Critical materials: the hidden landmines we already have...

The energy and digital transition is transforming our economy at an unprecedented rate. Electric vehicles, renewable energy, energy storage, digitalisation, artificial intelligence and smart grids are all technologies set to play a key role in the coming decades. However, they all have one thing in common: they rely on a range of raw materials, the availability of which has become a strategic concern worldwide.

Lithium, cobalt, nickel, manganese, graphite, rare earths, gallium, germanium, antimony and phosphorus are some examples of so-called critical materials – resources that are essential for the manufacture of batteries, photovoltaic panels, wind turbines, semiconductors, fertilisers and numerous electronic devices. Their importance is such that the European Union regularly updates a list of Critical Raw Materials (CRM) to identify those resources whose scarcity or dependence on external sources could jeopardise the competitiveness and security of the European economy.

Europe is in a particularly vulnerable position. Although it consumes a significant proportion of these materials, it has limited capacity to produce and process them, relying heavily on imports from third countries. In some cases, virtually the entire supply is concentrated among a small number of international suppliers, giving rise to significant economic, industrial and geopolitical risks.

In Spain, we face the same situation. Although we have certain mineral resources and a long tradition of mining, we continue to rely heavily on imports to supply strategic sectors. This dependence is particularly significant in a context where demand for critical materials continues to grow, driven by the decarbonisation, electrification and digitalisation of the economy.

However, there is an opportunity that has remained in the background for decades. Beyond conventional geological resources, we have a vast quantity of valuable materials found in streams that we usually regard as waste or by-products. What has so far been seen as an environmental problem could become a strategic source of raw materials to strengthen our industrial autonomy.

When waste becomes a goldmine of opportunity

Traditionally, the extraction of raw materials has been associated with conventional mining. However, in recent years the concept of ‘urban mining’ has gained momentum; this approach views the waste generated by our society as genuine deposits of resources.

One of the most obvious examples is lithium-ion batteries. The exponential growth in electric vehicles and energy storage systems will mean that millions of batteries will reach the end of their useful life over the coming decades. This waste contains significant quantities of lithium, cobalt, nickel, manganese and graphite – materials whose primary extraction is often associated with high economic, environmental and social costs

*Extraction of materials from a lithium-ion battery at the end of its service life*

Recovering these materials using advanced recycling technologies allows them to be reintroduced into the value chain, reducing the need to import new raw materials and minimising the environmental impact associated with their extraction.

A similar phenomenon occurs with photovoltaic panels. Although most existing installations remain in operation, the number of modules reaching the end of their useful life will increase significantly in the coming years. In addition to glass and aluminium, these panels contain silver, high-purity silicon and other strategic materials, the recovery of which can help to close the production cycle for new renewable technologies.

The enormous potential of electronic waste

Waste electrical and electronic equipment is another of the most promising sources of critical materials. Computers, mobile phones, televisions, telecommunications equipment and a wide range of other devices contain valuable metals which, in many cases, occur in higher concentrations than those found in some currently mined ore deposits.

Rare earths, indium, gallium, copper, gold, silver and palladium are just a few examples of the elements found in this electronic waste. However, a significant proportion continues to be lost due to inadequate collection systems or recycling processes that fail to recover all the materials present.

Improvements in separation, sorting and recovery technologies can transform this waste into one of Europe’s main sources of strategic raw materials.

The hidden legacy of mining

Paradoxically, some of the future sources of critical materials could be found precisely in the waste generated by past mining operations. For decades, mining produced enormous quantities of waste rock, spoil heaps and tailings ponds, the composition of which was assessed solely on the basis of the resources that were economically viable at the time. Many elements that we now consider critical had no commercial value at the time and were left stored in these deposits.

We now know that many types of mining waste contain significant concentrations of rare earth elements, cobalt, scandium, germanium, antimony and other strategic materials. The application of new characterisation and recovery technologies is enabling us to reconsider these environmental liabilities as potential resources.

So-called ‘reminería’ also offers an additional advantage: it enables the recovery of valuable materials whilst contributing to the environmental restoration of degraded areas, thereby reducing the risks associated with soil and water pollution. In Spain, which has a long history of mining, these deposits represent an opportunity that has yet to be fully explored.

Industries also harbour valuable resources

Numerous industrial processes generate waste streams with significant potential for the recovery of critical materials. Steel slag, steelworks dust, industrial ash, metallurgical sludge and certain types of waste from the chemical industry contain strategic elements which, in many cases, end up being used in low-value applications or even sent for disposal.

Hydrometallurgical, electrochemical and biotechnological processes are demonstrating that it is possible to recover materials such as zinc, vanadium, manganese, chromium, gallium and rare earths from these streams. This approach not only reduces the need for primary extraction, but also fits perfectly with the principles of the circular economy, where waste from one activity becomes a resource for another.

The case of spent catalysts used in the chemical, petrochemical and energy industries also deserves special attention. These materials contain metals of high economic value, the recovery of which is becoming increasingly attractive from both a technical and strategic perspective.

Phosphorus: a critical material for food sovereignty

When people talk about critical materials, they usually think of batteries, semiconductors or renewable technologies. However, one of Europe’s most strategic resources is phosphorus, which we might call ‘the jewel in the crown’.

This element is essential for the production of fertilisers and, consequently, for agriculture and food security. Unlike other resources, there is no known substitute for its biological function, which makes its availability a matter of global concern.

Europe is heavily dependent on imports of phosphate rock and phosphate fertilisers, which are concentrated in a small number of countries. Consequently, the recovery of phosphorus from secondary sources has become an increasing priority.

Sewage sludge, ash from its incineration, digestate produced in biogas plants, livestock manure and certain agri-food waste contain significant amounts of phosphorus that can be recovered and reused in the production of fertilisers.

As well as strengthening industrial self-sufficiency, these strategies help to improve our food sovereignty and reduce the pressure on limited natural resources.

The unseen resources of rivers, reservoirs and seas

There are also potential sources that have only just begun to attract attention. Sediments accumulated in rivers, reservoirs, harbours and coastal areas contain materials that have been transported over decades by industrial, mining and urban activities. At certain sites, these sediments contain significant concentrations of metals that could be recovered using appropriate technologies.

*A waterproof membrane used in water treatment processes.*

Regular dredging operations generate large volumes of material that are usually managed as waste or used for purposes with little added value. However, a more detailed characterisation could reveal currently untapped opportunities for recovery. A similar situation applies to certain seabeds, where the presence of minerals rich in manganese, nickel, copper or cobalt has sparked growing international interest. Although the direct exploitation of these resources poses significant environmental challenges, their existence highlights that there are still numerous potential sources yet to be investigated.

A matter of industrial sovereignty

Recovering critical materials from secondary sources will not completely eliminate the need for imports, nor will it replace conventional mining. However, it can play a decisive role in strengthening European industrial resilience and reducing our exposure to increasingly uncertain international markets.

To achieve this, it will be necessary to develop more efficient recovery and separation technologies, improve waste collection and traceability systems, promote favourable regulatory frameworks, and encourage collaboration between public authorities, businesses and technology centres.

Ultimately, the transition to a more sustainable economy will depend not only on discovering new resources, but also on our ability to recognise the value of those we already have. Spent batteries, disused solar panels, mining waste, industrial slag, sewage sludge, river sediments and electronic waste constitute veritable reserves of critical materials scattered across our territory.

Perhaps the most important mines of the future are not those that have yet to be mined, but those we have been creating for years without being fully aware of their value. Making the most of them could become one of the keys to strengthening the industrial, technological and food sovereignty of Spain and Europe in the coming decades.