Deposit Build-up and Corrosion in a Copper Flash Smelting Heat Recovery Boiler

摘要

The aim of the work was to improve the understanding of deposit formation and corrosion in a copper flash smelting plant, focusing on the effects of process gas temperature (400-900 A degrees C) and heat-transfer surface temperature (160-320 A degrees C) on deposit formation and corrosion rate. The rate of build-up increased as a function of process gas temperature, which was explained by a larger extent of sintering at higher temperatures, resulting in slagging and thus, in better adhesion of particles hitting the surface. The corrosion rate increased as a function of process gas temperature. Iron sulphate (FeSO4 or Fe-2(SO4)(3)) was found at the interface between the deposit and the corroded metal surface, suggesting that corrosion was induced by sulphuric acid (H2SO4) from the reaction between SO3 (originating from SO2 in the process gas) and water vapour.