XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2043
The vertical dashed red and dark red lines are the aperture
sizes used in the tests.
In Figure 8, the y-axis is the screening efficiency [%].
In Figure 9, the y-axis is the throughput rate [t/h]. In
Figure 10, the y-axis is the height of the material bed on the
screen [mm]. In all these figures, the x-axis is the distance
along the screen deck [mm], the vertical solid black line is
the length of the screen effective screening area, the solid
blue line with dots is the passing probability model result,
and the solid grey line with dots is the 1998s test result. In
Figure 10, the solid orange line with dots is the height of
the actual passage layer in the passing probability model.
In the passing probability model curves and the actual
passage layer curves, the lines with dots are used to describe
the number of calculation elements and the length of the
material throws (single particle trajectory due to stroke) on
the screen deck. When the vertical distance between these
dots is smaller, the length of the throw is smaller and there
are more calculation elements in the model. This can be
seen as the quickening of the dots, which comes from the
fact that the material enters the lower sloped deck sectors
as it travels on the screen deck. Due to this, the transport
speed of the material decreases and the length of the throw
decreases.
deck sectors. The TS18.60 screen and machine parameters
used in the tests were also fed to the passing probability
model, including the screen rotation speed, the hit param-
eter in each of the deck sectors, the inclinations in each of
the deck sectors, the width of the effective screening area,
the effective length of the sectors, the nominal length of the
stroke, the wire diameter in the screening media and the
size of the aperture or apertures. As a result, the size distri-
butions of oversize and undersize material were obtained.
In addition, the screening efficiency, the throughput rate,
and the height of the material bed along the screen deck
were predicted.
The passing probability model results were compared
with 1998s test results. Model results that are in the error
limit (adjusted to 4% in the sensitivity analysis, Pohjasenaho
(2023) are tests 21 (data in Figure 6), 30, 31 and 32. The
results that are not within the error limit are not presented.
In Figure 7, obtained from the passing probability model,
the x-axis is the size of the fractions [mm], and the y-axis
is the cumulative amount of material [%].The solid black
line is the interpolated feed input to the model, the solid
red line is the model undersize curve, and the solid blue line
is the model oversize curve. The green dots are the 1998s
test oversize distribution obtained from the laboratory tests.
Figure 6. Test results from the test number 21 (Viilo 1998)
The vertical dashed red and dark red lines are the aperture
sizes used in the tests.
In Figure 8, the y-axis is the screening efficiency [%].
In Figure 9, the y-axis is the throughput rate [t/h]. In
Figure 10, the y-axis is the height of the material bed on the
screen [mm]. In all these figures, the x-axis is the distance
along the screen deck [mm], the vertical solid black line is
the length of the screen effective screening area, the solid
blue line with dots is the passing probability model result,
and the solid grey line with dots is the 1998s test result. In
Figure 10, the solid orange line with dots is the height of
the actual passage layer in the passing probability model.
In the passing probability model curves and the actual
passage layer curves, the lines with dots are used to describe
the number of calculation elements and the length of the
material throws (single particle trajectory due to stroke) on
the screen deck. When the vertical distance between these
dots is smaller, the length of the throw is smaller and there
are more calculation elements in the model. This can be
seen as the quickening of the dots, which comes from the
fact that the material enters the lower sloped deck sectors
as it travels on the screen deck. Due to this, the transport
speed of the material decreases and the length of the throw
decreases.
deck sectors. The TS18.60 screen and machine parameters
used in the tests were also fed to the passing probability
model, including the screen rotation speed, the hit param-
eter in each of the deck sectors, the inclinations in each of
the deck sectors, the width of the effective screening area,
the effective length of the sectors, the nominal length of the
stroke, the wire diameter in the screening media and the
size of the aperture or apertures. As a result, the size distri-
butions of oversize and undersize material were obtained.
In addition, the screening efficiency, the throughput rate,
and the height of the material bed along the screen deck
were predicted.
The passing probability model results were compared
with 1998s test results. Model results that are in the error
limit (adjusted to 4% in the sensitivity analysis, Pohjasenaho
(2023) are tests 21 (data in Figure 6), 30, 31 and 32. The
results that are not within the error limit are not presented.
In Figure 7, obtained from the passing probability model,
the x-axis is the size of the fractions [mm], and the y-axis
is the cumulative amount of material [%].The solid black
line is the interpolated feed input to the model, the solid
red line is the model undersize curve, and the solid blue line
is the model oversize curve. The green dots are the 1998s
test oversize distribution obtained from the laboratory tests.
Figure 6. Test results from the test number 21 (Viilo 1998)