ABSTRACT
In this paper, formation of zinc sulfide species during roasting of ZnO with FeS2 was investigated and its contribution on flotation was illustrated. The evolution process, phase and crystal growth were investigated by thermogravimetry (TG), X-Ray diffraction (XRD) along with thermodynamic calculation and scanning electron microscopy-Energy-dispersive X-ray spectroscopy (SEM-EDS), respectively, to interpret the formation mechanism of ZnS species. It was found that ZnS was initially generated at about 450 °C and then the reaction prevailed at about 600 °C. The generated FexS would dissolve into ZnS and then form (Zn, Fe)S compound in form of Fe2Zn3S5 when temperature increased to about 750 °C. This obviously accelerated ZnS phase formation and growth. In addition, it was known that increasing of ZnO dosage had few effects on the decomposition behavior of FeS2. Then, flotation tests of different zinc oxide materials before and after treatment were performed to further confirm that the flotation performances of the treated materials could be obviously improved. Finally, a scheme diagram was proposed to regular its application to mineral processing. It was systematically illustrated that different types of ZnS species needed to be synthetized when sulfidization roasting-flotation process was carried out to treat zinc oxide materials.
ABSTRACT
The dissolubility and surface properties of chalcopyrite were studied in different mechanical stirring time and different pH value solution under argon and oxygen atmosphere by ICP-MS, AFM and XPS analysis. Besides, the XRD tern and crystal structure of chalcopyrite and its dissolution model in aqueous solution were established. The laboratory results indicate that the relationship between copper and iron concentrations in solution and time in pure water can be derived as the equation c = ks(a)t+b. The lower pH value makes it easier for chalcopyrite to dissolve, and that the surface oxidation is slow has minor effect on the dissolubility. In pure water, the dissolution of chalcopyrite has little influence on the effective specific surface area, and the dissolution is controlled by surface chemical reaction under acidic conditions. After long time dissolution, the surface of the chalcopyrite assumes copper-rich state relative to iron and the surface roughness and lattice imperfections increase.
