Interesting new the one from the MIT (Massachusetts Institute of Technology) also published in Nature and commented by the materials chemical Donald Sadoway, claiming the discovery of a new method of producing steel that is "free" of CO2 emissions, the process, known as molten oxide electrolysis (MOE), was initially employed to generate oxygen. The product generated was oxygen and, astonishingly, steel.
The Iron & Steel industry has been less successful in reducing CO2emissions till now, specially in the traditional steelmaking route, that also requires huge amounts of investments and assets to run. The everlasting ULCOS project neither looks like ending with solutions. The report on the study details the working of MOE, a process which uses electricity as a means of breaking down iron oxide (key raw material) into its metal form and releasing oxygen. Very pure steel was produced as an unintentional by-product of the process, without any CO2 generation.
Conventional steel-making route involves heating iron oxide in a furnace along with coke at temperatures ranging from 900°C to 1,300°C and producing hot metal with impurities such as carbon and trace amounts of sulphur, and huge amounts of CO2. MOE (see 'Molten oxide electrolysis' process), however, works at 1,600°C, produces pure carbon-free steel and zero CO2 emission. Like any other electrolysis process, MOE consists of two oppositely charged plates (electrodes) immersed in a solution containing iron oxide along with other metal oxides (electrolyte). Electricity is passed through these electrodes into the electrolyte and the end product is molten iron, which collects on the negatively charged electrode and oxygen is released from the positive electrode.
Since the purpose of the study, funded by the National Aeronautics and Space Administration (NASA), was to generate oxygen using lunar soil to be used in possible future human bases on the moon, the process was performed on lunar-like soil, rich in iron oxide, extracted from the Meteor Crater in Arizona
Being an electricity-intensive process, MOE consumes approximately 3,500 units of electricity to produce one tonne of steel. This electricity was supplied from a carbon-free source (possibly a renewable source) and had an emission factor (ratio between the amount of carbon dioxide produced and the amount of raw material processed) of 0.09 kg of CO2 per unit of electricity generated (kWh). Total CO2 generated was 0.315 tonne CO2 per tonne of steel.
There are multiple details to specify and continue to develop before fixing positions over viability and feasibility, as like how to adjust carbon compositions for each steel grade that could require other installations, the electricity consumption, its emissions, and many other, but no doubt that this technology is interesting. In fact it seems the AISI (American Iron and Steel Institute) has already declared MOE as a probable technology to reduce CO2 emissions from the Iron and Steel industry.