Masters Theses

Abstract

"It has been only in recent years that hafnium-free zirconium has been made available for commercial use. When economical methods were developed in 1950 to remove hafnium from zirconium, a metal was produced which not only exhibited good corrosion resistance and desirable physical properties, but which also had a very low absorption cross section for thermal neutrons. These factors have led to its most important application to date, that of a structural material for nuclear reactors.

The outstanding non-nuclear property of zirconium is its corrosion resistance to most mineral acids. Hafnium-free zirconium exhibits outstanding resistance to all mineral acids with the exceptions of hydrofluoric acid, concentrated sulfuric and phosphoric acids, and aqua regia. The resistance of zirconium to the attack of these reagents is dependent upon the amounts of impurities present. Small amounts of such impurities as oxygen, nitrogen, and carbon will decrease the corrosion resistance of zirconium. In general, hafnium-free zirconium (containing less than 0.1% hafnium) is more corrosion resistant than zirconium containing the usual two and one half per cent of hafnium.

The rate of dissolution of zirconium in hydrofluoric acid is greater than in any other mineral acid. Yet, very little published material is available concerning the chemistry of the zirconium-hydrofluoric acid reaction. The reaction of zirconium with concentrated nitric-dilute hydrofluoric acid mixtures has been investigated in connection with aqueous processing of zirconium-uranium reactor fuels. There have been only limited investigations of the quantitative aspects of the zirconium-hydrofluoric acid system.

It is the purpose of this investigation to provide additional information concerning the reaction of hafnium-free zirconium with hydrofluoric acid. The investigation will deal specifically with the rate of the chemical reaction, with factors which influence the rate of reaction, and if possible, an explanation of the rate in terms of reaction mechanism"--Introduction, pages 1-2.

Advisor(s)

James, William Joseph

Committee Member(s)

Straumanis, Martin E., 1898-1973
Rankin, Rolfe M., 1892-1974

Department(s)

Chemical and Biochemical Engineering

Degree Name

M.S. in Chemistry

Sponsor(s)

U. S. Atomic Energy Commission

Comments

Financial assistance received from the Board of Curators of the University of Missouri and the United States Atomic Energy Commission, (contract AT (11-1 - 73 Project 5)

Publisher

Missouri School of Mines and Metallurgy

Publication Date

1959

Pagination

vii, 137 pages

Note about bibliography

Includes bibliographical references (pages 133-134).

Rights

© 1959 Wayne G. Custead, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Zirconium -- MetallurgyChemical kineticsCorrosion and anti-corrosivesHydrofluoric acid

Thesis Number

T 1193

Print OCLC #

5924495

Electronic OCLC #

930389443

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