Doctoral Dissertations

Abstract

"The objectives of this research were to experimentally investigate the effects of organic solvents, entrained during solution purification by solvent extraction, on the zinc electrowinning efficiency and the characterization and evaluation of zinc electrolytes produced from waste oxides generated by the Ausmelt Pyroprocessing. The removal of cadmium ions from di-(2-ethylhexyl) phosphoric acid (D2EHPA) solvent extractant using different zinc solid reductants, and the dissolution of metallic Zn, Cd, and Pb in D2EHPA were also part of the present study.

The results have shown that the entrainment of D2EHPA, in the loaded spent electrolyte significantly affect the current efficiency of zinc electrowinning, but the detrimental effects can be eliminated by purifying the contaminated electrolyte with activated carbon. The results obtained using the Ausmelt electrolytes showed that these solutions can be successfully electrolyzed but rather extensive purification is required and control of the solution overpotential is essential.

The removal of Cd from D2EHPA was successfully accomplished using the galvanic stripping technique. It was found that zinc solid reductant alloyed with lead was superior to pure zinc for cadmium recovery and changes in the deposit morphology by the reaction/settling procedure enhance cadmium removal. The overall cadmium cementation is complex and is very dependent on oxygen content, temperature, agitation and type of zinc used. The results of the dissolution of Zn, Pb, and Cd powders in D2EHPA showed that a certain amount of water was necessary for a reaction to occur and the other variables, such as oxygen content, temperature, and agitation became significant only if the moisture condition was satisfied"--Abstract, page iv.

Advisor(s)

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

Committee Member(s)

Watson, John L.
Askeland, Donald R.
Kohser, Ronald A.
Johnson, James W., 1930-2002

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 1994

Journal article titles appearing in thesis/dissertation

  • The effect of entrained di-(2-ethyhexyl) phosphoric acid on zinc electrowinning
  • Zinc electrowinning from waste oxide generated using Ausmelt pyroprocessing
  • Galvanic stripping of cadmium from di-(2-ethylhexyl) phosphoric acid
  • Dissolution of metallic Pb and Cd in di-2-ethylhexyl phosphoric acid (D2EHPA)
  • The dissolution of metallic zinc in di-(2-ethylhexyl) phosphoric acid

Pagination

xxvi, 185 pages

Note about bibliography

Includes bibliographical references.

Rights

© 1994 Manuel Prospero Neira Avalos, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 6742

Print OCLC #

32474905

Electronic OCLC #

1079065210

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