CFD Analysis of the Flow Field in an SBS Furnace Under Thick Slag Layer Conditions for Nickel Smelting

The demand for metallic nickel has been growing steadily. Laterite nickel ore, as an oxide mineral, contains a higher nickel content than sulfide ores, enabling more economical smelting in the nickel extraction process. However, an extremely thick slag layer generated during side-blown smelting of laterite nickel ore alters the bath circulation characteristic of conventional smelting processes. To address this, this study employs a validated Multi-Fluid VOF model to analyze the flow field characteristics of the side-blown furnace bath under varying slag layer thicknesses. Within the slag thickness range of 1.5-2.5 m, the ascending air plume shifts horizontally along the furnace wall with increasing slag thickness, entraining matte into the slag and promoting its diffusion toward the settling zone. Matte diffusion is governed by bath circulation: backflow from the settling zone dominates at lower slag thickness, while vertical kinetic energy from splashed melt reflux dominates at higher thickness. This reflux-induced circulation is blocked by the dense matte layer, causing no disturbance to the bottom matte and thus favoring slag-matte separation. Increasing slag thickness raises the near-wall circulation zone and plume entry point, reducing gas holdup near the tuyere and weakening oxygen-matte contact.