CFD Simulation of Convection in a Reactor for the Production of Titanium Sponge by the Kroll Method

Abstract

In this study, numerical simulations are performed for convective flow in a titanium reduction reactor under both unheated and heated conditions. The VOF multiphase flow model was used for the simulation, using a total of 986,521 hexahedral structured meshes and considering turbulence using LES (Large Eddy Simulation). The titanium reactor contains liquid magnesium at a temperature of 1123K. Magnesium chloride was added to the charging port at a rate of 5.6 × 10−6 m/s. In this process, the strong exothermic chemical reaction on the surface of the magnesium solution and the heating of the reactor cause strong temperature gradients, and these temperature gradients lead to strong convection inside the reactor. As the reaction progresses, the titanium sponge gradually accumulates at the bottom of the reactor, and the density of magnesium chloride precipitates close to magnesium chloride. The precipitation process of magnesium chloride in a titanium reduction reactor was numerically simulated by using the three-dimensional unsteady state method. The results show that convection causes magnesium chloride to precipitate as a droplet in the form of a vortex, and the transient velocity of the settling process reaches the maximum near the reactor interface. Simultaneously, changing the heating state can affect the flow structure of the reactor and create favorable conditions for the reaction.