Separation of arsenic and antimony from dust with high content of arsenic by a selective sulfidation roasting process using sulfur
(State Key Laboratory of Complex Non-ferrous Metal Resources Clean Utilization, Engineering Research Center of Metallurgical Energy Conservation and Emission Reduction of Ministry of Education, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China)
Abstract: The separation of arsenic and antimony from dust with high content of arsenic was conducted via a selective sulfidation roasting process. The factors such as roasting temperature, roasting time, sulfur content and nitrogen flow rate were investigated using XRD, EPMA and SEM-EDS. In a certain range, the sulfur addition has an active effect on the arsenic volatilization because the solid solution phase ((Sb,As)2O3) in the dust can be destroyed after the Sb component in it being vulcanized to Sb2S3 and this generated As2O3 continues to volatile. In addition, an amorphization reaction between As2O3 and Sb2O3 is hindered through the sulfidation of Sb2O3, which is also beneficial to increasing arsenic volatilization rate. The results show that volatilization rates of arsenic and antimony reach 95.36% and only 9.07%, respectively, under the optimum condition of roasting temperature of 350 °C, roasting time of 90 min, sulfur content of 22% and N2 flow rate of 70 mL/min. In addition, the antimony in the residues can be reclaimed through a reverberatory process.
Key words: dust; arsenic; antimony; sulfur; selective sulfidation roasting; separation