Modelling of silver anode dissolution and the effect of gold as impurity under simulated industrial silver electrorefining conditions

Arif T. Aji, Petteri Halli, Amaury Guimont, Benjamin P. Wilson, Jari Aromaa, Mari Lundström*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

As Au content causes passivation during silver electrorefining process, a kinetic study and modelling of Au–Ag alloy in synthetic silver electrolyte is presented. In this research, the possibility to process high gold Doré efficiently through the simple adjustment of electrolyte conditions and the process current density is demonstrated. Measurements of binary Au–Ag alloys in a synthetic silver electrolyte with silver concentration ([Ag+]) of 40, 70 and 100 g/dm3 were conducted at temperatures between 25 and 45 °C. Results show that efficient processing of Doré with a higher gold content up to 20% can be achieved in a low [Ag+] (40 g/dm3) electrolyte with a current density (j) of 180–300 A/m2. For an intermediate electrolyte with [Ag+] of 70 g/dm3, for Au limit of 13–14%, the current density can be increased to j of 500–600 A/m2, for a Au content of 13–14%. Finally, using high concentration electrolyte of [Ag+] = 100 g/dm3, a high current density ˃1000 A/m2 can only be efficiently applied when Au content is limited to 6–8%. Based on empirical kinetic modelling, this study shows an effective approach on the processing Doré with wide range of Au content.

Original languageEnglish
Article number105105
Number of pages7
JournalHydrometallurgy
Volume189
DOIs
Publication statusPublished - 15 Jul 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • Au – Ag alloy
  • Cyclic polarization
  • Kinetic modelling
  • Passivation
  • Silver electrorefining

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    CMEco: Circular Metal Ecosystem

    Aji, A., Kalliomäki, T., Seisko, S., Leikola, M., Jafari, S., Peng, C., Agarwal, V., Elomaa, H., Hamuyuni, J., Khalid, M. K., Lundström, M., Halli, P., Sinisalo, P., Wilson, B., Revitzer, H., Partinen, J. & Wang, Z.

    01/01/201731/12/2019

    Project: Business Finland: Other research funding

    RAMI: RawMatTERS Finland Infrastructure (RAMI)

    Karppinen, M.

    01/01/201631/12/2018

    Project: Academy of Finland: Other research funding

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