Abstract:Sawdust is used to provide a reducing atmosphere for roasted blast furnace dust and to recover iron from it, realizing the resource utilization of blast furnace dust while saving energy in a green way. Based on the single-factor test, effects of roasting temperature, roasting time, and reducing agent ratio on iron grade and iron recovery of magnetic separation recovered concentrate were analyzed by response surface method design, and a mathematical prediction model between the independent variables and response values was established. The optimal process conditions for recovering iron from blast furnace dust by magnetization roasting were determined according to the model: roasting temperature of 686.65 ℃, roasting time of 25.03 min, and reducing agent ratio of 1︰8.6. The predicted magnetic iron grade of 68.325% and recovery rate of 90.945% is obtained at this condition, and the difference between experimental verification value and predicted value of the model is within 0.3%, indicating that the model optimization results are reliable. It can be applied to iron extraction process of blast furnace ash by magnetizing roasting of sawdust.