Potentiodynamic Polarization Behavior and Microscopic Examination of Tungsten Carbide Hard Metal Materials in Supported Ammoniacal Medium

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2020-01-01 DOI:10.4152/pea.202003185

N. Randhawa, P. K. Katiyar

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引用次数: 3

Abstract

Electrochemical methods for the recycling of tungsten carbide (WC-10Co) resources suffer from passivation in the acidic medium caused by WO3 and also in NaOH electrolytes, due to hydroxide formation. We found that an ammoniacal solution is a promising electrolyte for sustainable electrochemical dissolution of both tungsten (W) and cobalt (Co). The ammoniacal medium performs greatly when supported with Cl, SO4 2and CO3 2ions. Poor dissolution/corrosion tendency of WC-10Co in a diluted NH4OH solution enhanced many folds in the presence of Cl , SO4 2and CO3 2ions. Among these supporting ions, Cl emerged as the most suitable for the electrochemical leaching of W and Co from the WC-10Co, accompanying the least noble behavior of WC-10Co. An electrolyte composed of 150 g/L of ammonia and 5% (w/v) of NH4Cl yielded the maximum anodic current density. Microscopic examination of the electrochemically treated samples shows scattered active sites responsible for the oxidative dissolution of WC-10Co. The usefulness of W and Co dissolution in ammonia-additive salt followed the order NH4OH-NH4Cl>NH4OH(NH4)2SO4>NH4OH-(NH4)2CO3..

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负载态氨介质中碳化钨硬质金属材料的动电位极化行为及显微观察

由于氢氧化物的形成，碳化钨(WC-10Co)资源的电化学回收方法在由WO3引起的酸性介质和NaOH电解质中受到钝化。我们发现氨溶液是一种很有前途的电解液，可以持续地溶解钨(W)和钴(Co)。氨介质在Cl、so42和co32离子的负载下表现良好。WC-10Co在稀释的NH4OH溶液中较差的溶解/腐蚀倾向在Cl、so42和co32离子存在下增强了许多倍。在这些支持离子中，Cl是最适合从WC-10Co中电化学浸出W和Co的离子，并且伴随着WC-10Co的最不高贵的行为。由150 g/L氨和5% (w/v) NH4Cl组成的电解液产生最大的阳极电流密度。电化学处理样品的显微检查显示分散的活性位点负责氧化溶解WC-10Co。W和Co在氨添加盐中的溶解作用顺序为NH4OH- nh4cl >NH4OH(NH4)2SO4>NH4OH-(NH4)2CO3。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.