| A cyclone reactor system for the partial reduction and melting of taconite concentrate fines has been engineered, designed and operated. A non-transferred arc plasma torch was employed as a heat source. Taconite fines, carbon monoxide, and carbon dioxide were fed axially into the reactor, while the plasma gas was introduced tangentially into the cyclone. The average reactor temperature was maintained at above 1400{dollar}spcirc{dollar}C, and reduction experiments were performed under various conditions.; The influence of the following parameters on the reduction of taconite was investigated experimentally; carbon monoxide to carbon dioxide inlet feed ratio, carbon monoxide inlet partial pressure, and average reactor temperature. The interactions of the graphite lining with carbon dioxide and taconite were also studied.; The extent of the reduction was not greatly affected by the presence of carbon dioxide in the feed gas and increasing carbon monoxide partial pressures increased the degree of metallization slightly. In contrast, the average reactor temperature exerted a pronounced influence on taconite reduction.; The reduction reactions are believed to be chemically controlled, but mass transfer limitations appear to influence these reactions at higher temperatures.; The Boudouard reaction, at the temperatures employed, was very fast, resulting in very low carbon dioxide partial pressures, and thus had insignificant influence on the final degree of metallization. Also, the reaction between the molten product and the graphite lining contributed to the high levels of oxygen removal.; An attempt was made to characterize the flow behavior of the molten product within the cyclone. The results suggest that the system may approach a plug flow reactor, with little back mixing.; Finally, a fundamental mathematical model was developed. The model describes the flow dynamics of gases and solid particles in a cyclone reactor, energy exchange, mass transfer, and the chemical kinetics associated with cyclone smelting of taconite concentrate fines. The influence of the various parameters on the reduction and melting of taconite particles was evaluated theoretically. |
