XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 669
In the flotation process at pH 7 it has no effect on
the recovery because the magnesium forms no precipitates
and the LPAM is responsible for affecting the low flotabil-
ity of the molybdenite. The relationship of pH with the
adsorption of the flocculant is affected by several phenom-
ena such as the degree of anionicity of the PAM, its shear
level, and the physicochemical properties of the aqueous
medium among others. Some studies have shown that the
long chains of the LPAM decrease the contact area of the
particle with the bubble because the whole and extended
chain is adsorbed on specific sites of the particle causing
low adsorption of the collector and affecting its recovery
(Echeverry 2020).
Some studies indicate that the effect of magnesium is
greater than calcium in seawater flotation, which is attrib-
uted to the higher concentration of magnesium ions relative
to calcium and the Kps value of Mg (OH)2 (Kps=1.8×10–11)
which is lower than that of Ca (OH)2 (Kps= 6×10–6) (S.
Castro et al., 2015). These effects begin to manifest at pH
greater than 9.5 (Castro and Laskowski 2011 Chen et al.,
2020 Qiu et al., 2016 Castro et al., 2014).
CONCLUSION
The presence of calcium and magnesium ions affect the nat-
ural floatability of molybdenite especially at pH 9 and 11
due to the formation of precipitates that prevent a higher
recovery of the mineral. The effect of polyacrylamide is
presented in several forms that increase the depression of
the mineral causing a reaction in the dissolved calcium and
magnesium ions.
At pH 7 the molybdenite recovery is higher compared
to pH 9 and 11, however, it does not have the best results.
This effect can be caused only by the LPAM, because at
this acidity level there is no evidence of the formation of
any precipitate caused by calcium and magnesium ions. In
this context the long chains of the LPAM when extended
adsorb on the mineral avoiding its natural floatability.
ACKNOWLEDGMENTS
The authors acknowledge the financial support of the Water
Research Centre for Agriculture and Mining (CRHIAM) of
the Universidad de Concepcion sponsored by the ANID/
FONDAP/15130015 project. Leopoldo Gutierrez also
wants to thank ANID/ACT210030, ANID/FSQE210002,
ANID/Fondecyt/1211705, ANID/FONDEF IDeA I+D/
ID22I10102 projects.
REFERENCES
Alvarez, A., Gutierrez, L., &Laskowski, J. S. 2018. Use of
polyethylene oxide to improve flotation of fine molyb-
denite. Minerals Engineering, 127, 232–237. doi:
10.1016/j.mineng.2018.08.018.
Ametov, I., Grano, S., Zanin, M., Gredelj, S., Magnuson, R.,
Bolles, T., &Triffett, B. 2008. Copper and molybde-
nite recovery in plant and batch laboratory cells in por-
phyry copper rougher flotation. Proceedings of the 24th
International Mineral Processing Congress, .
Arinaitwe, E., &Pawlik, M. 2009. A method for measur-
ing the degree of anionicity of polyacrylamide-based
flocculants. International Journal of Mineral Processing,
91(1–2), 50–54. doi: 10.1016/j.minpro.2008.12.002.
Arinaitwe, E., &Pawlik, M. 2013. A role of flocculant
chain flexibility in flocculation of fine quartz. Part I.
Intrinsic viscosities of polyacrylamide-based floccu-
lants. International Journal of Mineral Processing, 124,
50–57. doi: 10.1016/J.MINPRO.2013.01.006.
Castro, S., &Laskowski, J. S. 2011. Froth flotation in
saline water. KONA Powder and Particle Journal, 29,
4–15. doi: 10.14356/KONA.2011005.
Castro, S., &Laskowski, J. S. 2015. Depressing effect of floc-
culants on molybdenite flotation. Minerals Engineering,
74, 13–19. doi: 10.1016/j.mineng.2014.12.027.
Castro, S., Lopez-Valdivieso, A., &Laskowski, J. S. 2016.
Review of the flotation of molybdenite. Part I: Surface
properties and floatability. International Journal of
Mineral Processing, 148, 48–58. doi: 10.1016/j.minpro
.2016.01.003.
Chen, Y., Chen, X., &Peng, Y. (2020). The effect of sodium
hydrosulfide on molybdenite flotation in seawater and
diluted seawater. Minerals Engineering, 158, 106589.
doi: 10.1016/j.mineng.2020.106589.
Estrada, D., Echeverry, L., Ramirez, A., &Gutierrez, L.
2020. Molybdenite Flotation in the Presence of
a Polyacrylamide of Low Anionicity Subjected to
Different Conditions of Mechanical Shearing. Minerals,
10(10), 895. doi: 10.3390/min10100895.
Gunson, A. J., Klein, B., Veiga, M., &Dunbar, S.
2012. Reducing mine water requirements. Journal
of Cleaner Production, 21(1), 71–82. doi: 10.1016
/j.jclepro.2011.08.020.
Hirajima, T., Suyantara, G. P. W., Ichikawa, O., Elmahdy, A.
M., Miki, H., &Sasaki, K. 2016. Effect of Mg2+ and
Ca2+ as divalent seawater cations on the floatability of
molybdenite and chalcopyrite. Minerals Engineering,
96–97, 83–93. doi: 10.1016/j.mineng.2016.06.023.
