Nd对锌电积用Pb-Ag合金阳极性能的影响

采用恒流极化、失重法和抗拉强度测试研究不同含量Nd的加入对锌电积用铅银合金阳极主要性能(稳定阳极电位、耐腐蚀性能及力学性能)的影响,并在此基础上采用循环伏安(CV)和计时电位(CP)等电化学手段对恒流极化条件下Nd的作用机理进行研究。结果表明:0.03%Nd(质量分数)加入可以将Pb-Ag合金的抗拉强度提高21.8%;锌电积条件下,铅阳极表面腐蚀膜主要成分为PbO2及PbSO4,Nd加入可以抑制PbSO4的形成,从而明显降低阳极腐蚀速率;由于Nd能降低析氧过电位,且对高阻抗PbSO4的生成具有抑制作用,使得Pb-Ag合金的阳极电位亦有一定程度的下降。Nd对锌电积阳极主要性能均有较大程度的改进作用,是很好的锌电积阳极改性剂,具有较好的工业应用前景。

Influence of Nd on Pb-Ag alloy anode for zinc electrowinning

The effects of different Nd additions on the three main properties(anode potential,decay resistance and mechanical property) of lead-silver alloy anode for zinc electrowinning used in galvanizing were investigated by using constant-current polarization,weight-loss method and mechanics performance testing.On this basis,using electrochemical methods,such as cyclic voltammetry(CV) and chronopotentiometry(CP) were used to study the mechanism of action of Nd in galvanostatic polarization conditions.The results show that,0.03% Nd(mass fraction) addition can enhance the tensile strength of Pb-Ag alloy about 21.8%.The lead anode surface corrosion film mainly composes of PbO2 and PbSO4 in zinc electrowinning conditions,Nd addition can inhibit the formation of PbSO4,consequently reduce the anode corrosion rate obviously.Also there is a certain degree to decline the anode potentials of Pb-Ag alloy due to the Nd reduction of over-potential of oxygen evolution and inhibitory effect of high-impedance PbSO4.So,Nd is a good modifier for zinc electrowinning anode which can improve the three main properties of lead-silver anode.