XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2167
would require highly oxidizing conditions on the mineral
surface and according to Wali et al., (2023) higher dosage
of collector.
CONCLUSIONS
This contribution has considered the reactivity of thiol col-
lectors on some platinum group minerals common to the
Great Dyke and the Bushveld complex, namely the sulfides,
arsenides and tellurides of Pt and Pd. Using the now recog-
nized tool of the Pourbaix diagram to designate Eh and pH
regions that facilitate hydrophobicity the paper provides
a potential blueprint for flotation chemistry control or
management of PGMs during flotation. An assessment of
the literature and the floatability of PGMs in the industry
indicates that the flotation of these minerals is not solved
simply by addressing the flotation chemistry alone. It was
noted that although telluride minerals have a high propen-
sity for oxidation of collector, they also have a high propen-
sity for oxidation of the mineral surface which counteracts
achievement of hydrophobicity. Arsenide minerals which
are notoriously poorly floting are noted to oxidise collector
on the mineral surface however higher dosage of collector
would be required to achieve a notable degree of hydropho-
bicity for flotation. The Eh-pH diagrams also indicate that
high collector dosages aided by highly oxidizing conditions
would provide ideal conditions for flotation of arsenides.
For most of the minerals it is not necessarily highly oxi-
dizing conditions that are necessary to ensure hydropho-
bicity, but the Eh-pH diagrams suggest that operation at
a lower Eh range when optimized with other operational
parameters can facilitate sufficient recoveries for successful
operation. Ultimately this contribution suggests the opti-
mization of Eh and pH alongside other operational param-
eters can facilitate effective recoveries of PGMs.
REFERENCES
Berlincourt, L.E., Hummel, H.H., Skinner, B.J., 1981.
Phases and Phase Relations of the Platinum-Group
Elements, in: Cabri, L.J. (Ed.), Platinum-Group
Elements: Mineralogy, Geology, Recovery. Canadian
Institute of Mining and Metallurgy, pp. 19–45.
Buckley, A.N., Woods, R., 1994. Xanthate chemisorption
on lead sulfide. Colloids Surfaces A Physicochem. Eng.
Asp. 89, 71–76. doi: 10.1016/0927-7757(94)02857-5.
Carelse, C., Manuel, M., Chetty, D., Taguta, J., Safari, M.,
Youlton, K., 2022. The flotation behaviour of liber-
ated Platinum Group minerals in Platreef ore under
reduced reagent conditions. Miner. Eng. 190, 107913.
doi: 10.1016/j.mineng.2022.107913.
Chimonyo, W., Wiese, J., Corin, K., O’Connor, C., 2017.
The use of oxidising agents for control of electrochemi-
cal potential in flotation. Miner. Eng. 109, 135–143.
doi: 10.1016/j.mineng.2017.03.011.
Corin, K.C., McFadzean, B.J., Shackleton, N.J.,
O’connor, C.T., 2021. Challenges related to the pro-
cessing of fines in the recovery of platinum group miner-
als (PGMs). Minerals 11. doi: 10.3390/min11050533.
Crawford, R., Ralston, J., 1988. The influence of particle
size and contact angle in flotation. Dev. Miner. Process.
12, 203–224. doi: 10.1016/B978-0-444-88284
-4.50011-1.
Fuerstenau, M.C., Jameson, G.J., Yoon, R.H., 2007. Froth
flotation: a century of innovation. SME.
Lotter, N.O., Bradshaw, D.J., Barnes, A.R., 2016.
Classification of the Major Copper Sulphides into
semiconductor types, and associated flotation char-
acteristics. Miner. Eng. 96, 177–184. doi: 10.1016/j.
mineng.2016.05.016.
Majima, H., Takeda, M., 1968. Electrochemical studies
of the xanthate-dixanthogen system on pyrite. Trans.
AIME 241, 431–436.
Nagaraj, D.R., Farinato, R.S., 2016. Evolution of flotation
chemistry and chemicals: A century of innovations and
the lingering challenges. Miner. Eng. 96, 2–14. doi:
10.1016/j.mineng.2016.06.019.
O’Connor, C.T., 2013. Investigations into the Recovery of
Platinum Group Minerals from the Platreef Ore of the
Bushveld Complex of South Africa. Platin. Met. Rev.
57, 302–310.
Penberthy, C.J., Oosthuyzen, E.J., Merkle, R.K.W., 2000.
The recovery of platinum-group elements from the
UG-2 chromitite, Bushveld Complex–a mineralogi-
cal perspective. Mineral. Petrol. 68, 213–222. doi:
10.1007/s007100050010.
Ralston, J., 1991. Eh and its consequences in sulphide
mineral flotation. Miner. Eng. 4, 859–878. doi:
10.1016/0892-6875(91)90070-C.
Rand, D.A.J., Woods, R., 1984. Eh measurements in
sulphide mineral slurries. Int. J. Miner. Process. 13,
29–42. doi: 10.1016/0301-7516(84)90009-7.
Rao, S.R., Leja, J., 2004. Surface Chemistry of Froth
Flotation: Reagents and mechanisms. Plenum
Publishers.
Shackleton, N.J., 2007. Surface Characterization and
Flotation Behaviour of the Platinum and Palladium
Arsenide, Telluride and Sulphide Mineral Species.
