On the development of metallic inert anode for molten CaCl2–CaO System

✍ Scribed by Huayi Yin; Lili Gao; Hua Zhu; Xuhui Mao; Fuxing Gan; Dihua Wang

• Book ID: 103828489
• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 776 KB
• Volume: 56
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2011.01.026

✦ Synopsis

Some fundamental aspects related to inert anode development in molten CaCl 2 -CaO were investigated based on thermodynamic analysis, electrochemistry of metals and solubility of oxide measurements. The Gibbs free energy change of several key anodic reactions including electro-stripping of metals, electro-formation of metallic oxides, electro-dissolution of metallic oxides as well as oxygen and chlorine evolution was calculated and documented, for the first time, as a reference to develop metallic inert anode in chloride based melts. The anodic behaviors of typical metals (Ni, Fe, Co, Mo, Cu, Ag, and Pt) in the melt were investigated. The results confirmed the thermodynamic stability order of metals in the melts and revealed that surface oxide formation can increase the stability of the electrodes in CaO containing melt. Furthermore, solubility of several oxides (NiO, Fe 2 O 3 , Cr 2 O 3 , Co 3 O 4 , NiFe 2 O 4 ) in pure CaCl 2 or CaCl 2 -CaO melts was measured to evaluate the stability of oxide coating or a cermet inert anode in the melt. It was found that the solubility of NiO decreased with increasing CaO concentration, while that of Fe 2 O 3 increased. Ni coated with NiO film had much higher stability during anodic polarization.