Conventional and new ways of recycling e-waste

How exactly does the recycling of electrical equipment actually work? What problems arise and what new processes are being tested? The sixth station of the Zirkel.Training provided information on these topics. We were virtual guests – with 44 participants – at the Institute for Energy Systems and Energy Technology at the Ruhr West University of Applied Sciences in Bottrop.

Current challenges and the response of conventional recycling

Prof. Dr.-Ing. Saulo H. Freitas Seabra da Rocha began by explaining why efficient recycling is becoming increasingly important. On the one hand, there are the ever shorter product life cycles of electrical appliances, which are leading to an increasing per capita volume of electronic waste. On the other hand, metal prices, e.g. of copper or tin, are also rising, making recycling more worthwhile.

Nevertheless, the recycling rates of metals and rare earths from end-of-life products are still extremely low: while steel has a rate of 31%, the figure for copper is only 17% and for lithium or rare earths such as neodymium it is vanishingly small.

Manual dismantling of electronic scrap - uneconomical

But how do you get the metals? A comparative study of manual and automatic dismantling processes showed that the manual dismantling of small electrical appliances takes about 16 minutes on average. However, to match the material value that is recovered, the process would have to become ten times faster. In other words, manual disassembly is uneconomical.

Current processes

To explain these current recycling processes for e-waste, Prof. Saulo Seabra had sought expert support from Michael Maurer, lecturer in waste management at the Ruhr West University of Applied Sciences and project manager at Zech Umwelt GmbH. For more than 20 years, Michael Maurer has been dealing with the question of how to bring secondary raw materials back into the cycle that are qualitatively accepted by industry and at the same time economical.

Using a video, the speakers demonstrated and explained the current process steps in electronic scrap processing: from collection at recycling centers to shredding and complex sorting using various processes (magnetic separators, eddy current separators, NIR separators).

It became clear how difficult it can be to separate compounds of different materials again and to obtain fractions whose purity and form (e.g. particle size) can be used again as raw materials. Often, thermal recycling is the method of choice for mixed fractions, i.e., use as RDF (refuse derived fuel). At the same time, the industry expects secondary raw materials to be (almost) as good as primary raw materials in terms of quality, but cheaper.

Recycling with the help of object identification and robotized disassembly

As an alternative to the procedure shown, Prof. Saulo Seabra presented what he is currently testing as part of the “Prosperkolleg” project in the Circular Digital Economy Lab research and demonstration laboratory together with Prof. Uwe Handmann and his colleagues.

The first station of the disassembly line here is object identification via X-ray images and AI-supported image recognition. The identified components are used to automatically generate a cutting plan, which is then followed by robotic cutting, e.g. using a waterjet cutter. The result is fractions that contain recyclable materials that are concentrated and as pure as possible.

A cordless screwdriver, for example, can be cut up in such a way that the motor, battery, gearbox, etc. remain intact and can be separated.

Throughout the process, the objects are moved by robotic arms. Following this disassembly process, the clean fractions can then be further processed using conventional methods. The time saved compared to manual disassembly is clear: in less than a minute, a unit is disassembled.

And the economic efficiency of this process? Of course, investments are initially required to set up such plants. However, framework conditions such as rising raw material prices or CO2 pricing may soon make this profitable.

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