XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2645
These strategies aim to produce a high-value, small-volume
byproduct alongside a cement-grade bulk material, mini-
mizing resource utilization and enhancing overall market
potential.
The first considered alternative is to beneficiate the
limestone by a traditional rougher-cleaner froth flotation
circuit with regrinding of the rougher concentrate (results
reported in Table 4). In this alternative, a final concentrate
with a calcite grade of 93.8% is produced, representing
30.4% of the material fed to the circuit. This final concen-
trate has the potential to be used in lime and pulp plants.
The main drawback of this circuit is that two wet tailing
streams are generated, representing 69.6% of the material.
While combined, their calcite grade (69.3%) may meet
cement production standards, the high drying costs render
them economically unattractive, ultimately inflating tail-
ings management costs and undermining resource utiliza-
tion. In this alternative, 2.3 tons of solids are discarded as
tailings per ton of high-grade final product generated.
The second alternative consists of a pre-concentration
step using SBS followed by just one rougher stage of flota-
tion of the SBS concentrate to generate a final product with
similar characteristic to the one obtained in the first alter-
native. As shown in Figure 5 a screening stage is required
to generate narrow size fractions for SBS, and removing
the fines which cannot be processed in SBS. The undersize
Figure 5. Flowsheets proposed for the processing of limestone. A) Rougher and cleaner froth flotation in two stages of
grinding. B) Screening and SBS followed by froth flotation
These strategies aim to produce a high-value, small-volume
byproduct alongside a cement-grade bulk material, mini-
mizing resource utilization and enhancing overall market
potential.
The first considered alternative is to beneficiate the
limestone by a traditional rougher-cleaner froth flotation
circuit with regrinding of the rougher concentrate (results
reported in Table 4). In this alternative, a final concentrate
with a calcite grade of 93.8% is produced, representing
30.4% of the material fed to the circuit. This final concen-
trate has the potential to be used in lime and pulp plants.
The main drawback of this circuit is that two wet tailing
streams are generated, representing 69.6% of the material.
While combined, their calcite grade (69.3%) may meet
cement production standards, the high drying costs render
them economically unattractive, ultimately inflating tail-
ings management costs and undermining resource utiliza-
tion. In this alternative, 2.3 tons of solids are discarded as
tailings per ton of high-grade final product generated.
The second alternative consists of a pre-concentration
step using SBS followed by just one rougher stage of flota-
tion of the SBS concentrate to generate a final product with
similar characteristic to the one obtained in the first alter-
native. As shown in Figure 5 a screening stage is required
to generate narrow size fractions for SBS, and removing
the fines which cannot be processed in SBS. The undersize
Figure 5. Flowsheets proposed for the processing of limestone. A) Rougher and cleaner froth flotation in two stages of
grinding. B) Screening and SBS followed by froth flotation