1975
Study on Enhancing Magnetic Separation Recovery of Ultrafine
Specularite by Polymer-Bridging Flocculation
Shuang Zhang, Wenbo Li, Shaokai Cheng
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
National-Local Joint Engineering Research Center of High-Efficient Exploitation Technology
for Refractory Iron Ore Resources, Shenyang, China
ABSTRACT: To minimize the loss of ultrafine specularite during high-intensity magnetic separation, two
starch flocculants have been developed to enhance magnetic recovery. This type of flocculant adsorbed by the
magnetic concentrate also acts as a depressant in the subsequent reverse flotation process, which has great
application potential. The results indicated that under the optimal conditions, the iron recovery, iron grade, and
beneficiation efficiency of the magnetic separation concentrate after treatment with CM-CS-60 and CM-TS-25
were increased by 16.9% and 23.9%, 3.78% and 6.34%, 17.07% and 23.47%, respectively. Related analytical
tests were performed to analyze the microscopic morphology of specularite flocs and the flocculation mechanism
of two starch agents on specularite. The polymer flocculants undergo hydrogen bonding and chemical adsorption
on the surface of specularite without interacting with quartz, exhibiting excellent selectivity.
Keywords: starch flocculant pharmaceutical modification ultrafine specularite high-intensity magnetic
separation
INTRODUCTION
Iron ore resources are abundant in China but are primar-
ily complex and challenging to process [1, 2]. The domi-
nant method for separating such ores is low/high-intensity
magnetic separation-reverse flotation [3]. However, the
efficiency of high-intensity magnetic separation for fine-
grained iron minerals is low, with tailings constituting
over 75% of the total tailings discharge [4]. This signifi-
cantly hampers the utilization of weakly magnetic iron ore
resources. Therefore, improving the recovery of fine-grained
iron minerals is crucial for enhancing ore utilization and
achieving emission reduction and efficiency increase. The
pre-addition of flocculants before high-intensity magnetic
separation can selectively aggregate fine iron ore, increas-
ing the apparent particle size and thereby improving the
recovery of iron minerals [5–7]. Comparative analysis of
flocculant characteristics indicates that high-molecular-
weight polysaccharide flocculants have significant potential
[8]. These flocculants exhibit excellent selectivity, and when
introduced into the high-intensity magnetic concentrate,
they can effectively act as inhibitors for iron minerals in
reverse flotation. This has no adverse effects on flotation
and proactively suppresses iron minerals.
Common polymeric polysaccharides include cassava
starch, corn starch, chitosan, cellulose, and chitin. Li et al.
[9] used starch as the raw material, ethanol as the solvent,
and chloroacetic acid as the etherification agent to prepare
high-substitution carboxymethyl starch drugs using a sec-
ondary alkali addition method, with a maximum substitu-
tion degree of up to 1.21. Deng et al. [10] used chitosan as

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Extracted Text (may have errors)

1975
Study on Enhancing Magnetic Separation Recovery of Ultrafine
Specularite by Polymer-Bridging Flocculation
Shuang Zhang, Wenbo Li, Shaokai Cheng
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
National-Local Joint Engineering Research Center of High-Efficient Exploitation Technology
for Refractory Iron Ore Resources, Shenyang, China
ABSTRACT: To minimize the loss of ultrafine specularite during high-intensity magnetic separation, two
starch flocculants have been developed to enhance magnetic recovery. This type of flocculant adsorbed by the
magnetic concentrate also acts as a depressant in the subsequent reverse flotation process, which has great
application potential. The results indicated that under the optimal conditions, the iron recovery, iron grade, and
beneficiation efficiency of the magnetic separation concentrate after treatment with CM-CS-60 and CM-TS-25
were increased by 16.9% and 23.9%, 3.78% and 6.34%, 17.07% and 23.47%, respectively. Related analytical
tests were performed to analyze the microscopic morphology of specularite flocs and the flocculation mechanism
of two starch agents on specularite. The polymer flocculants undergo hydrogen bonding and chemical adsorption
on the surface of specularite without interacting with quartz, exhibiting excellent selectivity.
Keywords: starch flocculant pharmaceutical modification ultrafine specularite high-intensity magnetic
separation
INTRODUCTION
Iron ore resources are abundant in China but are primar-
ily complex and challenging to process [1, 2]. The domi-
nant method for separating such ores is low/high-intensity
magnetic separation-reverse flotation [3]. However, the
efficiency of high-intensity magnetic separation for fine-
grained iron minerals is low, with tailings constituting
over 75% of the total tailings discharge [4]. This signifi-
cantly hampers the utilization of weakly magnetic iron ore
resources. Therefore, improving the recovery of fine-grained
iron minerals is crucial for enhancing ore utilization and
achieving emission reduction and efficiency increase. The
pre-addition of flocculants before high-intensity magnetic
separation can selectively aggregate fine iron ore, increas-
ing the apparent particle size and thereby improving the
recovery of iron minerals [5–7]. Comparative analysis of
flocculant characteristics indicates that high-molecular-
weight polysaccharide flocculants have significant potential
[8]. These flocculants exhibit excellent selectivity, and when
introduced into the high-intensity magnetic concentrate,
they can effectively act as inhibitors for iron minerals in
reverse flotation. This has no adverse effects on flotation
and proactively suppresses iron minerals.
Common polymeric polysaccharides include cassava
starch, corn starch, chitosan, cellulose, and chitin. Li et al.
[9] used starch as the raw material, ethanol as the solvent,
and chloroacetic acid as the etherification agent to prepare
high-substitution carboxymethyl starch drugs using a sec-
ondary alkali addition method, with a maximum substitu-
tion degree of up to 1.21. Deng et al. [10] used chitosan as

