XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 233
later modified and expanded into a continuously operating
one with a design throughput capacity of 500 kg/h.
The generation of the high-voltage electrical impulses
occurs through a state-of-the-art Marx generator built spe-
cifically for this purpose. The Marx generator consists of
15-stages and allows the high voltage electrical impulses
to be created by parallel charging of the capacitors in each
stage and discharging in series. The machine also has an
integrated water processing module (closed loop) as well
as an external control panel, which allows monitoring and
controlling of the process parameters.
The ELIZE pilot plant relies on the flow of the material
between the electrodes without necessarily having a con-
tact with them. The material is brought into the processing
chamber and the water is pumped in the opposite direc-
tion, counteracting the sink velocity of the particles, hence
allowing a regulation of the residence time and the particle
location at any given moment. The concept underlying the
pilot plant has been patented (Lieberwirth, 2018).
The design of the process chamber includes the geo-
metric design of the electrodes and their arrangement, the
distance between the electrodes, the resulting electrical
field, and the relative position of the material. For this pur-
pose, the electrical field conditions in the process chamber
were modelled, see Figure 2.
The simulation included the evaluation of an electrode
distance up to 100 mm, which represents a significant
increase from the 60 mm originally used for the laboratory
unit. The results showed that the use of a compact group of
particles resulted in a continuous electrical field, thus a con-
tinuous path for the discharge of the high-voltage electrical
impulse. From these results, it was possible to conclude that
the approach proposed allowed the treatment of several
particles at once with a single electrical discharge (impulse).
Furthermore, the presence of a compact group of par-
ticles, e.g., small particle size, increases the efficiency of the
process and allows an increase of the material throughput,
which is one of the upmost requirements for an industrial
application. The main objective of this system development
is a weakening of the particles microstructure by introduc-
ing cracks into the material. It is expected that the pres-
ence of these cracks reduces the energy needed in further
mechanical processing.
The flow chart depicting the integration of the contin-
uous high-voltage electrical impulse comminution system
can be seen in Figure 3. In Figure 4, a picture of the actual
machine is presented. In Table 1, the technical capacities of
the system are given.
The material to be tested is first placed in the hopper,
which has a maximum capacity of 0.5 m3. The material is
then discharged by a vibrating feeder and falls into a receiv-
ing hopper. The material passes then to the process cham-
ber by gravity forces only. The material in the processing
chamber is treated with single electrical impulses when an
impulse is ignited. The material is then transported with
a dewatering screw conveyor and falls onto a dewatering
screen. From here the material is conducted into a container
waiting to be analysed or for further processing. During the
entire process, a continuous water counterflow circulates
through the system. Particles finer than 0.5 mm are carried
away and transported through the overflow gate located in
the upper part of the processing chamber.
The given capacities for the output voltage, frequency
and impulse energy are adjustable and allow a selection of
the processing parameters depending on the material.
Figure 2. Electrical field distribution in a group of particles in a system with 100 mm
electrode distance (Anders et al., 2020)
later modified and expanded into a continuously operating
one with a design throughput capacity of 500 kg/h.
The generation of the high-voltage electrical impulses
occurs through a state-of-the-art Marx generator built spe-
cifically for this purpose. The Marx generator consists of
15-stages and allows the high voltage electrical impulses
to be created by parallel charging of the capacitors in each
stage and discharging in series. The machine also has an
integrated water processing module (closed loop) as well
as an external control panel, which allows monitoring and
controlling of the process parameters.
The ELIZE pilot plant relies on the flow of the material
between the electrodes without necessarily having a con-
tact with them. The material is brought into the processing
chamber and the water is pumped in the opposite direc-
tion, counteracting the sink velocity of the particles, hence
allowing a regulation of the residence time and the particle
location at any given moment. The concept underlying the
pilot plant has been patented (Lieberwirth, 2018).
The design of the process chamber includes the geo-
metric design of the electrodes and their arrangement, the
distance between the electrodes, the resulting electrical
field, and the relative position of the material. For this pur-
pose, the electrical field conditions in the process chamber
were modelled, see Figure 2.
The simulation included the evaluation of an electrode
distance up to 100 mm, which represents a significant
increase from the 60 mm originally used for the laboratory
unit. The results showed that the use of a compact group of
particles resulted in a continuous electrical field, thus a con-
tinuous path for the discharge of the high-voltage electrical
impulse. From these results, it was possible to conclude that
the approach proposed allowed the treatment of several
particles at once with a single electrical discharge (impulse).
Furthermore, the presence of a compact group of par-
ticles, e.g., small particle size, increases the efficiency of the
process and allows an increase of the material throughput,
which is one of the upmost requirements for an industrial
application. The main objective of this system development
is a weakening of the particles microstructure by introduc-
ing cracks into the material. It is expected that the pres-
ence of these cracks reduces the energy needed in further
mechanical processing.
The flow chart depicting the integration of the contin-
uous high-voltage electrical impulse comminution system
can be seen in Figure 3. In Figure 4, a picture of the actual
machine is presented. In Table 1, the technical capacities of
the system are given.
The material to be tested is first placed in the hopper,
which has a maximum capacity of 0.5 m3. The material is
then discharged by a vibrating feeder and falls into a receiv-
ing hopper. The material passes then to the process cham-
ber by gravity forces only. The material in the processing
chamber is treated with single electrical impulses when an
impulse is ignited. The material is then transported with
a dewatering screw conveyor and falls onto a dewatering
screen. From here the material is conducted into a container
waiting to be analysed or for further processing. During the
entire process, a continuous water counterflow circulates
through the system. Particles finer than 0.5 mm are carried
away and transported through the overflow gate located in
the upper part of the processing chamber.
The given capacities for the output voltage, frequency
and impulse energy are adjustable and allow a selection of
the processing parameters depending on the material.
Figure 2. Electrical field distribution in a group of particles in a system with 100 mm
electrode distance (Anders et al., 2020)