3834 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
..9741 f Va
Win 2 761 0
l l 3 b tl,plh =+^(8)
In the wet grinding circuit, the classification performed by
the hydrocyclones has been modeled as a single partition
curve independent of the ore type also described by Lynch’s
equation (Eq. 5).
Selection of Model Parameters
The parameters for all components used in the simulations
of the selected grinding circuits are presented in Table 1.
These parameters were obtaining by performing batch
grinding tests using a 30×30 cm ball mill, at 67% of criti-
cal speed, mill filling of 30% and voids filling of 100%.
The three components in the dry grinding circuit are rep-
resented by C1, C2 and C3 representing, hypothetically,
clinker, limestone and gypsum. The breakage function was
considered invariable with component, while the selection
function had its s1 parameter varying for each component
depending on the selected case study. In the case of the iron
ore grinding, the two ore types present different parameters
for both selection and breakage function, being the CC ore
more amenable to grinding.
RESULTS
Dry Grinding Circuit
Table 2 shows the initial conditions and results for the three
case studies after the system reaches steady state conditions.
It is evident that in all case studies, the final proportions
of each component in the hold-up and circulating load are
uneven, unlike the feed. In case #1, there is a greater accu-
mulation of component C3, which is expected owing to its
lower specific breakage rate (s
1 in Table 1). Similarly, C2,
the material that has higher grindability is the one that is
accumulated the least. In case #2, the difference is caused by
the partition curve calculated for each component, which
varies according to their density. Figure 1 illustrates this dif-
ference at the beginning and end of the simulation, once
it reaches steady state. The higher the material density, the
greater the fraction of each size class reported to the oversize
(coarse fraction), since the mass of the particles increases.
The influence of the feed rate to the classifier is also
evident. At the beginning of the operation (Figure 1a), the
output flow from the mill for this case was 390 t/h. Towards
the end, this value drops to 122 t/h, causing variations in
the parameters β, β* and C (Figure 1b). This difference is
Table 1. Breakage and selection function parameters for the materials used in the simulations
Component
Breakage Function Selection Function
D* (mm) ω Φ β γ s1 (1/min) α µ (mm) Λ
Dry Cement Grinding Circuit
C1 1.00 0 0.336 4.08 0.60 0.431* 0.971 1.88 2.72
C2 1.00 0 0.336 4.08 0.60 0.474 0.971 1.88 2.72
C3 1.00 0 0.336 4.08 0.60 0.388* 0.971 1.88 2.72
Wet Iron Ore Grinding Circuit
FN 0 0.507 0.60 3.23 0.59 0.88 1.82 1.17 3.25
CC 0 0.507 0.90 5.01 0.85 3.47 2.45 0.61 2.66
*Parameter changes depending on the case study
Table 2. Simulation parameters for dry grinding circuit
Simulation Case #1 #2 #3
Component C1 C2 C3 C1 C2 C3 C1 C2 C3
Feed composition (%)33.4 33.3 33.3 33.4 33.3 33.3 33.4 33.3 33.3
Specific breakage rate (1/min)* 0.431 0.474 0.388 0.474 0.474 0.474 0.431 0.474 0.388
Density (kg/m3) 2700 2700 2700 2300 2700 3200 2300 2700 3200
Initial hold-up composition (%)20.0 30.0 50.0 20.0 30.0 50.0 20.0 30.0 50.0
Steady state hold-up composition (%)33.3 31.7 35.0 30.3 33.2 36.5 30.0 31.5 38.5
Circulating load (%feed rate) 159 143 163
Recycle composition (%)33.2 30.8 36.0 28.1 33.1 38.8 28.0 30.4 41.6
*s
1 parameter from Eq. 2.
..9741 f Va
Win 2 761 0
l l 3 b tl,plh =+^(8)
In the wet grinding circuit, the classification performed by
the hydrocyclones has been modeled as a single partition
curve independent of the ore type also described by Lynch’s
equation (Eq. 5).
Selection of Model Parameters
The parameters for all components used in the simulations
of the selected grinding circuits are presented in Table 1.
These parameters were obtaining by performing batch
grinding tests using a 30×30 cm ball mill, at 67% of criti-
cal speed, mill filling of 30% and voids filling of 100%.
The three components in the dry grinding circuit are rep-
resented by C1, C2 and C3 representing, hypothetically,
clinker, limestone and gypsum. The breakage function was
considered invariable with component, while the selection
function had its s1 parameter varying for each component
depending on the selected case study. In the case of the iron
ore grinding, the two ore types present different parameters
for both selection and breakage function, being the CC ore
more amenable to grinding.
RESULTS
Dry Grinding Circuit
Table 2 shows the initial conditions and results for the three
case studies after the system reaches steady state conditions.
It is evident that in all case studies, the final proportions
of each component in the hold-up and circulating load are
uneven, unlike the feed. In case #1, there is a greater accu-
mulation of component C3, which is expected owing to its
lower specific breakage rate (s
1 in Table 1). Similarly, C2,
the material that has higher grindability is the one that is
accumulated the least. In case #2, the difference is caused by
the partition curve calculated for each component, which
varies according to their density. Figure 1 illustrates this dif-
ference at the beginning and end of the simulation, once
it reaches steady state. The higher the material density, the
greater the fraction of each size class reported to the oversize
(coarse fraction), since the mass of the particles increases.
The influence of the feed rate to the classifier is also
evident. At the beginning of the operation (Figure 1a), the
output flow from the mill for this case was 390 t/h. Towards
the end, this value drops to 122 t/h, causing variations in
the parameters β, β* and C (Figure 1b). This difference is
Table 1. Breakage and selection function parameters for the materials used in the simulations
Component
Breakage Function Selection Function
D* (mm) ω Φ β γ s1 (1/min) α µ (mm) Λ
Dry Cement Grinding Circuit
C1 1.00 0 0.336 4.08 0.60 0.431* 0.971 1.88 2.72
C2 1.00 0 0.336 4.08 0.60 0.474 0.971 1.88 2.72
C3 1.00 0 0.336 4.08 0.60 0.388* 0.971 1.88 2.72
Wet Iron Ore Grinding Circuit
FN 0 0.507 0.60 3.23 0.59 0.88 1.82 1.17 3.25
CC 0 0.507 0.90 5.01 0.85 3.47 2.45 0.61 2.66
*Parameter changes depending on the case study
Table 2. Simulation parameters for dry grinding circuit
Simulation Case #1 #2 #3
Component C1 C2 C3 C1 C2 C3 C1 C2 C3
Feed composition (%)33.4 33.3 33.3 33.4 33.3 33.3 33.4 33.3 33.3
Specific breakage rate (1/min)* 0.431 0.474 0.388 0.474 0.474 0.474 0.431 0.474 0.388
Density (kg/m3) 2700 2700 2700 2300 2700 3200 2300 2700 3200
Initial hold-up composition (%)20.0 30.0 50.0 20.0 30.0 50.0 20.0 30.0 50.0
Steady state hold-up composition (%)33.3 31.7 35.0 30.3 33.2 36.5 30.0 31.5 38.5
Circulating load (%feed rate) 159 143 163
Recycle composition (%)33.2 30.8 36.0 28.1 33.1 38.8 28.0 30.4 41.6
*s
1 parameter from Eq. 2.