iv
This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications
Executive Summary
The Issue
The demand for indium could intensify significantly if thin-film materials relying on this
element—specifically, copper-indium-gallium-selenide (CIGS) and III-V thin-films—become
preferred photovoltaic (PV) materials. Yet the indium supply is potentially fragile for several
reasons:
•
Markets for metallic forms of indium are small, (about 1000 tonnes per annum [tpa]
of world production and use. Any new, widespread use could dramatically alter overall
demand, which could grow faster than production capacity for up to about a decade,
given the length of time needed to significantly increase production capacity. During this
decade, indium prices could be high and volatile enough that thin-film manufacturers find
it uncompetitive compared to competing PV materials.
•
Indium is currently produced almost solely as a byproduct of zinc smelting and
refining.
1
As a byproduct, indium benefits from sharing some production costs with its
associated main product. Thus, costs of producing indium as a byproduct are undoubtedly
lower than if it were produced by itself. If future demand for indium exceeds the
quantities available as a byproduct, more costly sources of indium will be necessary to
satisfy demand from thin-film producers, raising the possibility that indium prices could
be much higher than current and recent prices.
•
Relevant for the long term, indium is one of the scarcer elements, at least in terms of
average abundance in the Earth’s crust. Thus, even if indium were available in the
short to medium term at prices making CIGS materials competitive with competing
photovoltaic materials, such competitiveness could be short lived.
Overall, the concern implied by these three factors is whether the availability or prices of indium
constrain the expansion of thin-film materials. Fully answering this question would require
detailed evaluation of its demand and supply.
This study focuses only on the supply side of the question and examines the following, narrower
question: If the demand for indium grows significantly, what are the likely sources of
incremental production, in what quantities, and what might be the expected production costs and
prices?
The Approach
This study examines the availability of indium from three temporal perspectives:
1
A byproduct is produced along with a main product. The main product, more specifically its prices and production costs, largely
determine the commercial viability of the mining operation. The associated byproduct, in contrast, has little effect on the overall
viability of the mine, although of course the price received for the byproduct must be sufficient to justify the additional costs of
separating and recovering the byproduct rather than discarding it. An intermediate situation arises when more than one product
importantly influences the viability of an operation; in this case, each product is a coproduct.
v
This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications
1. It describes the present based on estimates of current production capacities and associated
production costs.
2. It evaluates the medium term, roughly 5–20 years into the future, based on known
developed and undeveloped indium resources.
3. Most speculatively, it examines the long term, beyond 20 years or so into the future,
based on (a) the general relationship in the recent past between the concentration of
mineral ores for a range of metals; and (b) likely future ore grades for indium.
The Findings
At present, indium availability has the following characteristics (based on recent data and
information):
•
Indium reserves are an estimated 15,000 tonnes, more than two thirds of which are in
China. A broader estimate, including reserves and resources, from the Indium
Corporation of America (Moss et al. 2011) is total reserves and resources of
approximately 50,000 tonnes, with some 47% in China and the Commonwealth of
Independent States and 53% in other countries.
2
•
Indium is produced
mainly as a byproduct of zinc, and to a lesser extent as a byproduct of
copper, tin, and polymetallic deposits from mineral ores containing less than 100 parts
per million (ppm) (or less than 0.01%) indium.
3
We estimate that the indium content of
zinc and other ores from which indium was recovered in 2013 was ~700 tonnes. Zinc
ores accounted for ~90% of production. For reasons discussed later, we believe these
estimates are well below the actual levels of mine production. Considering only zinc ores,
mine production of indium was geographically concentrated in China, Peru, Canada,
Australia, and the United States, which together accounted for more than 75% of world
production in 2013.
•
Primary refined production of indium was ~770 tonnes in 2013 (Tolcin
2014a).
4
Production over the last few years was ~600 to ~800 tpa. About half of global
primary refined indium is produced in China. The remaining production is predominantly
in Belgium, Canada, Japan, Peru, and South Korea.
•
Secondary refined production capacity was ~610 tonnes in 2013, almost all of which
represents recycling of manufacturing wastes rather than recovery from end-of-life (EOL)
products. Of this total tonnage, 510 tonnes (84%) occurs in or near manufacturing centers
in Japan, South Korea, and China, and is recovered from spent indium-tin oxide
sputtering targets used in the production of flat-panel displays.
2
A reserve is the quantity of material that is known with a high degree of certainty to exist in the Earth’s crust and can be
extracted and recovered at a profit with current technologies and under current legal and regulatory regimes and current prices
and production costs. As such, a reserve is only a fraction of the material in the crust. Resources of a particular material are
larger than reserves in that resources represent material that is known with some degree of certainty to exist in the crust and might
be technically, legally, and commercially viable to produce under some conceivable circumstances.
3
Ore is rock that contains one or more valuable minerals, from which the desired material is recovered (in this case, indium). Ore
is mined and then serves as the input for subsequent processing, upgrading, and recovery of the desired material.
4
Primary production uses raw minerals as inputs. Secondary production uses manufacturing wastes and materials from EOL
products as inputs.