A detailed study of the physical and chemical characteristics of a flue dust sample from a coal-fired copper reverberatory furnace was carried out. The studies revealed that the majority of the copper in the flue dust is strongly associated with iron in the form of a cuprous ferrite, cufeo2 (delafossite). The flue dust has an extremely fine size distribution with 70% of the particles below 37 um in size. The recovery of copper from the flue dust was investigated using an ammoniacal carbonate solution. The results indicate that a reductive roast prior to leaching is necessary to obtain high extractions. In order to better understand the leaching characteristics of the flue dust, attempts were made to synthesize and study the leaching of the main copper-bearing constituent, cufeo2. The dissolution of the cufeo2 was found to depend on the extent of reduction, particle size, and stirring speed. A film diffusion model was proposed to describe the kinetics of leaching of cufeo2.