Characterization of Copper Smelting Flue Dusts from a Bottom-Blowing Bath Smelting Furnace and a Flash Smelting Furnace

The smelting technology and flue dust treatment have an influence on the physical and chemical characteristics of flue dusts collected in copper smelting. We characterized flue dusts from a Bottom-Blowing Bath Smelting (BBS) process and from a Flash Smelting (FS) process by determining their comprehensive physical, chemical, and mineralogical characteristics. Annual flue dust generation data showed that the rate of the BBS process (2 to 3 pct) was clearly lower than that of FS process (5 to 6 pct). The results revealed that copper smelting flue dusts from the FS exhibited a larger entrainment of solids and a smaller particle size than the BBS. The crystallographic and chemical compositions of the samples indicated that the FS flue dusts have a higher degree of crystallinity than those of the BBS. Fe₃O₄, CuSO₄ and PbSO₄, Fe₃O₄, CuFe₅O₈ were the predominant crystalline phases in the FS and BBS flue dusts, respectively. In the FS and BBS flue dusts, amorphous multicomponent Cu-Zn-FeO_x and Cu-Zn-S phases were formed, respectively. Mineralogical examinations and a stepwise chemical extraction confirmed that the majority of arsenic existed in amorphous form and mostly as pentavalent As⁵⁺ arsenate or As₂O₅ except that in BBS-ESPD.