Abstract:High occurrence rate of flue dust, as well as its derived flue gas nodulation and boiler agglomeration, is one of the key challenges to be solved in the further development of flash smelting technology. A set of industrial flash furnace flue dust samples was obtained by a self-made negative pressure rapid cooling sampler. The temperature of the corresponding off-gas was also measured by thermocouples, including the roof zone of the settler, the uptake, and the boiler. Dust samples have been systematically analyzed with the consideration of the temperature profile. The results show that flue dust is mainly composed of small spherical particles or irregular large particles formed by small particle aggregation. The average particle size rises from 1.11 μm to 2.17 μm along with the flow direction of off gas. The flue dust mainly contains elements such as Cu, Fe, Pb, S, As, O, etc. As the smoke moves forward, the metal element content in the dust continuously decrease. XRD results indicate that the main phase of dust is Fe3O4, CuFe2O4, Cu2O, CuSO4, and As2O3. Combined with the flue gas temperature data, it is found that there are unreacted copper matte and slag phase in the sedimentation tank area with mechanical entraining. Due to the sudden drop of temperature in the boiler area, the oxides convert to sulfates, and the substances with high As and Pb are easy to volatilize, and most of them precipitate and settle in the middle and back of the boiler.