A process for producing liquid steel is disclosed. Carbon monoxide and oxygen may be combusted in a high temperature reactor. Iron and iron oxide materials, along with scrap steel if desired, may be placed in the high temperature reactor. Carbon dioxide produced in the high temperature reactor may be circulated through a back reactor vessel. Coke masses may be placed in the back reactor vessel. The coke may be formed by circulating heated carbon monoxide counter current to crushed coal in a rotary kiln. The carbon dioxide circulated through the back reactor vessel reacts with the coke to form carbon monoxide. The carbon monoxide may be conveyed to the high temperature reactor to be combusted with oxygen to produce the heat for forming the liquid steel.