Modernizing manufacturing methods

As companies in all market sectors move towards modernizing methods in terms of the way they manufacture, supply and recycle products and manage resources, key factors surrounding business growth, economic stability and sustainable impact all need to be taken into account. The electronics industry and players in PCB manufacturing and assembly in particular, are constantly faced with issues related to resource management – water, energy bills, waste, toxic, hazardous materials – and issues surrounding rare earth metals.

According to Reclaim, an EU-based initiative and part of the 7th Framework Programme, the global demand for rare metals like gallium, indium, yttrium and europium is steadily rising due to the explosive growth of ‘green technologies’ such as photovoltaics (PV) and solid-state lighting (SSL). To avoid getting dependent from markets other than European origin recycling systems for PV, SSL and other electronic waste are needed.

According to Reclaim, the problems lie in the disconnection and sorting of the parts with the targeted materials from the waste and in the release, concentration and purification of the reclaimed metals.

Reclaim targets two main advancements over the current state-of-the-art:
• it is to provide methods for the efficient and economical retrieval of the identified key metals (gallium, indium and rare-earth elements) from e-waste that are not pre-existing.
• the recycling system and the underlying technologies are to be tuned towards the treatment of waste from emerging green technologies (PV and SSL) that is presently still insignificant but anticipated to be a crucial source of these key metals in the future.

Recycling concept
The balanced selection of separation, dissolution, recovery, concentration and purification techniques will lead to an overall concept that will be competitive on a small-scale basis with a regional take-back approach.

Disconnection methods
The thermal immersion method that is being considered for un-bonding the soldering joints that are commonly used for electrical interconnections in printed-circuit boards and the like is (semi)-continuous, without hazardous fumes, and recovers the solder materials as well as separates the electronic components. Unlike the conventional means of manual disconnection (by burning or heating of the assemblies over a metal plate), this novel method is apt for industrialization.

Sorting methods
The targeted sorting methods that classify electronic parts with different ‘keymetal’ profiles will be designed for (semi)-automatic use to replace the current labor-intensive practice of hand-picking, and will be so selective that the individual fractions will not be contaminated with undesired substances from other fractions. Such systems (e.g., based on computer vision or light-induced breakdown spectroscopy) are known from other sectors like metals recycling, but the required real-time sorting of E-waste types is to be tailored for the presence of any of the concerned key metals by product appearance, spectroscopic properties and/or other attributes.

Concentration
The application of (hybrid) membrane processes including slug-flow (or emulsion) pertraction for these key metals is new, featuring high selectivity, high productivity and a limited number of unit operations. This in turn contributes to a low footprint of the process as compared to conventional approaches (such as classical solvent extraction using mixer settlers).

Purification
The considered technologies of nanofiltration and reverse osmosis – that are adopted from sectors like seawater desalination and wastewater treatment – are typified by the high rejection of ionic species, thus producing a concentrated retentate and high quality of water (fit for re-use) with low associated footprint.

Explosive growth
Prospective global supply and demand for gallium, indium and other key metals show an increasing discrepancy, amongst others due to the explosive growth of green technologies such as photovoltaics (PV) and solid-state lighting (SSL). While their primary production is highly controlled by a few countries, recycling systems to reclaim these materials from discarded products are not yet in place. This makes Europe susceptible for the provision of materials that are crucial for meeting policies on energy saving and renewability, as well as challenges the further development of the concerned industrial sectors.

Hence, Reclaim states there is a strong need to establish recycling systems for PV, SSL and other electronic waste and capitalise on these as yet unexploited and growing deposits of key materials. The bottlenecks are in the disconnection and sorting of the parts with the targeted materials from the waste and in the release, concentration and purification of the reclaimed metals. More in particular, the concerned materials tend to be used as compounds (gallium arsenide, gallium nitride, indium tin oxide) rather than in their elemental form and to be applied as thin layers on substrates in overall very low amounts.

Overall, Reclaim’s objectives are
(1) technological solutions that relieve current bottlenecks in the recycling of gallium, indium and rare-earth elements, and
(2) demonstration of their application potential by means of a pilot implementation in an industrial setting.

The project is to result in separation methods for electronic assemblies that reduce manual work (>80% automation) as well as in subsequent recovery methods that yield recycled materials of commercial-grade quality (>99-99.99%, depending on the element), apt to fit an industrial context and being environmentally compliant. To this end, (thermal) disconnection methods, part recognition methods and hydrometallurgical refining processes will be developed. Impact assessments will also be included.

Rare earth experts unite
Another EU initiative, the European Rare Earths Competency Network (ERECON) is looking at ways of addressing the issue of rare earth supply security by improving access to rare earths, reducing their consumption and enhancing extraction conditions across Europe.

Experts in this group have highlighted the importance of raw materials for the continent as well as the specific challenges related to rare earths. They believe a joint effort is needed to unite the fragmented capabilities from research and industry and to keep the issues on top of the public and policy agenda. ERECON states that Europe is well-equipped to take the scientific and technological lead in rare earth technologies. The European Union imports more than 90% of its rare earth metal needs from countries like China as there is not enough internal supply. And experts predict that demand for these metals will only grow as consumer preferences shift towards hi-tech and green products. ERECON is guided by a Steering Committee that sets the agenda of the Working Group meetings of rare earth experts. All members form a geographically balanced group, representing all parts of the value chain.