Iron Recovery Approach from Steel Slag Using Droplet Coalescence Technique

Currently, the world’s utilization rate of steel slag is relatively low, and it is primarily used for landfills, which has a negative impact on the environment and a cost to the economy. Compared to ironmaking slags, steelmaking slag has a relatively high percentage of total iron (between 20 and 35%). The high iron content of slag is a concern for the metalworking industry. Due to the presence of micron-sized iron particles that become trapped, the recovery of iron from slag was limited. Iron entrapment during the reduction of iron oxides in slag systems is a significant issue that reduces the iron yield from the system. This study examines the iron recovery mechanism from molten slag. At the molten stage, the force of attraction between molecules of individual components varies, rendering them an immiscible fluid, particularly metallic iron due to significant difference in density. In this study, iron recovery tracking parameters such as iron agglomeration and its settling time have been examined numerically. Using the commercial CFD software Ansys Fluent, a numerical calculation was performed to predict the size of the metal particle, the settling velocity, and the settling time. A three-dimensional numerical simulation was established using the volume of fluid (VOF) model and slag basicity’s ranging from 0.9 to 1.5. In addition, the particle orientation and equivalent droplet radius of metallic iron droplets are examined to support the mechanism and compared with real scenario.