3812 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
paper, the following comminution ratios: S20, S50, S80 and
S95 (Table 3).
The results show that the pressing force F and the
moisture content M have a positive effect on the fineness
of HPGR products. The ore crushed at F =100 kN and
M=0% showed minimal variations in individual Sx values,
which ranged from 2.35 for S20 to 1.79 for S95, according
to the operational practice. But for the moisture content
2 and 4% and F=100 kN, a much higher comminution
ratio was obtained for d20 and the subsequent comminu-
tion ratios were significantly lower. The trend is similar to
hyperbolic. For the F value 130 kN situation is similar for
S20, but the peak for S20 for products P5 and P6. A decrease
in the value of individual Sx, together with increasing the
x, is rather proportional for P6 and hyperbolic for P4 and
P5. For the highest pressing force (F=160 kN), a significant
peak can be observed for all HPGR products for S20, and
the trend the decreasing of Sx values together with increas-
ing x, is closer to hyperbolic than proportional (Figure 4).
The highest values of Sx were obtained for S20, espe-
cially for moisture content greater than 0%. It indicates
that for this type of material it is more beneficial when the
feed moisture is greater than 0%, because the HPGR prod-
ucts contain relatively higher amount of the finest particles,
compared to M =0%.
The energetic effects of HPGR were also evaluated by
determining the Bond energy consumption index (Wi) for
each HPGR product (2). The Wi value for each sample was
determined three times to verify the level of variation.
W
d D80
10W 1 1 kWh/Mg ,
i
80
=-c m (2)
Wi =Bond’s work index value [kWh/Mg],
D80 =80% particle for feed [mm],
d80 =80 percent particle for grinding product [mm].
The calculated Wi values are presented in Table 3. The
results show that both the pressing force F and the moisture
content M have an impact on the bond values Wi. Together
with increasing of the force of F, the values of Wi decrease,
but the decrease is less than proportional, together with fur-
ther increasing of F (i.e., from 13 to 16 kN).
Table 2. Values of specific comminution ratios for all HPGR products
Pressing Force F =100 kN F =130 kN F =160 kN
Moisture Content 0% 2% 4% 0% 2% 4% 0% 2% 4%
s20 2.35 7.15 8.32 4.38 6.37 9.06 5.68 8.96 9.99
s50 2.30 3.43 4.03 2.67 3.68 6.15 3.20 4.65 6.17
s80 1.82 2.29 2.70 1.90 2.62 3.51 2.11 3.21 3.86
s95 1.79 2.04 2.43 1.82 2.42 2.80 1.96 2.66 3.58
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25
Particle size, d [mm]
P7
P8
P9
Feed
Figure 3. PSD curves for HPGR products crushed at F =160 kN
F(d),
[%]
paper, the following comminution ratios: S20, S50, S80 and
S95 (Table 3).
The results show that the pressing force F and the
moisture content M have a positive effect on the fineness
of HPGR products. The ore crushed at F =100 kN and
M=0% showed minimal variations in individual Sx values,
which ranged from 2.35 for S20 to 1.79 for S95, according
to the operational practice. But for the moisture content
2 and 4% and F=100 kN, a much higher comminution
ratio was obtained for d20 and the subsequent comminu-
tion ratios were significantly lower. The trend is similar to
hyperbolic. For the F value 130 kN situation is similar for
S20, but the peak for S20 for products P5 and P6. A decrease
in the value of individual Sx, together with increasing the
x, is rather proportional for P6 and hyperbolic for P4 and
P5. For the highest pressing force (F=160 kN), a significant
peak can be observed for all HPGR products for S20, and
the trend the decreasing of Sx values together with increas-
ing x, is closer to hyperbolic than proportional (Figure 4).
The highest values of Sx were obtained for S20, espe-
cially for moisture content greater than 0%. It indicates
that for this type of material it is more beneficial when the
feed moisture is greater than 0%, because the HPGR prod-
ucts contain relatively higher amount of the finest particles,
compared to M =0%.
The energetic effects of HPGR were also evaluated by
determining the Bond energy consumption index (Wi) for
each HPGR product (2). The Wi value for each sample was
determined three times to verify the level of variation.
W
d D80
10W 1 1 kWh/Mg ,
i
80
=-c m (2)
Wi =Bond’s work index value [kWh/Mg],
D80 =80% particle for feed [mm],
d80 =80 percent particle for grinding product [mm].
The calculated Wi values are presented in Table 3. The
results show that both the pressing force F and the moisture
content M have an impact on the bond values Wi. Together
with increasing of the force of F, the values of Wi decrease,
but the decrease is less than proportional, together with fur-
ther increasing of F (i.e., from 13 to 16 kN).
Table 2. Values of specific comminution ratios for all HPGR products
Pressing Force F =100 kN F =130 kN F =160 kN
Moisture Content 0% 2% 4% 0% 2% 4% 0% 2% 4%
s20 2.35 7.15 8.32 4.38 6.37 9.06 5.68 8.96 9.99
s50 2.30 3.43 4.03 2.67 3.68 6.15 3.20 4.65 6.17
s80 1.82 2.29 2.70 1.90 2.62 3.51 2.11 3.21 3.86
s95 1.79 2.04 2.43 1.82 2.42 2.80 1.96 2.66 3.58
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25
Particle size, d [mm]
P7
P8
P9
Feed
Figure 3. PSD curves for HPGR products crushed at F =160 kN
F(d),
[%]