2376 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
may be improved by sulfidizing at a lower potential than
–300 mV. Nevertheless, this work has illustrated a new sul-
fidization approach to consider when dealing with oxidized
sulfide ores in practice.
CONCLUSION
Conventional sulfidization at –300 mV showed limited
improvement in the flotation of the oxidized pyritic gold
ore due to “superficial sulfidization” which produced hydro-
phobic sulfur oxidation products on the surface of oxidized
pyrite without promoting enough collector-induced flota-
tion. Although the sulfidization at –300 mV was able to
form a new iron sulfide phase on the surface of oxidized
pyrite, this new phase could not be sustained at the higher
potential required for collector adsorption.
The addition of Cu(II) ions during grinding could
not activate pyrite during the flotation of the oxidized
ore. Instead, this approach depressed pyrite flotation as a
result of the formation of hydrophilic copper hydroxide on
the surface. In contrast, the addition of Cu(II) ions dur-
ing grinding could improve the flotation of oxidized pyrite
with sulfidization. The combination of Cu(II) ions addi-
tion and sulfidization made the formation of a Cu(I)S
phase possible, which promoted collector-induced flotation
and therefore improved the flotation of oxidized pyrite. The
study also demonstrated that the formation of Cu(I)S on
the surface of oxidized pyrite and the flotation of oxidized
pyrite could be further improved by replacing Cu(II) ions
directly with Cu(I) ions.
The study recommends a new sulfidization process that
can be used to improve the flotation of oxidized pyritic
ores. The knowledge developed from the study may also
be used to improve the flotation of metal oxides and other
types of sulfide ores.
ACKNOWLEDGMENT
The financial support from the Australian Research Council
(ARC), Newmont USA Ltd and Newcrest Mining Ltd
through an ARC Linkage Project (LP160100619) is grate-
fully acknowledged.
REFERENCES
Cao, Z., Chen, X., and Peng, Y., 2018. The role of sodium
sulphide in the flotation of pyrite depressed in chalco-
pyrite flotation. Miner Eng 119:93–98.
Chandra, A.P., Puskar, L., Simpson, D.J., and Gerson, A.R.,
2012. Copper and xanthate adsorption onto pyrite sur-
faces: Implications for mineral separation through flo-
tation. Int J Miner Process 114–117:16–26.
Clark, D.W., Newell, A.J.H., and Chilman G.F., and
Capps, P.G., 2000. Improving flotation recovery of
copper sulphides by nitrogen gas and sulphidisation
conditioning. Miner Eng 13(12):1197–1206.
Hicyilmaz, C., Emre Altun, N., Ekmekci, Z., and Gokagac,
G., 2004. Quantifying hydrophobicity of pyrite after
copper activation and DTPI addition under elec-
trochemically controlled conditions. Miner Eng 17
(7–8):879–890.
Figure 5. Cyclic voltammograms of oxidized pyrite in the presence of Cu(II) and Cu(I) ions with sulfidization
may be improved by sulfidizing at a lower potential than
–300 mV. Nevertheless, this work has illustrated a new sul-
fidization approach to consider when dealing with oxidized
sulfide ores in practice.
CONCLUSION
Conventional sulfidization at –300 mV showed limited
improvement in the flotation of the oxidized pyritic gold
ore due to “superficial sulfidization” which produced hydro-
phobic sulfur oxidation products on the surface of oxidized
pyrite without promoting enough collector-induced flota-
tion. Although the sulfidization at –300 mV was able to
form a new iron sulfide phase on the surface of oxidized
pyrite, this new phase could not be sustained at the higher
potential required for collector adsorption.
The addition of Cu(II) ions during grinding could
not activate pyrite during the flotation of the oxidized
ore. Instead, this approach depressed pyrite flotation as a
result of the formation of hydrophilic copper hydroxide on
the surface. In contrast, the addition of Cu(II) ions dur-
ing grinding could improve the flotation of oxidized pyrite
with sulfidization. The combination of Cu(II) ions addi-
tion and sulfidization made the formation of a Cu(I)S
phase possible, which promoted collector-induced flotation
and therefore improved the flotation of oxidized pyrite. The
study also demonstrated that the formation of Cu(I)S on
the surface of oxidized pyrite and the flotation of oxidized
pyrite could be further improved by replacing Cu(II) ions
directly with Cu(I) ions.
The study recommends a new sulfidization process that
can be used to improve the flotation of oxidized pyritic
ores. The knowledge developed from the study may also
be used to improve the flotation of metal oxides and other
types of sulfide ores.
ACKNOWLEDGMENT
The financial support from the Australian Research Council
(ARC), Newmont USA Ltd and Newcrest Mining Ltd
through an ARC Linkage Project (LP160100619) is grate-
fully acknowledged.
REFERENCES
Cao, Z., Chen, X., and Peng, Y., 2018. The role of sodium
sulphide in the flotation of pyrite depressed in chalco-
pyrite flotation. Miner Eng 119:93–98.
Chandra, A.P., Puskar, L., Simpson, D.J., and Gerson, A.R.,
2012. Copper and xanthate adsorption onto pyrite sur-
faces: Implications for mineral separation through flo-
tation. Int J Miner Process 114–117:16–26.
Clark, D.W., Newell, A.J.H., and Chilman G.F., and
Capps, P.G., 2000. Improving flotation recovery of
copper sulphides by nitrogen gas and sulphidisation
conditioning. Miner Eng 13(12):1197–1206.
Hicyilmaz, C., Emre Altun, N., Ekmekci, Z., and Gokagac,
G., 2004. Quantifying hydrophobicity of pyrite after
copper activation and DTPI addition under elec-
trochemically controlled conditions. Miner Eng 17
(7–8):879–890.
Figure 5. Cyclic voltammograms of oxidized pyrite in the presence of Cu(II) and Cu(I) ions with sulfidization