China Nonferrous Metallurgy

In the boiling chlorination process of high titanium slag, segregation behavior of high titanium slag and petroleum coke is prone to occur, affecting the mass and heat transfer of the boiling chlorination process and the reaction rate. To address this issue, this study uses high titanium slag and petroleum coke as raw materials, with chlorine gas as the fluidization medium. The Grace formula and Gupta formula are employed to calculate the initial fluidization velocity and the complete fluidization velocity, respectively. Based on the Eulerian two-fluid model and the drag force model, numerical simulations are performed, and the velocity contours under different correction factors for the complete fluidization velocity, the volume fraction distribution of particles at different heights, and the dynamic characteristics of bubbles are analyzed. The following main conclusions are obtained. The calculated complete fluidization velocity is 0.157 m/s. The simulation results indicate that at this velocity, only a stable bubble phase is initially formed above the distributor plate within the bed, making it difficult to generate significant particle disturbance effects. A uniform mixing can be achieved at a gas velocity corresponding to a correction factor of 1.6 times. Radial analysis of the bed shows that as the fluidization time (1.0~3.0 s) increases, the gradient of particle volume fraction gradually weakens, and the lateral distribution tends to become uniform, confirming that turbulent mixing has an inhibitory effect on segregation. Bubble behavior is the root cause of segregation. During the rise of bubbles, petroleum coke is entrained and carried to the bed surface, leading to the segregation of high titanium slag towards the bottom and petroleum coke towards the top during the boiling chlorination process. The results of this study can provide a theoretical basis and technical reference for improving the reaction rate and operational stability of the boiling chlorination process of high titanium slag.