2639
Beneficiation of Limestone: Synergy Between
Sorting and Flotation
de Amores, I., Seiler, S., Tomey, E., Sánchez, G.
Departamento Ingeniería de Materiales y Minas, Facultad de Ingeniería, Universidad de la República, Uruguay
ABSTRACT: Limestone exhibits extensive industrial applications owing to its versatility in serving diverse
compositional requirements. While cement production dominates its consumption, the economic potential of
limestone relies on its calcite content, particularly for high-value, grade-sensitive industries like lime and pulp
production. Unlocking the full potential of limestone necessitates efficient beneficiation strategies that bridge
the gap between abundant resource and high-grade demands. Froth flotation, despite its effectiveness in calcite
enrichment, suffers from two key shortcomings: the high energy demands of fine grinding, and the generation
of substantial wet tailings, raising environmental concerns and necessitating additional processing steps. In this
work, the effect of implementing a preconcentration step before the direct flotation of calcite is evaluated in a
limestone sample. A comparison is presented between the flotation performance with and without particle sorting
as a preconcentrating step. Laboratory experiments were performed using a representative sample from Queguay
Formation limestone in Uruguay. Implementation of sensor-based sorting prior to froth flotation resulted in a
concentrate that meets the specifications for lime and pulp plants feedstock. This combined approach offers the
potential for minimized wet tailing generation through selective mineral recovery and reduced grinding costs
due to pre-concentration of the target mineral. This innovative approach offers a promising sustainable and
cost-effective alternative for limestone beneficiation process.
INTRODUCTION
Limestone, a sedimentary rock abundantly found in
Uruguay, is primarily composed of the mineral calcite.
This versatile resource serves as the main feedstock in
the cement production, but it holds substantial potential
beyond its established role in the local cement industry
(Cernuschi, 2014). For example, cellulose production has
become increasingly important in the country in recent
years, and it also demands limestone as feedstock, which
is currently sourced from international markets. Pulp
mills demands significantly higher purity on limestone to
ensure the causticizing process efficiency (Ribeiro, Santos,
&Tran, 2007 Ulmgren, 1997). The Queguay Formation,
located in the northwest zone of the country, features a
non-metamorphosed limestone that contains silica inclu-
sions in the form of quartz. The presence of quartz, repre-
senting more than 15% by mass of the rock, limits its direct
application in more demanding industries such as pulp
plants. With the aim of expanding these potential applica-
tions of limestone from Queguay Formation, the authors
of this work have conducted previous studies focused on
independent applications of froth flotation and sensor-
based sorting (de Amores, Seiler, Tomey, &Sánchez, 2023
Tomey, Seiler, de Amores, &Sánchez, 2023). However,
these individual strategies encountered operational or per-
formance constraints, prompting the exploration of alter-
native or combined approaches.
Sensor-based sorting (SBS) is a real-time dry process-
ing technique employed in the mineral processing industry.
Beneficiation of Limestone: Synergy Between
Sorting and Flotation
de Amores, I., Seiler, S., Tomey, E., Sánchez, G.
Departamento Ingeniería de Materiales y Minas, Facultad de Ingeniería, Universidad de la República, Uruguay
ABSTRACT: Limestone exhibits extensive industrial applications owing to its versatility in serving diverse
compositional requirements. While cement production dominates its consumption, the economic potential of
limestone relies on its calcite content, particularly for high-value, grade-sensitive industries like lime and pulp
production. Unlocking the full potential of limestone necessitates efficient beneficiation strategies that bridge
the gap between abundant resource and high-grade demands. Froth flotation, despite its effectiveness in calcite
enrichment, suffers from two key shortcomings: the high energy demands of fine grinding, and the generation
of substantial wet tailings, raising environmental concerns and necessitating additional processing steps. In this
work, the effect of implementing a preconcentration step before the direct flotation of calcite is evaluated in a
limestone sample. A comparison is presented between the flotation performance with and without particle sorting
as a preconcentrating step. Laboratory experiments were performed using a representative sample from Queguay
Formation limestone in Uruguay. Implementation of sensor-based sorting prior to froth flotation resulted in a
concentrate that meets the specifications for lime and pulp plants feedstock. This combined approach offers the
potential for minimized wet tailing generation through selective mineral recovery and reduced grinding costs
due to pre-concentration of the target mineral. This innovative approach offers a promising sustainable and
cost-effective alternative for limestone beneficiation process.
INTRODUCTION
Limestone, a sedimentary rock abundantly found in
Uruguay, is primarily composed of the mineral calcite.
This versatile resource serves as the main feedstock in
the cement production, but it holds substantial potential
beyond its established role in the local cement industry
(Cernuschi, 2014). For example, cellulose production has
become increasingly important in the country in recent
years, and it also demands limestone as feedstock, which
is currently sourced from international markets. Pulp
mills demands significantly higher purity on limestone to
ensure the causticizing process efficiency (Ribeiro, Santos,
&Tran, 2007 Ulmgren, 1997). The Queguay Formation,
located in the northwest zone of the country, features a
non-metamorphosed limestone that contains silica inclu-
sions in the form of quartz. The presence of quartz, repre-
senting more than 15% by mass of the rock, limits its direct
application in more demanding industries such as pulp
plants. With the aim of expanding these potential applica-
tions of limestone from Queguay Formation, the authors
of this work have conducted previous studies focused on
independent applications of froth flotation and sensor-
based sorting (de Amores, Seiler, Tomey, &Sánchez, 2023
Tomey, Seiler, de Amores, &Sánchez, 2023). However,
these individual strategies encountered operational or per-
formance constraints, prompting the exploration of alter-
native or combined approaches.
Sensor-based sorting (SBS) is a real-time dry process-
ing technique employed in the mineral processing industry.