2036 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
with dotted black lines was selected as a region to study
and compare the mean axial flow behavior of the fluid and
injected phosphate particles along radial positions of the
cyclone’s rotational axis. The DMS fluid flow was negative
(flowing toward underflow) near the walls, meaning that
the material flowed downward in the outer vortex, carrying
with it particles in this region toward the bottom. Toward
the centre, the axial velocity was positive (ascending
toward the overflow) in the inner vortex. It was observed
that the coarser low grade particles (density 2.65 g/cm3)
in the selected region tended to have a higher downward
axial velocity than the fluid. Finer lower grade particles
tended to be transported with the fluid at similar velocities,
although there was more variability in their behavior. Both
sizes tended to be located in the outer vortex flowing in the
direction of the underflow with very few particles captured
ascending in the inner vortex. By contrast, the higher grade
coarser particles (density 2.3 g/cm3) were mainly located
in the inner vortex with ascending velocity, although quite
scattered and with several instances having negative veloci-
ties. The finer higher grade material showed a high degree
of consistency, with velocities close to that of the DMS
fluid and readily carried upward toward the overflow.
The results showed agreement with prior studies on
dense medium cyclones whereby density was a greater
influence on the likelihood of correct deportment than par-
ticle size (Pillay et al., 2022). Finer particles tended to be
entrained with the dense fluid and separated based on their
density to the respective outlets based on the cut size while
coarser particles showed higher variability in their behavior
and likelihood of separation.
CONCLUSIONS
Results highlighted that that the total sample mass was
contained mainly at three densities of 2.65, 2.6 and 2.3 g/
cm3 with negligible masses at others. For P2O5, the sample
showed a bi-modal distribution at 2.65 and 2.3 g/cm3,
meaning that near density material around narrow cut
points would be complex to separate. To produce the high-
est possible grade concentrate in the floats product, while
simultaneously maximizing the mass yield, the targeted cut
point for DMS pilot tests was 2.5g/cm3. The cleanest phos-
phate product had a low mass yield of 16.1% at a P2O5
grade of 30.1%.
CFD highlighted the distinct manner of separation
between the bimodal densities and particle sizes compared.
It was observed that coarser particles of higher densities
readily reported to the underflow, while finer particles
showed some variability in behavior. Finer lower density
material also showed a high degree of consistency, with
velocities close to that of the DMS fluid and readily car-
ried upward toward the overflow. Based on this, density was
observed to have the greater influence on the likelihood of
correct deportment than particle size. Finer particles tended
to be transported with the dense fluid and separated to the
respective outlets correctly based on density while coarser
particles showed higher variability in their behavior and
likelihood of separation.
While the single stage DMS operation was demon-
strated to be feasible, two-stage DMS operation is recom-
mended to improve product quality and overall recovery,
while sustaining stable pilot conditions. For this the sinks
would then undergo a second processing stage at a higher
cut point of 2.65 g/cm3 which would create the opportu-
nity to recover the P2O5 present at the higher density.
REFERENCES
ANSYS, Inc. (2016) ANSYS Fluent User’s Guide, Release
17.2.
Aketi, V. A. K., Vakamalla, T. R., Narasimha, M.,
Sreedhar, G. E., Shivakumar, R., &RajanKumar.
(2016). Computational Fluid Dynamic study on
the effect of near gravity material on dense medium
cyclone treating coal using Discrete Phase Model and
Algebraic Slip mixture multiphase model. The Journal
of Computational Multiphase Flows, 9(2), 58–70. doi:
10.1177/1757482X16677755.
Galvin, K. P., &Iveson, S. M. (2022). New challenges for
gravity concentration and classification of fine particles.
Minerals Engineering, 190, 107888. doi: 10.1016/j.
mineng.2022.107888.
Gimbun, J., Chuah, T. G., Choong, T. S. Y., &Fakhru’l-
Razi, A. (2005). A CFD Study on the Prediction
of Cyclone Collection Efficiency. International
Journal for Computational Methods in Engineering
Science and Mechanics, 6(3), 161–168. doi:
10.1080/15502280590923649.
Manninen, M., Taivassalo, V., &Kallio, S. (1996). On
the mixture model for multiphase flow. VTT Technical
Research Centre of Finland. VTT Publications No.
288 https://publications.vtt.fi/pdf/publications/1996
/P288.pdf.
Pillay, K., Mainza, A. N., Chetty, D., &Becker, M. (2022).
Mineralogical Factors Affecting the Dense Medium
Separation of Nickel Sulfide Ores. Minerals, 12(10).
