Re
[Xe]6s
2
4f
14
5d
5
75
186.2
USGS Mineral Resources Program
Rhenium—A Rare Metal Critical to Modern Transportation
Rhenium is a silvery-white, metallic element with an extremely high melting point (3,180 degrees
Celsius) and a heat-stable crystalline structure, making it exceptionally resistant to heat and wear. Since the
late 1980s, rhenium has been critical for superalloys used in turbine blades and in catalysts used to produce
lead-free gasoline.
One of the rarest elements, rhenium has an average abundance of less than one part per billion in the
continental crust. Rhenium was the last stable, naturally occurring element discovered. Although its existence
was predicted in 1871—Russian chemist Dmitri Mendeleev noted two vacant slots below manganese on the
periodic table of elements—rhenium was not isolated until 1925, when German chemists Walker Noddack,
Ida Tacke, and Otto Berg detected it in platinum ore.
Rhenium rarely occurs as a native element or as its own sulfide mineral—rheniite (ReS
2
) —and often
occurs as a substitute for molybdenum in molybdenite (MoS
2
). Most extracted rhenium is a byproduct
of copper mining, with about 80 percent recovered from flue dust during the processing of molybdenite
concentrates from porphyry copper deposits.
How Do We Use Rhenium?
Over 80 percent of the rhenium consumed
worldwide is used in superalloy production. These
nickel-base alloys contain either 3 or 6 percent
rhenium, which is critical to the manufacture of
turbine blades for jet aircraft engines and industrial
gas turbine engines. The high-temperature properties
of rhenium allow turbine engines to be designed
with finer tolerances and operate at temperatures
higher than those of engines constructed with other
materials. These properties allow prolonged engine
life, increased engine performance, and enhanced
operating efficiency.
The other major use of rhenium, which
accounts for about 10 percent of worldwide rhenium consumption, is in platinum-rhenium catalysts. The
petroleum industry uses platinum-rhenium catalysts to produce high-octane, lead-free gasoline. These
catalysts boost the octane level of refined gasoline and improve refinery efficiency. Secondary applications
of rhenium include the manufacture of electrical contact points, flashbulbs, heating elements, vacuum tubes,
X-ray tubes and targets, and uses in various medical procedures.
Where Does Rhenium Come From?
Nearly all primary (not recycled) rhenium is a byproduct of copper mining. Rhenium resources,
largely contained in porphyry copper deposits, supply about 80 percent of the rhenium produced by mining.
Molybdenite, which commonly contains between 100 and 3,000 parts per million rhenium, is the principal
source of rhenium in porphyry copper deposits. Porphyry copper ores typically contain less than 0.5 grams
per metric ton rhenium, but rhenium production is feasible because of the large ore tonnage processed
(hundreds of millions to billions of metric tons [1,000 kilograms per metric ton]), the presence of sufficient
molybdenite to make its recovery economically practical, and the presence of specialized facilities that allow
rhenium recovery from molybdenite.
Sediment-hosted stratabound copper deposits in Kazakhstan (sandstone-type) and Poland
(Kupferschiefer [“copper schist”] or reduced facies-type) supply most of the remaining rhenium produced
by mining. Small amounts of rhenium are recovered by processing roll-front-type sandstone uranium ores in
Kazakhstan and elsewhere. The residence site of rhenium in these copper deposits is poorly understood. Much
of the rhenium in Kazakhstan’s sandstone-hosted deposits may be in dzhezkazganite, a complex mineral
containing rhenium, molybdenum, copper, and lead, whereas rhenium in Poland’s Kupferschiefer deposits
may be contained in castaingite, a copper-rich molybdenite.
Rhenium is recovered from gases released during the roasting of molybdenite concentrates from
porphyry copper deposits and of copper sulfide ores from sediment-hosted stratabound copper deposits.
During the roasting process, rhenium is oxidized and passed up a flue stack with sulfur gases. Scrubbing of
the flue dusts and gases produces sulfuric acid and other fluids that contain dissolved rhenium. The rhenium
is ultimately precipitated from these fluids as ammonium perrhenate (NH
4
ReO
4
), a white powder that is the
principal form in which rhenium is marketed.
U.S. Department of the Interior
U.S. Geological Survey
Fact Sheet 2014 –3101
April 2015
A
s part of a broad mission to
conduct research and provide
information on nonfuel mineral
resources, the U.S. Geological
Survey (USGS) supports science
to understand
• How and where rhenium
resources form and concen
trate in the Earth’s crust
• How rhenium resources
interact with the environment
to affect human and
ecosystem health
• What the trends are in
rhenium supply and
demand in domestic and
inter national markets
• Where undiscovered rhenium
resources might be found
Why is this information
important? Read on to learn
about rhenium and the important
role it plays in the national
economy, in national security,
and in the lives of Americans
every day.
