XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3083
as well as ore quality during the time. Three flotation tests
were performed for each month samples. All tests were done
in the same condition using dry lime. Not adding frother,
and both collectors would be dosed at 5 g/t. Recovery was
dropped by 3% to 84.43% in 1st month sample because
of the impact of Estrella pit water. In addition, mass pull
dropped by 7%. Ran one of the tailings through 50 and
100 mesh to determine if it was consistent with controls,
ended up having 17.7% retained on 150 microns compared
to an average of 17.4 on the control samples.
In the 2nd month, the second bucket was decanted.
The entire process of preparation was done. Three flotation
tests were performed. In this set of tests, recovery dropped
by 4% compared to control tests. Also, mass pull dropped
significantly. In months 3, 4, and 5th recovery dropped by
5, 7, and 10%, respectively (Figures 8 and 9). In all tests,
for all months, mass pull dropped significantly (Figure 10).
The main reasons behind decreasing recovery as well as
mass pull is the presence of various ions in Estrella pit water
as it can be seen in table 3 how extremely the ion and com-
pound concentrations in the pit water increased compare to
the process water. Those ions can impact minerals surface
chemistry and change their properties, consequently lead-
ing to decreased recovery and mass pull.
The pit water contains 590 mg/L Ca2+, which can
activate some unwanted minerals. On the other hand, it
can depress pyrite in copper flotation, and consequently
reduce mass pull. In addition, the concentration of SO42–
(8400 mg/L) in pit water is extremely high, which in the
higher pH after adding lime forms gypsum (CaSO4).
Precipitated gypsum usually results in poor selectivity and
recovery (Grano et al., 1995). Ozlem Bicak et al. showed
the lowest Cu recovery per unit mass pull was obtained with
high concentrations of Ca2+ and S2O3 2− at Cu-Zn flota-
tion (Bicak et al., 2018). Also the presence of 6400 mg/L
of Fe, 5600 mg/L of Mg, 952 mg/L of Mn in the pit water
after lime addition forms Mg(OH)2, Fe(OH)2, Mn(OH)2,
calcium carbonate (CaCO3), and other insoluble Ca salts.
The precipitation of these compounds on the mineral sur-
face changes their surface chemistry and as a result, nega-
tively impacts on flotation performance (Castro, 2018).
CONCLUSION
In this study, the impact of Estrella pit water on Estrella
ore was considered. Samples were exposed to the Estrella
pit water for 5 months. The results showed an enormous
impact of compounds in the water on recovery as recovery
decreased from 87% to 77%. In addition, the presence of
various ions in the water depresses a considerable amount
of the minerals, resulting to decrease mass pull from 14 to
6%. Moreover, it increased the lime consumption from 2.5
to 11.5 kg/ton.
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14
Time (min)
Control M1 M2 M3 M4 M5
Figure 8. Recovery, and kinetic curve of Estrella ore for different months
Recovery%
as well as ore quality during the time. Three flotation tests
were performed for each month samples. All tests were done
in the same condition using dry lime. Not adding frother,
and both collectors would be dosed at 5 g/t. Recovery was
dropped by 3% to 84.43% in 1st month sample because
of the impact of Estrella pit water. In addition, mass pull
dropped by 7%. Ran one of the tailings through 50 and
100 mesh to determine if it was consistent with controls,
ended up having 17.7% retained on 150 microns compared
to an average of 17.4 on the control samples.
In the 2nd month, the second bucket was decanted.
The entire process of preparation was done. Three flotation
tests were performed. In this set of tests, recovery dropped
by 4% compared to control tests. Also, mass pull dropped
significantly. In months 3, 4, and 5th recovery dropped by
5, 7, and 10%, respectively (Figures 8 and 9). In all tests,
for all months, mass pull dropped significantly (Figure 10).
The main reasons behind decreasing recovery as well as
mass pull is the presence of various ions in Estrella pit water
as it can be seen in table 3 how extremely the ion and com-
pound concentrations in the pit water increased compare to
the process water. Those ions can impact minerals surface
chemistry and change their properties, consequently lead-
ing to decreased recovery and mass pull.
The pit water contains 590 mg/L Ca2+, which can
activate some unwanted minerals. On the other hand, it
can depress pyrite in copper flotation, and consequently
reduce mass pull. In addition, the concentration of SO42–
(8400 mg/L) in pit water is extremely high, which in the
higher pH after adding lime forms gypsum (CaSO4).
Precipitated gypsum usually results in poor selectivity and
recovery (Grano et al., 1995). Ozlem Bicak et al. showed
the lowest Cu recovery per unit mass pull was obtained with
high concentrations of Ca2+ and S2O3 2− at Cu-Zn flota-
tion (Bicak et al., 2018). Also the presence of 6400 mg/L
of Fe, 5600 mg/L of Mg, 952 mg/L of Mn in the pit water
after lime addition forms Mg(OH)2, Fe(OH)2, Mn(OH)2,
calcium carbonate (CaCO3), and other insoluble Ca salts.
The precipitation of these compounds on the mineral sur-
face changes their surface chemistry and as a result, nega-
tively impacts on flotation performance (Castro, 2018).
CONCLUSION
In this study, the impact of Estrella pit water on Estrella
ore was considered. Samples were exposed to the Estrella
pit water for 5 months. The results showed an enormous
impact of compounds in the water on recovery as recovery
decreased from 87% to 77%. In addition, the presence of
various ions in the water depresses a considerable amount
of the minerals, resulting to decrease mass pull from 14 to
6%. Moreover, it increased the lime consumption from 2.5
to 11.5 kg/ton.
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14
Time (min)
Control M1 M2 M3 M4 M5
Figure 8. Recovery, and kinetic curve of Estrella ore for different months
Recovery%
