Vanadium’s alloying properties have been known about for well over a century. Henry Ford used it in 1908 to make the body of his Model T stronger and lighter.
For the same reasons – and also for its heat resistance – it was used to make portable artillery pieces and body armour in the First World War.
But vanadium’s history seemingly goes back even further. Indeed, mankind may have been unwittingly exploiting the metal as far back as the 3rd Century BC.
That is when “Damascus steel” first began to be manufactured.
Swords made of the steel were said to be so sharp that a hair would split if it were dropped on to the blade.
Damascus steel scimitars were credited with enabling Muslim warriors to fight off the Crusades.
Circa 1250, A crusader and Muslim warrior in hand-to-hand combat.
Samples taken from a handful of antiques were found to contain tiny amounts of impurities, including – crucially – vanadium.
Bizarrely, this two-millennium-old steel-making tradition vanished in the mid-18th Century. The vanadium-rich iron deposits in southern India from which the steel was fashioned must finally have become exhausted, or so the theory goes.
Today, vanadium mainly goes into structural steel, such as in bridges and the “rebar” used to reinforce concrete.
It is a small and sometimes volatile market. Supply is dominated by China, Russia and South Africa, where the metal is extracted mostly as a useful by-product from iron ore slag and other mining processes.
How does a Vanadium Redox Flow Battery work?
Vanadium – yellow, blue, green and violet
Consists of two giant tanks of different solutions of vanadium dissolved in sulphuric acid, separated by a membrane
The battery produces an electrical current as the fluids are pumped past electrodes on either side of the battery
In one tank, the vanadium releases electrons, turning from blue to yellow
In the other tank, the vanadium receives electrons, turning from green to violet
The electrons pass around a circuit, generating a current, while at the same time a matching number of protons (hydrogen ions) pass across the membrane between the two solutions
The BBC’s headquarters in London – home to 7,000 employees – would need one the size of two 12-metre trailers, Radvak says, perched up on the roof or perhaps buried underground.
His firm is providing the batteries’ key ingredient, the electrolyte (the fluid in the battery).
It is the same chemical solution as in Sella’s demonstration, and – conveniently enough – is also the end-product of the standard process of using sulphuric acid to leach the vanadium out of its ore.
Radvak says that among his target customers are large corporate electricity consumers such as the Metropolitan Transport Authority, which runs New York’s subway, and with whom his firm has just signed a pilot deal to supply Cellcube batteries.