Investigations of the impact of deposit thickness on the amount of heat transferred during roasting copper concentrates in a fluidised bed

During copper smelting, copper concentrates containing organic carbon compounds are subjected to the roasting process in a fluidised-bed furnace. The roasted concentrate formed in the process contains substances which deposit on the surfaces of the tubes present inside the furnace. The deposits contribute to the reduction of the heat flux absorbed from the bed. This study investigates the morphology, chemical composition and thermophysical properties of the deposits. The impact of the increase in the deposit thickness on the increase in the deposit surface temperature and the reduction of the heat flux absorbed by water was determined. A deposit taken from an industrial facility was analysed. It was established that, for a deposit with a thickness of 40 mm, there was an approximately 80 % decline in the absorbed energy as compared to a clean tube surface.