Recirculation of Chilean Copper Smelting Dust with High Arsenic Content to the Smelting Process

Most of the dust generated from the copper smelting process in Chili has been stored after the stabilization by hydrometallurgical process because it contains high concentration of arsenic. However, in recent years, the generation of dust has increased because of degrading the quality of concentrate. In addition, the environmental regulations become stricter. On the other hand, valuable metals such as copper and zinc are contained in the dust at high concentrations and it is desirable to recover them. In this study, the effect of recirculation of dust to the smelting process was examined in order not only to decrease the amount of dust but also to recover copper. The generation of dust and the distribution of arsenic, lead, zinc and so on among the matte, slag and gas phases were evaluated as a function of the amount of recirculated dust, partial pressure of oxygen and temperature. It was found that the direct return of dust to the smelting process was quite effective for the recovery of copper and the reduction of dust amount, but the acceptable amount of returnable dust was limited by the produced matte quality. [doi:10.2320/matertrans.M-MRA2008817]