XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1301
applications in the EU and the United States for the 2022–
2023 period, based on reports by the European Commission
and USGS (USGS, 2023). Strontium compounds were
majorly used in drilling fluids in the US (65%) and mini-
mally in the EU (less than 1%). The EU reported higher
shares in applications like magnets and pyrotechnics (40%
each) compared to the US (13% each). Additional small
shares were distributed across applications such as master
alloys, zinc production, and pigments.
Strontium—a Critical Raw Material for the
European Union
The European Commission published the first list of Critical
Raw Materials (CRMs) in 2011. The first list consisted of
14 raw materials considered essential for the advancement
of key emerging technologies in Europe, such as battery
technology, solar panels, permanent magnets, and other
clean technologies (Massari &Ruberti, 2013). Since then,
the list of CRMs has been updated at three-year intervals in
2014, 2017, 2020, and 2023.
The list of CRMs is created based on two main param-
eters, i.e., Supply Risks (SR) and Economic Importance
(EI) of the raw material for the whole European Union’s
(EU) economy. The SR parameter assesses the potential risk
of a disruption in the supply of the material within the EU
(European Commission, 2017). The EI parameter provides
insights into a material’s significance to the EU economy,
considering its utilization in end-use applications and the
value it adds to the relevant manufacturing sectors within
the EU. The thresholds for the parameter remain at SR ≥
1.0 and EI ≥ 2.8, and any raw material which reaches or
exceeds these thresholds is categorised as a CRM.
Strontium was recognised as a critical raw material for
the first time in 2020. The latest report from 2023 con-
sists of 32 critical raw materials, among which strontium
remains included, with an EI of 2.6 and an SR of 6.5.
The creation of the list has incentivised investment into
the production of CRMs both within the EU and abroad
(European Commission, 2023).
BENEFICIATION OF STRONTIUM
MINERALS
The mineral processing techniques used for the ben-
eficiation of strontium-bearing minerals depend on the
properties of each ore deposit, as several techniques have
been employed. In the case of celestine—the most com-
mon strontium mineral—most operations have histori-
cally exploited coarse-rich ores that could be enriched by
hand picking, achieving grades over 90% of SrSO4 (Ariza-
Rodríguez et al., 2022 MacMillan et al., 2000). In those
kinds of operations, celestine ore extraction commonly
begins with the removal of overburden, followed by the
digging of a shallow pit from which the ore is extracted.
The Run of Mine (RoM) ore is later subjected to crushing
and sizing operations followed by hand-picking samples
based on colour, size and weight (Ariza-Rodríguez et al.,
2022 Bulatovic, 2015 Castillejos et al., 1996).
Nowadays, several other mineral processing techniques
are used to separate the celestine from the gangue—typi-
cally calcite (El-Midany &Ibrahim, 2011), limonite and
clay (Bulatovic, 2015). The beneficiation process aims to
obtain a concentrate of celestine with the required grade—
commonly over 90% (Castillejos et al., 1996 Selim et al.,
2010)—to manufacture compounds of strontium. Ariza-
Rodríguez et al. (2022) demonstrated that low to medium-
grade celestine mineral (about 60% celestine), which used
to be considered uneconomical in hand-sorting operations
and accumulated in dumps and mine tailings, can be con-
centrated through grinding and size separation. The coarser
fractions (5 mm) have a greater concentration of celestine
(up to 12 percent units more) due to the selective loss of
calcite and other minerals (quartz, clays, and iron oxides).
This process, however, cannot be applied to high-grade
minerals (about 90% celestine) as there is no additional
increase in the concentration of celestine.
In another study, however, El-Midany et al. (2011)
highlighted the limitations in the separation of celestine
from calcite using attrition scrubbing, a method that is
essentially based on size separation and is widely used for
soil washing. Based on the difference in the hardness and
friability between celestine and calcite, the authors expected
calcite to be collected in the fine fraction. However, their
results showed that calcite was present both in the fine and
coarse fractions due to interlocking, lack of liberation at
coarser sizes, and therefore required fine grinding.
Another separation technique used in the concentra-
tion of celestine is gravitational separation. Selim et al.
(2010) studied the use of jigs for coarse size (–15 +2 mm)
and shaking tables for finer size (–0.5 +0.08 mm) celes-
tine concentration, defining optimal operating conditions
by varying pulp density, stroke length, water flow rate, and
table slope. The use of a Falcon concentrator was studied
by El-Midany &Ibrahim (2011) to process fine celes-
tine ore (80 μm), finding that the calcite content plays
a significant role, especially at low centrifugal speed and
fluidization water pressure where the best results can be
achieved. Gravitational separation using jigs and tables can
also be used as a pre-concentration method before mov-
ing to other techniques such as flotation (Bulatovic, 2015).
