Effect of reducing atmosphere on the direct reduction of iron oxides pellets

The present paper describes the direct reduction kinetics of industrial iron oxide pellets in various compositions of hydrogen and carbon monoxide. Different types of pellets with various percentages of total iron content and metal oxides were examined. They were reduced at different temperatures and pressure (700–1100 ◦ C and 1–6 bar) in various atmosphere with different contents of hydrogen and carbon monoxide. The reduction behaviour was described in terms of time to reduction, rate of reduction and kinetics constant. All the obtained results were analysed through the employment of a commercial multi-objective optimization tool (modeFrontier) in order to precisely define the weight that each single parameter has on the reduction behaviour of the pellets. The performed analyses allowed also to correlate the different processing parameters and the pellets properties in order to define the kinetics conditions as well as the factors limiting the reduction process.