Argon Oxygen Decarburization, frequently referred to as “AOD”, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. By melting a charge in a furnace, and then placing it into the AOD vessel, the metal producer is able to utilize lower cost charge materials, improve mechanical properties, recover nearly 100% of metallic charge elements, and remove dissolved gases, as well as most of the carbon and sulfur. No other process offers similar capabilities in the foundry.
The AOD vessel is a brick lined steel shell with provision for introduction of oxygen and inert gas (argon or nitrogen) below the surface of the molten metal. This introduction causes significant agitation and, therefore, intimate slag-metal contact. Through the management of an additional high oxygen partial pressure gas mix and argon, the metal is refined and can reduce carbon levels to 0.01% or lower. Silicon and aluminum are added to remove more valuable metals from their oxides, resulting in a near 100% recovery.