University of Cape Town.
would require highly oxidizing conditions on the mineral
surface and according to Wali et al., (2023) higher dosage
of collector.
CONCLUSIONS
This contribution has considered the reactivity of thiol col-
lectors on some platinum group minerals common to the
Great Dyke and the Bushveld complex, namely the sulfides,
arsenides and tellurides of Pt and Pd. Using the now recog-
nized tool of the Pourbaix diagram to designate Eh and pH
regions that facilitate hydrophobicity the paper provides
a potential blueprint for flotation chemistry control or
management of PGMs during flotation. An assessment of
the literature and the floatability of PGMs in the industry
indicates that the flotation of these minerals is not solved
simply by addressing the flotation chemistry alone. It was
noted that although telluride minerals have a high propen-
sity for oxidation of collector, they also have a high propen-
sity for oxidation of the mineral surface which counteracts
achievement of hydrophobicity. Arsenide minerals which
are notoriously poorly floting are noted to oxidise collector
on the mineral surface however higher dosage of collector
would be required to achieve a notable degree of hydropho-
bicity for flotation. The Eh-pH diagrams also indicate that
high collector dosages aided by highly oxidizing conditions
would provide ideal conditions for flotation of arsenides.
For most of the minerals it is not necessarily highly oxi-
dizing conditions that are necessary to ensure hydropho-
bicity, but the Eh-pH diagrams suggest that operation at
a lower Eh range when optimized with other operational
parameters can facilitate sufficient recoveries for successful
operation. Ultimately this contribution suggests the opti-
mization of Eh and pH alongside other operational param-
eters can facilitate effective recoveries of PGMs.
REFERENCES
Berlincourt, L.E., Hummel, H.H., Skinner, B.J., 1981.
Phases and Phase Relations of the Platinum-Group
Elements, in: Cabri, L.J. (Ed.), Platinum-Group
Elements: Mineralogy, Geology, Recovery. Canadian
Institute of Mining and Metallurgy, pp. 19–45.
Buckley, A.N., Woods, R., 1994. Xanthate chemisorption
on lead sulfide. Colloids Surfaces A Physicochem. Eng.
Asp. 89, 71–76. doi: 10.1016/0927-7757(94)02857-5.
Carelse, C., Manuel, M., Chetty, D., Taguta, J., Safari, M.,
Youlton, K., 2022. The flotation behaviour of liber-
ated Platinum Group minerals in Platreef ore under
reduced reagent conditions. Miner. Eng. 190, 107913.
doi: 10.1016/j.mineng.2022.107913.
Chimonyo, W., Wiese, J., Corin, K., O’Connor, C., 2017.
The use of oxidising agents for control of electrochemi-
cal potential in flotation. Miner. Eng. 109, 135–143.
doi: 10.1016/j.mineng.2017.03.011.
Corin, K.C., McFadzean, B.J., Shackleton, N.J.,
O’connor, C.T., 2021. Challenges related to the pro-
cessing of fines in the recovery of platinum group miner-
als (PGMs). Minerals 11. doi: 10.3390/min11050533.
Crawford, R., Ralston, J., 1988. The influence of particle
size and contact angle in flotation. Dev. Miner. Process.
12, 203–224. doi: 10.1016/B978-0-444-88284
-4.50011-1.
Fuerstenau, M.C., Jameson, G.J., Yoon, R.H., 2007. Froth
flotation: a century of innovation. SME.
Lotter, N.O., Bradshaw, D.J., Barnes, A.R., 2016.
Classification of the Major Copper Sulphides into
semiconductor types, and associated flotation char-
acteristics. Miner. Eng. 96, 177–184. doi: 10.1016/j.
mineng.2016.05.016.
Majima, H., Takeda, M., 1968. Electrochemical studies
of the xanthate-dixanthogen system on pyrite. Trans.
AIME 241, 431–436.
Nagaraj, D.R., Farinato, R.S., 2016. Evolution of flotation
chemistry and chemicals: A century of innovations and
the lingering challenges. Miner. Eng. 96, 2–14. doi:
10.1016/j.mineng.2016.06.019.
O’Connor, C.T., 2013. Investigations into the Recovery of
Platinum Group Minerals from the Platreef Ore of the
Bushveld Complex of South Africa. Platin. Met. Rev.
57, 302–310.
Penberthy, C.J., Oosthuyzen, E.J., Merkle, R.K.W., 2000.
The recovery of platinum-group elements from the
UG-2 chromitite, Bushveld Complex–a mineralogi-
cal perspective. Mineral. Petrol. 68, 213–222. doi:
10.1007/s007100050010.
Ralston, J., 1991. Eh and its consequences in sulphide
mineral flotation. Miner. Eng. 4, 859–878. doi:
10.1016/0892-6875(91)90070-C.
Rand, D.A.J., Woods, R., 1984. Eh measurements in
sulphide mineral slurries. Int. J. Miner. Process. 13,
29–42. doi: 10.1016/0301-7516(84)90009-7.
Rao, S.R., Leja, J., 2004. Surface Chemistry of Froth
Flotation: Reagents and mechanisms. Plenum
Publishers.
Shackleton, N.J., 2007. Surface Characterization and
Flotation Behaviour of the Platinum and Palladium
Arsenide, Telluride and Sulphide Mineral Species.
University of Cape Town.