3518 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Scenario 2: LIMS, Sulphide Flotation, Gravity
Separation, and Leaching
Grinding for Sulphides Flotation
Similar to Scenario 1, a 1-kg test charge was ground under
specified conditions to 80% passing 156 micrometers for
subsequent magnetic separation and flotation.
Low Intensity Magnetic Separation (LIMS)
The pulp was subjected to LIMS using three distinct mag-
netic field strengths: 540, 1020, and 1650 Gauss. The non-
magnetic portion was used for sulphide flotation, and the
magnetic portion was analyzed chemically.
Rougher Flotation of Iron Sulphides
In test condition CTOP-4, the non-magnetic fraction
underwent rougher flotation in a 4-litre cell. Reagents were
added after conditioning, with specific intervals for concen-
trate collection. The specific operational details and dosages
of reagents used during the flotation process under Test
Condition CTOP-4 are summarized in Table 6.
Falcon Concentrator
Post-flotation, tailings were processed in a Falcon concen-
trator to recover tungsten, demonstrating the integrated
approach in scenario 2.
Leaching
Following gravity separation using the Falcon concentrator,
the separated concentrate was dried and then mixed in a
V-Blender. This blended gravity separation concentrate was
then split into two 100-gram charges. One charge under-
went atmospheric leaching in a 1-L water-jacketed baffled
reactor equipped with an overhead stirrer at a 20% solid
pulp density. The other charge was subjected to mechano-
chemical leaching in an in-house made Eibenstock HER
32/2.3 P stirred vertical mill, lined with Teflon and utiliz-
ing Burundum cylindrical grinding media, with the mill
operating at 67% solids. Both leaching processes employed
sodium hydroxide (NaOH) as the lixiviant. At the end of
the leaching process, the contents were filtered, and the
pregnant leach solution (PLS) was collected for further
analysis. Residues were washed and also collected for com-
prehensive analysis using the ICP method to determine the
tungsten extraction level and perform a mass balance.
Design of Experiments
Building on the findings from our initial assessment of
sulphide content in the Cantung tailings, we proceeded
to further refine our approach for sulphide removal using
flotation technique. Following the completion of screening
experiments that initially identified key variables affecting
sulphide removal using flotation, a Design of Experiments
(DOE) was conducted. The primary goal of this DOE was
to identify the optimal conditions for recovering sulphides
from the Cantung tailings. We aimed to maximize sulphur
recovery to the concentrate while simultaneously minimiz-
ing the mass pull to the concentrate and reducing the sul-
phur grade of the tailings. The specific variables chosen for
the DOE included the concentrations of SIPX (Sodium
Isopropyl Xanthate), Aero 6493, and SHMP (Sodium
Hexametaphosphate). Selected variables in the experiment
were based on their significant impacts during the scoping
stage.
RESULTS
Figure 1 shows the copper grade versus copper recovery for
Tests F6 and F7. The copper recovery for both tests was
approximately 90%. The copper grade for Test F6 was
approximately 0.49% and about 0.40% for Test F7 the
highest copper upgrade ratio in the first stage of cleaning
was about 2.5.
Figure 2 illustrates the iron recovery versus copper
recovery. Test F7 resulted in higher iron recovery than
that of Test F6. This explains the lower copper grade in
Table 6. Operational details and reagent dosages for test condition CTOP-4
Parameter Details
Cell Volume 4-litre
Conditioning Speed 1800 rpm
Conditioning Duration 10 minutes
pH Adjustment Sodium hydroxide diluted to 5%, pH adjusted to 8
Flotation Concentrate Collection Times (minutes) 3.5, 4.5, 3.5, 3.5
Sodium Hexametaphosphate 162 g/t per concentrate, total 648 g/t, 5% dilution, conditioned for 3 minutes
Copper Sulphate 100 g/t, 5% dilution, conditioned for 5 minutes
Sodium Isopropyl 98 g/t per concentrate, total 392 g/t
Aero 6493 (Solvay) 54 g/t per concentrate, total 216 g/t, each addition conditioned for 1 minute
Aerofroth 65 (Solvay) 7.5 g/t for the first and third concentrates, total 15 g/t
Scenario 2: LIMS, Sulphide Flotation, Gravity
Separation, and Leaching
Grinding for Sulphides Flotation
Similar to Scenario 1, a 1-kg test charge was ground under
specified conditions to 80% passing 156 micrometers for
subsequent magnetic separation and flotation.
