XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2941
0.34 g/t which is lower than 0.38 g/t Au content from the
mechanical laboratory cell.
Cleaner Feed
Imhoflot G-Cells obtained an excellent concentrate grade
with an average of 31.32 g/t at a very high recovery of
91.67%. Test 3 showed a concentrate grade of 37.86 g/t at
a high recovery of 92.73% (Test 3). The cleaner tails con-
tains an average Au content of only 2.9 g/t. Importantly,
the recovery of CaO and SiO2 in the concentrate is only
approximately 5.9 and 21.7% respectively. The Imhoflot
concentrate contains ca. 3.6%, 24.6% and 8.0% of CaO,
SiO2 and Al2O3, respectively.
CONCLUSIONS
It has been pointed out in the previous article (Hoang et
al., 2022) that the existing mechanical cells in an operating
gold beneficiation plant are working well for the intermedi-
ate particle sizes (d80 of about 75–100 µm), however, they
do not work adequately for the fines (said below 38 µm)
and ultra-fines (less than 10 µm). The energy dissipation
within conventional cells does not seem to be sufficient for
an effective fine particle-bubble collision and attachment,
resulting in low recoveries for those fine particles. Also, due
to the high entrained of ultrafine gangue thus a negative
effect on the Au grade. The plant operator aims to achieve
the gold content in the tailings at 0.3 g/t. Unfortunately,
the final tailings contain about 0.4–0.5 g/t, which is very
high in terms of resource efficiency and economics. The
optical microscopic investigation indicated that the main
gold loss is from ultrafine gold grains (2 µm). The main
reasons are the limitation of existing mechanical cells in the
recovery of the fines and ultrafines and the poor liberation
of complex gold-bearing particles.
Imhoflot G-cells can achieve a high grade while mini-
mizing entrainment, with the advanced reactor in the high
shear environment generating tiny bubbles that selec-
tively collect the fine particles. The application of the pilot
Imhoflot G-cells type on different streamlines again showed
very promising results, i.e., very high-grade concentrates
and good recovery with only two G-14 cells. Based on the
flotation results, the following conclusions can be drawn:
• Scavenger froth concentrate stream: The concentrate
grade of up to 30 g/t is quickly obtained in the first
cell for the high kinetics particles. The final concen-
trate contains an average grade of about 20.8 g/t of
Au at a recovery of up to 66% (average recovery of
about 54.2%). Note that the overall recovery will be
higher if we put more cells in series, to be considered
when designing the flowsheet.
• Final tailings stream: The final tailings still contains
about 0.4–0.46 g/t Au, with a significant amount
of ultrafine liberated gold that is lost to the tailings.
Applying only two G-14 cells, obtained a concentrate
of 3.5 g/t Au at a recovery of up to 48% (an average
recovery of 30%) operated in an open circuit. The
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7
Au grade, g/t
Imhoflot G-Cell Lab mechanical cell Feed grade
Figure 7. Halbich upgrading visualization of the laboratory mechanical flotation (13 tests) and
pilot Imhoflot G-14 cells (7 tests)
Au
recovery,
%
0.34 g/t which is lower than 0.38 g/t Au content from the
mechanical laboratory cell.
Cleaner Feed
Imhoflot G-Cells obtained an excellent concentrate grade
with an average of 31.32 g/t at a very high recovery of
91.67%. Test 3 showed a concentrate grade of 37.86 g/t at
a high recovery of 92.73% (Test 3). The cleaner tails con-
tains an average Au content of only 2.9 g/t. Importantly,
the recovery of CaO and SiO2 in the concentrate is only
approximately 5.9 and 21.7% respectively. The Imhoflot
concentrate contains ca. 3.6%, 24.6% and 8.0% of CaO,
SiO2 and Al2O3, respectively.
CONCLUSIONS
It has been pointed out in the previous article (Hoang et
al., 2022) that the existing mechanical cells in an operating
gold beneficiation plant are working well for the intermedi-
ate particle sizes (d80 of about 75–100 µm), however, they
do not work adequately for the fines (said below 38 µm)
and ultra-fines (less than 10 µm). The energy dissipation
within conventional cells does not seem to be sufficient for
an effective fine particle-bubble collision and attachment,
resulting in low recoveries for those fine particles. Also, due
to the high entrained of ultrafine gangue thus a negative
effect on the Au grade. The plant operator aims to achieve
the gold content in the tailings at 0.3 g/t. Unfortunately,
the final tailings contain about 0.4–0.5 g/t, which is very
high in terms of resource efficiency and economics. The
optical microscopic investigation indicated that the main
gold loss is from ultrafine gold grains (2 µm). The main
reasons are the limitation of existing mechanical cells in the
recovery of the fines and ultrafines and the poor liberation
of complex gold-bearing particles.
Imhoflot G-cells can achieve a high grade while mini-
mizing entrainment, with the advanced reactor in the high
shear environment generating tiny bubbles that selec-
tively collect the fine particles. The application of the pilot
Imhoflot G-cells type on different streamlines again showed
very promising results, i.e., very high-grade concentrates
and good recovery with only two G-14 cells. Based on the
flotation results, the following conclusions can be drawn:
• Scavenger froth concentrate stream: The concentrate
grade of up to 30 g/t is quickly obtained in the first
cell for the high kinetics particles. The final concen-
trate contains an average grade of about 20.8 g/t of
Au at a recovery of up to 66% (average recovery of
about 54.2%). Note that the overall recovery will be
higher if we put more cells in series, to be considered
when designing the flowsheet.
• Final tailings stream: The final tailings still contains
about 0.4–0.46 g/t Au, with a significant amount
of ultrafine liberated gold that is lost to the tailings.
Applying only two G-14 cells, obtained a concentrate
of 3.5 g/t Au at a recovery of up to 48% (an average
recovery of 30%) operated in an open circuit. The
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7
Au grade, g/t
Imhoflot G-Cell Lab mechanical cell Feed grade
Figure 7. Halbich upgrading visualization of the laboratory mechanical flotation (13 tests) and
pilot Imhoflot G-14 cells (7 tests)
Au
recovery,
%