Abstract: To control the splash behavior in the desulfurization process of the hot metal ladle with top injection, a water model was established using a 180 t hot metal ladle of a steel plant as a prototype based on the similar principle. The formation mechanism of splashing in a top-blown hot metal ladle was explored, and the effects of the number and diameter of orifices on controlling splashing were investigated. Numerical simulation was used to calculate the gas-liquid two-phase flow behavior in the water model. The results show that the bubbles that rise to the hot metal-slag interface form droplets on the upper surface of their liquid film. Then the gas released by bursting bubbles provides upward momentum to droplets and causes splashing. If the side orifice diameters remain unchanged, converting the two-orifice lance into a three-orifice lance by adding a bottom orifice is not conducive to reduce splash. This is because the addition of a bottom orifice makes the flow rate of the side orifice smaller, so that the initial velocity of bubbles decreases, which leads to poor diffusion of bubbles in the liquid phase and concentration of bubbles near the lance. However, reducing the diameter of the three orifices can increase the initial velocity of the bubbles and enhance their diffusion in the liquid phase. Moreover, it can also decrease the escape velocity of the bubbles at the free surface. When the orifice diameter is reduced from 2.0 mm to 1.6 mm, the splash amount decreases from 27.5 mg to 25.8 mg, indicating that splash is effectively suppressed compared with that of the original two-orifice lance. The optimum orifice diameter of the three-orifice lance in this experiment is 1.8 mm. Industrial trials show that compared with the conventional lance, the three-orifice lance improves the desulfurization rate by 1.2 percentage points and reduces iron loss due to splashing by 5.9 kg/t.

Key words: hot metal ladle; splash; three-orifice lance; diameter of orifices; physical simulation; numerical simulation