Optimization of the Parameters Affecting the Metallization Degree of Sponge Iron in a Midrex Plant Using Central Composite Design

This research used response surface methodology with a central composite design to optimize the metallization degree of the Midrex-type Gohar plant of Golgohar Iron and Steel Development Company, Sirjan City. For this purpose, the effect of furnace bed temperature, bustle gas temperature, process gas CO2, reformed gas CO 2, and process gas flow/ton was investigated on the metallization degree of the sponge iron. The statistical analysis showed that the furnace bed temperature is the most effective parameter for the quality of the sponge iron in Midrex, and the most significant interaction was observed between the furnace bed temperature and the reformed gas CO2. The coefficient of determination and the standard error for the model were obtained at 0.9901 and less than 5%, respectively, which indicates the model was optimal. According to the optimization results, the best metallization degree of 93 was obtained in the furnace bed temperature of 727 °C, process gas CO 2 of 17.29%, bustle gas temperature of 859.55 °C, reformed gas CO2 of 2.98%, and process gas flow/ton of 1146 Nm3/ton.