Tungsten - Mining Journal

2
OVERVIEW
CONTENTS
Overview 2-4
Exploration 5-6
Map 8-9
Profi les:
Amanta Resources 7
Geodex Minerals 10
Malaga 11
North American Tungsten 12
Oriental Resources 13
Ormonde Mining 14
Queensland Ores 15
Cover: montage of scheelite and tungsten images,
with ‘w’ the chemical symbol for wolfram
Photo: North American Tungsten
Published in June 2008 by:
Mining Communications Ltd
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Supplement editor: Chris Hinde
Design and production: Tim Peters,
Karen Leverington, Vickie Johnstone
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© Mining Communications Ltd 2008
An Aspermont company
ITIA
The International Tungsten Industry Association
was inaugurated in Brussels in February 1988, and
is registered as an association with scientifi c
purposes under Belgian law. The members of ITIA,
from 17 countries, include mining companies,
processors/consumers, trading companies and
assayers. Website: www.itia.org.uk
scheelite
concentrate
primary tungsten
(concentrates)
66%
� nal
product
90%
loss through
dissipation & discard
55%
wolframite
concentrate
TOTAL TUNGSTEN DEMAND
scrap from used parts
24%
June 2008 Mining Journal special publication Tungsten
Heavy stone
The name tungsten is taken from the Swedish for
heavy stone (tung sten), but the element is also
widely referred to as wolfram after one of its ores
Although not isolated until 225 years
ago, tungsten has a history dating
back to before Georg Agricola, who is
thought to have described the ore in
1546. Tin miners extracting cassiterite
in the Erz Mountains of Saxony in the 17th century
noted that certain ores reduced the amount of tin recovered
“like a wolf devours a sheep” (the effect of the
ore being likened to wolf’s froth, volf rahm in German).
In 1758, the Swedish chemist and mineralogist,
Axel Fredrik Cronstedt, discovered and described an
unusually heavy mineral that he called ‘tung sten’. Although
he was convinced that this mineral contained
a new and as yet undiscovered element, it was not
until 1781 that a fellow Swede, Carl Wilhelm Scheele
(who worked as a pharmacist and private tutor in
Uppsala and Köping) succeeded in isolating the oxide
(tungsten trioxide).
Torbern Bergman, working at Uppsala, predicted
that the acid isolated by Mr Scheele contained a new
metal, which should be possible to prepare by coal
reduction. One year later, a Spanish nobleman,
Don Juan José de Elhuyar, studied at the University of
Uppsala under Bergman. Back in Spain in 1783, Juan
José and his brother, Fausto de Elhuyar de Suvisa,
were the fi rst to prepare tungsten metal by the
method suggested by Bergman. They named it wolfram.
Jöns Jacob Berzelius (1816), and later Friedrich
Wöhler (1824), described the oxides and bronzes of
tungsten, and also proposed the name wolfram.
In 1821, KC von Leonhard proposed the name
scheelite for the mineral CaWO4. In 1847, R Oxland
took out a patent for the manufacture of sodium
tungstate and tungstic acid. This forms the starting
point of the metallurgy of tungsten.
Industry schematic
secondary tungsten
(concentrates)
34%
scrap from
processing
10%
CONVERSION
Tungsten conversion measurements
W 1.2616 WO3
Ton 2,000lb
Ton 0.907t
Tonne 2,204.6lb
Tonne 100MTU (metric tonne units)
Short ton unit 20lb (1% short ton)
MTU 1.1023STU
MTU 10kg (1% metric tonne)
MTU 22.04lb
The fi rst attempts to produce tungsten steel
were made in 1855 by J Jacob and F Koeller at the
Reichraming steel works in Austria. Further improvements
in alloying and hardening of steels by tungsten
were made late in the 19th century, and rapid growth
and widespread application followed. The launch of
high-speed steels by Bethlehem Steel took place in
1900 at the World Exhibition in Paris.
The second important breakthrough in tungsten
applications was made by WD Coolidge in 1908
and 1909. Mr Coolidge succeeded in preparing a
ductile tungsten wire by thermo-mechanical
processing. Metal powder (WC) was pressed to
bars, sintered and forged to thin rods. Very thin
wire was then drawn from these rods. This was the
beginning of tungsten-powder metallurgy, which was
instrumental in the rapid development of the lamp
industry.
The next important milestone in the chronology
of tungsten is 1923, which marks the invention of
hard-metal (combining WC and cobalt by liquid-phase
sintering) by K Schröter. The corresponding
application for a patent was granted to Osram
Studiengesellschaft in Berlin, and licensed to Krupp in
Essen in 1926. Hard-metal (cemented carbide) is now
the main application for tungsten.
HISTORY LESSON
The brothers José and Fausto Elhuyar are credited
with the discovery of the element in Spain
during 1783. They had found an acid made from
wolframite that was identical to an acid made
from scheelite (tungstic acid), and subsequently
succeeded in isolating tungsten through reduction
of this acid with charcoal.
Carl Wilhelm Scheele had ascertained two
years earlier that a new acid (at the time named
tungstenite) could be made from scheelite. Mr
Scheele and Torbern Bergman suggested that
it could be possible to obtain a new metal by
reducing this acid.