XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3673
former highly occluded mineral so that high-purity iron
concentrate could be obtained. Based on the results of the
above experiment, the feasibility of the process was verified
through semi-industrial tests.
RESULTS AND DISCUSSION
Establishment of an Evaluation System for Preparation
of High-Purity Iron Concentrate
To effectively determine whether any ordinary iron concen-
trate can be used to prepare high-purity iron concentrate,
it is essential to establish a feasibility assessment system.
Therefore, 10 kinds of concentrate from different regions
in China were selected to study the intrinsic relation-
ship between the mineralogy characteristics of raw mate-
rial processes and beneficiation indicators. Furthermore,
a feasibility evaluation system for preparing high-purity
iron concentrate was established to screen raw materi-
als for the rapid preparation of high-purity iron concen-
trate. As shown in Table 1, the total Fe grades of the ten
samples ranged from 63.46% to 66.86%. From the FeO
content, it can be seen that the primary occurrence state of
the iron element is magnetite. Thus, the iron concentrate
could be upgraded by the low-intensity magnetic separa-
tion. The prerequisite for efficient mineral separation in
mineral processing operations is the degree of dissociation
between the target mineral and gangue minerals. The type
of conjoined species is one of the critical factors affecting
the dissociation of mineral monomers. According to the
different occlusion methods, it can be divided into adjoin-
ing, wrapping, and anti-wrapping types. The main differ-
ence between the wrapping and anti-wrapping type is the
nature of core mineral in the wrapping. The anti-wrapped
type is that magnetite wraps fine-grained gangue minerals,
while the wrapped type is the opposite. Therefore, as shown
in Figure 2, microscopic observation was used to count
the types and contents of conjoined magnetite and gangue
minerals in the concentrate. Samples No. 1, 9, and 10
have a lower content of anti-wrapped magnetite occluded
gangue. In contrast, samples 4, 5, 6, 7, and 8 were mainly
anti-wrapped magnetite occluded gangue. The main min-
eral in the outer core is magnetite, and therefore, magnetic
separation cannot remove the gangue impurities. During
the flotation process, the quartz cannot be exposed at the
flotation interface, which causes the collector to be unable
to float. This will make it more challenging to prepare ultra-
pure iron concentrate for samples No. 4–8.
Another factor that affects the beneficiation is the crys-
tal particle size of the target mineral. Figure 2(b) shows the
magnetite particle size distribution in the sample. It can be
seen that the magnetite in samples numbered 2, 4, 5, 6,
7, and 8 are mainly distributed in the particle size below
Raw ore
Pre-connection
Grinding
Weak magnetic
separation
Grinding
Electromagnetic Selection
Electromagnetic Selection
Electromagnetic Selection
Reverse flotation
Tailing 1
Tailing 2
Middling 1
Middling 2
Middling 3
Middling 4 Concentrate
Figure 1. Principle flows in the pre-concentration and magnetic separation-reverse
flotation process (PCMF)
former highly occluded mineral so that high-purity iron
concentrate could be obtained. Based on the results of the
above experiment, the feasibility of the process was verified
through semi-industrial tests.
RESULTS AND DISCUSSION
Establishment of an Evaluation System for Preparation
of High-Purity Iron Concentrate
To effectively determine whether any ordinary iron concen-
trate can be used to prepare high-purity iron concentrate,
it is essential to establish a feasibility assessment system.
Therefore, 10 kinds of concentrate from different regions
in China were selected to study the intrinsic relation-
ship between the mineralogy characteristics of raw mate-
rial processes and beneficiation indicators. Furthermore,
a feasibility evaluation system for preparing high-purity
iron concentrate was established to screen raw materi-
als for the rapid preparation of high-purity iron concen-
trate. As shown in Table 1, the total Fe grades of the ten
samples ranged from 63.46% to 66.86%. From the FeO
content, it can be seen that the primary occurrence state of
the iron element is magnetite. Thus, the iron concentrate
could be upgraded by the low-intensity magnetic separa-
tion. The prerequisite for efficient mineral separation in
mineral processing operations is the degree of dissociation
between the target mineral and gangue minerals. The type
of conjoined species is one of the critical factors affecting
the dissociation of mineral monomers. According to the
different occlusion methods, it can be divided into adjoin-
ing, wrapping, and anti-wrapping types. The main differ-
ence between the wrapping and anti-wrapping type is the
nature of core mineral in the wrapping. The anti-wrapped
type is that magnetite wraps fine-grained gangue minerals,
while the wrapped type is the opposite. Therefore, as shown
in Figure 2, microscopic observation was used to count
the types and contents of conjoined magnetite and gangue
minerals in the concentrate. Samples No. 1, 9, and 10
have a lower content of anti-wrapped magnetite occluded
gangue. In contrast, samples 4, 5, 6, 7, and 8 were mainly
anti-wrapped magnetite occluded gangue. The main min-
eral in the outer core is magnetite, and therefore, magnetic
separation cannot remove the gangue impurities. During
the flotation process, the quartz cannot be exposed at the
flotation interface, which causes the collector to be unable
to float. This will make it more challenging to prepare ultra-
pure iron concentrate for samples No. 4–8.
Another factor that affects the beneficiation is the crys-
tal particle size of the target mineral. Figure 2(b) shows the
magnetite particle size distribution in the sample. It can be
seen that the magnetite in samples numbered 2, 4, 5, 6,
7, and 8 are mainly distributed in the particle size below
Raw ore
Pre-connection
Grinding
Weak magnetic
separation
Grinding
Electromagnetic Selection
Electromagnetic Selection
Electromagnetic Selection
Reverse flotation
Tailing 1
Tailing 2
Middling 1
Middling 2
Middling 3
Middling 4 Concentrate
Figure 1. Principle flows in the pre-concentration and magnetic separation-reverse
flotation process (PCMF)