Another gravity separation equipment used in celestine
applications in the EU and the United States for the 2022–
2023 period, based on reports by the European Commission
and USGS (USGS, 2023). Strontium compounds were
majorly used in drilling fluids in the US (65%) and mini-
mally in the EU (less than 1%). The EU reported higher
shares in applications like magnets and pyrotechnics (40%
each) compared to the US (13% each). Additional small
shares were distributed across applications such as master
alloys, zinc production, and pigments.
Strontium—a Critical Raw Material for the
European Union
The European Commission published the first list of Critical
Raw Materials (CRMs) in 2011. The first list consisted of
14 raw materials considered essential for the advancement
of key emerging technologies in Europe, such as battery
technology, solar panels, permanent magnets, and other
clean technologies (Massari &Ruberti, 2013). Since then,
the list of CRMs has been updated at three-year intervals in
2014, 2017, 2020, and 2023.
The list of CRMs is created based on two main param-
eters, i.e., Supply Risks (SR) and Economic Importance
(EI) of the raw material for the whole European Union’s
(EU) economy. The SR parameter assesses the potential risk
of a disruption in the supply of the material within the EU
(European Commission, 2017). The EI parameter provides
insights into a material’s significance to the EU economy,
considering its utilization in end-use applications and the
value it adds to the relevant manufacturing sectors within
the EU. The thresholds for the parameter remain at SR ≥
1.0 and EI ≥ 2.8, and any raw material which reaches or
exceeds these thresholds is categorised as a CRM.
Strontium was recognised as a critical raw material for
the first time in 2020. The latest report from 2023 con-
sists of 32 critical raw materials, among which strontium
remains included, with an EI of 2.6 and an SR of 6.5.
The creation of the list has incentivised investment into
the production of CRMs both within the EU and abroad
(European Commission, 2023).
BENEFICIATION OF STRONTIUM
MINERALS
The mineral processing techniques used for the ben-
eficiation of strontium-bearing minerals depend on the
properties of each ore deposit, as several techniques have
been employed. In the case of celestine—the most com-
mon strontium mineral—most operations have histori-
cally exploited coarse-rich ores that could be enriched by
hand picking, achieving grades over 90% of SrSO4 (Ariza-
Rodríguez et al., 2022 MacMillan et al., 2000). In those
kinds of operations, celestine ore extraction commonly
begins with the removal of overburden, followed by the
digging of a shallow pit from which the ore is extracted.
The Run of Mine (RoM) ore is later subjected to crushing
and sizing operations followed by hand-picking samples
based on colour, size and weight (Ariza-Rodríguez et al.,
2022 Bulatovic, 2015 Castillejos et al., 1996).
Nowadays, several other mineral processing techniques
are used to separate the celestine from the gangue—typi-
cally calcite (El-Midany &Ibrahim, 2011), limonite and
clay (Bulatovic, 2015). The beneficiation process aims to
obtain a concentrate of celestine with the required grade—
commonly over 90% (Castillejos et al., 1996 Selim et al.,
2010)—to manufacture compounds of strontium. Ariza-
Rodríguez et al. (2022) demonstrated that low to medium-
grade celestine mineral (about 60% celestine), which used
to be considered uneconomical in hand-sorting operations
and accumulated in dumps and mine tailings, can be con-
centrated through grinding and size separation. The coarser
fractions (5 mm) have a greater concentration of celestine
(up to 12 percent units more) due to the selective loss of
calcite and other minerals (quartz, clays, and iron oxides).
This process, however, cannot be applied to high-grade
minerals (about 90% celestine) as there is no additional
increase in the concentration of celestine.
In another study, however, El-Midany et al. (2011)
highlighted the limitations in the separation of celestine
from calcite using attrition scrubbing, a method that is
essentially based on size separation and is widely used for
soil washing. Based on the difference in the hardness and
friability between celestine and calcite, the authors expected
calcite to be collected in the fine fraction. However, their
results showed that calcite was present both in the fine and
coarse fractions due to interlocking, lack of liberation at
coarser sizes, and therefore required fine grinding.
Another separation technique used in the concentra-
tion of celestine is gravitational separation. Selim et al.
(2010) studied the use of jigs for coarse size (–15 +2 mm)
and shaking tables for finer size (–0.5 +0.08 mm) celes-
tine concentration, defining optimal operating conditions
by varying pulp density, stroke length, water flow rate, and
table slope. The use of a Falcon concentrator was studied
by El-Midany &Ibrahim (2011) to process fine celes-
tine ore (80 μm), finding that the calcite content plays
a significant role, especially at low centrifugal speed and
fluidization water pressure where the best results can be
achieved. Gravitational separation using jigs and tables can
also be used as a pre-concentration method before mov-
ing to other techniques such as flotation (Bulatovic, 2015).
Another gravity separation equipment used in celestine