Review of Extraction, Processing, Properties, and Applications of Reactive Metals: 1999 TMS Annual Meeting, San Diego, CA, February 28 - March 15, 1999

220 Pages·1999·13.414 MB·English

by  Brajendra Mishra

REVIEW OF EXTRACTION,
PROCESSING^ PROPERTIES
& APPLICATIONS OF
REACTIVE METALS
Edited by
Brajendra Mishra

REVIEW OF EXTRACTION,
PROCESSING, PROPERTIES &
APPLICATIONS OF
REACTIVE METALS
Proceedings of Symposium sponsored by
the Reactive Metals Committee of
the Light Metals Division (LMD) of
TMS (The Minerals, Metals & Materials Society)
1999 TMS Annual Meeting
San Diego, CA
February 28- March 15,1999
Edited by
Brajendra Mishra
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TABLE OF CONTENTS
Zirconium and Hafnium
J.C. Haygarth, R.A. Graham 1
Extractive Metallurgy of Molybdenum
M.C.Jha 73
Niobium
B. Mishra, P. Termsuksawad 83
Berryllium
B. Mishra, D.h. Olson 135
Titanium Metal: Extraction to Application
J. Gambogi, S.J. Gerdemann 175
Author Index 211
v

ZIRCONIUM AND HAFNIUM
John C. Haygarth and Ronald A. Graham
Oremet-Wah Chang
An Allegheny-Teledyne Company
1600 Old Salem Road, NE, Albany, OR 97321-4548
Abstract
Zirconium and hafnium occur together in nature. Both have high melting-points and form stable
compounds with most elements. The stability of the oxides and their ability to form a tightly-
adhering layer confers a high level of corrosion resistance in aqueous and other media. Zirconium
has a low capture cross-section for thermal neutrons, and this attribute accounts for its extensive
use for nuclear fuel cladding and other reactor core structural materials. Hafnium with its high
cross-section finds application in control rods. Zirconium and hafnium find use in chemical pro­
cess equipment in acid and basic media, and for alloy additives. Zirconium compounds having
commercial use include the oxides, sulfates, carbonates and tetrachlorides.
Zirconium and hafnium are obtained from zircon, ZrSi0 , and baddeleyite, ZrO Zircon is
4 r
produced commercially from mining beach and dune heavy sand deposits in Australia, South
Africa, Florida, and elsewhere. Baddeleyite is mined in South Africa and in the Kola Peninsula
in Russia.
Several processes are used to decompose zircon and baddeleyite. For nuclear applications haf­
nium (starting at about 1.5-3%) must be separated from the zirconium to less than 100 ppm. This
is done commercially by any of four processes, dependent partially on the initial step used.
Owing to the high oxygen affinity of both metals and the high solubility of oxygen in them, all
commercially operated reduction processes start with either the chlorides, fluorides, or double
fluorides with potassium or sodium. The metals as initially won are then subjected to melting to
consolidate and purify them for metallurgical processing.
Consolidation to ingot is usually done by vacuum arc melting, with electron beam melting used
only if some additional purification is needed. Two or three successive melting operations provide
ingots up to 760 mm diameter, weighing approximately eight tonnes. The ingots are processed
using conventional hot and cold working techniques. Both metals can be welded, cast, machined,
ground, pickled and formed using mostly conventional techniques, with allowances for the reac­
tive nature of the metals with the atmosphere.
Review of Extraction, Processing, Properties and Applications of Reactive Metals
Edited by Brajendra Mishra
TMS (The Minerals, Metals & Materials Society), 2001
1
Topical Index
Introduction
Literature Sources on Zirconium and Hafnium
Discovery and History
Occurence
Commercial Deposit
General Properties and Applications of the Elements
and some of their Alloys and Compounds
Applications of the Metals and their Alloys
other than in the Nuclear and Chemical Industries
Safety Precautions
Properties and Applications of some Zirconium and Hafnium Compounds
Decomposition of Zirconium Ores
Preparation of Zirconium Compounds and Intermediates
Separation of Zirconium and Hafnium: Commercial Processes
Alternative Separation Processes
Reduction to the Metals
Alternative Reduction Processes
Purification of the Metals
Vacuum Arc Consolidation
Recycling of Zirconium and Hafnium
Therm omechanical Processing
Powder Metallurgy
Joining Techniques
Castings
Fabrication
Physical Metallurgy
Metallography
References
2