Short answers, pulled from the story.
Vanadium was first identified in 1801 by Spanish-Mexican mineralogist Andrés Manuel del Río, who extracted it from Mexican "brown lead" ore. The element was officially rediscovered and named in 1831 by Swedish chemist Nils Gabriel Sefström, who called it vanadium after Vanadís, the Old Norse name for the goddess Freyja.
Vanadium forms stable nitrides and carbides in steel that significantly increase the metal's strength. Approximately 85% of all vanadium produced is used as ferrovanadium or as a steel additive, appearing in applications from axles and crankshafts to surgical instruments and high-speed tool steels with hardness above HRC 60.
The vanadium redox battery is a flow battery that stores energy in aqueous vanadium ions held in different oxidation states, using the +5/+4 couple at one electrode and the +3/+2 couple at the other. First proposed in the 1930s and developed commercially from the 1980s onward, it is already used for grid-scale energy storage.
In 2022, China, South Africa, and eastern Russia together produced more than 96% of the world's 100,000 tons of vanadium, with China alone supplying 70%. Much of this output comes from vanadium-bearing magnetite in ultramafic gabbro bodies, where vanadium is recovered from the slag produced during iron-making.
Sea squirts concentrate vanadium in specialized blood cells called vanadocytes at levels up to ten million times higher than surrounding seawater. Marine algae use vanadium bromoperoxidase to produce an estimated 1-2 million tons of bromoform annually, and some nitrogen-fixing bacteria use a vanadium nitrogenase in place of the more common molybdenum version.
All vanadium compounds are considered toxic, with tetravalent VOSO4 reported to be at least five times more toxic than trivalent V2O3. The US OSHA limits workplace exposure to vanadium pentoxide dust to 0.05 mg/m3 over an 8-hour workday, and vanadium has been identified as a carcinogenic component of PM2.5 air pollution.