Reaction Sequences in Flash Smelting and Converting Furnaces: An In-depth View

Flash smelting and flash converting are mature technologies in copper and nickel sulfide smelting. The sensitivity of operation concerning the furnace design is evident. It is obvious that when two unit operations are carried out in separate spaces in the same furnace, skills related to maintenance of suspension oxidation of fine minerals, fluxing, fluid as well as heat flows and the overall energy balance are required. Despite these fundamental features, the flow-sheet wide understanding of linking the suspension oxidation of sulfides with the subsequent smelting processes in the furnace as well as the chemistry of its off-gas train is largely absent in the scientific literature. This review gives a detailed outlook on the microscale phenomena in flash smelting and flash converting furnaces accumulated during the last decades. It connects their vital features and chemistries with the reaction tendencies and heat fluxes in the different parts and reaction zones of the furnace as well as in the off-gas train from the smelter to the acid plant. Graphic Abstract