XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1959
lower the possibility of removing (or concentrating) them
from the pulp in which they are present.
Various modifications have been made to improve the
performance of these separators, such as changes in the pro-
files of the teeth of grooved plates and the gaps of the matri-
ces, which directly affect the Magnetic Field and Magnetic
Field Gradient. These modifications have brought signifi-
cant gains in the utilization of various ores but have not
substantially improved the recovery of ultrafine particles.
Other parameters such as feed rate, pulp feed velocity,
magnetic field, and solids percentage have been extensively
tested but have not produced significant results for these
particle sizes.
Since the invention of this Magnetic Separator model,
also called Jones in honor of its inventor, a standard height
of 220mm has been adopted for the rotor and consequently
for the magnetic matrices. In mid-2023, efforts were made
to alter this dimension to increase the residence and expo-
sure time of particles to the magnetic field, yielding excel-
lent results that will be discussed.
Initial bench tests were conducted evaluating matrix
heights at 220mm, 356mm, 440mm, 660mm, and 880mm
to determine the height with the best cost-benefit ratio for
industrial equipment application. These tests were con-
ducted with a sample in which 80% of the particles were
less than 30µm, and the iron content of the feed was 42%.
Based on the results obtained, a new pilot-scale machine
was built to perform tests with the 440mm height matrix,
named HighMAG (Figure 3). The comparison between
the usual Minimag, 220mm in height, and the Minimag
HighMAG can be seen in Figure 2 and Figure 3.
The modification made to industrial machines can be
seen in Figure 4. In summary, only the height of the rotors
and matrices were changed, all other components and the
operating principle were maintained.
One of the samples tested on a pilot scale (Figure 2
and 3) had 40% of particles smaller than 10µm, and the
iron content in the feed was 41%. Three different percent-
ages of solids in the feed were tested: 20%, 30%, and 40%.
These tests were conducted by comparing the usual height,
220mm, with the HighMAG, 440mm. All other param-
eters, such as GAP and matrix model, magnetic field, water
pressure for middlings and concentrate wash remained
constant.
The test parameters can be viewed in Table 1, Table 2
and Table 3.
RESULTS
The results from the bench-scale tests indicated the con-
tinuation of these studies. As mentioned earlier, using the
sample for this scale with P80=30µm, the usual matrix,
220mm, was compared with the 356mm height matrix,
Figure 2. Minimag® for 220mm height 1H Matrix Figure 3. Minimag® for 440mm height 2H Matrix
lower the possibility of removing (or concentrating) them
from the pulp in which they are present.
Various modifications have been made to improve the
performance of these separators, such as changes in the pro-
files of the teeth of grooved plates and the gaps of the matri-
ces, which directly affect the Magnetic Field and Magnetic
Field Gradient. These modifications have brought signifi-
cant gains in the utilization of various ores but have not
substantially improved the recovery of ultrafine particles.
Other parameters such as feed rate, pulp feed velocity,
magnetic field, and solids percentage have been extensively
tested but have not produced significant results for these
particle sizes.
Since the invention of this Magnetic Separator model,
also called Jones in honor of its inventor, a standard height
of 220mm has been adopted for the rotor and consequently
for the magnetic matrices. In mid-2023, efforts were made
to alter this dimension to increase the residence and expo-
sure time of particles to the magnetic field, yielding excel-
lent results that will be discussed.
Initial bench tests were conducted evaluating matrix
heights at 220mm, 356mm, 440mm, 660mm, and 880mm
to determine the height with the best cost-benefit ratio for
industrial equipment application. These tests were con-
ducted with a sample in which 80% of the particles were
less than 30µm, and the iron content of the feed was 42%.
Based on the results obtained, a new pilot-scale machine
was built to perform tests with the 440mm height matrix,
named HighMAG (Figure 3). The comparison between
the usual Minimag, 220mm in height, and the Minimag
HighMAG can be seen in Figure 2 and Figure 3.
The modification made to industrial machines can be
seen in Figure 4. In summary, only the height of the rotors
and matrices were changed, all other components and the
operating principle were maintained.
One of the samples tested on a pilot scale (Figure 2
and 3) had 40% of particles smaller than 10µm, and the
iron content in the feed was 41%. Three different percent-
ages of solids in the feed were tested: 20%, 30%, and 40%.
These tests were conducted by comparing the usual height,
220mm, with the HighMAG, 440mm. All other param-
eters, such as GAP and matrix model, magnetic field, water
pressure for middlings and concentrate wash remained
constant.
The test parameters can be viewed in Table 1, Table 2
and Table 3.
RESULTS
The results from the bench-scale tests indicated the con-
tinuation of these studies. As mentioned earlier, using the
sample for this scale with P80=30µm, the usual matrix,
220mm, was compared with the 356mm height matrix,
Figure 2. Minimag® for 220mm height 1H Matrix Figure 3. Minimag® for 440mm height 2H Matrix