4
Design of Experiment
A Design of Experiment (DOE) methodology was utilized
to address the complexity arising from the multitude of
variables, involving several reagents at different dosages and
pH ranges. DOE techniques provide an efficient means
for process optimization without restricting the study.
The selected DOE not only effectively processes multifac-
eted variables but also serves as a powerful tool for mak-
ing any necessary formulation adjustments (Anderson &
Whitcomb, 2002).
In Phase 01 of the foaming research, a custom design of
experiments (DOE) was used that incorporated a mixture
component consisting of nine reagents, each varying from
0% to 100%. Additionally, two numerical factors were
included: pH, which ranged from 4 to 11, and frother con-
centration, which varied from 10 to 500 ppm. A total of 85
experimental runs were conducted to thoroughly examine
the impact of the reagents under these specified conditions.
A similar methodology was used for microflotation
experiments, which were carried out using an analog sam-
ple. This approach involved 11 reagents as mixture compo-
nents, with proportions ranging from 0% to 100%. One
numerical factor was included, specifically the pH, which
varied from 7.5 to 10.5. Additionally, there was a categori-
cal factor that differentiated between tests conducted with
starch and those without it. In total, 167 runs were required
to complete the research.
Microflotation Cell
The microflotation procedure was used to quickly screen
reagents and laid the groundwork for the following flotation
tests (see Figure 3 for a visual representation of the experi-
mental setup).
The procedure began by conditioning the system for 5
minutes using a 10-gram sample. All reagents were added
simultaneously during the conditioning phase. After con-
ditioning in a beaker, the resulting slurry was transferred
to the flotation cell. Distilled water was added to reach the
reference level. During the flotation process, a froth depth
of 1 inch and an airflow rate of 0.5 L/min were maintained,
resulting in a superficial gas velocity (Jg) of 0.83 cm/s.
Flotation Denver Cell
Flotation tests were conducted using a Denver flotation
cell with a capacity of 2.5 Liters. The procedure started by
adjusting the pH according to the test plan, followed by
a 5-minute conditioning phase during which all reagents
were added simultaneously. The air valve was then opened
completely to initiate the flotation process. In tests involv-
ing gelatinized starch, the starch was added and condi-
tioned for 5 minutes before adjusting the pH to the desired
level. The main conditions for the tests are summarized in
Table 4.
RESULTS AND DISCUSSION
Foam Analysis
Figure 4 compares the results from the foam analyzer high-
lighting the diversity of biosurfactants. It presents a com-
parison of three different biosurfactants, showcasing results
that reflect the highest and lowest Foam Volume Stability
(FVS) and the lowest Sauter mean radius (R32). These
Figure 3. Microflotation cell setup
Design of Experiment
A Design of Experiment (DOE) methodology was utilized
to address the complexity arising from the multitude of
variables, involving several reagents at different dosages and
pH ranges. DOE techniques provide an efficient means
for process optimization without restricting the study.
The selected DOE not only effectively processes multifac-
eted variables but also serves as a powerful tool for mak-
ing any necessary formulation adjustments (Anderson &
Whitcomb, 2002).
In Phase 01 of the foaming research, a custom design of
experiments (DOE) was used that incorporated a mixture
component consisting of nine reagents, each varying from
0% to 100%. Additionally, two numerical factors were
included: pH, which ranged from 4 to 11, and frother con-
centration, which varied from 10 to 500 ppm. A total of 85
experimental runs were conducted to thoroughly examine
the impact of the reagents under these specified conditions.
A similar methodology was used for microflotation
experiments, which were carried out using an analog sam-
ple. This approach involved 11 reagents as mixture compo-
nents, with proportions ranging from 0% to 100%. One
numerical factor was included, specifically the pH, which
varied from 7.5 to 10.5. Additionally, there was a categori-
cal factor that differentiated between tests conducted with
starch and those without it. In total, 167 runs were required
to complete the research.
Microflotation Cell
The microflotation procedure was used to quickly screen
reagents and laid the groundwork for the following flotation
tests (see Figure 3 for a visual representation of the experi-
mental setup).
The procedure began by conditioning the system for 5
minutes using a 10-gram sample. All reagents were added
simultaneously during the conditioning phase. After con-
ditioning in a beaker, the resulting slurry was transferred
to the flotation cell. Distilled water was added to reach the
reference level. During the flotation process, a froth depth
of 1 inch and an airflow rate of 0.5 L/min were maintained,
resulting in a superficial gas velocity (Jg) of 0.83 cm/s.
Flotation Denver Cell
Flotation tests were conducted using a Denver flotation
cell with a capacity of 2.5 Liters. The procedure started by
adjusting the pH according to the test plan, followed by
a 5-minute conditioning phase during which all reagents
were added simultaneously. The air valve was then opened
completely to initiate the flotation process. In tests involv-
ing gelatinized starch, the starch was added and condi-
tioned for 5 minutes before adjusting the pH to the desired
level. The main conditions for the tests are summarized in
Table 4.
RESULTS AND DISCUSSION
Foam Analysis
Figure 4 compares the results from the foam analyzer high-
lighting the diversity of biosurfactants. It presents a com-
parison of three different biosurfactants, showcasing results
that reflect the highest and lowest Foam Volume Stability
(FVS) and the lowest Sauter mean radius (R32). These
Figure 3. Microflotation cell setup