Zinc fuming from lead blast furnace slag

Laboratory studies have been carried out to recover zinc from an industrial lead blast furnace slag using carbon as an external reducing agent. Experiments were conducted at 1573 K with and without carbon addition, and with different flow rates of argon or air as stirring gas. Results show that rate of zinc fuming increases with increase in carbon content of the melt and flow rate of the stirring gas (air or argon). In melts containing no carbon the results suggest that ZnO reduction took place by the diffusion of Fe+2 ions in the melt. Chemical reaction at the gas-slag interface was the rate controlling step in melts containing varying amounts of carbon. The type of stirring gas (air or argon) or the flow rate did not influence the reaction mechanism. Results from this investigation agree favorably with those reported in the literature on the zinc fuming process.