In the flotation process at pH 7 it has no effect on
the recovery because the magnesium forms no precipitates
and the LPAM is responsible for affecting the low flotabil-
ity of the molybdenite. The relationship of pH with the
adsorption of the flocculant is affected by several phenom-
ena such as the degree of anionicity of the PAM, its shear
level, and the physicochemical properties of the aqueous
medium among others. Some studies have shown that the
long chains of the LPAM decrease the contact area of the
particle with the bubble because the whole and extended
chain is adsorbed on specific sites of the particle causing
low adsorption of the collector and affecting its recovery
(Echeverry 2020).
Some studies indicate that the effect of magnesium is
greater than calcium in seawater flotation, which is attrib-
uted to the higher concentration of magnesium ions relative
to calcium and the Kps value of Mg (OH)2 (Kps=1.8×10–11)
which is lower than that of Ca (OH)2 (Kps= 6×10–6) (S.
Castro et al., 2015). These effects begin to manifest at pH
greater than 9.5 (Castro and Laskowski 2011 Chen et al.,
2020 Qiu et al., 2016 Castro et al., 2014).
CONCLUSION
The presence of calcium and magnesium ions affect the nat-
ural floatability of molybdenite especially at pH 9 and 11
due to the formation of precipitates that prevent a higher
recovery of the mineral. The effect of polyacrylamide is
presented in several forms that increase the depression of
the mineral causing a reaction in the dissolved calcium and
magnesium ions.
At pH 7 the molybdenite recovery is higher compared
to pH 9 and 11, however, it does not have the best results.
This effect can be caused only by the LPAM, because at
this acidity level there is no evidence of the formation of
any precipitate caused by calcium and magnesium ions. In
this context the long chains of the LPAM when extended
adsorb on the mineral avoiding its natural floatability.
ACKNOWLEDGMENTS
The authors acknowledge the financial support of the Water
Research Centre for Agriculture and Mining (CRHIAM) of
the Universidad de Concepcion sponsored by the ANID/
FONDAP/15130015 project. Leopoldo Gutierrez also
wants to thank ANID/ACT210030, ANID/FSQE210002,
ANID/Fondecyt/1211705, ANID/FONDEF IDeA I+D/
ID22I10102 projects.
REFERENCES
Alvarez, A., Gutierrez, L., &Laskowski, J. S. 2018. Use of
polyethylene oxide to improve flotation of fine molyb-
denite. Minerals Engineering, 127, 232–237. doi:
10.1016/j.mineng.2018.08.018.
Ametov, I., Grano, S., Zanin, M., Gredelj, S., Magnuson, R.,
Bolles, T., &Triffett, B. 2008. Copper and molybde-
nite recovery in plant and batch laboratory cells in por-
phyry copper rougher flotation. Proceedings of the 24th
International Mineral Processing Congress, .
Arinaitwe, E., &Pawlik, M. 2009. A method for measur-
ing the degree of anionicity of polyacrylamide-based
flocculants. International Journal of Mineral Processing,
91(1–2), 50–54. doi: 10.1016/j.minpro.2008.12.002.
Arinaitwe, E., &Pawlik, M. 2013. A role of flocculant
chain flexibility in flocculation of fine quartz. Part I.
Intrinsic viscosities of polyacrylamide-based floccu-
lants. International Journal of Mineral Processing, 124,
50–57. doi: 10.1016/J.MINPRO.2013.01.006.
Castro, S., &Laskowski, J. S. 2011. Froth flotation in
saline water. KONA Powder and Particle Journal, 29,
4–15. doi: 10.14356/KONA.2011005.
Castro, S., &Laskowski, J. S. 2015. Depressing effect of floc-
culants on molybdenite flotation. Minerals Engineering,
74, 13–19. doi: 10.1016/j.mineng.2014.12.027.
Castro, S., Lopez-Valdivieso, A., &Laskowski, J. S. 2016.
Review of the flotation of molybdenite. Part I: Surface
properties and floatability. International Journal of
Mineral Processing, 148, 48–58. doi: 10.1016/j.minpro
.2016.01.003.
Chen, Y., Chen, X., &Peng, Y. (2020). The effect of sodium
hydrosulfide on molybdenite flotation in seawater and
diluted seawater. Minerals Engineering, 158, 106589.
doi: 10.1016/j.mineng.2020.106589.
Estrada, D., Echeverry, L., Ramirez, A., &Gutierrez, L.
2020. Molybdenite Flotation in the Presence of
a Polyacrylamide of Low Anionicity Subjected to
Different Conditions of Mechanical Shearing. Minerals,
10(10), 895. doi: 10.3390/min10100895.
Gunson, A. J., Klein, B., Veiga, M., &Dunbar, S.
2012. Reducing mine water requirements. Journal
of Cleaner Production, 21(1), 71–82. doi: 10.1016
/j.jclepro.2011.08.020.
Hirajima, T., Suyantara, G. P. W., Ichikawa, O., Elmahdy, A.
M., Miki, H., &Sasaki, K. 2016. Effect of Mg2+ and
Ca2+ as divalent seawater cations on the floatability of
molybdenite and chalcopyrite. Minerals Engineering,
96–97, 83–93. doi: 10.1016/j.mineng.2016.06.023.