To substitute or not to substitute?

Increasing the availability of raw materials in Europe to enable businesses to operate is an ever evolving challenge. Europe depends almost entirely on imports for a number of strategic metals. Many resources are only available from a limited number of sources which creates the possibility of supply restrictions. So what are the potential solutions? The historic option would have been to simply mine more as demand increases. But many metals are not mined at all in Europe and mining operations always raise serious social and environmental concerns. Nevertheless, in the current political climate there may be an appetite for new mines. The U.S. have taken the radical step to reopen a mine at Mountain Pass, which was previously closed as uneconomic, in order to secure a domestic supply of rare earth elements.

Recycling has been used to increase in stocks supply of metals for year. Increasingly, recycling is becoming a viable option for the less common metals. And it makes sense. Why mine metal when it is far more concentrated in a particular waste stream than it can be found in the Earth’s crust? But there are still plenty of metals for which no economically viable recycling process exists and there will always be issues of collection, sorting, contamination and standardisation between virgin and recycled material.

So is substitution the answer? It seems obvious to remove the expensive or scarce metal from your application or process and replace it with something cheaper or more readily available.

If only it were that simple! Of course the reason for using a particular scarce or expensive metal is because it has particular chemical or physical properties which confer a specific function to that application or process. Replacing the material, whilst still retaining that function, can be a time-consuming and expensive process and there is no guarantee of success. For example, scientists have long searched for a substitute for palladium and platinum in automotive catalytic converters but without making any real progress. Conversely, there are many examples where the substitution approach has provided an innovative solution and in many cases generated new business opportunities. Organic molecules with 3D structures that enable them to act as catalysts (organocatalysts) have been used to replace some metal catalysts in chemical synthesis. Quantum dots are being developed as a replacement for phosphors containing rare earths in LEDs and flat panel displays.

There is no simple answer to securing supplies of the materials needed to enable the energy and technology requirements of Europe’s citizens. The answer lies in a diverse approach in which a combination of strategies, including mining, recycling and substitution, are applied to tackle the issue. Substitution, whilst challenging, can be a particularly interesting option, especially where further mining or recycling are not feasible. CRM_InnoNet will look to identify sectors and applications for which substitution could be particularly interesting and will generate a substitution roadmap to inform policy makers and scientists of the opportunities available.

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