2
equaled 3.3 N/mm2, 4.3 N/mm2, and 5.3 N/mm2. Three
levels of moisture were analysed: 0, 2 and 4%. The initial
gap width in the press was set to 4 mm, and the speed of
rolls was 25 rpm (0.4 m/s). Characteristics of each test,
together with registered basic parameters and calculated
indices are presented in Table 1.
The throughput of the press (Q) and the specific energy
consumption (Esp) were determined for each single test
according to equations (1) and (2).
*
*
Q6t/h@ t6s@
m6kg@
1000
3600
=(1)
Esp6tkWh P6kW@
Q6t/h@ /t@ =(2)
Where: m – the weight of the individual sample, t – dura-
tion of a single test, D – roll diameter, l – roll length, Q –
capacity, P – consumed power of a motor.
The HPGR product underwent the size analysis
and the procedure of determining the Bond work index.
Following laboratory sieves [mm] were used in the deter-
mination of particle size distribution of HPGR products:
10, 6.3, 5, 3.15, 2, 1, 0.5, 0.315, 0.2 and 0.1. The Bond
index was determined according to the procedure worked
out by Bond (Bond 1961). The maximum particles in the
sample were passing through the closing sieve 3.35 mm,
used in the procedure. Individual tests were performed in
a standard laboratory Bond’s ball mill with dimensions
305 mm × 305 mm, filled with 20.1 kg of grinding media
(steel balls) with different diameters varied from 15.2 to
38.1 mm, and approximately 0.7 dm3 (Q =1.1 kg, see
Figure 1. Laboratory HPGR device: a) motor, b) floating
roll, c) fixed roll, d) feed bin, e) bin opening chute, f)
product collecting bin
Figure 2. Particle size distribution of the feed material for
HPGR tests
Figure 3. Scheme of investigations: procedure of HPGR
crushing tests (left), scheme determination of the Bond work
index Wi (right)
Table 1. Results of experiments
Pressure
Fsp, [N/
mm2]
Moisture
content M,
[%]
Throughput
Q, [t/h]
Esp
[kWh/t]
3.3 0 3.47 2.24
3.3 2 3.40 2.33
3.3 4 3.27 2.46
4.3 0 3.33 2.82
4.3 2 3.28 2.93
4.3 4 3.16 3.22
5.3 0 3.19 3.30
5.3 2 3.14 3.41
5.3 4 3.08 3.82
equaled 3.3 N/mm2, 4.3 N/mm2, and 5.3 N/mm2. Three
levels of moisture were analysed: 0, 2 and 4%. The initial
gap width in the press was set to 4 mm, and the speed of
rolls was 25 rpm (0.4 m/s). Characteristics of each test,
together with registered basic parameters and calculated
indices are presented in Table 1.
The throughput of the press (Q) and the specific energy
consumption (Esp) were determined for each single test
according to equations (1) and (2).
*
*
Q6t/h@ t6s@
m6kg@
1000
3600
=(1)
Esp6tkWh P6kW@
Q6t/h@ /t@ =(2)
Where: m – the weight of the individual sample, t – dura-
tion of a single test, D – roll diameter, l – roll length, Q –
capacity, P – consumed power of a motor.
The HPGR product underwent the size analysis
and the procedure of determining the Bond work index.
Following laboratory sieves [mm] were used in the deter-
mination of particle size distribution of HPGR products:
10, 6.3, 5, 3.15, 2, 1, 0.5, 0.315, 0.2 and 0.1. The Bond
index was determined according to the procedure worked
out by Bond (Bond 1961). The maximum particles in the
sample were passing through the closing sieve 3.35 mm,
used in the procedure. Individual tests were performed in
a standard laboratory Bond’s ball mill with dimensions
305 mm × 305 mm, filled with 20.1 kg of grinding media
(steel balls) with different diameters varied from 15.2 to
38.1 mm, and approximately 0.7 dm3 (Q =1.1 kg, see
Figure 1. Laboratory HPGR device: a) motor, b) floating
roll, c) fixed roll, d) feed bin, e) bin opening chute, f)
product collecting bin
Figure 2. Particle size distribution of the feed material for
HPGR tests
Figure 3. Scheme of investigations: procedure of HPGR
crushing tests (left), scheme determination of the Bond work
index Wi (right)
Table 1. Results of experiments
Pressure
Fsp, [N/
mm2]
Moisture
content M,
[%]
Throughput
Q, [t/h]
Esp
[kWh/t]
3.3 0 3.47 2.24
3.3 2 3.40 2.33
3.3 4 3.27 2.46
4.3 0 3.33 2.82
4.3 2 3.28 2.93
4.3 4 3.16 3.22
5.3 0 3.19 3.30
5.3 2 3.14 3.41
5.3 4 3.08 3.82