinc product in the ZnSO4-MnSO4-H2SO4 electrolyte were also studied. The morphology of the anodic passive layer was characterized by scanning electron microscopy (SEM). The results show that the current density greatly affects the electrochemical behavior of the anode and the cathode during zinc electrowinning irrespective of Mn2+. With an increase in the current density, the anodic potential, corrosion rate, cathode current efficiency, and quantity of anode slime increased while the Pb content in the zinc product decreased. When the current density decreased from 500 to 200 A·m-2 in the ZnSO4-MnSO4-H2SO4 electrolyte, the stable anodic potential and the corrosion rate decreased by 64 mV and 40%, respectively. Under a lower current density, the anodic potential stabilizes more easily and the passive layer that forms on the surface of the anode is denser and it adheres better to the base body, which is advantageous for the reduction of the corrosion rate. Therefore, to reduce the anodic potential, corrosion rate, and the quantity of anode slime, increase the cathode current efficiency and quality of zinc product, we suggested that the ideal working condition for zinc electrowinning is a higher cathodic current density and lower anodic current density.

Key words: Zinc electrowinning, Current density, Pb-Ag anode, Anodic potential, Corrosion rate

MSC2000: 

  • O646