Elektrolyse von Lösungen aus der Aufbereitung von NiMeH-Akkus

Translated title of the contribution: Electrolysis of solutions from the processing of nickel-metalhydride-batteries

Alexander Poscher

Research output: ThesisMaster's Thesis

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Abstract

This master thesis describes an electrochemical process to separate nickel, cobalt and iron from a solution, which is attained by leaching of nickel-metalhydride-batteries with hydrochloric acid and subsequent separation of rare earths. Performing an experimental design it was found that the separation of nickel, cobalt and iron by electrolysis in a cell with common assembly is possible, even though high oxygen contents could be measured within the samples. The surface structure of the deposits can be generally described as porous and of dendritic morphology. Current efficiencies appear in the range of 15 to 79 %, depending on the electrolysis parameters which are represented by temperature, electrode gap and current density. Finally the energy consumptions were calculated with results between 2.96 and 9.75 kWh/kg. Furthermore research was undertaken, concerning current density-potential-graphs, conductivity measurements of the electrolyte, as well as iron precipitation by oxidation. A long-time test of eighteen hours showed a current efficiency of 40 %. The determination of the pH-value points out that the recirculation of the spent electrolyte into the leaching step cannot be realized, because of a too small pH-drop during the electrochemical deposition.
Translated title of the contributionElectrolysis of solutions from the processing of nickel-metalhydride-batteries
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Luidold, Stefan, Co-Supervisor (internal)
  • Antrekowitsch, Helmut, Supervisor (internal)
Award date16 Dec 2011
Publication statusPublished - 2011

Bibliographical note

embargoed until null

Keywords

  • nickel
  • NiMeH
  • batteries
  • cobalt
  • iron
  • electrolysis
  • electrochemical deposition
  • rare earths

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