Elektrolyse von Lösungen aus der Aufbereitung von NiMeH-Akkus
Research output: Thesis › Master'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.
Details
Translated title of the contribution | Electrolysis of solutions from the processing of nickel-metalhydride-batteries |
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Original language | German |
Qualification | Dipl.-Ing. |
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Award date | 16 Dec 2011 |
Publication status | Published - 2011 |