稀土Pr对有色金属电积用Pb基阳极性能的影响

Properties of Lead Based Anode for Nonferrous Electrowinning with Different Pr Contents

采用二步重熔法制备了不同Pr含量的Pb-Pr合金阳极材料,通过材料力学性能测试、阳极腐蚀测试研究了稀土元素Pr对Pb-Pr合金阳极抗拉强度、耐腐蚀性的影响,并利用循环伏安曲线(CV)和线性极化曲线研究了Pr对Pb-Pr合金阳极电化学行为的影响。研究结果表明:合金抗拉强度随Pr含量增大而增大,当合金中Pr含量达到2.0%(质量分数)时,合金抗拉强度为21.1 MPa,较纯Pb抗拉强度提高了85.1%;稀土元素Pr添加量在1.0%以下时不会对铅基阳极腐蚀性能产生明显影响,当Pr添加量超过1.0%时,Pr的添加使得恒流极化时阳极生成的Pb O2膜层疏松、多孔,降低了铅基合金的耐腐蚀性,当合金中Pr含量达到2.0%时,腐蚀速率提高到13.78 g·cm-2·h-1,较纯Pb(13.10g·cm-2·h-1)提高了5.19%;稀土元素Pr能降低合金电极稳定电位,且电位值随稀土元素含量的增加而减小,Pr含量达到2.0%时,阳极稳定电位约为2.190 V,与纯铅阳极稳定电位(2.314 V)相比下降5.4%。

Pb-Pr anode alloys with different contents of rare earth element Pr were prepared with two-stage remelting method. The effects of Pr in Pb-Pr anode on tensile strength and corrosion resistance were investigated by measurement of mechanical properties and corrosive tests. The electrochemical behavior of alloy anode was also discussed based on cyclic voltammetry（ CV） curves and linear polarization curves. The results showed that tensile strength increased with Pr content increasing. When Pr content was 2. 0%（ mass fraction）,the tensile strength reached 21. 1 MPa,which was 85. 1% higher than that of pure Pb anode. When Pr content was below1. 0%,it had no obvious influence on the corrosion resistance. Pr addition of more than 1. 0% caused the formation of loose and porous Pb O2 layer during constant current polarization,which reduced the corrosion resistance of lead-based alloys. When Pr content was2. 0%,corrosion rate reached 13. 78 g·cm- 2·h- 1,which was 5.19% higher compared with that of pure Pb anode（ 13. 10 g·cm- 2·h- 1）. It could also reduce the anode stable potential,and the potential value decreased with rare earth metal content increasing. When Pr content was 2. 0%,the anode stable potential was about 2. 190 V,which decreased by 5. 4% compared with that of pure Pb anode（ 2. 314 V）.