Without a doubt, steel is one of the most important materials in our species history as it allowed for the construction of skyscrapers, machines, and more. Its manufacture is also one of the largest industrial sources of carbon dioxide, constituting 5% of all of the world's CO2 emissions. Researchers at MIT though have found a way to possibly remove all CO2 emissions from the production of steel, and potentially other metals as well.
Ironically the solution the researchers developed to address this Earth-bound issue came from work concerning the Moon. With is considerably low mass, the Moon has no atmosphere to speak of, but if humans are ever to inhabit it, there must be an oxygen source. One method being considered is to release the oxygen from iron oxide in Moon dust. As iron oxide is the primary component of iron ore, which steel is made from, the researchers looked for a way to apply the method for steel production. The key was to find an electrode that could survive the temperatures of molten iron oxide while still conducting electricity. What they discovered was an alloy of chromium and iron, which are both inexpensive.
Along with zero CO2 emissions (replaced with oxygen emissions) the researchers found this method can produce very pure steel, which is a definite advantage to its adoption and use. One disadvantage though is its inability to produce the millions of tons of steel per year to be economical in large-scale plants. Instead, it may only find a home in smaller plants that only need to output hundreds of thousands of tons of steel in a year.