Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6605864 | Electrochimica Acta | 2016 | 34 Pages |
Abstract
Spongiform metallic chromium was obtained directly from K2CrO4 in the equimolar CaCl2-KCl molten salt by electrolysis at 1173Â K and this reduction mechanism was discussed. The chemical composition and microstructure of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The reduction mechanism was analyzed by cyclic voltammetry, square wave voltammetry and potentiostatic electrolysis. K2CrO4 is soluble in the molten chlorides. The soluble CaCrO4 was easily formed in the molten CaCl2-KCl before electrolysis and dissociated to Ca2+ and CrO42â. The CrO42â was firstly electro-reduced to CaCr2O4 by a three-electron-transfer process and CaO was released simultaneously. The generated CaO with a high solubility was dissolved into the CaCl2-KCl molten salt and electro-reduced to metallic calcium. As the electrolysis proceeded, the amount of released CaO increased and more CaO was electro-reduced to Ca. CrO42â can be reduced to CaCr2O4 by electrolysis and calcium reduction simultaneously. Then, CaCr2O4 was further reduced to metallic chromium by the dissolved Ca in the near-cathode region. However, the inclusion of a little CaCr2O4 brought oxygen into metallic Cr powders.
Keywords
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Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Wei Weng, Mingyong Wang, Xuzhong Gong, Zhi Wang, Dong Wang, Zhancheng Guo,