THE EFFECT OF VOLATILE MATTER OF NON-COKING COAL ON THE REDUCTION OF IRON OXIDE AT NON-ISOTHERMAL CONDITION

The volatile matter of non-coking coal was used for the reduction of hematite in argon atmosphere at nonisothermal condition. A thermal gravimeter furnace enable to use an ۸۰ mm-height crucible was designed for the experiments to measure the weight changes of about ۱۰ grams samples. A two-layered array of coal and alumina and four-layered array of iron oxide, alumina, coal and alumina was used for the devolatilization and reduction experiments, respectively. The net effect of volatile reduction of Fe ۲O۳was determined and it was observe that ۴۵% reduction has been achieved. Three distinct regions were recognized on the reduction curve. The reduction of hematite to magnetite could be completely distinguished from the two other regions on the reduction curve. At ۶۰۰-۹۵۰°C, the reduction was accelerated. ۶۳% of volatile matter resulted in ۲۵% of total reduction before ۶۰۰°C while the remaining volatile matter contributed to ۷۵% of the total reduction. From the reduction rate diagram, the stepwise reduction of the iron oxides could be concluded. The partial overlap of the reduction steps were identified through the XRD studies. The starting temperature of magnetite and wüstite reduction were determined at about ۵۸۵°C and at ۸۱۰°C, respectively.

Keywords:

volatile matter , iron oxide , non-coking coal , non isotherm , reduction