Metal oxide dissolution is central to most metal processing and is generally carried out using mineral acids. An alternative approach has been demonstrated for metal sulfides using electrochemical oxidation. Here the so-called paint casting method was employed to investigate the electrochemical dissolution and recovery of selected metal oxides. Cyclic voltammetry showed that all of the metal oxides were electrochemically active in deep eutectic solvent media, and the majority displayed a redox couple that could be potentially assigned to the redox behaviour of the oxide moiety. Bulk anodic dissolution was carried out on the metal oxides, and it was shown that dissolution was enhanced to up to >10 000 times in pH neutral solutions. The rate of electrochemical dissolution was shown to be influenced by the band gap of the compounds. It is proposed that oxidation of the oxide moiety, potentially to the superoxide, enables the solubilisation of the metal ions. The metal speciation appears to remain the same as for chemical dissolution.

中文翻译：

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电化学氧化可替代金属氧化物在深共熔溶剂中的溶解

金属氧化物的溶解是大多数金属加工的关键，通常使用无机酸进行。对于使用电化学氧化的金属硫化物，已经证明了另一种方法。在这里，采用所谓的油漆浇铸方法来研究所选金属氧化物的电化学溶解和回收。循环伏安法表明，所有金属氧化物在深共熔溶剂介质中均具有电化学活性，并且大多数显示出氧化还原对，该氧化还原对可能与氧化物部分的氧化还原行为有关。在金属氧化物上进行本体阳极溶解，结果表明在pH中性溶液中溶解度提高至> 10000次。电化学溶解的速率显示出受化合物带隙的影响。建议将氧化物部分氧化成潜在的超氧化物能使金属离子增溶。金属形态似乎与化学溶解相同。