Doctoral Dissertations

Abstract

"The effect of various impurities, commonly found in zinc electro-winning solutions, on the surface morphology of deposited zinc was investigated. Individual additions of the impurities Al, Ag, Cd, Co, Cr, Cu, Ge, Mn, Ni, Sb, Sn, Ti, PbO₂ , PbSO₄, and HCl were studied. In a few cases additives of animal glue, gum arabic, and Na₂SiO₃, were used individually or in combination, to determine their effect on the surface structure of the deposited zinc. Comparisons were then made with deposits from a pure electrolyte consisting of H₂SO₄ and Zn⁺², 200 and 65 g/l, respectively. The zinc was deposited on a 99.9% pure AI sheet using Pt anodes in all but a few cases. Time, temperature, current density, and impurity concentrations were also varied for a few of the impurities. The bulk of the work was conducted at 40º C and 75 A/ft² (82 mA/cm²). Zinc was also deposited using Pb-Ag (0.75%) anodes with or without a precoated PbO₂ layer, obtained by electrolyzing in a NaF solution. Pressed PbO₂ anodes were also used to determine the stability of the anode under the electrolyzing conditions. The surface morphology was examined by a scanning electron microscope (SEM). X-ray diffraction techniques were used to determine crystal orientation. A non-dispersive X-ray spectrometer was used in an attempt to locate impurity concentrations on the zinc deposit when pitting or re-solution occurred. The impurities were categorized by the effect they had on current efficiency, morphology, and apparent mechanism of H₂ evolution from the cathode"--Abstract, page ii.

Advisor(s)

O'Keefe, T. J. (Thomas J.)

Committee Member(s)

Morris, Arthur E., 1935-
Johnson, James W., 1930-2002
James, William Joseph
Kisslinger, Fred, 1919-2010

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Sponsor(s)

United States. Bureau of Mines

Publisher

University of Missouri--Rolla

Publication Date

1972

Pagination

viii, 63 pages

Note about bibliography

Includes bibliographical references (pages 54-55).

Rights

© 1972 Haruhisa Fukubayashi, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Zinc -- Electrometallurgy
Electrolysis
Extraction (Chemistry)

Thesis Number

T 2751

Print OCLC #

6034068

Electronic OCLC #

884344966

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