Direct co-reduction of natural minerals into multicomponent alloys

<title>Abstract</title> <p> Traditional alloy manufacturing relies on the production of high-purity metallic elements and masteralloys, followed by energy-intensive melting of those purified constituents ^1,2 . Other techniques have emerged in recent years, such as the hydrogen reduction of mixed oxides ^3,4 . However, because of hydrogen’s position in the Ellingham diagram ⁵ , there is a major limit to the metal oxides that can be reduced using hydrogen gas or plasma. Our work offers an important alternative, based on the use of (i) natural minerals, (ii) aluminium as the reductant (2.5x more powerful than hydrogen) and (iii) much higher processing temperatures (&gt;1500 ̊C). With these novelties, we are able to achieve aluminothermic reduction, liquid alloying and shape casting directly from mixtures of natural minerals, such as roasted scheelite, columbite, chromite, haematite, pentlandite, colemanite and zircon ^6,7 . Here, we demonstrate a new one-step chemical route for the manufacturing of high-strength, castable alloys (e.g. NiCoCrFeWAl and NiCoCrFeNbTaAl) with 6-7 alloying elements directly from these mineral ores. Interestingly, minor 1% impurities in the starting minerals can lead to beneficial effects in the downstream alloys, including higher entropies and precipitation hardening. This upends the definition of what an ‘impurity’ is in a mineral; and challenges the metallurgical dogma that purity equals quality. In summary, our work opens up significant opportunities to further integrate mineralogy, geochemistry, metallurgy, alloy design and near-net-shape manufacturing into a more unified sub-field, called GEO-ALLOYS. </p>