Kinetic modeling on hot metal desulfurization with mechanical stirring

Abstract

A kinetic model on hot metal desulfurization with mechanical stirring was established using FactSage Macro Processing. The sulfur diffusion in the molten steel and reactions at the interface between the molten steel and the desulfurizer particle were considered. Calculated results agreed well with experimental results, indicating that the model can be used to predict the desulfurization rate and cost with various temperatures, chemical compositions, rotation speeds, and desulfurizer additions. The higher impeller rotation speed from 80 to 120 r/min, higher temperature from 1573 to 1673 K, smaller particle size from 2.5 to 1.5 μm, and more desulfurizer addition from 0.35 to 0.64 kg/t were suggested to improve the desulfurization rate. Moreover, to synthetically increase the desulfurization efficiency and lower the cost, contours of S content and cost during the desulfurization process with various desulfurizer additions and time were calculated. Based on industrial cost data analysis of the added desulfurizer, the refractory erosion, and electric power consumption, the total cost of the hot metal desulfurization with time step (Δt) was fitted as ${\text{Cost}}_{{{\text{total}}}} = 0.0{66} + {1}.{58} \times {1}0^{{ - {7}}} \cdot \Delta t$. The less desulfurizer addition and longer desulfurization time contributed to lowering the cost, while more desulfurizer addition was conducive to improving the desulfurization efficiency.