XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2103
downstream are prepared. However, irrespective of the
controlled parameters the material properties also have sig-
nificant effect on the separation and grinding efficiencies.
Due to the varying liberation status of different compo-
nents after grinding, density differences arise in the particle
system. The particles with varying sizes and density classes
result in a multicomponent particle system.
In the past, limited studies have been attempted to
understand the multi-density particle behaviour during the
classification process in hydrocyclones [1–4]. Most of these
studies have observed a significant change in the cut-size
and solids recovery to the underflow for its’ components
compared with the overall mixture behaviour. The changes
in in performance is attributed to the particle density dif-
ference compared to the overall or average mixture density.
However, it is not clear how the interaction of different
density components affects the separation of particles dur-
ing classification in a hydrocyclone. Some notable studies
involving the behaviour of components in hydrocyclones
include Cho [5] who focused on describing the classifica-
tion of binary, ternary and quaternary component mixtures
of minerals such as coal, limestone, magnetite, and quartz
in the laboratory and pilot-scale hydrocyclone. Narasimha
et al. [2], proposed a conceptual multi-component hydro-
cyclone model by extending a single density component
mathematical model developed by the same workers.
Mainza et al.[3] studied the deportment of chromite and
silica components in the UG2 platinum ore. Recently Padhi
et al. [4,5] performed physical experiments and computa-
tional simulations using CFD which showed that differ-
ent density components do not act independently during
classification in a dual component system, even when they
are fully liberated and proposed the particle displacement
mechanism to describe the interaction of lighter and heavier
components inside the hydrocyclone.
Attempting to understand the complex nature of par-
ticle separation in the hydrocyclone has occupied research-
ers for a long time several mathematical models have been
developed using different approaches over the past four
decades [6–9]. The two commonly used models are (Plitt
et. Al, 1976) [10] and (Nageswarao, 1978) [11], which have
been incorporated into the MODSIM [12] and JKSimMet
simulator [13,14]software, respectively. These models are
successfully used in grinding circuit simulations worldwide.
Recently the authors have developed and implemented an
improved hydrocyclone model in JKSimMet latest ver-
sion[1]. Although some of the existing mathematical mod-
els can describe hydrocyclone classification performance
for the ore’s single average density, their predictions for
ores with wide differences in the component densities are
usually poor. It is important to ensure that fine particles
deport to the overflow and coarse particles to the underflow
in process plants. In several instances like lead/zinc regrind
circuits, coal partitioning, or UG2 platinum ore (Upper
group 2 platinum ore, South Africa), single averaged density
hydrocyclone models are unable to predict the classification
performance well because of the multi-density occurrence
in the ores. Since the principle of separation in a hydrocy-
clone is driven by centrifugal forces and settling, particle
density is an important property. It can’t be ignored in the
model meant for the classification applications that involve
ores with significantly different component densities.
In this study, an attempt to understand the multi-
component particle behaviour and the interactions inside
the flow system is made using the physical experiments and
simulations utilizing computational fluid dynamics tech-
nique. The multi-density suspension properties, such as vis-
cosity and the hindered settling velocity are studied. These
properties are used in the multicomponent mathematical
model equations describing the separation performance
parameters such as cut-size, flow rate, solids recovery, and
sharpness of separation.
METHODOLOGY
Hydrocyclone Laboratory Experiments
The classification experiments were performed using 2, 3
and 4-inch diameter hydrocyclones a custom-made labo-
ratory scale test rig. A schematic of the test rig and pho-
tographs of the experimental set up are same as described
in Padhi et al., (2019) [5]. The design specifications of the
hydrocyclones used are given in Figure 1. The test rig has
a 200 litres sump and is set up to collect the slurry from
the overflow and underflow streams. It is equipped with
a Warmen 5 HP model pump to deliver the feed slurry
suspension to hydrocyclone. The slurry mixture is pre-
pared in the sump to meet the selected hydrocyclone feed
requirements for the test. To ensure the uniform mixing
of slurry suspension in the system, one part of the slurry
from the pump delivery line goes to bypass/recirculation.
The bypass line is utilized to regulate the operating pres-
sure for the hydrocyclone. The preliminary hydrocyclone
experiments were performed using only water, followed
by a slurry composed of different proportions of magne-
tite and quartz in the mixtures. The particle size distribu-
tions of quartz and magnetite were analysed and are given
in Figure 2. The d63.2 for silica and magnetite from the size
analysis performed were 44 and 37 microns, respectively.
The lower and upper size bound for magnetite and quartz
is recorded as 0.406–1500 and 1.15–1500 microns, respec-
tively. In these experiments, an attempt was made to keep
downstream are prepared. However, irrespective of the
controlled parameters the material properties also have sig-
nificant effect on the separation and grinding efficiencies.