A single crystal bar of high purity (99.999%) rhenium, a
remelted rhenium bar, and a 1-cm
3
rhenium cube. Photo-
graph by Alchemist-hp (http://commons.wikimedia.org/wiki/
File:Rhenium_single_crystal_bar_and_1cm3_cube.jpg)
Nickel-base superalloys used in the
turbine blades of jet engines are the most
common use of rhenium. Photograph by
Tony Hisgett from Birmingham, United
Kingdom. (Available at http://commons.
wikimedia.org/wiki/File:Inlet_of_jet_
engine.jpg)
Rhenium Supply and Demand Worldwide
Worldwide mine production of rhenium in 2012 was 52,600 kilograms (kg); about 27,000 kg were
produced from porphyry copper mines in Chile (Polyak, 2013). Rhenium is also produced from porphyry
copper deposits in Peru, the United States, Kazakhstan, Uzbekistan, Russia, and Armenia. The United States’
rhenium production in 2012 was 7,900 kg (Polyak, 2013).
Rhenium resources in the United States are located in Arizona and Utah, with smaller resources found
in Montana, New Mexico, and Nevada. An unmined deposit in Alaska contains a large inferred rhenium
resource. Identified U.S. rhenium resources are estimated to be about 5 million kg, and the identified rhenium
resources for the rest of the world are approximately 6 million kg (Polyak, 2013). The largest identified
rhenium resources outside the United States are in Chile, Peru, Canada, Poland, and Kazakhstan.
Rhenium recycling processes continue to develop. Because the turbine blade life cycle in jet engines is
approximately 10 years, significant quantities of second-generation blades, which contain 3 percent rhenium,
are accumulating. Technological advances will eventually allow second-generation blades to be recycled so
that recovered rhenium can be used to manufacture third-generation blades, potentially reducing primary
rhenium requirements by about 50 percent. The number of companies that process molybdenum-rhenium scrap
and tungsten-rhenium scrap continues to grow, especially in the United States and Germany. In addition, spent
platinum-rhenium catalysts are recycled, and the rhenium is recovered.
World consumption of rhenium was estimated at 50,000 to 55,000 kg per year in 2012, and it is estimated that worldwide rhenium consumption
will increase to about 71,500 kg by 2015. The United States is the largest consumer of rhenium with an apparent consumption of 48,000 kg in 2012.
In the United States, nearly 80 percent of consumed rhenium is imported, mostly from Chile and Kazakhstan.
Molybdenite is a gray, metallic mineral
found in veins and disseminated in most
porphyry copper deposits. It commonly
contains hundreds to thousands of parts
per million of rhenium as a substitute for
molybdenum in its crystalline structure
and is the main source of rhenium.
Photograph by David John.
Did you know...
Rhenium is named for the Rhine River, which comes from the Latin word, Rhenus
How Do We Ensure Adequate Supplies of Rhenium for the Future?
The United States is unlikely to meet its rhenium requirements with domestic
resources. Although there are substantial, proven rhenium reserves in porphyry
copper deposits in the United States, special facilities are required to extract
rhenium from the molybdenite concentrates recovered from these deposits. In the
United States, only one molybdenum concentrate roasting facility is equipped
to recover rhenium and although a second plant is under construction and could
increase U.S. production by about 50 percent, the potential rhenium production
from these plants is far less than current U.S. consumption. Therefore, it is
likely that imports will continue to supply most of the rhenium consumed in the
United States.
To determine where future rhenium supplies might be located, USGS
scientists study how and where rhenium resources are concentrated in Earth’s
crust and use that knowledge to assess the likelihood that undiscovered rhenium
resources exist. Techniques used to assess mineral resources were developed by
the USGS to support the stewardship of Federal lands and better evaluate mineral
resource availability in a global context. The USGS also compiles statistics and
information on the worldwide supply of, demand for, and flow of rhenium. These
data inform U.S. national policymakers.
The Butte porphyry copper-molybdenum deposit is mined in the
Continental Pit. Rhenium is recovered from molybdenite concentrates
produced from the Butte deposit. Porphyry copper deposits are the
world’s largest source of rhenium. Photograph by David John.
Did you know...
Rhenium has 28 isotopes.
188
Re and
186
Re are short-lived (90 and 17 hours, respectively)
radioactive isotopes used to treat liver and bone cancer and arthritis
Re
[Xe]6s
2
4f
14
5d
5
75
186.2
For More Information
• On production and consumption of rhenium:
http://minerals.usgs.gov/minerals/pubs/commodity/rhenium/
• On porphyry copper deposit models:
http://pubs.usgs.gov/sir/2010/5070/b/
Reference Cited
Polyak, D.E., 2013, Rhenium [advance release], in Metals and
minerals: U.S. Geological Survey, Minerals Yearbook 2012,
v. I, 5 p., accessed August 12, 2014, at
http://minerals.usgs.
gov/minerals/pubs/commodity/rhenium/myb1-2012-rheni.pdf
.
The USGS Mineral Resources Program is the principal Federal provider of
research and information on rhenium and other nonfuel mineral resources.
For more information, please contact:
Mineral Resources Program Coordinator
U.S. Geological Survey
913 National Center
Reston, VA 20192
Telephone: 703–648–6100
Fax: 703–648–6057
Email:
minerals@usgs.gov
Home page:
http://minerals.usgs.gov
Text prepared by David John.
ISSN 2327– 6932 (online)
http://dx.doi.org/10.3133/fs20143101