Steel is one of the most useful materials on the planet. A backbone of modern life, it’s used in skyscrapers, cars, airplanes, bridges, and more. Unfortunately, steelmaking is an extremely dirty process.The most common way it’s produced involves mining iron ore, reducing it in a blast furnace through the addition of coal, and then using an oxygen furnace to burn off excess carbon and other impurities. That’s why steel production accounts for around 7 to 9 percent of humanity’s greenhouse gas emissions worldwide, making it one of the dirtiest industries…