Models for the diffusion coefficient of cupric ion and limiting current density in a copper electrorefining electrolyte

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Abstract

The diffusion rate of cupric ions and limiting current density are important factors that determine the rate of copper mass transport in electrolytes proximal to the electrodes used in electrorefining. As a result, diffusion can critically affect both the rate and morphology of cathodic copper deposition thus it is crucial that it be optimized to improve production. The diffusion coefficient of cupric ion (DCu(II)) in copper electrolytes has been previously researched but the values detailed in the literature show significant variations and moreover arsenic - a common impurity - is generally excluded. Furthermore, in previous studies the models have only been validated with model solutions rather than real industrial electrolytes. In this study, the limiting current density and diffusion coefficient of cupric ion were defined for synthetic electrolytes containing copper (40-60 g/dm3), nickel (0-20 g/dm3), sulfuric acid (130-220 g/dm3) and arsenic (0-45 g/dm3). The cathodic limiting current densities were measured at three temperatures (50, 60, 70 °C) with linear sweep voltammetry using the rotating disc electrode (RDE) as the cathode. By utilizing the limiting current density, models for the DCu(II) were constructed using Levich equation. The validity of the DCu(II) model for technical use was confirmed through their application to industrial electrorefining electrolytes with known element concentrations. Consequently, this study provides improved models for limiting current density and diffusion coefficient of cupric ion that can be utilized for industrial process optimization.

Details

Original languageEnglish
Title of host publicationIMPC 2018 - 29th International Mineral Processing Congress
Publication statusPublished - 1 Jan 2019
MoE publication typeA4 Article in a conference publication
EventInternational Mineral Processing Congress - Moscow, Russian Federation
Duration: 17 Sep 201821 Sep 2018
Conference number: 29

Conference

ConferenceInternational Mineral Processing Congress
Abbreviated titleIMPC
CountryRussian Federation
CityMoscow
Period17/09/201821/09/2018

    Research areas

  • Arsenic impurities, Copper electrorefining electrolyte, Cupric ion, Diffusion coefficient, Limiting current density

ID: 31381400