What is ruthenium, where is it found, how is it produced, its strategic uses and why recycling is essential for the global supply chain and the circular economy?

by Marco Arezio

Ruthenium is one of the most fascinating and least known metals to the general public , but at the same time one of the most strategic for the modern technological industry.

A member of the platinum group, it stands out for its chemical and physical properties that make it valuable in numerous fields, from electronics to catalysis to energy applications. Despite its rarity, ruthenium plays a key role in the development of high-performance materials, and its recycling represents a crucial challenge for the circular economy.

What is ruthenium and what are its properties?

Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a hard, brittle, silvery-white transition metal belonging to the platinum family. Its hardness and resistance to oxidation, even at high temperatures, make it extremely durable. It is considered one of the rarest metals in the Earth's crust, with an estimated presence of just 0.001 parts per million. These characteristics place it among the materials of high strategic value, so much so that it is closely monitored internationally along with other critical metals such as rhodium, iridium, and palladium.

Where to find it and how to get it

Ruthenium is almost never found in its pure state in nature. It occurs in minute quantities in ores containing platinum, osmium, and nickel. The main deposits are located in Russia, South Africa, and North America, where it is extracted as a byproduct of platinum and nickel refining. Once separated, ruthenium is purified through complex chemical processes, which involve the formation of oxides and chlorides to allow its subsequent reduction and refining. Processing requires sophisticated technologies and a high degree of technical expertise, which contributes to its high cost on the international market.

The main industrial uses

Ruthenium has a wide and varied range of uses. In the electronics industry, it is used to produce thick-film resistors and highly corrosion-resistant electrical contacts. In the chemical and catalytic fields, it plays a key role as a catalyst in hydrogenation and oxidation reactions, contributing to the production of fertilizers, synthetic fuels, and advanced chemicals. In the energy sector, ruthenium is used in fuel cells and in certain alloys designed to withstand extreme pressure and heat. An emerging field involves nanotechnology and the use of ruthenium in organometallic compounds for pharmaceutical research, where ruthenium-based molecules with anticancer properties are being studied.

Who controls world production?

Global ruthenium production is concentrated in just a few countries, making its supply chain particularly sensitive to geopolitical factors. Russia and South Africa account for the largest share of extraction and refining, while other regions, such as North America and, to some extent, Australia, contribute less. This geographic concentration poses the risk of price and supply fluctuations, which is why the European Union and other economic blocs closely monitor the PGM market. Large multinational mining companies, already active in platinum and palladium, are also major players in ruthenium production.

Ruthenium Recycling: Challenges, Techniques, and Opportunities in the Circular Economy

Ruthenium, due to its scarcity and high value, cannot be considered a disposable material. For this very reason, recovery and recycling strategies are crucial, not only to ensure the continuity of the production chains that use it, but also to reduce the environmental impact associated with its extraction and primary processing. Unlike other metals found in nature, ruthenium is present only in infinitesimal quantities and almost always as a byproduct of platinum or nickel refining. Consequently, every gram recovered through recycling makes a significant contribution both economically and to sustainability.

The main sources of recyclable ruthenium

Ruthenium can be recovered from several matrices:

- Spent catalysts: Many chemical and petrochemical processes use ruthenium-based catalysts. Once their lifecycle is over, these materials represent a valuable reserve of recoverable metal.

- Discarded electronic components: Thick-film resistors, electrical contacts, and other microcomponents contain traces of ruthenium, which, if properly treated, can be extracted.

- Industrial processing waste: dust, sludge and residues deriving from the production and refining processes of platinum metals contain percentages of ruthenium that must not be dispersed.

These secondary sources often have a higher concentration of metal than natural deposits, making recycling not only convenient but also essential for security of supply.

Ruthenium recovery techniques

Recycling ruthenium is not easy, as it requires sophisticated chemical and metallurgical processes to separate it from similar metals such as platinum, palladium, or iridium. The most common techniques are:

- Hydrometallurgical processes: These involve the use of acidic and oxidizing solutions capable of dissolving ruthenium-containing alloys. Subsequently, through selective precipitation processes or solvent extraction, the metal is isolated and concentrated.

- Pyrometallurgical processes: These are based on the use of high temperatures to melt waste materials and separate the ruthenium through controlled oxidation and reduction reactions.

- Recovery from catalysts: A combination of thermal oxidation and chemical dissolution is often used, to then reduce the ruthenium to metallic form or to purified compounds ready for further industrial use.

One of the major difficulties is that ruthenium, unlike platinum or palladium, can assume different oxidation states and form complex compounds, which require targeted methodologies to be traced back to the pure metal.

Technological innovations in ruthenium recycling

In recent years, scientific research has sought to make recovery processes more sustainable. Advanced bio-leaching techniques, which use microorganisms to dissolve precious metals, are emerging as less impactful alternatives to the intensive use of strong acids. Similarly, the use of new membrane separation and ion extraction technologies promises to improve yields and reduce energy costs.

Traceability is also a crucial aspect: many manufacturers are investing in systems for identifying and specifically collecting components containing ruthenium, so as not to disperse it into the electronic waste chain.

The environmental and economic benefits of recycling

Recycling ruthenium has a twofold benefit. On the one hand, it avoids the environmental impact associated with primary mining, which requires enormous amounts of energy and produces toxic waste. On the other, it ensures a more stable supply, less dependent on the geopolitical fluctuations that characterize mining countries. Recovering ruthenium from industrial waste also reduces the risk of heavy metals leaking into the environment, contributing to the protection of ecosystems.

Ruthenium as an infinitely recyclable metal

One of the strengths of ruthenium, like other platinum group metals, is that it does not lose its properties during recycling cycles. This means it can be reintroduced into production processes multiple times without any loss of quality. This characteristic makes it perfectly compatible with the principles of the circular economy, in which the concept of waste is abolished and precious resources remain in circulation within the industrial system.

Future prospects for ruthenium recycling

With increasing demand in sectors such as fuel cells, advanced alloys, and pharmaceutical compounds, the need for ruthenium is expected to grow. For this reason, recovery techniques will become increasingly strategic and integrated into industrial value chains. It is expected that, in the coming years, countries with greater technological capacity will invest not only in mining, but especially in strengthening recycling infrastructure. In this scenario, Europe has a significant opportunity to reduce its dependence on imports of critical metals and become a hub for the recovery and regeneration of PGMs, including ruthenium.

Strategic impact and future prospects

With the growing demand for advanced materials for electronics, electric mobility, and green chemistry, the importance of ruthenium is set to increase. However, its limited availability and control by a few producing countries pose significant challenges. Scientific research is focused in two main directions: on the one hand, developing industrial processes that use increasingly smaller quantities of ruthenium, and on the other, expanding recycling systems to recover it from waste. It is precisely in this balance between growing demand and environmental sustainability that the future of this rare but indispensable metal will be played out.

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