Recycling Special & Precious Metals

Recycled metals are playing an increasingly important market role next to primary mine supply...

ONE OF THE world's largest precious metals recycling facilities, Umicore Precious Metals Refining near Antwerp is a division of the Belgium-based Umicore Group, which – besides refining and recycling metal for industry, produces some 100 tonnes of London Good Delivery Gold Bars each year.

Here, Tom Vulcan of HardAssetsInvestor.com speaks with Kris Van den Broeck, sales manager of Special Metals – New Markets and Products, at the Hoboken plant...

Tom Vulcan (Hard Assets Investor): What metals do you refine at your facility in Hoboken?

Kris Kris Van den Broeck: We recover here some 17 metals. With the addition of gallium, I like to call it now 17-and-half. But we'll come to that later.

We refine precious metals – gold, silver and five platinum group metals; i.e., platinum, palladium, rhodium, iridium and ruthenium – as well as special metals (indium, selenium and tellurium) and, together with arsenic, antimony and bismuth, the base metals copper, lead, nickel and tin. But we do not produce base metals for the sake of base metals; we use them in the flow sheet [the sequence of processing operations] as collector metals to refine other metals – primarily the precious metals.

HAI: How would you describe your new CIGS [copper, indium, gallium and (di)selenide] production scrap recycling flow sheet at Hoboken?

Kris Van den Broeck: For many years we have been a very large producer of indium, selenium and tellurium. The first industrial operation started some time in the '70s. We have a capacity of some 50 tonnes of indium per year, 600 tonnes of selenium – including grades going from the technical grades that are used in the glass and pigment industries, to the more high-purity grades used in optics and photovoltaics [PVs]. We are also one of the largest producers of tellurium worldwide, with a capacity of 150 tonnes per year.

HAI: So you decided to look at the CIGS world to see if you could offer a recycling service?

Kris Van den Broeck: Yes. Because we are a selenium supplier to many PV companies, we also try to help them with the issue of production waste. So, we started collecting samples and working with our research and development department to develop a new flow sheet. And, since 2009, we have been recycling that kind of material on an industrial scale. We specialize here in Hoboken in treating complex raw materials, preferably including precious metals, but, in this case, they are complex enough for us to handle without their containing precious metals. By the way, in this case, some of these special metals (I refer to indium), tend to have prices almost as high as those of precious metals.

HAI: Of the metals you recycle, which are the most difficult to recycle and which the easiest?

Kris Van den Broeck: Within the world of CIGS production scrap – a niche market within a niche market – the most difficult one is selenium, due to metallurgical considerations and also the need to pay specific attention to certain environmental aspects of its processing and transportation.

HAI: And the easiest?

Kris Van den Broeck: I don't think any of them is very easy, because I don't have confirmation that another company can recycle at the size that we can today. Our capacity today, on an industrial scale, is 50 tonnes of this type of waste.

For reference, here in Hoboken, each year we treat about 300,000 to 350,000 tonnes of incoming materials. We recognized both that there are some CIGS producers that have similar material available, and that this material is complex enough for our organization. At first you need your special flow sheet to separate the metals. And then you need your processes to start, once again, from the separated intermediate products to go to further high-purity materials.

HAI: Do you see recycled metals playing an increasingly important part as an alternative resource to primary metals?

Kris Van den Broeck: Of course! Because these materials are readily available. And these materials have a significantly lower burden on the environment compared to mining. They have already started their "first life". The nice thing about these metals is that you can infinitely recycle them. It's just a matter of good collection and good processes to recycle them.

But of course some products are better for recycling than others. For example, the selenium that goes into glass as a decolorizer, this is something you cannot recycle. The end-of-life glass products only contain about a couple of ppm [parts per million].

HAI: A tiny amount...

Kris Van den Broeck: Less than tiny! On the other hand, some other materials are better suited for recycling. Look at this type of waste from the production of CIGS PV cells. Or mobile phones. Or printed circuit boards. We also do catalysts from the automotive and petrochemical industries. And waste streams from the photographic industry. Hence, in the end, we can refine and recycle 17 metals. As mentioned earlier, I like to call it 17-and-half metals; the last half is gallium, which comes out as a gallium intermediate product.

HAI: What about new recycling projects?

