Efficient Recycling of Silver and Copper from Sintering Dust by Chlorination Roasting Process

In this study, the Ag and Cu evolution in the sintering dust was extracted by chlorination roasting process, and the mechanism of the process was analyzed by atomic absorption spectroscopy, X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectrometry. In addition, in order to better understand the chlorination roasting process, the mechanism and thermodynamics of roasting reaction were analyzed. The recovery of Ag and Cu reached 99.05% and 59.32%, respectively, under the conditions of roasting temperature of 1423 K, holding time of 60 min, and the air flow rate of 400 L/h. Thermodynamic analysis showed that MgO and SiO2 could promote the production of Cl2 and HCl and that CuO could be chlorinated by Cl2 at 1421 K, but it was not amenable for HCl. Compared with CuO, Ag was more easily chlorinated at high temperatures. Experimental results indicate that silver and copper can be efficiently extracted, indicating that the chlorination roasting is a promising pyrometallurgical treatment for the recycling of sintering dust.