3020 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
given in Table 3. EDTA_Cu is mainly used for assessment
of surface oxidation of the copper minerals and presence
of secondary copper minerals. EDTA_Cu of enriched ore
was considerably higher than that of the sulfide ore sample,
indicating presence of higher amount of secondary copper
minerals and higher degree of surface oxidation. The other
sulfide minerals, i.e., pyrite, galena and sphalerite in the
enriched ore sample also have a higher degree of surface
oxidation.
Column Leach Tests
The column leach tests were conducted in a small-scale col-
umn using 5.5 kg ore sample of p100=19 mm particle size.
Agglomeration was applied using 12 kg/t cement in the C4
and C6 tests, 5 kg/t in C8 tests. The Test C7 was performed
without agglomeration, but lime addition to adjust the
pH=11. The initial cyanide concentration was adjusted to
2000 ppm and maintained during the tests. Samples from
the leach solution were taken daily to measure the copper
concentration, free cyanide and pH.
Flotation Tests
The leach residue samples were dried under open air con-
ditions and crushed to –2 mm using laboratory scale jaw
crusher and roller crusher. The crushed material was ground
in a ball mill using high-chrome balls. The standard flota-
tion conditions were applied on all leach residue samples.
The flotation tests were conducted using a Denver flota-
tion machine with 5 lt cell volume. The depressants Na2S
(0.5 kg/t), ZnSO4 (1 kg/t) and MBS (3 kg/t) were intro-
duced in the grinding stage. The ore was ground to p80=38
µm particle size. Danafloat D-507E was used as the collec-
tor in the copper flotation stage. After the copper rougher
flotation stage, the pulp pH was increased to pH 11.5 using
lime. In the Zn flotation stage, CuSO4 (0.5 kg/t) was used
for activation of sphalerite and SIPX (sodium isopropyl
xanthate) was used as the collector. The flotation products
were assayed for Cu, Pb, Zn and Fe by using an XRF.
RESULTS AND DISCUSSION
The flotation tests were conducted in two main sections.
In the first section, the flotation behaviour of the enriched
ore and the standard sulfide ore were compared and the
possible problems with the flotation of enriched ore were
discussed. In the second section, various reagent schemes
were tested to improve the copper recovery and Cu/Zn
selectivity.
Flotation Characteristics of the Enriched Ore
Selective copper flotation is generally achieved at pH
11–11.5 using lime and a copper selective collector, such
as dithiophosphate or dithiophosphinate type of collectors.
This simple reagent scheme may not be successful if there
is an undesirable sphalerite activation in the ore. Figure 1
shows the Cu/Zn selectivity curves of the standard sulfide
ore and the enriched ore sample at pH 11. The copper and
zinc recoveries followed the same trend in the sulfide ore.
The zinc recovery was higher than the copper recovery in
the enriched ore. The high degree of undesirable sphaler-
ite activation is observed in both ore types. This could be
attributed to the CuS-like rimming observed on sphaler-
ite and activation due to the dissolved copper ions during
grinding and flotation stages.
Comprehensive flotation studies were conducted to
improve the Cu/Zn selectivity and the copper flotation
recovery of the sulfide ore. The results showed that the
optimum flotation performance could be achieved by using
a strong depressant reagent scheme sodium metabisulfite
(3 kg/t), ZnSO4 (500 g/t) and Na2S (500 g/t). The depres-
sants were added in the milling stage. The redox potential
of the pulp should be around –300 mV Ag/AgCl and the
pH=6.5 after milling. The flotation was conducted after
pre-aeration stage at pH 6.5. Danafloat 507E (a mixture
of dialkyl dithiophosphate and thionocarbamate) was used
as the standard collector in the copper flotation stage. This
reagent scheme and flotation conditions are called as the
“standard conditions” in the paper.
Figure 1 shows the Cu/Zn selectivity of the sulfide
ore was improved considerably under the standard flota-
tion conditions. The same conditions were applied on the
enriched ore sample. Both the copper and zinc recoveries
decreased below 10% without any sign of Cu/Zn selectiv-
ity. Given that alternative reagent schemes and different
reagent dosages were tested to better understand flotation
behavior of the enriched ore.
Testing Alternative Reagent Schemes to Improve Cu/Zn
Selectivity
Several flotation conditions tested for selective Cu/Zn flo-
tation were tested for the Enriched ore. The summary of
the test conditions is given in Table 4. The test conditions
involve the standard reagent scheme applied on the regular
sulfide ore, flotation in the absence of depressants, surface
Table 3. Results of EDTA extraction test for the enriched ore
sample
EDTA Extraction (%)
Cu Fe Pb Zn
Enriched Ore 13.725 0.059 29.508 0.582
MCS Sulfide Ore 1.48 0.06 20.18 0.24
given in Table 3. EDTA_Cu is mainly used for assessment
of surface oxidation of the copper minerals and presence
of secondary copper minerals. EDTA_Cu of enriched ore
was considerably higher than that of the sulfide ore sample,
indicating presence of higher amount of secondary copper
minerals and higher degree of surface oxidation. The other
sulfide minerals, i.e., pyrite, galena and sphalerite in the
enriched ore sample also have a higher degree of surface
oxidation.
