Reduction, carburization and melting behavior of iron ore pellets containing coal char or graphite on heating

Reactions in iron ore-coal char composite pellets heated in nitrogen atmosp here at temperatures between 1100 degreesC and 1350 degreesC were investiga ted. Coarsening and melting of reduced iron particles through their carburi zation were furthermore investigated for iron ore-coal char (pellet P-c,P-l ) and iron ore-graphite (pellet P-g,P-i) composite pellets. Direct carburiz aiton of iron in contact with carbon is superior to indirect carburization through gas phase. Melting of P-c,P-l started above 1350 degreesC while mel ting of P-g,P-i above 1200 degreesC. The mechanism of formation of core and shell, which were observed for both kinds of the pellets by heating for a certain time, was also discussed. Furthermore, heating experiments with ele ctrolytic iron-coal char (pellet P-c,P-e) and electrolytic iron-graphite (p ellet P-g,P-e) composite pellets in N-2 and CO-10%CO2 were conducted to stu dy the effect of gasification of carbon on melting of the iron. It is concl uded that the gasification of carbon has a strong effect on the carburizati on by direct contact mechanism between iron and carbon, which finally deter mines the melting starting temperature of reduced iron.