Effect of chloride ions on deposition behavior and morphology of zinc in electrowinning

Hiroaki Nakano, Satoshi Oue, Hisaaki Fukushima, Shigeo Kobayashi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

To clarify the effect of chloride ions on the deposition behavior and crystal morphology of Zn at the initial stage of an electrowinning, the partial polarization curve, current efficiency, and AC impedance for a Zn deposition as well as its morphology and crystal orientation were investigated. In solutions containing chloride ions, the partial polarization curve for Zn deposition was evidently depolarized and the polarization resistance was decreased. By increasing the concentration of the chloride ions from 600 to 6,000 mg/L, the degree of depolarization and the decrease in the polarization resistance became significantly large. On the other hand, the partial polarization curve for the hydrogen evolution was almost unchanged by the presence of the chloride ions. As a result, the current efficiency of the Zn deposition at the initial stage at current densities from 100 to 2,000 A/m2 increased 3 or 10 % with the chloride ions. The crystal of the deposited Zn from the solutions containing the chloride ions became aggregated and large. This tendency was remarkable as the concentration of the chloride ions was increased to 6,000 mg/L. In the Zn deposition at 500 A/m2, the orientation index of the {0001} plane and the crystallite size of Zn increased a bit with the chloride ions. This is attributed to the decrease in overpotential for the Zn deposition with the chloride ions.

Original languageEnglish
Title of host publicationProceedings - European Metallurgical Conference, EMC 2017
PublisherGDMB Verlag GmbH
Pages1695-1709
Number of pages15
ISBN (Electronic)9783940276759
Publication statusPublished - Jan 1 2017
Event9th European Metallurgical Conference, EMC 2017 - Leipzig, Germany
Duration: Jun 25 2017Jun 28 2017

Publication series

NameProceedings - European Metallurgical Conference, EMC 2017
Volume4

Conference

Conference9th European Metallurgical Conference, EMC 2017
CountryGermany
CityLeipzig
Period6/25/176/28/17

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All Science Journal Classification (ASJC) codes

  • Metals and Alloys

Cite this

Nakano, H., Oue, S., Fukushima, H., & Kobayashi, S. (2017). Effect of chloride ions on deposition behavior and morphology of zinc in electrowinning. In Proceedings - European Metallurgical Conference, EMC 2017 (pp. 1695-1709). (Proceedings - European Metallurgical Conference, EMC 2017; Vol. 4). GDMB Verlag GmbH.