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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications
manufacturers. Assuming that most LCD/flat-panel display manufacturers now recycle
manufacturing waste implies primary indium demand of ~730 tonnes and the successful
deposition of ~400 tonnes, of which ~220 tonnes is from primary indium and ~180 tonnes is
from new scrap recycling. The amount generated by new scrap recycling reduced primary
indium demand by 608.5 tonnes (Appendix B reports these figures in detail).
When considering the cost of secondary supply, we note that before 1996, recycling was not a
significant source of supply. Before 1995, indium prices were $125–$200/kg. Increased demand
caused prices to increase significantly in 1995 and 1996 to a peak of almost $600/kg. This surge
led manufacturers to rationalize their use of indium and incentivized producers to reclaim indium
waste. These factors simultaneously increased supply, decreased demand, and together with
other factors, resulted in reduced prices. Once prices relaxed, recycling of indium continued.
The response of secondary production to price fluctuations suggests that, in the medium term,
indium prices higher than $300–$400/kg are required to increase new scrap secondary
production capacity. Once the capacity is installed, producers can profitably recycle indium at
prices higher than about $175/kg. With this in mind, we use a short-term production cost for
secondary production of $175/kg and a medium-term cost of $350/kg in our analysis.
3.7.3 Recycling From End-of-Life Products
In addition to the recovery of indium from manufacturing waste, much research has been
conducted into the secondary recovery of indium from consumer waste. According to Roskill
(2010), a proprietary technique has been jointly developed between Sharp and Aqua Tech Co. to
recycle indium from LCD panels. The recycling process can be broadly described as comprising
two stages: (1) comminution, where consumer waste products are reduced into fine pieces; and
(2) recovery by chemical leaching or vaporization.
In Sharp and Aqua’s recycling process, high-purity indium can be recovered from a process that
uses only common chemicals, thereby eliminating the need for possible high-cost energy
resulting from a process dependent on high temperatures or pressures (Sharp Electronics UK
2012). The companies are continuing large-scale prototype studies to establish the viability of the
technique to operate as a closed-loop recycling system.
As an additional example, Figure 14 depicts a process to recover indium from the LCDs of
discarded cellular phones as described by Takahashi et al. (2009). The process is similar to that
used by Sharp/Aqua in that it can broadly be split into the same two-step process of comminution
and chemical concentration. In this proposed process, indium is recovered from discarded
cellular phones through chloride-induced vaporization. Following the comminution stage, sieved
material from discarded cell phones is treated with a solution of hydrochloric acid (HCl), which
alters the structure of the indium oxide and allows it to be vaporized at relatively low
temperature. Next, the vaporized indium compound is condensed on a cooled surface and
recovered. Takahashi et al. report that 84% of indium contained in LCDs is recovered.
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This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications
Figure 14. An example of recycling LCDs from discarded mobile phones using vaporization
(Takahashi et al. 2009)
Secondary production of indium from consumer waste is not a material source of supply because
less than 1% of indium contained in EOL products is recycled (Buchert et al. 2012). A key issue
for consideration in the recycling of indium from consumer waste is the interaction between the
value of the recycled material and the degree of dispersion of the raw material. A greater degree
of dispersion implies that the cost of collecting, sorting, recycling, and refining is likely to be
higher than if the raw material were concentrated within a single product at a single location and
in large quantities. These costs are then compared to the value of the material that can be
recovered to ascertain whether its recycling is economic. As discussed by Dahmus and Gutowski
(2007), certain products, such as catalytic convertors, automobiles, and batteries, are economic to
recycle. Other items such as computers, televisions, cell phones, and small electronic items fall
beneath an apparent recycling boundary.
Although the recycling of indium from EOL products has significant potential, old scrap is not
currently a significant source. The low recycling rate implies that the costs of collecting, sorting,
and refining such scrap (because of the highly dissipative use of indium in consumer products)
are still higher than long-term indium price expectations. In addition, dedicated recycling from
concentrated sources of indium such as EOL solar panels is a supply source reserved for the
future because the average solar panel has a life expectancy of approximately 20 years and
recyclers are hesitant to commit capital to dedicated facilities until they can be assured that the
base loads of plant feed are available (Van den Broeck 2010). Thus, because of its low contribu-
tion and high costs, we exclude consumer waste as a source of indium in our short-term analysis.
3.8 Total Primary and Secondary Production
In summary, indium primary production was approximately 770 tonnes in 2013 (Tolcin 2014a).
Production is relatively concentrated, with about half currently in China. Since the indium price
increases in 1995 and 1996, secondary production has been a significant contributor to overall
supply, reducing primary indium demand by approximately 609 tonnes in 2013. Significant
secondary supply of approximately 610 tonnes principally takes place close to high-tech
manufacturing centers such as Japan (59%, 300 tonnes), South Korea (7%, 36 tonnes), and China
Liquid Crystal Display (LCD)
Pre-treatment
Incineration
Heat treatment
Indium
Crushing
Sieving
HCl treatment
Drying
Vaporization of
Sn
Vaporization of In
Tin