XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 777
INTRODUCTION
The process water quality is a key component in the
industrial flotation process and a large water consump-
tion is required to process the huge mineral treatments.
Commonly, the concentrator plants recover and recycle
the process water, which is about 80% of the process water
(Moraga, 2023). Therefore, the complementary 20% is the
fresh make up water, normally from underground sources.
However, due to environmental constraints, including the
shortage of the freshwater resources, the flotation plants
have started replacing underground water by seawater or
desalinated water. The change in makeup water quality
will change the process water, which can have a signifi-
cant effect on metallurgical performance (Liu et al., 2013).
Additionally, concentrators plants have had the need to
reduce water consumption. Gunson et al. (2012) identified
mine water reduction, reuse and recycle options: evapora-
tion reduction strategies, paste tailings disposal, filtered
tailings disposal, ore pre-sorting and a combination of the
most effective options. A key result of the study was that a
combination of ore preconcentration and filtered tailings
disposal could reduce water consumption by 74% or more.
Several studies have analyzed the effect of water qual-
ity on metallurgical performance of minerals. For example,
Kirjavainen et al. (2002) studied the effect of calcium and
thiosulfate ions on flotation of a Ni–Cu ore. It was observed
that the ions improved the floatability of sulfides at the
normal process pH. Calcium activated nickel and copper
sulfides, and increased xanthate adsorption on the sulfides.
On the other hand, the thiosulfate reduced the effect of
hydrophilic compounds on sulfide particles, improving
their flotation. Additionally, Boujounoui et al. (2015) car-
ried out a preliminary study on the effect of water quality
on the flotation of galena, sphalerite, chalcopyrite, and pyr-
rhotite using asymmetrical fractional factorial design. This
study identified five ions (Cu2+, Zn2+, Mg2+, Ca2+, SO42–)
that have a significant influence on the flotation of these
sulfide minerals. Then, Manono et al. (2016) investigated
the effect of typical electrolytes present in process water
(e.g., sodium, calcium, magnesium, NO3–, SO42–) on the
flotation of a Merensky ore. The results suggested that the
influence of ion type depends on its ability to enhance or
retard gangue activation.
More recently, Le et al. (2020a) analyzed the major
issues encountered when performing sampling for physi-
cochemical and chemical parameters in process water.
These results show that microorganisms were abundant in
process waters and likely affect the mining water chemis-
try. In addition, Corin et al. (2024) studied the effect of
specific ions and temperature on the separation of gangue
from valuable minerals in batch flotation of a low-grade
Cu-Ni-PGE ore. Water and solids recoveries were impacted
by Ca2+ and SO42–. An increase in SO42– alone caused
an increase in copper recovery whilst decreasing the cop-
per grade. Additionally, nickel was more temperature sen-
sitive in comparison to copper. The study demonstrated
that there are specific ion concentration ranges beyond
which flotation performance was adversely affected. The
higher ionic concentrations and their corresponding ionic
strengths resulted in a more stable froth and consequently
an improvement in recoveries.
Particularly, several studies have been conducted to
investigate the effect of saline water on mineral flotation.
Wang and Peng (2014) observed an increased mineral flota-
tion in saline water, primarily on coal flotation, but results
are contradictory in some circumstances. Hirajima et al.
(2016) developed a fundamental study of the effect of two
divalent cations in seawater, Mg2+ and Ca2+, on the float-
ability of chalcopyrite and molybdenite. The results showed
that both MgCl2 and CaCl2 solutions depress the floatabil-
ity of chalcopyrite and molybdenite at pH values higher
than 9.
On the other hand, it has been observed that the min-
erals can be partially dissolved during the concentration
process, increasing the ionic strength of the process water.
Therefore, the water system in a plant can reach an equi-
librium depending on the makeup water quality and the
feed mineral characteristics. Changes in the makeup water
quality will affect the process water either by diluting or
enhancing the final ionic strength, in addition to the effect
of the mineral dissolution. Thus, the minerals recovery by
flotation will depend on the mineral characteristics and
the process water quality. Dzingai et al. (2020) developed
a study to simulate the effect of the water recirculation
on flotation by ion-spiking, specifically Ca2+, and Mg2+.
Dzingai et al. (2021) evaluated the effect of water recycling
on flotation, using the same technique, for a low-grade
Cu–Ni–PGM ore, where the effect of NO3−, SO42− and
S2O32−, was analysed.
Le et al. (2020b) showed an experimental methodol-
ogy to predict water changes in mineral processing plants
operating with closed water circulation (Dissolution Tests),
chasing three main objectives: (1) predicting the tendency
of the accumulation of elements and compounds into the
process water during comminution, flotation, and storage
in tailings facilities (2) establishing a relationship between
laboratory results and plant historical water quality data
and (3) predicting the potential effect of recycling water on
flotation performance. The results showed a good correla-
tion between the water matrix of the actual process water
INTRODUCTION
The process water quality is a key component in the
industrial flotation process and a large water consump-
tion is required to process the huge mineral treatments.
