Spatial distributions of plasma variables (concentration, temperature, and velocity) were calculated for alumina and carbon species injected in an argon thermal plasma. The plasma behavior was modeled from arc initiation through free plume expansion by combining a plasma code with a plume code. The model assumed a direct current, constrictor type, arc heater. This research, supported by the U.S. Bureau of Mines under the Strategic and Critical Materials Program, is examining the feasibility of using thermal plasmas for ore reduction. The process investigated in this paper is the carbothermic reduction of alumina.