Rao, B. V. (2004). Weibull partition surface rep-
resentation for gravity concentrators. Minerals
Engineering, 17(7), 953–956. doi: 10.1016/j.mineng
.2004.03.001.
with dotted black lines was selected as a region to study
and compare the mean axial flow behavior of the fluid and
injected phosphate particles along radial positions of the
cyclone’s rotational axis. The DMS fluid flow was negative
(flowing toward underflow) near the walls, meaning that
the material flowed downward in the outer vortex, carrying
with it particles in this region toward the bottom. Toward
the centre, the axial velocity was positive (ascending
toward the overflow) in the inner vortex. It was observed
that the coarser low grade particles (density 2.65 g/cm3)
in the selected region tended to have a higher downward
axial velocity than the fluid. Finer lower grade particles
tended to be transported with the fluid at similar velocities,
although there was more variability in their behavior. Both
sizes tended to be located in the outer vortex flowing in the
direction of the underflow with very few particles captured
ascending in the inner vortex. By contrast, the higher grade
coarser particles (density 2.3 g/cm3) were mainly located
in the inner vortex with ascending velocity, although quite
scattered and with several instances having negative veloci-
ties. The finer higher grade material showed a high degree
of consistency, with velocities close to that of the DMS
fluid and readily carried upward toward the overflow.
The results showed agreement with prior studies on
dense medium cyclones whereby density was a greater
influence on the likelihood of correct deportment than par-
ticle size (Pillay et al., 2022). Finer particles tended to be
entrained with the dense fluid and separated based on their
density to the respective outlets based on the cut size while
coarser particles showed higher variability in their behavior
and likelihood of separation.
CONCLUSIONS
Results highlighted that that the total sample mass was
contained mainly at three densities of 2.65, 2.6 and 2.3 g/
cm3 with negligible masses at others. For P2O5, the sample
showed a bi-modal distribution at 2.65 and 2.3 g/cm3,
meaning that near density material around narrow cut
points would be complex to separate. To produce the high-
est possible grade concentrate in the floats product, while
simultaneously maximizing the mass yield, the targeted cut
point for DMS pilot tests was 2.5g/cm3. The cleanest phos-
phate product had a low mass yield of 16.1% at a P2O5
grade of 30.1%.
CFD highlighted the distinct manner of separation
between the bimodal densities and particle sizes compared.
It was observed that coarser particles of higher densities
readily reported to the underflow, while finer particles
showed some variability in behavior. Finer lower density
material also showed a high degree of consistency, with
velocities close to that of the DMS fluid and readily car-
ried upward toward the overflow. Based on this, density was
observed to have the greater influence on the likelihood of
correct deportment than particle size. Finer particles tended
to be transported with the dense fluid and separated to the
respective outlets correctly based on density while coarser
particles showed higher variability in their behavior and
likelihood of separation.
While the single stage DMS operation was demon-
strated to be feasible, two-stage DMS operation is recom-
mended to improve product quality and overall recovery,
while sustaining stable pilot conditions. For this the sinks
would then undergo a second processing stage at a higher
cut point of 2.65 g/cm3 which would create the opportu-
nity to recover the P2O5 present at the higher density.
REFERENCES
ANSYS, Inc. (2016) ANSYS Fluent User’s Guide, Release
17.2.
Aketi, V. A. K., Vakamalla, T. R., Narasimha, M.,
Sreedhar, G. E., Shivakumar, R., &RajanKumar.
(2016). Computational Fluid Dynamic study on
the effect of near gravity material on dense medium
cyclone treating coal using Discrete Phase Model and
Algebraic Slip mixture multiphase model. The Journal
of Computational Multiphase Flows, 9(2), 58–70. doi:
10.1177/1757482X16677755.
Galvin, K. P., &Iveson, S. M. (2022). New challenges for
gravity concentration and classification of fine particles.
Minerals Engineering, 190, 107888. doi: 10.1016/j.
mineng.2022.107888.
Gimbun, J., Chuah, T. G., Choong, T. S. Y., &Fakhru’l-
Razi, A. (2005). A CFD Study on the Prediction
of Cyclone Collection Efficiency. International
Journal for Computational Methods in Engineering
Science and Mechanics, 6(3), 161–168. doi:
10.1080/15502280590923649.
Manninen, M., Taivassalo, V., &Kallio, S. (1996). On
the mixture model for multiphase flow. VTT Technical
Research Centre of Finland. VTT Publications No.
288 https://publications.vtt.fi/pdf/publications/1996
/P288.pdf.
Pillay, K., Mainza, A. N., Chetty, D., &Becker, M. (2022).
Mineralogical Factors Affecting the Dense Medium
Separation of Nickel Sulfide Ores. Minerals, 12(10).
Rao, B. V. (2004). Weibull partition surface rep-
resentation for gravity concentrators. Minerals
Engineering, 17(7), 953–956. doi: 10.1016/j.mineng
.2004.03.001.