Column Leach Tests
The column leach tests were conducted in a small-scale col-
umn using 5.5 kg ore sample of p100=19 mm particle size.
Agglomeration was applied using 12 kg/t cement in the C4
and C6 tests, 5 kg/t in C8 tests. The Test C7 was performed
without agglomeration, but lime addition to adjust the
pH=11. The initial cyanide concentration was adjusted to
2000 ppm and maintained during the tests. Samples from
the leach solution were taken daily to measure the copper
concentration, free cyanide and pH.
Flotation Tests
The leach residue samples were dried under open air con-
ditions and crushed to –2 mm using laboratory scale jaw
crusher and roller crusher. The crushed material was ground
in a ball mill using high-chrome balls. The standard flota-
tion conditions were applied on all leach residue samples.
The flotation tests were conducted using a Denver flota-
tion machine with 5 lt cell volume. The depressants Na2S
(0.5 kg/t), ZnSO4 (1 kg/t) and MBS (3 kg/t) were intro-
duced in the grinding stage. The ore was ground to p80=38
µm particle size. Danafloat D-507E was used as the collec-
tor in the copper flotation stage. After the copper rougher
flotation stage, the pulp pH was increased to pH 11.5 using
lime. In the Zn flotation stage, CuSO4 (0.5 kg/t) was used
for activation of sphalerite and SIPX (sodium isopropyl
xanthate) was used as the collector. The flotation products
were assayed for Cu, Pb, Zn and Fe by using an XRF.
RESULTS AND DISCUSSION
The flotation tests were conducted in two main sections.
In the first section, the flotation behaviour of the enriched
ore and the standard sulfide ore were compared and the
possible problems with the flotation of enriched ore were
discussed. In the second section, various reagent schemes
were tested to improve the copper recovery and Cu/Zn
selectivity.
Flotation Characteristics of the Enriched Ore
Selective copper flotation is generally achieved at pH
11–11.5 using lime and a copper selective collector, such
as dithiophosphate or dithiophosphinate type of collectors.
This simple reagent scheme may not be successful if there
is an undesirable sphalerite activation in the ore. Figure 1
shows the Cu/Zn selectivity curves of the standard sulfide
ore and the enriched ore sample at pH 11. The copper and
zinc recoveries followed the same trend in the sulfide ore.
The zinc recovery was higher than the copper recovery in
the enriched ore. The high degree of undesirable sphaler-
ite activation is observed in both ore types. This could be
attributed to the CuS-like rimming observed on sphaler-
ite and activation due to the dissolved copper ions during
grinding and flotation stages.
Comprehensive flotation studies were conducted to
improve the Cu/Zn selectivity and the copper flotation
recovery of the sulfide ore. The results showed that the
optimum flotation performance could be achieved by using
a strong depressant reagent scheme sodium metabisulfite
(3 kg/t), ZnSO4 (500 g/t) and Na2S (500 g/t). The depres-
sants were added in the milling stage. The redox potential
of the pulp should be around –300 mV Ag/AgCl and the
pH=6.5 after milling. The flotation was conducted after
pre-aeration stage at pH 6.5. Danafloat 507E (a mixture
of dialkyl dithiophosphate and thionocarbamate) was used
as the standard collector in the copper flotation stage. This
reagent scheme and flotation conditions are called as the
“standard conditions” in the paper.
Figure 1 shows the Cu/Zn selectivity of the sulfide
ore was improved considerably under the standard flota-
tion conditions. The same conditions were applied on the
enriched ore sample. Both the copper and zinc recoveries
decreased below 10% without any sign of Cu/Zn selectiv-
ity. Given that alternative reagent schemes and different
reagent dosages were tested to better understand flotation
behavior of the enriched ore.
Testing Alternative Reagent Schemes to Improve Cu/Zn
Selectivity
Several flotation conditions tested for selective Cu/Zn flo-
tation were tested for the Enriched ore. The summary of
the test conditions is given in Table 4. The test conditions
involve the standard reagent scheme applied on the regular
sulfide ore, flotation in the absence of depressants, surface
Table 3. Results of EDTA extraction test for the enriched ore
sample
EDTA Extraction (%)
Cu Fe Pb Zn
Enriched Ore 13.725 0.059 29.508 0.582
MCS Sulfide Ore 1.48 0.06 20.18 0.24