After having favored the spectacular growth of the Lorraine iron and steel industry, the process progressively faded away in front of the Siemens-Martin Open-hearth furnace, which also used the benefit of basic refractory lining, before disappearing in the mid-1960s: with the development of gas liquefaction and the cryogenic separation of O 2 from air, the use of pure oxygen became economically viable. Even if modern pure oxygen converters all operate with a basic medium, their performance and operation have little to do with their ancestor.