The paradox of critical materials: those materials that are difficult to supply and which escape recycling
In recent years, voices have been raised to denounce the geostrategic dependence of the French economy on certain materials. Even more surprisingly, these critical materials, for which France has little or no resources of its own, are hardly ever subject to recycling. However, giving them a second life could partly remedy the problem of this geostrategic dependence. So why are we struggling to set up processes for reusing these materials at the end of their lives? What solutions are beginning to emerge? A look back at the strategic challenge of reusing critical materials.
But if they create a supply dependency, why are they not recycled?
There are 3 major reasons for the lack of recycling of critical materials:
– The technical difficulties in recycling them, particularly for composite materials (which by nature have a complex structure)
– The economic costs of the recycling process are too high in relation to the residual value of the material
– Lack of valuation obligation
FOCUS ON THE TECHNICAL ISSUES THAT HINDER RECYCLING
For the recycling of carbon fiber reinforced composite materials
Today, although different technologies exist (pyrolysis, solvolysis, and vapothermolysis), the majority of industrialists use pyrolysis. This technique is easy to implement, but greatly limits the potential fields of application of recycled carbon fibers, because the size of the fibers is reduced by the grinding of the parts prior to pyrolysis and by the presence of resin residues. It is therefore now necessary to set up industrial pilots on solvolysis and vapothermolysis technologies in order to demonstrate the capacities to overcome the recycling challenge.
For the recycling of batteries and accumulators
Today pyrometallurgy techniques, which consume a lot of energy, are widely used (for recycling electronic cards for example). Hydrometallurgy is also developing but is not ideal either due to the acid solutions that must then be treated. The recycling of batteries and accumulators makes it possible to recover considerable volumes of zinc, cobalt and nickel, and to re-inject them into many fast-growing industries. It seems important to make progress on collection rates, but also on recycling techniques. The creation of a secondary cobalt industry is more topical than ever with the development of the electric car at the expense of internal combustion engines, which will increase the pressure on cobalt and lithium demand.
FOCUS ON THE HIGH COST OF RECYCLING
For glass-fiber-reinforced composite materials in relation to the residual value of these materials
Existing technologies for processing glass fiber reinforced composites aim to extract and reuse the glass fiber reinforcement while destroying the polymer matrix. However, the value of the fiberglass is much lower than the cost (economic and energy) of implementing recycling processes. It is necessary to consider different ways to recover large quantities of future waste (wind turbines in particular) and limit the burial or export of end-of-life parts.
In order to succeed in the challenge of recycling critical materials, three paths must be pursued in parallel
#1: Technological development of recycling techniques
Numerous projects are currently underway on the national stage in order to better valorize critical materials, we have selected emblematic projects.
- For critical materials reinforced with carbon fibers, Alpha Recyclage Composites (Occitania) has chosen to implement vapothermolysis. The composite is heated with steam, the resin is decomposed from the matrix and then the carbon fibers can be extracted. This technology should make it possible to envisage applications in sectors such as automotive and aeronautics, as the recycled carbon fibers retain 99% of their initial properties.
- For battery processing, as part of the UEX2 project, SNAM (Occitania) and the CEA have developed an industrial demonstrator capable of processing and upgrading any type of rechargeable li-ion battery, a project of great interest in the development of electric mobility.
- An important issue in the recycling of critical metals is the separation of metals in order to obtain high-purity ingots. The start-up Ajelis is working in this direction. It has developed a technology capable of selectively extracting rare earth metals in aqueous solution.
#2: Development of eco-design
In addition end of life of materials, projects are beginning to emerge in the design of new materials.
Arkema has overcome the difficulty of recycling composites and has chosen to develop materials that are more easily recyclable right from the design stage. A polymer resin is usually used that is often non-recyclable. Arkema has therefore developed a depolymerizable resin. The principle consists of coarsely grinding the parts; the resin is then hot depolymerized so that it can be recovered and purified into a resin with the same properties as virgin resin. Meanwhile, the remaining carbon or glass fibers can be reused. This resin is currently being tested on wind turbines with 25-metre blades.
#3: Regulatory obligations
Today, regulations to impose recycled content levels in new materials are still in their infancy, either locally or at the European level. But this does not prevent some cities from launching over-cycling initiatives. The aim of overcycling is to give a part a second life with a higher value than in conventional recycling. In this context, many wind turbine blades have been diverted into tunnels for children’s playgrounds, public benches in Rotterdam or bus shelters!
The collection, extraction, and refining of so-called critical metals are complex to implement today, but solutions are emerging and becoming more structured. Numerous local or transnational initiatives are being set up to reduce the European Union’s geostrategic dependence on the countries producing the metals it does not have in its basement (European Battery Alliance project), but these projects still include too few initiatives concerning recycling. At Alcimed, we are convinced that in order for the recycling of critical materials to have a significant impact and reduce dependence on imports, a strong position on the part of manufacturers is necessary: defining minimum rates of recycled materials in their specifications or systematically integrating eco-design into the design phases are all avenues on which to invest, in advance of the phase of legislation that will soon be imposed.
About the authors
Laurence, Senior Consultant in Alcimed’s Aerospace Defence team in France
Julia, Consultant in Alcimed’s Healthcare and Public Policy team in France
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