XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2217
Lead Nitrate
Lead nitrate is a source of Lead (Pb2+) ions. In a study by
Yang et al. (2022), pyrite exhibited significant flotation effi-
ciency with the addition of 9.5 × 10–4 mol/L of Pb2+ ions
at pH 9.0, achieving a recovery rate of 95.2% compared to
51.2% without lead ions (Figure 6).
A key factor in this enhanced floatability of pyrite is
the formation of lead oxide/hydroxide species on its sur-
face. These species are commonly recognized as the pri-
mary agents responsible for the increased flotation efficacy
in lead-activated pyrite (Yang et al., 2022). Furthermore,
research done by Yang et al., (2021, 2022) shows that lead
oxide/hydroxide species are present on the surfaces of oxi-
dized pyrite after exposure to lead ions. Their presence is
linked to the notable improvement in pyrite’s flotation
performance, even when the mineral is oxidized to varying
degrees. Figure 7 shows the adsorption mechanism of Pb
ions on pyrite and products formed.
Yang et al., (2022) revealed that after introducing Pb2+
ions, the surface of pyrite displayed three distinct peaks cor-
responding to lead, situated at energies of 137.9, 138.7,
and 139.8 electron volts (eV). The peak found at 137.9 eV
is typically linked to either Pb–O (lead-oxygen) or Pb–S
(lead-sulfur) bonding. However, it’s known that Pb–S
bonds tend to form under acidic conditions, while Pb–O
bonds are more likely to form in an alkaline environment.
Given that the study was conducted under alkaline con-
ditions, the peak at 137.9 eV is more likely indicative of
Pb–O rather than Pb–S.
The peak at 138.7 eV is due to the formation of Pb–
OH, a lead-hydroxide bond. Lastly, the peak at 139.8 eV is
associated with the formation of PbSO₄, lead sulfate. This
comprehensive analysis of the lead peaks on the pyrite sur-
face helps in understanding the chemical interactions and
changes occurring due to the addition of lead ions, provid-
ing valuable insights into the surface chemistry of pyrite in
the presence of lead (Yang et al., 2022).
Na2S and NH4HCO3
Other activators that have been used to activate lime
and cyanide-depressed pyrite are ammonium bicarbon-
ate (NH4HCO3) and Sodium sulfide (Na2S) have been
discussed by Cao et al., (2018) &Ranchev &Nishkov,
(2018). In their experiments, they show that pyrite recov-
ery increases with the addition of 1089g/t of NH4HCO3
producing a recovery of 81.68% from 64.09% standard test
while Na2S in the absence of PAX, reaching 74% at 480 g/t
of Na2S respectively. Na2S influences pyrite flotation even
Figure 5. Mechanisms with impact of Eh- Acidic pH on contact angle after activation
with Cu2+ in a FeS
2 -H
2 O system
Lead Nitrate
Lead nitrate is a source of Lead (Pb2+) ions. In a study by
Yang et al. (2022), pyrite exhibited significant flotation effi-
ciency with the addition of 9.5 × 10–4 mol/L of Pb2+ ions
at pH 9.0, achieving a recovery rate of 95.2% compared to
51.2% without lead ions (Figure 6).
A key factor in this enhanced floatability of pyrite is
the formation of lead oxide/hydroxide species on its sur-
face. These species are commonly recognized as the pri-
mary agents responsible for the increased flotation efficacy
in lead-activated pyrite (Yang et al., 2022). Furthermore,
research done by Yang et al., (2021, 2022) shows that lead
oxide/hydroxide species are present on the surfaces of oxi-
dized pyrite after exposure to lead ions. Their presence is
linked to the notable improvement in pyrite’s flotation
performance, even when the mineral is oxidized to varying
degrees. Figure 7 shows the adsorption mechanism of Pb
ions on pyrite and products formed.
Yang et al., (2022) revealed that after introducing Pb2+
ions, the surface of pyrite displayed three distinct peaks cor-
responding to lead, situated at energies of 137.9, 138.7,
and 139.8 electron volts (eV). The peak found at 137.9 eV
is typically linked to either Pb–O (lead-oxygen) or Pb–S
(lead-sulfur) bonding. However, it’s known that Pb–S
bonds tend to form under acidic conditions, while Pb–O
bonds are more likely to form in an alkaline environment.
Given that the study was conducted under alkaline con-
ditions, the peak at 137.9 eV is more likely indicative of
Pb–O rather than Pb–S.
The peak at 138.7 eV is due to the formation of Pb–
OH, a lead-hydroxide bond. Lastly, the peak at 139.8 eV is
associated with the formation of PbSO₄, lead sulfate. This
comprehensive analysis of the lead peaks on the pyrite sur-
face helps in understanding the chemical interactions and
changes occurring due to the addition of lead ions, provid-
ing valuable insights into the surface chemistry of pyrite in
the presence of lead (Yang et al., 2022).
Na2S and NH4HCO3
Other activators that have been used to activate lime
and cyanide-depressed pyrite are ammonium bicarbon-
ate (NH4HCO3) and Sodium sulfide (Na2S) have been
discussed by Cao et al., (2018) &Ranchev &Nishkov,
(2018). In their experiments, they show that pyrite recov-
ery increases with the addition of 1089g/t of NH4HCO3
producing a recovery of 81.68% from 64.09% standard test
while Na2S in the absence of PAX, reaching 74% at 480 g/t
of Na2S respectively. Na2S influences pyrite flotation even
Figure 5. Mechanisms with impact of Eh- Acidic pH on contact angle after activation
with Cu2+ in a FeS
2 -H
2 O system