3810 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
depending also on the type of material (Daniel 2007 Cao
et al. 2019 Baawuah et al. 2020 Saramak and Saramak
2020). The relationship between pressure and Bond index
is inverse, in turn, and this is due to the relatively higher
degree of material weakening achieved for higher opera-
tional pressure value (Saramak et al. 2017 Saramak and
Iwanów 2018). Operational pressure has also a significant
impact on product crushing ratio (Brożek and Naziemiec
2012 Thivierge et al. 2020). Investigations over other
HPGR parameters, like speed of rolls and gap, seem to be
of lower importance, but if properly controlled, they might
have a significant impact on throughput of HPGR device
(Lim et al. 1997 Thivierge et al. 2020). But investigations
over these parameters have much lower coverage in litera-
ture, compared to the pressure.
Various research programmes investigate the character-
istics of the material on HPGR effectiveness. This includes
both different types of material and changeable proper-
ties (i.e., particle size, moisture) for a given type of feed.
Although a slight increase in the moisture content of the
feed material can be effective in better comminution, a too
high water content affects the productivity of the process
(Saramak 2011 Saramak and Kleiv 2013).
There are, however, limitations in using of HPGR
machines. Operational practice shows that too high of a
moisture content can result in slippage of the material on
the surface of rolls. The relationship between operational
pressing force and breakage effectiveness is proportional,
but together with increasing of the pressure, especially for
high values, the achieved effects in comminution are less
than proportional. Thus, a higher unit energy consumption
and higher operational costs.
The main aim of the paper is to investigate the impact
of both the operational press of HPGR and material mois-
ture on energy consumption, crushing ratio, and genera-
tion of finest particle size fractions in HPGR comminution
products. Specific regressive models have been built, and
the level of impact of each parameter was investigated for
each case. These models were constructed on the basis of
the factorial experiment procedure, conducted under lab-
oratory conditions. It is worth noting that several similar
models were already presented and validated, but there is
no model that analyzes an impact of both these parameters
(i.e., operating pressure and material moisture) on the pro-
cess effectiveness measured through Bond working index.
MATERIALS AND METHODS
A series of laboratory comminution tests was carried out in
an HPGR-based crushing circuit. The laboratory HPGR
device used in the testing programme was equipped with
a set of plain surface, with diameter 300 mm and width
100 mm. The wear of the rollers was in good condition.
The maximum operational pressing force to achieve is
200 kN, which corresponds to a specific pressing force
exceeding 6 N/mm2. Smooth adjustment of the rotational
velocity of rolls, initial gap settings, as well as registration
of primary operational variables, like pressing force, speed,
and energy consumption, is possible. It is also possible to
collect central and edge products, to minimize an unfavor-
able phenomenon of potentially lower intensity of breakage
close to rolls edges. For that reason, only the centre product
was analyzed in terms of PSD and achieved comminution
intensity.
Sulphide copper ore consisted of three main lithologic
fractions: sandstone, carbonate and slate with following
proportions: 47%, 42%, and 11%, respectively, was used as
in experiments. The feed was homogenized prior to deter-
mination the mineralogy assay and PSD analysis therefore,
no significant differences in the results of the analyses. The
PSD was required to calculate the comminution ratios. The
scheme of experiments is presented in Figure 1.
The HPGR test programme included nine single
crushing tests at various levels of operational pressing force
F and material moisture M. The following values of F were
accepted for experiments: 100, 130 and 160 kN, and for
the moisture of the material 0, 2 and the 4% were selected,
and individual feed sample was prepared accordingly
Figure 1. Scheme of investigations
depending also on the type of material (Daniel 2007 Cao
et al. 2019 Baawuah et al. 2020 Saramak and Saramak
2020). The relationship between pressure and Bond index
is inverse, in turn, and this is due to the relatively higher
degree of material weakening achieved for higher opera-
tional pressure value (Saramak et al. 2017 Saramak and
Iwanów 2018). Operational pressure has also a significant
impact on product crushing ratio (Brożek and Naziemiec
2012 Thivierge et al. 2020). Investigations over other
HPGR parameters, like speed of rolls and gap, seem to be
of lower importance, but if properly controlled, they might
have a significant impact on throughput of HPGR device
(Lim et al. 1997 Thivierge et al. 2020). But investigations
over these parameters have much lower coverage in litera-
ture, compared to the pressure.
Various research programmes investigate the character-
istics of the material on HPGR effectiveness. This includes
both different types of material and changeable proper-
ties (i.e., particle size, moisture) for a given type of feed.
Although a slight increase in the moisture content of the
feed material can be effective in better comminution, a too
high water content affects the productivity of the process
(Saramak 2011 Saramak and Kleiv 2013).
There are, however, limitations in using of HPGR
machines. Operational practice shows that too high of a
moisture content can result in slippage of the material on
the surface of rolls. The relationship between operational
pressing force and breakage effectiveness is proportional,
but together with increasing of the pressure, especially for
high values, the achieved effects in comminution are less
than proportional. Thus, a higher unit energy consumption
and higher operational costs.
The main aim of the paper is to investigate the impact
of both the operational press of HPGR and material mois-
ture on energy consumption, crushing ratio, and genera-
tion of finest particle size fractions in HPGR comminution
products. Specific regressive models have been built, and
the level of impact of each parameter was investigated for
each case. These models were constructed on the basis of
the factorial experiment procedure, conducted under lab-
oratory conditions. It is worth noting that several similar
models were already presented and validated, but there is
no model that analyzes an impact of both these parameters
(i.e., operating pressure and material moisture) on the pro-
cess effectiveness measured through Bond working index.
MATERIALS AND METHODS
A series of laboratory comminution tests was carried out in
an HPGR-based crushing circuit. The laboratory HPGR
device used in the testing programme was equipped with
a set of plain surface, with diameter 300 mm and width
100 mm. The wear of the rollers was in good condition.
The maximum operational pressing force to achieve is
200 kN, which corresponds to a specific pressing force
exceeding 6 N/mm2. Smooth adjustment of the rotational
velocity of rolls, initial gap settings, as well as registration
of primary operational variables, like pressing force, speed,
and energy consumption, is possible. It is also possible to
collect central and edge products, to minimize an unfavor-
able phenomenon of potentially lower intensity of breakage
close to rolls edges. For that reason, only the centre product
was analyzed in terms of PSD and achieved comminution
intensity.
Sulphide copper ore consisted of three main lithologic
fractions: sandstone, carbonate and slate with following
proportions: 47%, 42%, and 11%, respectively, was used as
in experiments. The feed was homogenized prior to deter-
mination the mineralogy assay and PSD analysis therefore,
no significant differences in the results of the analyses. The
PSD was required to calculate the comminution ratios. The
scheme of experiments is presented in Figure 1.
The HPGR test programme included nine single
crushing tests at various levels of operational pressing force
F and material moisture M. The following values of F were
accepted for experiments: 100, 130 and 160 kN, and for
the moisture of the material 0, 2 and the 4% were selected,
and individual feed sample was prepared accordingly
Figure 1. Scheme of investigations