Boston Metal is an MIT spin-off working to decarbonize steel production through an innovative process: electrolysis of metal to reduce (= deoxidize) iron ore. This process consumes much less energy than its alternative, the use of hydrogen, and could even compete with the current dominant, highly polluting process using coke in blast furnaces.
Reduction of iron oxide by electrolysis
The current polluting solution: blast furnaces
To produce iron and then steel, the ore must first be deoxidized. This is because the ore is mainly composed of iron oxide. To achieve this, an extremely polluting process is used: the ore is placed on a bed of coke (solid carbon) heated to very high temperatures (2100°C). The carbon is then removed by oxidation, releasing even more CO2. In all, steel production accounts for 6% of global greenhouse gas emissions. This is the BF-BOF(Blast Furnace – Basic Oxygen Furnace) process.
Hydrogen to decarbonize steel?
One solution is to use hydrogen to reduce the ore: exposed to hydrogen, the oxygen in the ore is extracted without the ore having to melt. However, hydrogen is expensive to produce in a low-carbon environment, and the efficiency of the process is not guaranteed (is all the hydrogen consumed?). This is all the more problematic as H2 has a negative effect on the atmosphere: it delays the degradation of methane into CO2, the former being a greenhouse gas 23 times more potent. This is the DR-EAF(Direct Reduction – Electric Arc Furnace) process.
The Boston Metal solution
Boston Metal proposes directelectrolysis of molten iron ore(Melted oxide electrolysis, MOE), to generate the following reaction: “Fe2O3 e- => Fe O2″. The result is directly molten iron, with no need for an electric arc furnace. The catalyst
The process is so revolutionary that it may even prove more profitable than the current dominant solution. Indeed, blast furnaces are gigantic installations representing investments running into billions of euros. The Boston Metal solution, on the other hand, would be modular, capable of operating on a small scale. In particular, it would bring the installations closer to the mines. The process would be 35% less expensive than BF-BOF.
The success of this technology, which electrifies steel production, depends on the development of low-carbon electricity. Combined with the development of small modular reactors integrating nuclear power generation, heat and power, and industrial processes could accentuate this difference and make BF-BOF completely obsolete.
Extraction of low-concentration, non-value-added metals
Rocks extracted by the mining industry may contain compounds that are too low in concentration to be mined. These remnants, currently considered as waste, can be recovered using the process developed by Boston Metal. The company began this activity in Brazil in 2022 and markets the extracted metal.
History and progress of Boston Metal
History of Boston Metal’s MOE technology
This technology goes back a long way: as early as the 1980s, MIT researcher Donald R. Sadoway, working on an anode for aluminum production, developed an electrolytic cell to produce MOE. In the early 2010s, Sadoway and MIT colleague Antoine Allanore developed a means of extracting oxygen from the moon for NASA. They developed an electrolysis system to extract oxygen from rock. As you may have guessed, this is the process. Note that, similarly, space research had been a driving force, also to produce oxygen, in the development of alkaline electrolysis in the 50s.
For a long time, the problem was that the anode material was either consumed during the reaction (graphite), or out of reach (iridium for iron, for example). The production of iron posed the challenge of withstanding heat in excess of 1538°C (the melting point of iron) and resisting oxidation and corrosion. They solved these problems by developing chromium anodes. This solution, opening the door to industrialization of the process, was published in 2013 in the journal Nature.
It was also in this year that Boston Metal was born, under the name Boston Electrometallurgical Corporation.(source)
Boston Metal’s development
The company has raised several rounds of financing:
- Series A, in 2018, $20 million, led by Breakthrough Energy Ventures(BEV), with also Prelude Ventures and The Engine (and OGCI Climate Investments?).
- Series B, in 2021, $50 or $60 million, with two major mining companies, Vale and BHP(BHP Ventures). Other investors include Energy Impact Partners, Piva Capital and Devonshire Investors. The company grows from 8 to 65 employees.
- Series C, in 2023, of $120 million, is led by the world’s largest steel company: ArcellorMittal, through its XCarb® Innovation Fund. Microsoft’s Climate Innovation Fund and SiteGround Capital are also participating.
In 2022, the startup will open a subsidiary in Brazil to produce high-value metals from mining waste. They plan to market the tool itself in 2023.