Field synergy analysis of the convective transfer process in a flash smelting furnace

Abstract

The flash smelting process utilizes the rapid oxidation of micron-sized sulfide particles in an oxygen-enriched atmosphere to achieve high-yield continuous copper extraction. However, as production capacity increases, the emergence of unreacted particles and a downward shift in the intensely reactive region indicate a decline in heat and mass transfer efficiency between the gas and particles within the flash furnace. This necessitates a more detailed analysis to explore the changes and develop effective solutions. This study presents a validated CFD modeling to investigate the gas-particle reactive flow in the flash furnace. The field synergy principle is innovatively applied to analyze the convective heat and species transfer processes. The results reveal that convective species transfer within the air column performs well, but convective heat transfer is comparatively weaker. This imbalance leads to delays in the ignition and oxidation of sulfide particles, limiting improvements in production efficiency. To optimize the process, the effects of key operating airflows are examined. As a result, reducing process air velocity lowers the synergy angles within the air column, enhancing convective species transfer in the upper furnace region. Increasing the distribution air flow rate decreases the synergy angles in the middle region, improving heat transfer within the air column, though its effect on species transfer is limited. Overall, reducing process air velocity and increasing distribution air flow rate effectively enhances the convection, supporting higher production capacity upgrades.