A 3-D COMPUTER MODEL OF THE FLASH CONVERTING FURNACE SHAFT

A three-dimensional computer model for the Kennecott-Outokumpu flash converting process for copper matte is presented. The model incorporates the transport of momentum, heat and mass, and reaction kinetics between the gas and particles in a particle-laden turbulent gas jet. The k-e model is used to describe gas-phase turbulence in an Eulerian framework. The particle phase is treated from a Lagrangian viewpoint coupled to the gas phase through the source terms in the Eulerian gas-phase governing equations. Matte particles were represented as Cu2S·yFeSx. The oxidation products were assumed to be Cu2O, CuO, Fe3O4, and SO2 based on experimental observation. A reaction mechanism involving the external mass transfer of oxygen to the particle surface and diffusion through the oxide layers of Cu2O/Fe3O4 and CuO/Fe3O4 is proposed. Predictions of the mathematical model were compared with data collected in a large laboratory furnace, showing reasonable agreement in terms of fractional conversion of oxidation reactions and sulfur remaining in the reacted particles. Additionally, the simulation of an industrial flash converting furnace indicated that higher oxidation rates, a more even distribution of particles, and a more efficient use of the reactor volume are achieved with a burner having a distributor cone compared to a single-entry burner.