3878 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Example
Let us take Metso VTM-1500 as an example to demon-
strate our DEM model. The operating conditions are listed
as below:
Mill speed =19 rpm
Ball size/initial load =25.4mm/127 tons
Target power draw =880 kW
Implemented with the above mentioned algorithm and
embedded mechanism, the DEM model for VTM con-
tains initial ball load of 2 million balls, which is gradually
increased to 2.6 million balls to keep the power constant
given the wear. The simulation time is about 15 seconds
to reach steady state and then 24 seconds to complete the
wear simulation process, which represent about 180 days
(wall-clock time) of liner service life on average, noting that
the lifespan of liners covers a wide range resulting from the
operating conditions and the ore characteristics for each
site. The initial and the final mill charge are depicted in
Figure 3, where the front half media balls are taken away for
visualization purposes, and the colors reflect media shear
power. In Figure 3(b), the ball addition mechanism is illus-
trated, balls being released from the mill top to maintain
the mill power as the liner wears the formation of a cavity
is also observed in the critical region near the edge of the
liner bottom.
Figure 4 shows the comparison of simulated worn liner
geometry and the measured worn liner geometry it is seen
that the DEM model captures main wear characteristics.
Figure 5 shows the histories of mill power draw and
media charge it is seen that the power draw is maintained
around the target power of 880 kW. Table 1 shows the
results of power draw, shear power and media load at spe-
cific times. It is seen that the as far as the power is main-
tained around the target value the shear energy, which
reflects the grinding capacity, is kept at a stable range.
CONCLUSIONS
This paper has presented the new algorithm developed for
modelling Vertimill linear wear we provided details on the
model, and demonstrated the prediction accuracy by way
of an example. The main points are summarized as follow:
• A parametric DEM model for VTM liner wear has
been developed.
• The model can capture geometrical features of VTM
liner as it wears.
• The model can simulate the time histories of power
draw, collision energy and media mass at given oper-
ating conditions.
• Overall, the DEM model can practically be used to
predict the history of VTM liner wear and related
physical quantities.
Figure 3. Mill charge corresponding to liner (a) initial loading and (b) final loading
Table 1. Power, shear power and media load
Time
(second)
Power
(kW)
Shear Energy
(kW)
Ball Load
(ton)
0 883.1 791.2 127.0
8 879.9 789.6 137.8
16 876.0 788.1 152.5
24 875.5 788.8 169.9
Example
Let us take Metso VTM-1500 as an example to demon-
strate our DEM model. The operating conditions are listed
as below:
Mill speed =19 rpm
Ball size/initial load =25.4mm/127 tons
Target power draw =880 kW
Implemented with the above mentioned algorithm and
embedded mechanism, the DEM model for VTM con-
tains initial ball load of 2 million balls, which is gradually
increased to 2.6 million balls to keep the power constant
given the wear. The simulation time is about 15 seconds
to reach steady state and then 24 seconds to complete the
wear simulation process, which represent about 180 days
(wall-clock time) of liner service life on average, noting that
the lifespan of liners covers a wide range resulting from the
operating conditions and the ore characteristics for each
site. The initial and the final mill charge are depicted in
Figure 3, where the front half media balls are taken away for
visualization purposes, and the colors reflect media shear
power. In Figure 3(b), the ball addition mechanism is illus-
trated, balls being released from the mill top to maintain
the mill power as the liner wears the formation of a cavity
is also observed in the critical region near the edge of the
liner bottom.
Figure 4 shows the comparison of simulated worn liner
geometry and the measured worn liner geometry it is seen
that the DEM model captures main wear characteristics.
Figure 5 shows the histories of mill power draw and
media charge it is seen that the power draw is maintained
around the target power of 880 kW. Table 1 shows the
results of power draw, shear power and media load at spe-
cific times. It is seen that the as far as the power is main-
tained around the target value the shear energy, which
reflects the grinding capacity, is kept at a stable range.
CONCLUSIONS
This paper has presented the new algorithm developed for
modelling Vertimill linear wear we provided details on the
model, and demonstrated the prediction accuracy by way
of an example. The main points are summarized as follow:
• A parametric DEM model for VTM liner wear has
been developed.
• The model can capture geometrical features of VTM
liner as it wears.
• The model can simulate the time histories of power
draw, collision energy and media mass at given oper-
ating conditions.
• Overall, the DEM model can practically be used to
predict the history of VTM liner wear and related
physical quantities.
Figure 3. Mill charge corresponding to liner (a) initial loading and (b) final loading
Table 1. Power, shear power and media load
Time
(second)
Power
(kW)
Shear Energy
(kW)
Ball Load
(ton)
0 883.1 791.2 127.0
8 879.9 789.6 137.8
16 876.0 788.1 152.5
24 875.5 788.8 169.9