Low Intensity Magnetic Separation (LIMS)
The pulp was subjected to LIMS using three distinct mag-
netic field strengths: 540, 1020, and 1650 Gauss. The non-
magnetic portion was used for sulphide flotation, and the
magnetic portion was analyzed chemically.
Rougher Flotation of Iron Sulphides
In test condition CTOP-4, the non-magnetic fraction
underwent rougher flotation in a 4-litre cell. Reagents were
added after conditioning, with specific intervals for concen-
trate collection. The specific operational details and dosages
of reagents used during the flotation process under Test
Condition CTOP-4 are summarized in Table 6.
Falcon Concentrator
Post-flotation, tailings were processed in a Falcon concen-
trator to recover tungsten, demonstrating the integrated
approach in scenario 2.
Leaching
Following gravity separation using the Falcon concentrator,
the separated concentrate was dried and then mixed in a
V-Blender. This blended gravity separation concentrate was
then split into two 100-gram charges. One charge under-
went atmospheric leaching in a 1-L water-jacketed baffled
reactor equipped with an overhead stirrer at a 20% solid
pulp density. The other charge was subjected to mechano-
chemical leaching in an in-house made Eibenstock HER
32/2.3 P stirred vertical mill, lined with Teflon and utiliz-
ing Burundum cylindrical grinding media, with the mill
operating at 67% solids. Both leaching processes employed
sodium hydroxide (NaOH) as the lixiviant. At the end of
the leaching process, the contents were filtered, and the
pregnant leach solution (PLS) was collected for further
analysis. Residues were washed and also collected for com-
prehensive analysis using the ICP method to determine the
tungsten extraction level and perform a mass balance.
Design of Experiments
Building on the findings from our initial assessment of
sulphide content in the Cantung tailings, we proceeded
to further refine our approach for sulphide removal using
flotation technique. Following the completion of screening
experiments that initially identified key variables affecting
sulphide removal using flotation, a Design of Experiments
(DOE) was conducted. The primary goal of this DOE was
to identify the optimal conditions for recovering sulphides
from the Cantung tailings. We aimed to maximize sulphur
recovery to the concentrate while simultaneously minimiz-
ing the mass pull to the concentrate and reducing the sul-
phur grade of the tailings. The specific variables chosen for
the DOE included the concentrations of SIPX (Sodium
Isopropyl Xanthate), Aero 6493, and SHMP (Sodium
Hexametaphosphate). Selected variables in the experiment
were based on their significant impacts during the scoping
stage.
RESULTS
Figure 1 shows the copper grade versus copper recovery for
Tests F6 and F7. The copper recovery for both tests was
approximately 90%. The copper grade for Test F6 was
approximately 0.49% and about 0.40% for Test F7 the
highest copper upgrade ratio in the first stage of cleaning
was about 2.5.
Figure 2 illustrates the iron recovery versus copper
recovery. Test F7 resulted in higher iron recovery than
that of Test F6. This explains the lower copper grade in
Table 6. Operational details and reagent dosages for test condition CTOP-4
Parameter Details
Cell Volume 4-litre
Conditioning Speed 1800 rpm
Conditioning Duration 10 minutes
pH Adjustment Sodium hydroxide diluted to 5%, pH adjusted to 8
Flotation Concentrate Collection Times (minutes) 3.5, 4.5, 3.5, 3.5
Sodium Hexametaphosphate 162 g/t per concentrate, total 648 g/t, 5% dilution, conditioned for 3 minutes
Copper Sulphate 100 g/t, 5% dilution, conditioned for 5 minutes
Sodium Isopropyl 98 g/t per concentrate, total 392 g/t
Aero 6493 (Solvay) 54 g/t per concentrate, total 216 g/t, each addition conditioned for 1 minute
Aerofroth 65 (Solvay) 7.5 g/t for the first and third concentrates, total 15 g/t
