Masters Theses


Paul Laforest

Keywords and Phrases

Antimony; Arsenic; Copper; Electrorefining; Electrowinning; Manganese


"This work involves examining two industrial reports of methods to handle impurities in copper electrowinning and electrorefining. The first part evaluates the addition of Hydrostar, Cyquest N-900, DXG-F7, and Guartec EW to copper electrowinning electrolyte to affect MnO2 deposition on coated titanium anodes (CTAs). The second part examines the effects of anode chemistry and thiourea addition on the ductility of electrorefined copper starter sheet.

In part one, a laboratory cell was used to simulate a short cycle electrowinning cell via chronopotentiometric operation with an IrO2-Ta2O5 CTA at 40⁰C. A cyclic voltammetric sweep was applied after chronopotentiometry to remove any species which had formed on the CTA. The amount of MnO2 removed was quantified by simple application of Faraday's law to the reduction curve. The presence and increase of Mn was confirmed using SEM/EDS. Cyquest N-900 was the only smoothing agent that had a statistically observable effect on MnO2 deposition. Cyquest N-900 demonstrably reduced the amount of MnO2 present on the cathode surface confirming industrial reports.

In part two, another laboratory cell was constructed to simulate industrial conditions during copper electrorefining. Anode material, stripper cell electrolyte, and titanium cathode material were provided by an industrial sponsor. The cell was run continuously for two-week intervals. 21 hour copper deposits produced with a higher As/(Sb+Bi) molar ratio anode were shown to be significantly more ductile than those produced with a lower As/(Sb+Bi) molar ratio anode. The addition of thiourea to a third experimental series, using lower molar ratio anodes, showed that the additive increased the ductility of the cathode to an intermediate value"--Abstract, page iv.


Moats, Michael S.

Committee Member(s)

O'Keefe, Matthew
Miller, F. Scott, 1956-


Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering


Missouri University of Science and Technology

Publication Date


Journal article titles appearing in thesis/dissertation

  • Manganese dioxide deposition on catalytic titanium anodes - effect of smoothing agents
  • The effects of anode composition and thiourea on electrorefined starter sheet ductility and electrolyte composition


xi, 48 pages

Note about bibliography

Includes bibliographical references.


© 2015 Paul Laforest, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 11147

Electronic OCLC #


Included in

Metallurgy Commons