Dynamic Behavior of Sulfur in Rapid Smelting Redution of Carbon-Coated-Iron Ore

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As one of the new iron-making processes for the next century, direct-iron-ore-smelting reduction process is now attracting a great deal of attention in which noncaking coal and iron ore powder can be used directly without coke oven. Development of direct-iron-ore-smelting reduction process requires accurate understanding of reaction mechanism and kinetic evaluation in melting condition.As a part of fundamental study on the kinetics of rapid smelting reduction of iron oxide with solid carbon, particles of carbon-coated-iron ore were prepared by heating of mixture of iron ore and phenolphthalein as a model compound of coal tar at 773 K in an nitrogen stream. Reduction behavior of carbon-coated-iron ore particles during rapid heating has been observed by using a drop-tube reactor in a nitrogen stream at temperatures from 1073 K-1860 K.The change in iron forms during rapid heating was successfully simulated and kinetic parameters of successive reaction for metallic iron formation from hematite via wustite were determined. The carbon-coated-iron ore with sulfur addition was also prepared and sulfur distribution was investigated during rapid smelting reduction. The experimental results showed that sulfur existed as FeS in molten iron phase and formation of metallic iron was retarded by sulfur addition to solid carbon.