Formation of zinc sulfide species during roasting of ZnO with pyrite and its contribution on flotation

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.

Phase transformation analysis and process optimisation of low-grade lead–zinc oxysulphide ore carbothermal reduction

“…36 Therefore, lower p O 2 and higher temperatures are required in the reaction system to favour the region of metal sulphides. 36,37 This experiment was conducted in an argon environment; therefore, the reaction path slightly differs from that under air conditions. The solid-solid reduction reaction of C and metal oxides is conducted in the system.…”

Greener reactants, renewable energies and environmental impact mitigation strategies in pyrometallurgical processes: A review

“…Roasting can be associated with either exothermic or endothermic reactions. Actual roasting operations in pyrometallurgy include: (1) iron ore induration 26 ; (2) Zn sulfide conversion to ZnO using O 2 -enriched air blowing 27 ; (3) carbo-chlorination of titanium concentrate that transforms the titanium oxide into titanium chloride. 28 As for calcining furnaces, roasters used in pyrometallurgical processes are conventionally heated via burners and have a rotary drum system.…”

The production of high value pig iron nuggets from steelmaking by-products – A thermodynamic evaluation

“…It is likely as T increases the ZnO present at ambient conditions would react to form ZnS as a high excess of carbon and the presence of Fe2O3 promote sulfidation of zincite during roasting (Han et al, 2017). Studies of the sulfidation of ZnO using FeS as a sulfidization agent and demonstrated experimentally at temperatures > 450 °C (Zheng et al, 2018) suggests that ZnS would indeed form preferentially to FeS during the heating of BF dust as ZnO reacts with sulfur present in the material.…”