Commonly, the concentrator plants recover and recycle
the process water, which is about 80% of the process water
(Moraga, 2023). Therefore, the complementary 20% is the
fresh make up water, normally from underground sources.
However, due to environmental constraints, including the
shortage of the freshwater resources, the flotation plants
have started replacing underground water by seawater or
desalinated water. The change in makeup water quality
will change the process water, which can have a signifi-
cant effect on metallurgical performance (Liu et al., 2013).
Additionally, concentrators plants have had the need to
reduce water consumption. Gunson et al. (2012) identified
mine water reduction, reuse and recycle options: evapora-
tion reduction strategies, paste tailings disposal, filtered
tailings disposal, ore pre-sorting and a combination of the
most effective options. A key result of the study was that a
combination of ore preconcentration and filtered tailings
disposal could reduce water consumption by 74% or more.
Several studies have analyzed the effect of water qual-
ity on metallurgical performance of minerals. For example,
Kirjavainen et al. (2002) studied the effect of calcium and
thiosulfate ions on flotation of a Ni–Cu ore. It was observed
that the ions improved the floatability of sulfides at the
normal process pH. Calcium activated nickel and copper
sulfides, and increased xanthate adsorption on the sulfides.
On the other hand, the thiosulfate reduced the effect of
hydrophilic compounds on sulfide particles, improving
their flotation. Additionally, Boujounoui et al. (2015) car-
ried out a preliminary study on the effect of water quality
on the flotation of galena, sphalerite, chalcopyrite, and pyr-
rhotite using asymmetrical fractional factorial design. This
study identified five ions (Cu2+, Zn2+, Mg2+, Ca2+, SO42–)
that have a significant influence on the flotation of these
sulfide minerals. Then, Manono et al. (2016) investigated
the effect of typical electrolytes present in process water
(e.g., sodium, calcium, magnesium, NO3–, SO42–) on the
flotation of a Merensky ore. The results suggested that the
influence of ion type depends on its ability to enhance or
retard gangue activation.
More recently, Le et al. (2020a) analyzed the major
issues encountered when performing sampling for physi-
cochemical and chemical parameters in process water.
These results show that microorganisms were abundant in
process waters and likely affect the mining water chemis-
try. In addition, Corin et al. (2024) studied the effect of
specific ions and temperature on the separation of gangue
from valuable minerals in batch flotation of a low-grade
Cu-Ni-PGE ore. Water and solids recoveries were impacted
by Ca2+ and SO42–. An increase in SO42– alone caused
an increase in copper recovery whilst decreasing the cop-
per grade. Additionally, nickel was more temperature sen-
sitive in comparison to copper. The study demonstrated
that there are specific ion concentration ranges beyond
which flotation performance was adversely affected. The
higher ionic concentrations and their corresponding ionic
strengths resulted in a more stable froth and consequently
an improvement in recoveries.
Particularly, several studies have been conducted to
investigate the effect of saline water on mineral flotation.
Wang and Peng (2014) observed an increased mineral flota-
tion in saline water, primarily on coal flotation, but results
are contradictory in some circumstances. Hirajima et al.
(2016) developed a fundamental study of the effect of two
divalent cations in seawater, Mg2+ and Ca2+, on the float-
ability of chalcopyrite and molybdenite. The results showed
that both MgCl2 and CaCl2 solutions depress the floatabil-
ity of chalcopyrite and molybdenite at pH values higher
than 9.
On the other hand, it has been observed that the min-
erals can be partially dissolved during the concentration
process, increasing the ionic strength of the process water.
Therefore, the water system in a plant can reach an equi-
librium depending on the makeup water quality and the
feed mineral characteristics. Changes in the makeup water
quality will affect the process water either by diluting or
enhancing the final ionic strength, in addition to the effect
of the mineral dissolution. Thus, the minerals recovery by
flotation will depend on the mineral characteristics and
the process water quality. Dzingai et al. (2020) developed
a study to simulate the effect of the water recirculation
on flotation by ion-spiking, specifically Ca2+, and Mg2+.
Dzingai et al. (2021) evaluated the effect of water recycling
on flotation, using the same technique, for a low-grade
Cu–Ni–PGM ore, where the effect of NO3−, SO42− and
S2O32−, was analysed.
Le et al. (2020b) showed an experimental methodol-
ogy to predict water changes in mineral processing plants
operating with closed water circulation (Dissolution Tests),
chasing three main objectives: (1) predicting the tendency
of the accumulation of elements and compounds into the
process water during comminution, flotation, and storage
in tailings facilities (2) establishing a relationship between
laboratory results and plant historical water quality data
and (3) predicting the potential effect of recycling water on
flotation performance. The results showed a good correla-
tion between the water matrix of the actual process water