A KINETIC STUDY ON THE CARBOTHERMIC REDUCTION OF ZINC OXIDE FROM ELECTRIC ARC FURNACE DUST

In the present study, reduction of zinc oxide from the pellets made of steelmaking electric arc furnace dust has been investigated. Effects of such parameters as the type of carbon material (graphite, coke and charcoal) as well as time and temperature on the reduction reaction have been examined. The reduced (dimensionless) time method was applied to perform a kinetic analysis of the system. Experimental results showed that increasing the temperature in the range of ۹۲۵-۱۱۵۰°C results in a remarkable increase in the reduction rate. It was also shown that the reduction process is controlled by chemical reaction. Meaningful difference in the activation energy values calculated for reduction with graphite (۲۴.۷۵ kcal/mol), coke (۱۸.۱۳ kcal/mol) and charcoal (۱۱.۵۲ kcal/mol) indicate the predominant role of chemical reaction (carbon gasification) in the overall reaction rate and its rate-controlling mechanism. Carbothermal reduction of pelletized EAF dust proved to be an efficient reduction method, so that above ۹۰% reduction was achieved in about one hour at temperatures around ۱۱۰۰°C.

Keywords:

Electric arc furnace dust , zinc oxide carbothermic reduction , pelletizing , kinetics , mechanism , activation , energy