TUNGSTEN
By Gerald R. Smith
Mr. Smith, a physical scientist with 30 years of research and commodity experience
with the U.S. Bureau of Mines, has
been the commodity specialist for tungsten since 1986. Domestic survey data
were prepared by Dwayne Penn, statistical
assistant; and the world production table was prepared by Jeremy Tidwell,
international data coordinator.


The unique high-temperature
properties of tungsten and its alloys can
be utilized advantageously in the
production of numerous end-use items.
The high melting point, high density,
good corrosion resistance, and good
thermal and electrical conductivity
properties of tungsten and its alloys and
the excellent cutting and wear-resistant
properties of its carbide continue to
provide important items for consumption
in the domestic and military sectors.
Total reported domestic consumption
of tungsten in primary end-use categories
increased  by  about 10 %  in  1993
compared with that of 1992. Demand
generally increased in the cemented
carbide end-use sectors that included the
combined cutting tool, mining tool, oil
drilling equipment, and wear-resistant
component industries. Demand for mill
products made from metal powder as well
as demand for tungsten chemicals and
directly reusable tungsten scrap also
increased in 1993.  Counter to these
increases was a decrease in the use of
ferrotungsten in steels, which included
the tool, alloy, and stainless steel sectors.
A gradual strengthening of the U.S.
economy influenced the overall increase
in demand for tungsten products during
1993.
The average Metal Bulletin (London)
combined price for wolframite and
scheelite concentrates, instituted in April
1992, declined about 38%   in 1993
compared with that of 1992.    The
concentrate  price  trend  for  1993


continued the downward trend that
existed in 1992, increasing only slightly
in the final 2 months of the year.
Prices for ammonium paratungstate
(APT) on the world market decreased


during 1993, consistent with the declining
prices for concentrates. According to
quotations in Metals Week, the average
price for APT on the U.S. market, duty-
paid and delivered to processing plants,
decreased by 21% from an average of
$58.42 per metric ton unit (mtu) in
January to an average of $46.30 per mtu
by yearend. Similarly, quotations for
Chinese No. 1 Grade APT in Hong Kong
declined by 25% during the year from an
average price of $39.50 per mtu to an
average of $29.50 per mtu. The average
price of APT on the European free
market decreased by 26 %, from $47 per
mtu to $35 per mtu, according to
quotations published in Metal Bulletin
(London).
As a result of the weak tungsten
market, at least eight additional tungsten
mine operators in the West, including two
in the United States, were forced either to
reduce concentrate production, to suspend
production and place their mine on care-
and-maintenance status, or to close their
mines permanently.
The pattern of imports of tungsten
materials by U.S. processors during 1993
showed a further shift away from
tungsten concentrate and toward the
intermediates ammonium paratungstate,
tungsten oxide, and sodium tungstate.
The shift continued a trend that began in
1991, subsequent to the imposition of the
151 % antidumping tariff on imports of
concentrate from China that effectively
halted such imports. China, however,
continued to be the dominant supplier of
tungsten materials to the United States in
1993, providing about 44% of all
imported tungsten materials.
A summary of the important U.S. and
international statistics for 1993 and the


previous 4 years are shown in table 1.
(See table 1.)


DOMESTIC DATA COVERAGE


Domestic production data for tungsten
are developed by the U.S. Bureau of
Mines by means of two separate,
voluntary surveys. These surveys are
"Tungsten Ore and Concentrate" and
"Tungsten Concentrate and Tungsten
Products."  Of the 14 miing and 15
processing operations to which survey
requests were sent, response was received
from 64 % and 100%, respectively, of
those operations surveyed. Production
and  stock  totals  for  the  survey
respondents are shown in table 1.


BACKGROUND


Definitions
Tungsten, a silvery gray metal, has an
atomic number of 74 and an atomic
weight of 183.92. Its most outstanding
physical property is its high melting point
of 3,4100 C, the highest of all metals.
Tungsten is one of the heaviest elements,
with a density of 19.3 grams per cubic
centimeter at 200 C.    It has good
corrosion resistance, good thermal and
electrical conductivity, and a low
coefficient of expansion. At temperatures
above 1,650f C, tungsten has the highest
tensile strength of all metals.
Tungsten concentrate is sold in units of
tungsten trioxide (W03). In the United
States, sales are based on the short ton
unit of W03. This is equivalent to 1% of
a short ton, or 20 pounds of W03 and
contains 7.19 kilograms (15.86 pounds)
of tungsten. In most other countries,


1235


"UNGSTEN-1993










-  .     -  -                           I