Kris Van den Broeck: We are very proud that we are commissioning a pilot plant to recycle 7,000 tonnes of rechargeable batteries in Hoboken from May 2011. We are targeting the electrification of the automotive industry.

HAI: What are the advantages to manufacturers of having third parties, such as yourselves, recycle for them, rather than doing it themselves?

Kris Van den Broeck: One of the critical parts is to look at your core business. CIGS producers use these metals in their devices, and they understand the effects these metals have in their applications, but not necessarily everything about metallurgy or the refining of these kinds of materials. I would say that CIGS production scraps are too complex to be recycled by manufacturers. The CapEx and R&D costs would be massive. We are successful because we have significant knowledge of copper, indium and selenium, and are learning about gallium. (We are able to separate the gallium as a gallium intermediate product that can be further refined.)

HAI: At Umicore, do you buy scrap on your own account and recycle it? Or do you recycle on a toll basis? Or both?

Kris Van den Broeck: We have this philosophy that the customer is the king. Which means that we like to offer whenever possible a "closed loop service" where the customer sends the waste to us, we recycle the material and we send back the metals. In return the customer pays a treatment charge. But the customers can also choose whether to get one metal back and a credit for the others. Or he can get credit for everything. This we leave up to the customers to decide. In case of CIGS production scrap, they basically have a bank account with the four metals in it. It's a "continuous loop": either financially closed or physically closed.

Common to all transactions is, however, that all scrap material will be weighed, sampled and assayed, so the customer gets metal or credit following the determination of actual contents. We call these "assay-based" settlements.

HAI: In the future, will we see more end-of-life recycling of PV cells, or will it continue to be just of the wastes produced in manufacturing processes?

Kris Van den Broeck: We are recycling today what is economically viable. At end-of-life, from a recycling point of view, you are typically looking at more than 99% glass, and only a few hundred ppm of metals. We do have projects looking at this. Technically, we could recycle this type of waste, but, at the moment, we cannot do it on an economically viable basis.

Most panels have just started their life, and they are supposed to be in the field for some 20 years. In order to justify investment in building a dedicated end-of-life recycling plant, you need the base loads, and you need to be sure you can get enough. Some of the base loads are also complex to collect, because they are quite dispersed. You need to go into the field, or to collection points, or to get the end-of-life panels back from the roofs. This is a complex setup for a low-intrinsic-value type of waste. The main issue is that, currently, the base loads are not available.

HAI: Are the yield rates different for the different CIGS manufacturing processes?

Kris Van den Broeck: We do see differences. Many of the manufacturers have developed their own processes that have patents, etc., and if we analyze the scrap we see some differences. However, the big ballpark numbers are the same. These are: 50% selenium and 20-25% indium. Then we have up to 10% gallium. And the remainder is copper.

HAI: If, say, a CIGS PV cell contains a theoretical single unit of gallium, I've had enormous difficulty trying to find out just how much gallium has actually been used in the process to manufacture that cell. Have you any idea?

Kris Van den Broeck: The processes that are currently employed to mass-produce CIGS panels use evaporation or sputtering tools. These tools tend to have a low deposition yield. Today, I would say a minimum of two such theoretical units is needed to deposit one unit. Other technologies like electrodeposition or printing could do better, but they are not yet in mass production.

HAI: Of that one unit that goes to waste, how much can you get back through recycling? The whole one unit?

Kris Van den Broeck: You do need to take into account not only the composition of the material, but also the delta; i.e., the quantities of other impurities present in the production waste that could impact the recycling yield. The recycling service that we can offer to our customers is, from an eco-efficient viewpoint, a good value proposition.

HAI: What metals do you think really should be recycled, but are currently not being recycled?

Kris Van den Broeck: Maybe rare earths? Because they are valuable, if you look at the number of critical applications in which they are being used.

HAI: Are there any major environmental issues; for example, the production of toxic fumes, associated with recycling PV cells that are not faced by the original cell manufacturers? Or maybe more energy is consumed in the recycling of an object than in its original manufacture?

Kris Van den Broeck: That's a difficult question! The whole field of life-cycle analysis is very complex. We try to recover as much as possible, in the most stringently environmentally restricted area that you can imagine. Minimal emissions and maximum recycling yield: That's what we aim for.

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