Due to the varying liberation status of different compo-
nents after grinding, density differences arise in the particle
system. The particles with varying sizes and density classes
result in a multicomponent particle system.
In the past, limited studies have been attempted to
understand the multi-density particle behaviour during the
classification process in hydrocyclones [1–4]. Most of these
studies have observed a significant change in the cut-size
and solids recovery to the underflow for its’ components
compared with the overall mixture behaviour. The changes
in in performance is attributed to the particle density dif-
ference compared to the overall or average mixture density.
However, it is not clear how the interaction of different
density components affects the separation of particles dur-
ing classification in a hydrocyclone. Some notable studies
involving the behaviour of components in hydrocyclones
include Cho [5] who focused on describing the classifica-
tion of binary, ternary and quaternary component mixtures
of minerals such as coal, limestone, magnetite, and quartz
in the laboratory and pilot-scale hydrocyclone. Narasimha
et al. [2], proposed a conceptual multi-component hydro-
cyclone model by extending a single density component
mathematical model developed by the same workers.
Mainza et al.[3] studied the deportment of chromite and
silica components in the UG2 platinum ore. Recently Padhi
et al. [4,5] performed physical experiments and computa-
tional simulations using CFD which showed that differ-
ent density components do not act independently during
classification in a dual component system, even when they
are fully liberated and proposed the particle displacement
mechanism to describe the interaction of lighter and heavier
components inside the hydrocyclone.
Attempting to understand the complex nature of par-
ticle separation in the hydrocyclone has occupied research-
ers for a long time several mathematical models have been
developed using different approaches over the past four
decades [6–9]. The two commonly used models are (Plitt
et. Al, 1976) [10] and (Nageswarao, 1978) [11], which have
been incorporated into the MODSIM [12] and JKSimMet
simulator [13,14]software, respectively. These models are
successfully used in grinding circuit simulations worldwide.
Recently the authors have developed and implemented an
improved hydrocyclone model in JKSimMet latest ver-
sion[1]. Although some of the existing mathematical mod-
els can describe hydrocyclone classification performance
for the ore’s single average density, their predictions for
ores with wide differences in the component densities are
usually poor. It is important to ensure that fine particles
deport to the overflow and coarse particles to the underflow
in process plants. In several instances like lead/zinc regrind
circuits, coal partitioning, or UG2 platinum ore (Upper
group 2 platinum ore, South Africa), single averaged density
hydrocyclone models are unable to predict the classification
performance well because of the multi-density occurrence
in the ores. Since the principle of separation in a hydrocy-
clone is driven by centrifugal forces and settling, particle
density is an important property. It can’t be ignored in the
model meant for the classification applications that involve
ores with significantly different component densities.
In this study, an attempt to understand the multi-
component particle behaviour and the interactions inside
the flow system is made using the physical experiments and
simulations utilizing computational fluid dynamics tech-
nique. The multi-density suspension properties, such as vis-
cosity and the hindered settling velocity are studied. These
properties are used in the multicomponent mathematical
model equations describing the separation performance
parameters such as cut-size, flow rate, solids recovery, and
sharpness of separation.
METHODOLOGY
Hydrocyclone Laboratory Experiments
The classification experiments were performed using 2, 3
and 4-inch diameter hydrocyclones a custom-made labo-
ratory scale test rig. A schematic of the test rig and pho-
tographs of the experimental set up are same as described
in Padhi et al., (2019) [5]. The design specifications of the
hydrocyclones used are given in Figure 1. The test rig has
a 200 litres sump and is set up to collect the slurry from
the overflow and underflow streams. It is equipped with
a Warmen 5 HP model pump to deliver the feed slurry
suspension to hydrocyclone. The slurry mixture is pre-
pared in the sump to meet the selected hydrocyclone feed
requirements for the test. To ensure the uniform mixing
of slurry suspension in the system, one part of the slurry
from the pump delivery line goes to bypass/recirculation.
The bypass line is utilized to regulate the operating pres-
sure for the hydrocyclone. The preliminary hydrocyclone
experiments were performed using only water, followed
by a slurry composed of different proportions of magne-
tite and quartz in the mixtures. The particle size distribu-
tions of quartz and magnetite were analysed and are given
in Figure 2. The d63.2 for silica and magnetite from the size
analysis performed were 44 and 37 microns, respectively.
The lower and upper size bound for magnetite and quartz
is recorded as 0.406–1500 and 1.15–1500 microns, respec-
tively. In these experiments, an attempt was made to keep