The electrolyte solution inside each Redox One Flow Battery is a combination of Iron and Chromium, dissolved in a slightly acidic solution. These are the most abundant raw materials used for energy storage.
At Redox One, we have developed a proprietary process to make our Iron-Chromium electrolyte directly from the Chromite ore mined by our parent company Tharisa Minerals, in South Africa. Our multi-generational access through Tharisa means our supply chain is both plentiful and secure allowing us to easily & cost-effectively manufacture electrolyte for our Redox One Flow Batteries.
There are many other kinds of battery technology in the energy field, each with their own uses, pros, cons and specific applications – but it all starts with the minerals which are responsible for the reactions that charge and discharge the energy put into them. In understanding where each of the elements come from, how they are mined and what that means for battery technology, end-users can better understand the potential of the different kinds of batteries as well as the cradle-to-grave impacts of using them.
Let’s start with Iron and Chromium, the key mineral components of Redox One’s Flow Batteries.
Iron
Iron is the most abundant metal found in the earth’s crust, comprising about 94% of the metals mined each year making it the most widely used metal in modern civilization. China, Australia, Brazil, Russia and India are the world’s largest iron producers, mining via either open-pit or underground mines.
The Tharisa Mine is situated on the western side of South Africa’s Bushveld Complex in the Northwest Province, which is home to more than 70% of the world’s platinum and chrome resources. Tharisa Minerals mines and processes five MG chromitite layers. The mined reef is processed through innovative engineering at two separate plants, extracting both PGMs and chrome concentrates. This combined co-product output reduces unit costs and positions Tharisa Minerals in the lower cost quartile of operating costs in South Africa for both PGMs and chrome concentrates – which plays a major role in the cost-efficiency of our access to Chromium for our Flow Batteries.
The process of extracting Iron ore from the ground follows the process of drilling; blasting; excavating; ore dumping; crushing and screening. For our purposes at the Tharisa Mine, after the lumped iron ore is screened, it is stacked, reclaimed and pelleted.
Chromite
South Africa is home to the largest chromite reserves in the world, with annual production measured both in local sales and export sales, making up two thirds of the world’s total production. China imported approximately 90% of South Africa’s exports, while Indonesia remains an essential player in the downstream chrome industry, with Tharisa supplying some of Indonesia’s most modern and largest mills.
South Africa has a mature chrome value chain, with a socio-economic impact that includes approximately 20 000 jobs and about R42 billion in GDP per annum. Tharisa remains a major player in the global chrome industry, supplying approximately 10%-12% of China’s annual demand. The company also remains a significant player in the speciality chrome market, delivering roughly one-quarter of the average annual chrome output to these markets.
The mining method used for extracting chromite depends on the characteristics of the deposit, including whether it is stratiform or podiform, high grade or low grade, subsurface or near surface, massive or disseminated. As with most mining, the beneficiation (processing, crushing, separating, smelting, refining, etc.) of chromite depends on the characteristics of the ore deposit and on the mining methods used.
Vanadium
Vanadium is the 22nd most abundant element in the earth’s crust, with resources globally estimated at 63 million tons. The majority is located in China, Russia, South Africa and Australia.
Vanadium occurs in deposits of different kinds of rock, including siltstone, in which it constitutes less than 2% of the host rock. Significant quantities are also present in bauxite and carboniferous materials, such as coal, crude oil, oil shale, and tar sands.
In South Africa, Russia and China, Vanadium is extracted as a co-product in steelmaking. In South Africa, the iron is produced by a process involving the pre-reduction of the magnetite with powdered coal in a rotary kiln followed by reduction in a submerged arc electric furnace. The iron which is produced contains approximately 1.5% vanadium, which is removed as slag treating it at low temperatures with oxygen in a shaking ladle.
An alternative type of redox battery uses Vanadium ions as charge carriers, taking advantage of vanadium’s ability to exist in four different oxidation states. The demand for Long-Duration Energy Storage (LDES) batteries is a challenge for Vanadium producers, who simply won’t be able to meet the demand for the mineral for energy applications when it is such an essential component in steel production; defence; vehicles; aerospace; rebar and many others. Price volatility of Vanadium too, provides challenging realities.
Lithium
Lithium is a highly reactive alkali metal that offers excellent heat and electrical conductivity, which makes it particularly useful for the manufacture of glass, high-temperature lubricants, chemicals, pharmaceuticals, and lithium-ion batteries for electric cars and consumer electronics – like your mobile phone or as storage for your solar PV system at home.
Because of its high reactivity, Lithium metal is not found in nature – rather it is present as a constituent of salts or other compounds.
Lithium salts are found in underground deposits of brine, mineral ore and clay, as well as in seawater and geothermal well brines or water. Because Lithium metal doesn’t occur naturally, it must be extracted from these sources by a set of chemical processes.
Both brine and hard rock mining come with environmental and social costs. 60% of the world’s lithium stores are located in brine deposits in South America’s “lithium triangle,” sometimes in ecologically sensitive areas. A 2021 study found that Lithium concentration and production from brine can create about 11 tons of carbon dioxide per ton of Lithium, while mining Lithium from spodumene ore releases about 37 tons of CO2 per ton of Lithium produced.
Choosing an LDES solution is more than about the cost and performance of the battery – it’s about SUSTAINABILITY. If you’re using it to harness clean energy, it’s important to consider the availability and environmental cost of extracting the minerals along with the recycling the components and electrolyte at end of life.