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Effect of Solidification Rate of Copper Anodes on the Chemical and Electrochemical Dissolution during Electrorefining

bagheri, Reza | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44788 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Yoozbashizadeh, Hossein
  7. Abstract:
  8. In the present work,the effect of solidification rate on the electrochemical behavior of copperanodes of Sarcheshmeh copper complex has been studied.Inthis regard, three cylindrical coppers pecimens with different solidificationrates casted into water-cooled metal mold (A specimen), metal mold (B specimen) and sand mold (C specimen). Cylinders for microstructural and electrochemical investigation, alongthickness dividedinto several specimens. To investigate themicrostructure of the specimens, opticalmicroscopyand scanning electron microscopy(SEM)were used. ICP testhasbeen usedforelemental analysis of each specimen; and eventuallytoinvestigate theelectrochemical behavior ofeach of thespecimens,electrochemical impedancespectroscopy(EIS)and thedynamicpotentiometric have been carried out at corrosion potential of copper in electrolyte (700 mV). ICPtest resultsindicate that (A) specimen,cooled with higherratethan the otherspecimen, show uniform distributionofarsenic content (900 ppm)and〖MFR〗_1parameter (6.5) along its thickness. The result of dynamic potentiometric show that passivation tendency of (A) specimen which had uniform distribution of arsenic content and 〖MFR〗_1parameter along its thickness, is uniform and lower than other specimen. Passivation tendency of (B) specimen increased from airside to moldside. In impedance diagrams of all specimens, there are two semicircles which indicate oxide film formation on their surface. EIS result show that (A) and (B) specimen that solidified in non-equilibrium state, have lower dissolution resistance than C specimen (1.5 ohm); because of more surface activity than C specimen. Results indicate that (A) specimen has mostproperdissolution behavior in sarcheshmeh copper complex refinery electrolyte
  9. Keywords:
  10. Anodic Dissolusion ; Chemical Dissolution ; Electrochemical Dissolution ; Solidification Rate ; Copper Electrorefining ; Passivation

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