REDUCTION DINETICS OF ZINC OXIDE WITH METALLIC IRON UNDER NITROGEN STREAM

摘要

In order to clarify the reduction rate of zinc oxide with metallic iron under nitrogen stream, kinetic experiments were carried out in the temperature range between 1223 and 1373 K. Experimental data were analyzed in terms of the mixed-control kinetics based on the isothermal shrinking unreacted-core model, in which activities of ZnO and FeO were taken into account. The rate parameters were then determined.The reaction rate constant k_c and the effective diffusivity De are represented by the following equations:K_c/mol m~(-2) s~(-1)= exp {-185.2x10~3/(RT)+ 13.72}D_e/m~2s~(-1)= exp {-3433/T-8.620} where R is the gas constant.The activation energy of the reaction was 185 kJ mol~(-1). The calculated reduction curves by using the rate parameters hased on the shrinking unreacted-core model finely reproduced the experimental data.At temperature of only 50 K higher, the reaction rate of zinc oxide with metallic iron under nitrogen stream was comparable with that under vacuum.