From WEEE to New Metals – What happens inside the Smelting Plant Rönnskärsverken?
Virtually all metals can be recovered, and we strive for the highest possible material recovery rate. As producing new metals is an immensely energy-intense procedure, this is where we stand to make the greatest environmental gain. Recovering metals from already existing products requires only around 1 per cent of the energy needed for mining. However, one of the greatest challenges of rare metals recovery is that the metals are present in such small quantities that current recovery processes can simply not be made profitable enough. Boliden’s smelting plant Rönnskär in the north of Sweden is one of the world’s largest facilities for recovering metals from electronic scrap, and here, things keep advancing all the time.
Boliden’s smelting plant Rönnskär in Skelleftehamn is not only one of the most efficient copper smelters in the world, it can also process WEEE to recover valuable metals such as gold, silver, selenium, palladium and nickel. These substances are all very common in circuit boards. The Rönnskär facility extracts metals from copper and lead concentrates sourced from Boliden’s own mines as well as from external suppliers. Different kinds of recycling materials (from Sweden and other European countries) constitute another important source of raw materials used in metal production. Today, the Rönnskär smelter is a world leader in electronics recycling thanks to investing in and developing the Kaldo technology.
Linn Andersson, General Manager at Boliden Rönnskär, tells us about the facility:
Our main product is copper, but we also extract other metals like lead, silver and gold. Our copper production amounts to some 225,000 tonnes per year, but if we add up all our products, we reach a figure or around 1 million tonnes. Slightly less than one tenth of this has been sourced from recycled materials.
Of all the materials that arrive at our plant, we manage to turn 80 per cent into new products. We do get by-products and waste that contain substances that require this scrap to be stored in a repository – any materials with a mercury content that exceeds 0.1 per cent, for example. Our challenge is to extract as much valuable material as possible to reduce the amount of waste, but the small amounts of contaminated waste that are an unavoidable result of the smelting process need to be stored somewhere safe. Right now, in the spring of 2021, we are in the final stages of constructing an underground repository for permanent storage of hazardous waste. Next year, this waste will be stored in permanently sealed caverns 330 metres underground.
New Leaching Plant Reduces the Amount of Landfill
Another exciting piece of news is that we are constructing a new leaching plant which will be taken into operation in 2021. Since the ‘90s, we have accumulated around 300,000 tonnes of landfill waste from our smelting operations. This has so far been kept in storage, but with the new leaching plant we will be able to reduce this waste at the same time as we generate new products (primarily copper, lead, zink, gold and silver). We expect to have enough material to keep the new leaching plant busy for the first ten years. After that we will be able to accept similar kinds of waste materials from other sources.
Rare Metals Are Challenging
A key factor when working to improve today’s recycling processes is building in an awareness of the recycling stage early on, at the manufacturing stage. This also goes for the rare metals found in such small quantities that they cannot be recovered using our current processes. One possible way of securing these metals could be to ensure that the components in which they are found are removed early, at an upstream stage, so they can then be treated separately.
What Happens To the Recovered Metal?
Metals recovered from WEEE are not as “pure” as metal sourced through mining, so to obtain a high-quality end product these two flows need to be mixed. We already have the capacity to receive more WEEE, but that would then require us to scale up the mining to get the right balance between these flows. The quality would suffer if the proportion of aluminium was to exceed that of copper, which is why treating more waste would create a need for mining more metals. Looking at the future, it would be interesting to find out if different materials could be separated before they end up in the smelting furnace. As this would lead to a higher quality end product.
Most of our products go to manufacturers in Europe. Copper is a key product for manufacturers of pipes and cables. Our 12.5 kilo gold bars are mostly bought by banks. Another popular product for banks is silver, a product also favoured by electronics manufacturers. Finally, the lead we produce is largely used in the making of new batteries.