Simulation of Frozen Slag Inside Brickless Reaction Shaft of Flash Smelting Furnace

Abstract

Based on the principle of heat transfer, a three-dimensional model of frozen slag in the brickless reaction shaft of a flash smelting furnace was established by computing the temperature field and judging the moving boundary. In the modeling process, a cylindrical coordinate system was adopted to specify the point positions according to the geometry of the brickless reaction shaft, and an improved method was proposed to discretize the three-dimensional control equations. The model was then applied to investigate the influence of the operational [gas temperature (GT), cooling water temperature (CWT), and melting temperature of frozen slag (MTFS)] and structural (steel shell thickness, steel nail thickness, steel nail length, and distance between nails) parameters on the thickness of the frozen slag. The results showed that the GT, CWT, and MTFS have a marked impact on the thickness of frozen slag, which decreases at high temperature and increases when cooled; the structural parameters have little effect on the thickness of frozen slag in terms of heat transfer. Consequently, to form a layer of frozen slag with a desired thickness inside a brickless reaction shaft, it is important to avoid localized ultra-high temperatures in the inner chamber and to cool the steel shell using a strong flow of low-temperature water; mechanical (and not thermal) factors should take precedence when designing the steel nails of a brickless reaction shaft.