Magnesium removal process from molten aluminum using particles of silica sand was studied from a hydrodynamic point of view using computational fluid dynamics (CFD). The gas-liquid flow was modeled by a model of the Euler type for both gas and liquid phase transport. Newton´s law of motion was used to describe the subsurface motion of injected solid particles from the calculated flow field in one-way coupling. The kinetics of the transitory reaction was described by using the model proposed by Ohguchi and Robertson for transitory reactions. The contacting method of reaction for silica particles of 75, 210 and 425 µm was established according to its dynamic interaction with the two phases flow. When the particle size was increased, the residence time increased as well; however, the efficiency for the transitory reaction was decreased. The reaction rate simulation showed a good agreement with experimental results reported in the literature.

A multiphase- hydrodynamic model was solved with the phase field method and the Cahn-Hilliard equation to simulate the behavior of particle injection with nitrogen as conveying gas through a submerged lance into a lead bath in two dimensions. The residence and mixing time were obtained for different operating parameters like gas flow rate, lance depth, and different kettle and lance dimensions. The residence and mixing time decreased when the injection rate and the lance diameter increased. Therefore, the particle will have less opportunity to react with the liquid bath decreasing the refining metal processes efficiency. When the lance height and kettle dimensions were increased, the residence and mixing time also increased. In order to have an efficient disengagement of the particles from the carrier gas within molten lead, the operating parameters must take into account the residence and mixing times. The Cahn-Hilliard equation represents adequately the hydrodynamic behavior in the lance-kettle system studied.