FES researcher talks metal recycling

Industrial ecology professor Thomas Graedel and associate research scientist Barbara Reck of the Yale School of Forestry & Environmental Studies recently published a paper in “Science” calling for an improvement in the recycling of scarce specialty metals. Current techniques do not favor scarce metal recycling, and as a result, specialty metals are inefficiently recycled. In addition, manufacturers are only just learning of the economic benefits of following recycling practices. A lack of recycled rare metals — such as indium, tantalum and europium — have led manufacturers to use up has dwindling supply because these specialty metals are the only ones that can serve their respective production purpose. Reck, who contends that a feasible solution is to collect and recycle these metals more effectively, spoke with the News Friday afternoon.

Q: Could you provide some background that led you to consider this policy?

A: We have 60 metals on the periodic table, and 10 to 15 are the big ones — iron, aluminum, copper. What we found is that these are recycled relatively well: once they’re used in products and discarded at the end of their life, more than half of them come back and are recycled. And we have a few metals, those that we call specialty metals, which are currently not recycled at all at end-of-life, or only very little.

Q: But there are efforts currently being made to recycle these specialty metals?

A: They are sometimes recycled — not from end-of-life products, but during the manufacture of products. Here, they are recycled for two reasons: One, the fabricators are very well aware of the value that’s in these particular materials, and two, these are clean materials that are not contaminated through mixing during the use phase or at end-of-life collection.

Q: What are some of the applications of these specialty metals?

A: Indium, for example, is required for LCD technology used in televisions and touch screens for smartphones. There, it is currently non-substitutable. It is concerning to see how rapidly the use of these LCDs is growing when we consider that indium is currently entirely supplied from primary sources, while no recycled material is being used. Another example is tantalum, which is widely used in capacitors found in many electronics.

Q: On the note of substitutability, is it worth researching whether or not certain elements can be substituted for, as opposed to conceding that another element cannot be found for a given function, which in turn increases the need for recycling?

A: Yes, this is a huge topic, and there’s a lot of research going on. For example, indium in LCD technology — do we really need indium, or are there other material combinations that would provide similar properties? In a lot of these technologies, there is quite good knowledge where we have more substitution possibilities. But then there are some key applications for which no substitute materials can be used.

Q: Is there hope for something synthetic or artificial for these purposes?

A: In some cases you have nanotechnology that can come in. Sometimes you have a substitute that’s not a metal, like PVC or ceramics.

Q: What else must one consider in the recycling process?

A: One of the key factors for efficient recycling is economics. Economies of scale play a major role. That’s much easier to achieve for iron than for lithium.

Q: Is this — getting economies of scale — feasible with the specialty metals addressed in this policy?

A: That is currently a big challenge, and often it is not the case. If something is recycled at end-of-life, you have two other aspects [to consider]: Is it technologically feasible, and do I have enough material to allow economies of scale for this to make sense? We find both. We find those that are easily recyclable, that can be reprocessed with the same technology as the primary ores. But then, there are a lot of metals, where, until a few years ago, nobody even thought about [recycling] because they were used in so small amounts and the technology is more complicated.

Q: Is there some form of pollution reduction that comes as a result of recycling specialty metals?

A: Yes, you have much lower energy requirements when you recycle metals — up to 70 to 90 percent less energy when you use recycled materials as opposed to primary metals. That means lower carbon dioxide emissions, so there is definitely a big difference.

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