Kinetic study and modelling of silver dissolution in synthetic industrial silver electrolyte as a function of electrolyte composition and temperature. (1st July 2018)

• Record Type: Journal Article
• Authors: Aji, Arif T.; Aromaa, Jari; Wilson, Benjamin P.; Mohanty, Udit S.; Lundström, Mari
• Is Part Of: Corrosion science. Volume 138(2018)
• Page Start: 163
• Page End: 169
• Publication Date: 2018-07-01
• Subjects: Silver (A) -- Anodic dissolution (C) -- Polarization (B) -- Modelling studies (B) -- Kinetics (C); Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2018.04.014
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Use of microelectrode effect improved accuracy of Ag dissolution kinetic modelling. Optimum overpotential range of silver electrorefining is within 150–200 mV. Models show that [Ag + ], [HNO3 ] and T have positive impact to the Ag dissolution. Increasing [HNO3 ] and T reduce the current efficiency due to Ag re-dissolution. [HNO3 ] needs to be limited to below 5 g/dm 3 for high current efficient process. Abstract: The kinetics of silver dissolution in silver electrorefining process was investigated using a series of synthetic electrolytes and different electrode sizes. Kinetic models at corrosion potential and industrial range overpotentials were constructed as a function of electrolyte composition and temperature. The results revealed that overpotential of 150–200 mV vs. corrosion potential represented the values corresponding to the industrial silver electrolysis. In order to achieve a high current efficiency in silver electrorefining, our kinetic models suggest that concentration of HNO3 should be less than 5 g/dm 3 or 3 g/dm 3 for operation at 25 °C and 45 °C, respectively.