Numerical simulation of gas-liquid mixed top blowing to enhance momentum diffusion

The presence of magnetic iron in slag increases the viscosity of the matte-slag mixture, impeding the precipitation and separation of matte from the slag. Magnetic iron can be reduced by injecting diesel oil into the molten bath and the resulting reaction enhanced by adding nitrogen to the spray lance. This study establishes a three-dimensional mathematical unsteady flow model of a y-shaped pipe containing a gas-liquid mixture, which is top-blown to enhance momentum agitation. By changing the inlet velocity of the y-pipe branch while maintaining a constant oil inlet speed, eight working conditions with different oil-gas ratios were established. These were used to investigate the effect of changing the two-phase flow pattern in the vertical tube with the inlet gas-liquid ratio. The simulation results agree well with published water model results. Experimental and simulation results show that when the ratio of oil to gas is 1:2, due to tangential disturbance of the branch gas relative to the main oil phase, rotational flow forms during the mixed descent process. After entering the molten bath, the circumferential gas-liquid mixing disturbance forms the optimum effect of swirling flow diffusion in the molten bath. The complex flow pattern formed by the nonlinear momentum diffusion of diesel mixed with bubbles can effectively improve the reduction rate of magnetic iron in the molten bath, thus reducing copper content in the slag.