Replacement of argon with carbon dioxide in a reactor containing molten metal for the purpose of refining molten metal

A process for decarburizing molten metal or ferro-alloys, comprising:

• in a first phase, adjusting the temperature of a molten metal or ferro-alloys bath to a desired operating range,
• in a second phase, reducing the carbon content of the molten bath to a value correspond approximately to the carbon content of the bath in equilibrium with CO at a partial pressure of 1 atm and at a temperature within said desired operating range, and
• in a third phase, further reducing the carbon content of the bath from said value to substantially the desired carbon content,
• wherein during the first phase, a gas mixture comprising oxygen and carbon dioxide is introduced by subsurface injection into said molten bath, and during the second and third phases, a mixture comprising oxygen and an inert gas selected from the group consisting of argon, xenon, neon, helium and nitrogen is introduced in said molten bath, and wherein the carbon dioxide is preheated before introduction by subsurface injection.