A Novel Oxygen Evolution Anode for Electrowinning of Non‐ferrous Metals

Abstract

Electrowinning in chloride solutions is a wellknown process to produce a high purity of non-ferrous metals such as nickel and cobalt, where metal ions are reduced on the cathode and chlorine evolution occurs on the anode. The reduction of electric energy consumption in the process is important, which needs to reduce the overvoltage of chlorine evolution on the anode, so that it has been expected to develop a novel anode that has a high catalysis for chlorine evolution compared to current coated titanium anodes. A ruthenium-titanium composite oxide coated titanium (RuXTi1-XO2/Ti) electrode is a typical example of such anodes being used in commercial electrowinning using chloride solutions. This electrode is produced by thermal decomposition of a metal precursor solution, which is usually performed at about 500 C. On the other hand, we have previously revealed that RuXTi1XO2/Ti electrodes prepared at lower temperature have a higher catalysis for chlorine evolution than those prepared at such high temperatures [1, 2]. In this work, we further focused on the preparation of Ru-based coatings at different thermal decomposition temperatures and tried to develop a novel chlorine evolution anode with a low overpotential.