XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 561
grade was slightly increased as an apparent increase in the
cone speed. Additionally, the magnetite iron grade of tail-
ings was slowly increased from 1.06% for the cone speed
of 50 rpm to 1.33% for the cone speed of 70 rpm beyond
this range, the magnetite iron grade in tailings was signifi-
cantly increased to 3.07% for the cone speed of 80 rpm, as
clearly shown in Figure 4. This is easy to understand that,
at high separation cone speeds, some high-grade magnetic
intergrowths can’t overcome the effect of centrifugal force,
due to the insufficient magnetic capture force onto these
particles and, they enter into the tailings, improving its
magnetite iron grade.
From the cDMS experiments above, under the feed
particle size below 0.10 mm and the separation cone speed
of 70 rpm, the cDMS separator produced the optimal
performance for the given magnetite ore. Specifically, a
concentrate assaying 43.07% Fe in magnetite at 98.38%
magnetite recovery was produced from the magnetite ore
assaying 28.57% Fe in magnetite meanwhile, this separa-
tor has discarded 34.74% tailings by mass weight, at a mag-
netite iron grade in tailings reaching as low as 1.33%.
Capture Analysis of cDMS Separator to Magnetic
Particles
As described above, when the feed particle size is controlled
below 0.10 mm, the cDMS separator achieved the opti-
mum separation performance for the magnetite ore, with
the total iron and magnetite iron grades in tailings reduced
to 11.28%, and 1.33%, respectively. To elucidate this phe-
nomenon, the feed with particle size below 0.10 mm, and
the concentrate and tailings separated from the feed were
chosen to characterize their mineralogical characteristics
50 55 60 65 70 75 80
60
65
70
96
98
100
Concentrate, mass yield
Concentrate, magnetite recovery
Concentrate, magnetite Fe grade
Tailings, magnetite Fe grade
Separation cone speed (rpm)
0
2
4
40
42
44
Figure 4. cDMS-1000 performance for different separation cone speeds
using a microscopic analysis method, with results shown
in Figure 5.
As shown in Figure 5, the composition of metal miner-
als in the cDMS feed is relatively simple, mainly consisting
of magnetite and a small amount of pyrite and limonite.
The liberation of magnetite particles in the feed is rela-
tively high, with the number of liberated magnetite par-
ticles reaching 70%. Meanwhile, the cDMS feed contains
a portion of high-grade intergrown particles. However, the
cDMS concentrate primarily comprises magnetite with a
small amount of pyrite particles, and the liberation degree
for magnetite exceeding 80%. The enrichment of magne-
tite in the concentrate is relatively high, with few associated
particles of magnetite and gangue particles. In contrast,
the liberation degree for magnetite in the cDMS tailings is
obviously lower than that of concentrate, and the magne-
tite mainly exists in a symbiotic form with gangues.
The iron phase analysis of the concentrate below
–0.10 mm is shown in Table 4. It can be seen that the
magnetite distribution in the concentrate reached 94.70%,
with a satisfactory magnetite phase recovery reaching
98.38%, indicating that the cDMS separator has a strong
capture capability for magnetite particles. Furthermore, the
cDMS separator presents a relatively low recovery for sid-
erite iron, hematite iron, silicate iron, and sulfide iron, and
their recoveries are respectively 57.43%, 41.32%, 27.64%,
and 23.38%. This is due to the fact that these iron minerals
are weakly magnetic, and the cDMS separator operating
in low-intensity magnetic field failed to generate a mag-
netic force strong enough to capture these paramagnetic
particles.
Mass
yield
and
recovery
(%)
Grades
of
products
(%)