3
METHODOLOGY
Materials
There were three major materials used in this study. An
electrolyte solution (aqueous phase), which was prepared
using cupric sulfate (40g/L) and sulfuric acid (180g/L),
both purchased from GFS Chemicals. The solution mostly
contains cupric sulfate, which is a principal source of cop-
per whiles sulfuric acid serves as the supporting electrolyte.
An organic solution which contained 85 vol% LIX 964N
and 15 vol% SX-12 (both manufactured by BASF) served
as an organic phase for this study. LIX 964N is known for
its high efficiency in selectively extracting copper from
acidic solution. SX-12 on the other hand, helps in con-
trolling the viscosity of the organic phase. Finally, surfac-
tants, FC1100 (obtained from BASF) and Licorice extract
(manufactured by Horbäach ®). These surfactants have the
ability to reduce surface tension and encapsulate acid mist
particles, respectively. All of the materials that were used in
this study were selected because of their shown effectiveness
in solvent extraction and copper electrowinning.
Contact with Organic Solution
The electrolyte surfactant is brought into contact with
the Organic 1, 5, and 10 times before acid mist testing.
Initially, 20 mg of surfactant is added to 6 L of electro-
lyte. This electrolyte is mixed with a 6 L organic solution
containing 15% extractant and 85% diluent for 2 minutes
before settling for 3 minutes. The electrolyte is separated
from the organic solution. This method completes the one-
contact test. To achieve the subsequent 5 and 10 contact
tests, this technique is repeated 5 and 10 times, respectively,
with the same solution from the separating tank. A descrip-
tive image of the process is shown in Figure 2.
Acid Mist Testing
The next stage involved acid mist testing. A test chamber
measured the mist generation by bubbling oxygen into the
electrolyte solution. The chamber has a cross-section of
50 cm × 50 cm and a height of 1.5 meters. Air enters the
chamber from the bottom, and a 4-inch diameter exhaust
fan at the end of the chamber duct draws air outward at
5.22 m/s, resulting in a flow rate of 0.042282 m3/s. The
flow velocity in the chamber is 0.169128 m/s due to its
main body’s cross-sectional size of 0.5 m × 0.5 m. A poly-
propylene tank (31.8 × 16.5 × 22.2 cm) is placed on top
of a perforated plate with the electrolyte. A heating system
thermostatically regulated the electrolyte temperature at
40°C. The setup is shown in Figure 3.
During the sample operation, bubbles were created by
releasing oxygen gas through a gas diffuser immersed in
the electrolyte. The gas was released at a rate of 1.5 L/min,
controlled by an oxygen flow controller. When oxygen was
injected into the solution, bubbles formed and migrated to
the surface/air boundary. At this point, the bubbles rup-
tured, releasing droplets of acidic aerosols (acid mist) into
the experimental chamber’s air. These acidic droplets were
then transported to a monitoring point, where air samples
were collected. This was accomplished using an open-face
sampling cassette outfitted with a 37 mm quartz fiber filter
(Whatman QMA). Each sample was collected for 30 min-
utes at a flow rate of 5 L/min to ensure enough vaporized
aerosols were captured on the quartz fiber filter.
After collecting the samples, the filters were removed
from the sampling cassettes and placed in a 50 mL volu-
metric flask filled with deionized water. The filters were
then sonicated for fifteen minutes. The goal of the sonica-
tion is to agitate the deionized water, thereby washing off
all the acid that had been absorbed onto the filter paper.
Figure 2. Image showing the contact test process
METHODOLOGY
Materials
There were three major materials used in this study. An
electrolyte solution (aqueous phase), which was prepared
using cupric sulfate (40g/L) and sulfuric acid (180g/L),
both purchased from GFS Chemicals. The solution mostly
contains cupric sulfate, which is a principal source of cop-
per whiles sulfuric acid serves as the supporting electrolyte.
An organic solution which contained 85 vol% LIX 964N
and 15 vol% SX-12 (both manufactured by BASF) served
as an organic phase for this study. LIX 964N is known for
its high efficiency in selectively extracting copper from
acidic solution. SX-12 on the other hand, helps in con-
trolling the viscosity of the organic phase. Finally, surfac-
tants, FC1100 (obtained from BASF) and Licorice extract
(manufactured by Horbäach ®). These surfactants have the
ability to reduce surface tension and encapsulate acid mist
particles, respectively. All of the materials that were used in
this study were selected because of their shown effectiveness
in solvent extraction and copper electrowinning.
Contact with Organic Solution
The electrolyte surfactant is brought into contact with
the Organic 1, 5, and 10 times before acid mist testing.
Initially, 20 mg of surfactant is added to 6 L of electro-
lyte. This electrolyte is mixed with a 6 L organic solution
containing 15% extractant and 85% diluent for 2 minutes
before settling for 3 minutes. The electrolyte is separated
from the organic solution. This method completes the one-
contact test. To achieve the subsequent 5 and 10 contact
tests, this technique is repeated 5 and 10 times, respectively,
with the same solution from the separating tank. A descrip-
tive image of the process is shown in Figure 2.
Acid Mist Testing
The next stage involved acid mist testing. A test chamber
measured the mist generation by bubbling oxygen into the
electrolyte solution. The chamber has a cross-section of
50 cm × 50 cm and a height of 1.5 meters. Air enters the
chamber from the bottom, and a 4-inch diameter exhaust
fan at the end of the chamber duct draws air outward at
5.22 m/s, resulting in a flow rate of 0.042282 m3/s. The
flow velocity in the chamber is 0.169128 m/s due to its
main body’s cross-sectional size of 0.5 m × 0.5 m. A poly-
propylene tank (31.8 × 16.5 × 22.2 cm) is placed on top
of a perforated plate with the electrolyte. A heating system
thermostatically regulated the electrolyte temperature at
40°C. The setup is shown in Figure 3.
During the sample operation, bubbles were created by
releasing oxygen gas through a gas diffuser immersed in
the electrolyte. The gas was released at a rate of 1.5 L/min,
controlled by an oxygen flow controller. When oxygen was
injected into the solution, bubbles formed and migrated to
the surface/air boundary. At this point, the bubbles rup-
tured, releasing droplets of acidic aerosols (acid mist) into
the experimental chamber’s air. These acidic droplets were
then transported to a monitoring point, where air samples
were collected. This was accomplished using an open-face
sampling cassette outfitted with a 37 mm quartz fiber filter
(Whatman QMA). Each sample was collected for 30 min-
utes at a flow rate of 5 L/min to ensure enough vaporized
aerosols were captured on the quartz fiber filter.
After collecting the samples, the filters were removed
from the sampling cassettes and placed in a 50 mL volu-
metric flask filled with deionized water. The filters were
then sonicated for fifteen minutes. The goal of the sonica-
tion is to agitate the deionized water, thereby washing off
all the acid that had been absorbed onto the filter paper.
Figure 2. Image showing the contact test process