电流密度对锌电积用Pb-Ag平板阳极电化学行为的影响(英文)  

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

作　　者：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] 

机构地区：[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

出　　处：《物理化学学报》2010年第9期2369-2374,共6页Acta Physico-Chimica Sinica

基　　金：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500A·m-2降到200A·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64mV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.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.

关 键 词：锌电积 电流密度 Pb-Ag阳极 阳极电位 腐蚀率 

分 类 号：TG174.4[金属学及工艺—金属表面处理]