3010 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Cu-activated pyrite decreased dramatically under a higher
Eh than 50 mV (He et al., 2005), but there are few further
systematic studies on these interesting topics. Apparently,
such a flotation technique as strengthening the separation
of sphalerite and/or marmatite from associated pyrite and
pyrrhotite through Eh and/or DO regulation has not yet
attracted enough attention, but which perhaps provide a
feasible approach for optimizing marmatite-pyrite/pyrrho-
tite (Zn-S) selective flotation in real practice.
Therefore, this paper mainly focuses on enhancing
the Zn recovery and grade of the marmatite concentrates
obtained from high-sulfur polymetallic sulfide ores and
optimizing the separating results of the Zn-S selective flo-
tation. In situ Raman spectra were used to determine the
characterize the chemical phase of dissolved elements in the
pulp, respectively, before and after the depression of pyrite
and pyrrhotite with lime as well as the follow-up activation
of sphalerite with CuSO4. The findings in this study are
expected to favor the beneficiation of zinc-bearing sulfide
ores, and provide references for the utilization or research
on other similar multi-metal sulfide ores with high sulfur,
especially those containing pyrrhotite.
MATERIALS AND METHODS
Materials
Zinc-bearing polymetallic sulfide ore used in this study
obtained from Nam Paten, Khammouan province, Laos.
The chemical composition of raw ore had been listed in
Table 1. The mineralogical study on raw ore indicated that
it consisted of 12.1% marmatite, 43.2% pyrite, 29.4%
pyrrhotite, 1.37% cassiterite, 0.58% chalcopyrite, and
13.35% gangue minerals (the main gangue minerals were
quartz, chlorite and so on). The raw ore was crushed and
then screened to 2 mm for flotation test.
Analytical pure copper sulfate (CuSO4) and lime
(CaO) were used as activator for marmatite and depressant
for pyrite/pyrrhotite, respectively. Analytical pure terpin-
eol was used as frother and industrial pure (purity ≥ 92%)
butyl xanthate (BX) was used as collector. Laboratory tap
water was used in all tests, unless otherwise state.
Marmatite-Pyrite/Pyrrhotite Selective Flotation
The flow sheet of Zn-S selective flotation was shown in
Figure 1. The flotation tests were conducted with self-
aerated XFD-IV flotation machines with volume of
1.5 L (produced in Exploration Machinery Factory, Jilin,
China). The stirring speed of flotation machine was fixed
at 1794 rpm. The pulp was firstly stirred for 3 min with or
without lime, or stirred for different times with adding lime
and regulating Eh by aeration, and then pulp was filtered
for ICP-OES or Raman spectrum analysis.
Analytical Method
Redox potential was measured with a 501-type combined
electrode (Leici, Shanghai, China), whose working elec-
trode was platinum and reference electrode was silver/silver
chloride (Ag/AgCl). The results were reported in accor-
dance with the standard hydrogen electrode (SHE). The
JPB-607A dissolved oxygen meter with a 957-type DO
electrode (Leici, Shanghai, China) was used to quantita-
tively determine the dissolved oxygen (DO) in pulp. The
full-spectrum scanning analysis of the pulp filtrate was con-
ducted by ICP-OES (SPECTRO BLUE SOP, Germany)
before and after the action of lime. An inVia Raman micro-
scope (Renishaw, UK) with an excited laser of 532 nm was
used to characterize the dissolved constituents of the pulp
filtrate. Each sample was tested for more than three times
to minimize accidental factors.
Table 1. The chemical composition of raw ore sample (mass fraction, %)
Zn Fe S Sn Cu Ca As C SiO2 Na2O Al2O3 MgO
8.12 40.53 37.62 1.42 0.33 0.76 0.33 0.87 4.15 2.07 1.29 0.43
Permission from Li et al. (2023a).
