552 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
high acid consumption due the presence of carbonates.
Carbonate minerals, such as calcite (CaCO₃) and dolomite
(CaMg(CO₃)₂), react with the acidic solutions used in
leaching, neutralizing the acid and forming carbon dioxide
gas and soluble salts. This reaction significantly increases the
amount of acid required to maintain the necessary acidic
conditions for effective copper dissolution (Kappes, 2002).
The main focus of the test was to remove carbonates, which
have a lower atomic density when compared to the oxidized
coppers ores, and subsequently reduce acid consumption.
The study was conducted using industrial-scale equip-
ment (Steinert KSS CLI XT 200) in a laboratory setting.
Employing the XRT, 3D Laser and Colour sensor for the
classification algorithm, the methodology adopted was the
Feasibility Test. The methodology is detailed by Esteves
(2023), which utilizes a cascade separation process. Cascade
separation (Figure 5) involves applying different sensitivity
levels to create grade versus mass recovery and metallurgi-
cal recovery versus mass recovery curves. In this process,
the drop fraction from each stage is redirected to the feed,
sensitivity settings are adjusted, and the process is repeated
to remove an additional mass fraction. Although the test is
conducted in multiple stages, it is important to note that in
an industrial environment, the separation is performed in
a single stage.
Table 1 show a clear improvement in soluble copper
grades, along with a significant reduction in acid consump-
tion across the stages. The acid consumption is showed in
a percentage of the measured feed acid consumption. The
mass balance shows that the majority of the copper recov-
ery occurs in the Drop Step 3 and Eject Step 3 stage, which
also exhibits the lowest acid consumption. Specifically, in
the –2"+1" fraction, Drop 3 achieved 77.78% recovery
with an acid consumption of the feed. In contrast, Eject
1 and 2 accounts for approximately 7% of the mass and
less than 1% of the copper, also presenting acid consump-
tions in between 1.7 and 2 times the feed material. For the
–1" +0,5" size the Eject 1 material presented approximately
10% of mass, less than 2% of copper recovery and 2 times
the acid consumption.
The behaviour was consistent across the size fractions,
where initial ejects (Eject 1 and/or Eject 2) exhibit high
acid usage and low copper recovery, indicating an efficient
removal of carbonates predominantly in these stages. In this
sense, by rejecting in between 7% to 10% of the mass it is
possible to recover most of the copper while significantly
reducing acid consumption.
Figure 4. BWi and DWT for feed, product and waste stream of the pre-concentration stage (Esteves, 2023)
high acid consumption due the presence of carbonates.
Carbonate minerals, such as calcite (CaCO₃) and dolomite
(CaMg(CO₃)₂), react with the acidic solutions used in
leaching, neutralizing the acid and forming carbon dioxide
gas and soluble salts. This reaction significantly increases the
amount of acid required to maintain the necessary acidic
conditions for effective copper dissolution (Kappes, 2002).
The main focus of the test was to remove carbonates, which
have a lower atomic density when compared to the oxidized
coppers ores, and subsequently reduce acid consumption.
The study was conducted using industrial-scale equip-
ment (Steinert KSS CLI XT 200) in a laboratory setting.
Employing the XRT, 3D Laser and Colour sensor for the
classification algorithm, the methodology adopted was the
Feasibility Test. The methodology is detailed by Esteves
(2023), which utilizes a cascade separation process. Cascade
separation (Figure 5) involves applying different sensitivity
levels to create grade versus mass recovery and metallurgi-
cal recovery versus mass recovery curves. In this process,
the drop fraction from each stage is redirected to the feed,
sensitivity settings are adjusted, and the process is repeated
to remove an additional mass fraction. Although the test is
conducted in multiple stages, it is important to note that in
an industrial environment, the separation is performed in
a single stage.
Table 1 show a clear improvement in soluble copper
grades, along with a significant reduction in acid consump-
tion across the stages. The acid consumption is showed in
a percentage of the measured feed acid consumption. The
mass balance shows that the majority of the copper recov-
ery occurs in the Drop Step 3 and Eject Step 3 stage, which
also exhibits the lowest acid consumption. Specifically, in
the –2"+1" fraction, Drop 3 achieved 77.78% recovery
with an acid consumption of the feed. In contrast, Eject
1 and 2 accounts for approximately 7% of the mass and
less than 1% of the copper, also presenting acid consump-
tions in between 1.7 and 2 times the feed material. For the
–1" +0,5" size the Eject 1 material presented approximately
10% of mass, less than 2% of copper recovery and 2 times
the acid consumption.
The behaviour was consistent across the size fractions,
where initial ejects (Eject 1 and/or Eject 2) exhibit high
acid usage and low copper recovery, indicating an efficient
removal of carbonates predominantly in these stages. In this
sense, by rejecting in between 7% to 10% of the mass it is
possible to recover most of the copper while significantly
reducing acid consumption.
Figure 4. BWi and DWT for feed, product and waste stream of the pre-concentration stage (Esteves, 2023)