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Implications of Water Quality Variations on the Performance of
Rare Earth Mineral Flotation
B. Tadesse ,M. Jung, B. Albijanic, L. Dyer
Western Australian School of Mines, Curtin University, Kalgoorlie, WA, Australia
ABSTRACT: The presence of high concentrations of dissolved ions in groundwater, sea water or recycled
water may alter the water structure, particle surface wettability and colloidal interactions between bubbles
and particles, and can have a significant effect on mineral flotation. While the impact of water quality on the
flotation of precious and base metal minerals is well established, published studies regarding the effect of water
salinity on the flotation of rare earth bearing minerals are scant. This study attempts to quantify the effect
of water quality variation on flotation recovery and grade of rare earth minerals (e.g., monazite) and gain an
understanding on which ions existing in saline water affect flotation behaviour. The results showed that the
presence of certain ions led to significant depression of monazite flotation.
Keywords: Rare earth minerals, monazite, flotation, water quality
INTRODUCTION
Freshwater shortage, increasing competition for water
among multiple users, cost of purification and corporate
sustainability goals are the main factors driving the miner-
als industry to focus on water quality and usage. Increasing
water re-use and accessing alternative sources to freshwater
for mineral processing, particularly in flotation, are poten-
tial strategies being implemented to improve water effi-
ciency. In flotation, a reasonable water quality is needed
to develop an appropriate reagent scheme and optimize
operating conditions to maximise performance. High con-
centrations of dissolved ions in groundwater, sea water or
recycle water may alter the water structure, particle surface
wettability and colloidal interactions between bubbles and
particles (Wang and Pend, 2014), and therefore may have a
positive or negative effect on mineral flotation.
Several mine sites have introduced the use of saline
water in their mineral processing operations. Base metal
sulphide flotation plants at Mt Keith, Leinster and the
Kambalda Nickel Concentrator in Western Australia use
bore water with high ionic strength (Peng and Seaman,
2011). In Australia, bore water is accessed by drilling a
bore into underground aquifers and pumping to the sur-
face. Saline or sea water is also used in many other flota-
tion plants worldwide including copper plants in Chile
(Moreno et al., 2011), gold-rich copper ore processing
plants in Indonesia (Castro, 2012), and precious and base
metal sulphides flotation in South Africa (Corin et al.,
2011 Wiese et al., 2007).
The importance of water quality in flotation is being
increasingly recognised. There is a general agreement that
saline water enhances the flotation of gold and base metal
containing minerals. Although the mechanisms by which
saline water promotes flotation is not clear, destabilisation
of hydration layers surrounding the particles, inhibition of
bubble coalescence, and the compression of the electrical
double layer around particles have been proposed to explain
the increased mineral flotation in saline water (Wang and
Implications of Water Quality Variations on the Performance of
Rare Earth Mineral Flotation
B. Tadesse ,M. Jung, B. Albijanic, L. Dyer
Western Australian School of Mines, Curtin University, Kalgoorlie, WA, Australia
ABSTRACT: The presence of high concentrations of dissolved ions in groundwater, sea water or recycled
water may alter the water structure, particle surface wettability and colloidal interactions between bubbles
and particles, and can have a significant effect on mineral flotation. While the impact of water quality on the
flotation of precious and base metal minerals is well established, published studies regarding the effect of water
salinity on the flotation of rare earth bearing minerals are scant. This study attempts to quantify the effect
of water quality variation on flotation recovery and grade of rare earth minerals (e.g., monazite) and gain an
understanding on which ions existing in saline water affect flotation behaviour. The results showed that the
presence of certain ions led to significant depression of monazite flotation.
Keywords: Rare earth minerals, monazite, flotation, water quality
INTRODUCTION
Freshwater shortage, increasing competition for water
among multiple users, cost of purification and corporate
sustainability goals are the main factors driving the miner-
als industry to focus on water quality and usage. Increasing
water re-use and accessing alternative sources to freshwater
for mineral processing, particularly in flotation, are poten-
tial strategies being implemented to improve water effi-
ciency. In flotation, a reasonable water quality is needed
to develop an appropriate reagent scheme and optimize
operating conditions to maximise performance. High con-
centrations of dissolved ions in groundwater, sea water or
recycle water may alter the water structure, particle surface
wettability and colloidal interactions between bubbles and
particles (Wang and Pend, 2014), and therefore may have a
positive or negative effect on mineral flotation.
Several mine sites have introduced the use of saline
water in their mineral processing operations. Base metal
sulphide flotation plants at Mt Keith, Leinster and the
Kambalda Nickel Concentrator in Western Australia use
bore water with high ionic strength (Peng and Seaman,
2011). In Australia, bore water is accessed by drilling a
bore into underground aquifers and pumping to the sur-
face. Saline or sea water is also used in many other flota-
tion plants worldwide including copper plants in Chile
(Moreno et al., 2011), gold-rich copper ore processing
plants in Indonesia (Castro, 2012), and precious and base
metal sulphides flotation in South Africa (Corin et al.,
2011 Wiese et al., 2007).
The importance of water quality in flotation is being
increasingly recognised. There is a general agreement that
saline water enhances the flotation of gold and base metal
containing minerals. Although the mechanisms by which
saline water promotes flotation is not clear, destabilisation
of hydration layers surrounding the particles, inhibition of
bubble coalescence, and the compression of the electrical
double layer around particles have been proposed to explain
the increased mineral flotation in saline water (Wang and