–0.074 mm 61.17% Grinding
Lime 6500 g/t
Copper sulfate 1200 g/t
Butyl xanthate 60 g/t
Terpineol 20 g/t
2 min
1 min
Roughing
Concentrate
Raw ore 500 g
4 min
Aeration
10 min
Tailings
Figure 1. The principal flow sheet of marmatite-pyrite/
pyrrhotite (Zn-S) selective flotation
Cu-activated pyrite decreased dramatically under a higher
Eh than 50 mV (He et al., 2005), but there are few further
systematic studies on these interesting topics. Apparently,
such a flotation technique as strengthening the separation
of sphalerite and/or marmatite from associated pyrite and
pyrrhotite through Eh and/or DO regulation has not yet
attracted enough attention, but which perhaps provide a
feasible approach for optimizing marmatite-pyrite/pyrrho-
tite (Zn-S) selective flotation in real practice.
Therefore, this paper mainly focuses on enhancing
the Zn recovery and grade of the marmatite concentrates
obtained from high-sulfur polymetallic sulfide ores and
optimizing the separating results of the Zn-S selective flo-
tation. In situ Raman spectra were used to determine the
characterize the chemical phase of dissolved elements in the
pulp, respectively, before and after the depression of pyrite
and pyrrhotite with lime as well as the follow-up activation
of sphalerite with CuSO4. The findings in this study are
expected to favor the beneficiation of zinc-bearing sulfide
ores, and provide references for the utilization or research
on other similar multi-metal sulfide ores with high sulfur,
especially those containing pyrrhotite.
MATERIALS AND METHODS
Materials
Zinc-bearing polymetallic sulfide ore used in this study
obtained from Nam Paten, Khammouan province, Laos.
The chemical composition of raw ore had been listed in
Table 1. The mineralogical study on raw ore indicated that
it consisted of 12.1% marmatite, 43.2% pyrite, 29.4%
pyrrhotite, 1.37% cassiterite, 0.58% chalcopyrite, and
13.35% gangue minerals (the main gangue minerals were
quartz, chlorite and so on). The raw ore was crushed and
then screened to 2 mm for flotation test.
Analytical pure copper sulfate (CuSO4) and lime
(CaO) were used as activator for marmatite and depressant
for pyrite/pyrrhotite, respectively. Analytical pure terpin-
eol was used as frother and industrial pure (purity ≥ 92%)
butyl xanthate (BX) was used as collector. Laboratory tap
water was used in all tests, unless otherwise state.
Marmatite-Pyrite/Pyrrhotite Selective Flotation
The flow sheet of Zn-S selective flotation was shown in
Figure 1. The flotation tests were conducted with self-
aerated XFD-IV flotation machines with volume of
1.5 L (produced in Exploration Machinery Factory, Jilin,
China). The stirring speed of flotation machine was fixed
at 1794 rpm. The pulp was firstly stirred for 3 min with or
without lime, or stirred for different times with adding lime
and regulating Eh by aeration, and then pulp was filtered
for ICP-OES or Raman spectrum analysis.
Analytical Method
Redox potential was measured with a 501-type combined
electrode (Leici, Shanghai, China), whose working elec-
trode was platinum and reference electrode was silver/silver
chloride (Ag/AgCl). The results were reported in accor-
dance with the standard hydrogen electrode (SHE). The
JPB-607A dissolved oxygen meter with a 957-type DO
electrode (Leici, Shanghai, China) was used to quantita-
tively determine the dissolved oxygen (DO) in pulp. The
full-spectrum scanning analysis of the pulp filtrate was con-
ducted by ICP-OES (SPECTRO BLUE SOP, Germany)
before and after the action of lime. An inVia Raman micro-
scope (Renishaw, UK) with an excited laser of 532 nm was
used to characterize the dissolved constituents of the pulp
filtrate. Each sample was tested for more than three times
to minimize accidental factors.
Table 1. The chemical composition of raw ore sample (mass fraction, %)
Zn Fe S Sn Cu Ca As C SiO2 Na2O Al2O3 MgO
8.12 40.53 37.62 1.42 0.33 0.76 0.33 0.87 4.15 2.07 1.29 0.43
Permission from Li et al. (2023a).
–0.074 mm 61.17% Grinding
Lime 6500 g/t
Copper sulfate 1200 g/t
Butyl xanthate 60 g/t
Terpineol 20 g/t
2 min
1 min
Roughing
Concentrate
Raw ore 500 g
4 min
Aeration
10 min
Tailings
Figure 1. The principal flow sheet of marmatite-pyrite/
pyrrhotite (Zn-S) selective flotation