Masters Theses

Abstract

"Recovery problems encountered at some of the St. Joe Lead Company's milling facilities prompted the study of 6 different ores. High and low grade ores had characteristics that varied from poor lead - zinc selectivity to excessive lead losses to the flotation tailings. Three ores from both the Fletcher and Viburnum mills were studied through flotation tests, mill water analysis, and ore analysis using an ore microscope.

The major cause for poor recovery was found to be due to ore oxidation. Not only was lead, in the form of oxides, reporting to the tails, but high levels of copper ions were found to cause nonselective flotation of most sulfide minerals. Mineralogy problems encountered which were also responsible for the selectivity problems included the presence of hydrocarbons, cyanide soluble copper minerals, and intricately locked ore minerals.

To better understand the oxidation process of galena, two subsequent studies were performed. One study involved documenting the oxidation effect which various sulfides had on two crystal forms of galena. It was found that ore texture had more of an influence on galena oxidation than did any one mineral in the Viburnum Trend. In addition, no oxidation rate difference was found between cubic and octahedral galena.

In a separate experiment, sulfur 34 isotopes were used to trace galena crystal habit and oxidation during flotation. Two synthetic ores and samples from two Viburnum flotation circuits were analyzed for sulfur isotope and metal sulfide content. From this, a sulfur isotope range for galena was back-calculated. The galena sulfur isotope values were found not to vary during the flotation of a single, non-oxidized crystal. Isotope did vary within the flotation of an oxidized ore sample, indicating that octahedral galena was a slower floating galena in this case. Low isotope values in the last cells of the Viburnum mill rougher and cleaner circuits clearly showed that oxidized sulfide minerals were last to respond to flotation"--Abstract pp. ii-iii

Advisor(s)

John L. Watson

Committee Member(s)

Illegible Signature
Richard D. Hagni

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 1986

Pagination

xi, 91 pages

Note about bibliography

includes bibliographical references (pages 78-80)

Rights

© 1986 Michael G. Schroer, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 5350

Print OCLC #

14178530

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