Document Type : Research Paper
Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Gonabad, Gonabad,Iran
New Materials Technology and Processing Research Center, Department of Metallurgical Engineering, Neyshabur Azad University, Neyshabur, Iran
In this research, the reduction of iron and zinc oxides of Electric Arc Furnace (EAF) dust using volatile matter of non-coking coal was investigated. Reduction was performed by two types of coals at three different heating rates in the temperature range of 25-950 ℃. The weight percentages of volatile matters in types 1 and 2 of the coal were 37% and 24%, respectively. Factsage 6.1 software was used to determine thermodynamic feasibility of the reduction process. The chemical composition of the dust was determined by ICP method, before and after the reduction process. The results of thermodynamic simulations show that decreasing the heating rate of the coal from 18.4 to 13.5 ℃/min leads to complete reduction of iron and zinc oxides in both types of coals. A higher amounts of volatile matter in coal 1 has caused higher amounts of reduction degree. Experiments show that at high heating rates of the coal, only small fraction of iron and zinc oxides are reduced. At lower heating rates, reduction degree increases and the results of experiments are closer to the those of thermodynamic simulations. The best results were obtained at a heating rate of 13.5 ℃/min for coal 1. Under these conditions, reduction of iron and zinc oxides takes place by 75% and 89%, respectively. In addition, the weight percentage of iron in the dust has increased from 31% to 46% that provides the possibility of dust recharge into the furnace.