Precious metals from electronic scrap

Photo: Ari Väisänen says that the Department of Chemistry at the University of Jyväskylä is also studying the occurrence of substances at the nanoparticle scale. A new mass spectrometer device is helping in the work.

24.2.2017

Finns are developing a container-sized leaching plant for the processing of electrical and electronic waste, which could solve the environmental problems caused by the current processing of electrical and electronic waste around the world. It would recover precious metals and rare earths, which are desperately needed for global green technology.

Elina Saarinen

Electrical and electronic waste (EEW) contains so many precious metals and rare earths that a facility capable of recovering them would outperform mines. The problem is that current methods do not recover rare earths in particular. Huge amounts of valuable secondary raw materials are wasted: 50 million tons of equipment are already discarded globally every year, and the pace is accelerating.

The present is wasteful and destructive.

The EU has long been concerned about Europe's self-sufficiency and the security of supply for its industry, as China controls the sources of rare earth metals. Nevertheless, scrap equipment containing valuable secondary raw materials continues to flow from both the EU and the US to developing countries and China, where its separation and processing causes major environmental and health problems.

Even in Finland, up to half of the WEEE flow disappears beyond the reach of official collection systems. From the properly processed electronic equipment flow, mainly gold, palladium, silver and copper are recovered in large copper smelters, among other things.

"Rare earth metals cannot be captured by mechanical processing. The amounts in the components are so small that they should be removed chemically," expert, preparedness manager, Finnish Technology Industries Association Peter Malmstrom seal.

The Finnish consortium now intends to develop a container-sized plant capable of recovering precious metals and rare earth metals, based on hydrometallurgical methods patented by the Department of Chemistry of the University of Jyväskylä and Jyväskylän Energia Oy. The WEEEFiner project was included Sitra's circular economy roadmap listing last fall.

Even better deposits than the mine

It all started about six years ago, when the University of Jyväskylä began researching fly ash from peat combustion with Jyväskylä Energia. It was discovered that the ash contains small amounts of precious metals and also rare earth metals. The research results resulted in, among other things, a patented two-step extraction method and two doctoral theses: Siiri Perämäki argued for the recovery of rare earth metals and Ville Soikkeli the recovery of precious metals. (See Breaking news story on the topic.)

A year and a half ago, researchers from the Department of Chemistry at the University of Jyväskylä discussed with experts from the Finnish Technology Industries. It was noted that the methods could also be applied to the recovery of valuable metals from electrical and electronic waste.

When researchers analyzed electronic component waste from computers, mobile phones, and smart technology devices, they discovered that the scrap contains more precious metals and rare earths than ash – and many times more than normal mine deposits.

Especially circuit board scrap and magnets are like gold mines, or in this case even more valuable: mines of rare earth metals.

"Chipboard and hard disk chips can contain up to 600-750 milligrams of rare earth metals per kilogram. There can be twice as much silver. Magnets can contain up to 25% neodymium and valuable terbium can also be found," says a university lecturer at the Department of Chemistry at the University of Jyväskylä. Ari Vaisänen tells about the results.

He believes that the concentrations of corporate devices and tablets are even better than the currently studied SE scrap collected from households.

Three-dimensionality helps

The Department of Chemistry at the University of Jyväskylä, the Finnish Technology Industry and Elker Oy, which handles producer responsibility for electrical and electronic waste, have now started laboratory-scale experiments to test methods created in ash research on electrical and electronic waste.

Recycling operators have supplied, among other things, circuit board scrap for analysis. The Department of Chemistry is experimenting with combinations of processing methods.

According to Väisänen, the circuit board, hard disk and magnet scrap fed to the WEEEFiner plant is first either dissolved with mineral acids or burned into ash, the processing of which is already familiar to the people at the Department of Chemistry. In two-stage acid dissolution, metals can be separated based on their solubility. Metals are concentrated using liquid-liquid extraction. Precipitation into mixtures of two or three metals or certain types of compounds can be used in the separation. Molecular-level metal scavengers could also work.

In the future, the container plant process can be even more efficient if separation and precipitation methods can be replaced with new ion traps. The Department of Chemistry at the University of Jyväskylä is currently conducting another circular economy-related research project, which has just received funding from the Finnish Technology Industries Centennial Foundation and the Jane and Aatos Erkko Foundation's Future Makers. Researchers from three working groups are developing new 100D-printable materials. The materials can be printed using 3D technology, which means they can act as traps for metals classified as critical.

"Ideally, we would recover the precious metals in such a form that they would be ready-made, commercial compounds. Rare earth metals and their compounds have magnetic and optical properties that could allow them to be used directly as sensors," Väisänen envisions.

Handling in a container at the scrap yard

The researchers plan to scale up the process to a demonstration plant size. If the process worked in a container, it could create a new export product for Finland. It would be a revolutionary idea to process electrical and electronic waste in a room-sized container compared to the current hectare-sized copper smelters.

"The world will not be saved by having one big plant somewhere, but rather by moving the processing plant to where the e-waste is collected and processing it on site," says Malmström.

He compares the facility to a modern-day mill, where electronic scrap could be brought in and recycled raw materials or money could be recovered.

The consortium is now looking for partner companies to join. A more detailed budget, financing and the composition of partners will be confirmed during the spring. In order for the solution to be exportable, the processing must be economically viable.

To China, to the rescue

Only a few percent of rare earth metals are currently recycled globally, but their demand is growing rapidly, as they are needed in almost every renewable energy and energy efficiency technology, from wind and solar power plants to electric cars and LED lighting.

The most important for the high-tech industry are neodymium, dysprosium, praseodymium, terbium, samarium, yttrium, gadolinium and europium.

The United States has invested millions of dollars to extract earth metals from coal.

“For example, the need for dysprosium and neodymium is increasing, which means that their global market price can skyrocket quickly,” says Peter Malmström, an expert at the Federation of Finnish Technology Industries, reflecting on the security of supply for Finnish industry.

Facilities like WEEEFiner might not immediately solve Europe's need for raw materials, but they would serve as a trade policy demonstration that Europe is developing its own means of sourcing materials.

Väisänen says that researchers at the Department of Chemistry have already received curious contacts from around the world.

[Table source: JY/Department of Chemistry] The table shows the rare earth metal concentrations of one neodymium magnet, as well as the value (USD / ton) and world market price on 31.12.2016 December XNUMX.