1
25-061
Models of Breakage Effectiveness in HPGR Depending on
Operational Press Parameters
Daniel Saramak
AGH University of Krakow, Poland
Agnieszka Saramak
AGH University of Krakow, Poland
INTRODUCTION
A big issue in crushing and grinding operations in raw
materials handling is high energy consumption and low
breakage effectiveness. According to the Legendre [7],
only 10% of energy input is directly consumed on the feed
material breakage, while the remaining portion is dissipated
in the form of heat and noise [8]. In the industry of lime-
stone powder production, the grinding operations consti-
tute integral part of technological circuits, and the energy
consumption in operations of industrial comminution con-
sume as high as 2% of world energy [14].
High-pressure grinding is the technology with proved
energy benefits both in ore processing circuits and in lime-
stone grinding. The promising results concerned mostly the
achieved energy savings and good results of material break-
age were achieved and demonstrated in numerous investi-
gations [1,3,12]. However, it appears that a proper selection
of operational parameters of the press devise, determination
the feed material characteristics and adjustment of process
course san be of a key-significance in improving an effec-
tiveness the HPGR operation. Operational parameters of
devices and process course should be verified towards the
characteristics of the feed material, which mainly applies
to the particle size and shape of the feed material and its
moisture, and also mineralization in case of ores [2,4,9].
There are various investigations concerning an impact
of the operational pressing force on comminution results
which mostly refer to the determination of energy con-
sumption and crushing ratio [5,6,10,13]. Investigations
on the moisture content are less common, however their
results suggest that, in general, the HPGR feed with higher
moisture shows the tendency to higher comminution
intensity, while the energy consumption increases together
with increasing of feed material moisture. Investigations on
olivine sand feed [11] showed that crushing ratio decreases
for higher moisture, especially when the material is crushed
at higher pressing force.
HPGR devices, however, shouldn’t be regarded as a
unique and perfect solution for comminution of each type
of material. But they indeed may bring technological and
economic benefits, comparing to conventional crushing
and grinding machines, resulting in more favourable break-
age of material particles and lower consumption of energy
per unit mass of processed feed material.
Materials and Methods
The purpose of the paper was to carry out a series of crush-
ing tests on a limestone on the laboratory scale HPGR
device (Figure 1) which is equipped with a set of rolls with
plain surface, roll diameter 0.3 m and roll width 0.1 m.
A limestone rock was used in investigations. The mate-
rial was crushed in laboratory jaw crusher prior HPGR
experiments to the top size of 20 mm. About 100 kg of
material was used in investigations, and after jaw crusher
treatment the entire feed was homogenized and divided
into representative samples in a riffle splitter. The particle
size distribution of feed is presented in Figure 2.
The testing programme was presented in Figure 3 left
(HPGR crushing tests) and Figure 3 right (procedure of
determination the Bond work index Wi).
HPGR testing programme included nine single crush-
ing tests at three various levels of operational pressing force
F and two levels of material moisture M. The original force
F was recalculated on the pressure (Fsp), which values
25-061
Models of Breakage Effectiveness in HPGR Depending on
Operational Press Parameters
Daniel Saramak
AGH University of Krakow, Poland
Agnieszka Saramak
AGH University of Krakow, Poland
INTRODUCTION
A big issue in crushing and grinding operations in raw
materials handling is high energy consumption and low
breakage effectiveness. According to the Legendre [7],
only 10% of energy input is directly consumed on the feed
material breakage, while the remaining portion is dissipated
in the form of heat and noise [8]. In the industry of lime-
stone powder production, the grinding operations consti-
tute integral part of technological circuits, and the energy
consumption in operations of industrial comminution con-
sume as high as 2% of world energy [14].
High-pressure grinding is the technology with proved
energy benefits both in ore processing circuits and in lime-
stone grinding. The promising results concerned mostly the
achieved energy savings and good results of material break-
age were achieved and demonstrated in numerous investi-
gations [1,3,12]. However, it appears that a proper selection
of operational parameters of the press devise, determination
the feed material characteristics and adjustment of process
course san be of a key-significance in improving an effec-
tiveness the HPGR operation. Operational parameters of
devices and process course should be verified towards the
characteristics of the feed material, which mainly applies
to the particle size and shape of the feed material and its
moisture, and also mineralization in case of ores [2,4,9].
There are various investigations concerning an impact
of the operational pressing force on comminution results
which mostly refer to the determination of energy con-
sumption and crushing ratio [5,6,10,13]. Investigations
on the moisture content are less common, however their
results suggest that, in general, the HPGR feed with higher
moisture shows the tendency to higher comminution
intensity, while the energy consumption increases together
with increasing of feed material moisture. Investigations on
olivine sand feed [11] showed that crushing ratio decreases
for higher moisture, especially when the material is crushed
at higher pressing force.
HPGR devices, however, shouldn’t be regarded as a
unique and perfect solution for comminution of each type
of material. But they indeed may bring technological and
economic benefits, comparing to conventional crushing
and grinding machines, resulting in more favourable break-
age of material particles and lower consumption of energy
per unit mass of processed feed material.
Materials and Methods
The purpose of the paper was to carry out a series of crush-
ing tests on a limestone on the laboratory scale HPGR
device (Figure 1) which is equipped with a set of rolls with
plain surface, roll diameter 0.3 m and roll width 0.1 m.
A limestone rock was used in investigations. The mate-
rial was crushed in laboratory jaw crusher prior HPGR
experiments to the top size of 20 mm. About 100 kg of
material was used in investigations, and after jaw crusher
treatment the entire feed was homogenized and divided
into representative samples in a riffle splitter. The particle
size distribution of feed is presented in Figure 2.
The testing programme was presented in Figure 3 left
(HPGR crushing tests) and Figure 3 right (procedure of
determination the Bond work index Wi).
HPGR testing programme included nine single crush-
ing tests at three various levels of operational pressing force
F and two levels of material moisture M. The original force
F was recalculated on the pressure (Fsp), which values