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1974 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
of each valuable component is extremely low, far below the
industrial grade that can be economically utilized. Among
them, the mFe content is about 5%, while Cu and P2O5
contents are approximately 0.04% and 2%, respectively. It
is technically difficult for comprehensive recovery to taking
into account both economy and efficiency.
This paper proposes the concept of performing the
main separation process under rough grinding conditions
and reducing the feed quantity by multistage pre concen-
tration. This will allow for a high efficiency comprehensive
recovery flowsheet that is flexible and that can fully utilize
the properties of the ore. The industrial test results demon-
strate that an iron concentrate with a TFe grade of 65.23%
and an TFe recovery of 46.82%. The resulting phosphate
concentrate boasts a P2O5 grade of 33.10% and a recovery
of 63.04%. Additionally, the copper concentrate exhibits
a Cu grade of 16.12% with a recovery of 41.46%. These
outcomes indicate successful simultaneous recovery of iron,
phosphorus, and copper, showcasing favorable technical
and economic performance. The insights gleaned from this
study provide valuable guidance for similar mines aiming
to optimize their recovery processes.
FUNDING
This work was supported by National Key R&D Program
of China No.2022YFC2904702.
DATA AVAILABILITY STATEMENT
Not applicable.
CONFLICTS OF INTEREST
The authors declare no conflict of interest.
REFERENCES
[1] Wu Q J, Lv Z F, Cao J C.Research on the develop-
ment and utilization of iron ore large resource bases in
China[J]. Modern Ming, 2020,36(8):113–115,138.
[2] Yuan R C. Application and development trend of
new mineral processing technologys in ultra-lean
magnetite[J]. Modern Ming, 2022, 38 (11): 133–136.
[3] Li Y, Wang Y K, Niu Y P, et al. Experimental Study
on Mineral Processing of a Vanadium-bearing Ultra-
lean Magnetite Ore in Heilongj iang[J]. Nonferrous
Metals(Mineral processing section),2022(3):108–112.
[4] Zhou H H.Test of improving the quality and reducing
impurity for a ultralow-grade magnetite in Hebei[J].
Nonferrous Metals(Mineral processing section),2016,
(01): 52–55.
[5] Ruan Y Y, He D S, Chi R A. Review on beneficiation
techniques and reagents used for phosphate ores[J].
Minerals, 9 (2019) 253, doi: 10.3390/MIN9040253.
[6] Muhammad S, Ghulam B, Muhammad A,et
al.Synoptic view on P ore beneficiation techniques[J].
Alexandria Engineering Journal, 2022,61,3069–3092.
[7] Ao F S, Zhu J R, Xu F, et al. Application progress
of preconcentration and discarding technology[J].
Conservation and utilization of mineral resources, 2021,
41 (04): 157–163.
[8] Wang L, Teng X D, Wang S, et al. Experimental study
of dry preconcentration on ultralow-grade magnetite
ores [J]. China Mining Magazine, 2016, 25 (01):
115–117.
[9] Wang D Z.The research of Ultra-poor magnetite wet
coarse particles and sorting process[J]. China Mining
Magazine,2013,22(3):91–94.

Previous Page Next Page

Extracted Text (may have errors)

1974 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
of each valuable component is extremely low, far below the
industrial grade that can be economically utilized. Among
them, the mFe content is about 5%, while Cu and P2O5
contents are approximately 0.04% and 2%, respectively. It
is technically difficult for comprehensive recovery to taking
into account both economy and efficiency.
This paper proposes the concept of performing the
main separation process under rough grinding conditions
and reducing the feed quantity by multistage pre concen-
tration. This will allow for a high efficiency comprehensive
recovery flowsheet that is flexible and that can fully utilize
the properties of the ore. The industrial test results demon-
strate that an iron concentrate with a TFe grade of 65.23%
and an TFe recovery of 46.82%. The resulting phosphate
concentrate boasts a P2O5 grade of 33.10% and a recovery
of 63.04%. Additionally, the copper concentrate exhibits
a Cu grade of 16.12% with a recovery of 41.46%. These
outcomes indicate successful simultaneous recovery of iron,
phosphorus, and copper, showcasing favorable technical
and economic performance. The insights gleaned from this
study provide valuable guidance for similar mines aiming
to optimize their recovery processes.
FUNDING
This work was supported by National Key R&D Program
of China No.2022YFC2904702.
DATA AVAILABILITY STATEMENT
Not applicable.
CONFLICTS OF INTEREST
The authors declare no conflict of interest.
REFERENCES
[1] Wu Q J, Lv Z F, Cao J C.Research on the develop-
ment and utilization of iron ore large resource bases in
China[J]. Modern Ming, 2020,36(8):113–115,138.
[2] Yuan R C. Application and development trend of
new mineral processing technologys in ultra-lean
magnetite[J]. Modern Ming, 2022, 38 (11): 133–136.
[3] Li Y, Wang Y K, Niu Y P, et al. Experimental Study
on Mineral Processing of a Vanadium-bearing Ultra-
lean Magnetite Ore in Heilongj iang[J]. Nonferrous
Metals(Mineral processing section),2022(3):108–112.
[4] Zhou H H.Test of improving the quality and reducing
impurity for a ultralow-grade magnetite in Hebei[J].
Nonferrous Metals(Mineral processing section),2016,
(01): 52–55.
[5] Ruan Y Y, He D S, Chi R A. Review on beneficiation
techniques and reagents used for phosphate ores[J].
Minerals, 9 (2019) 253, doi: 10.3390/MIN9040253.
[6] Muhammad S, Ghulam B, Muhammad A,et
al.Synoptic view on P ore beneficiation techniques[J].
Alexandria Engineering Journal, 2022,61,3069–3092.
[7] Ao F S, Zhu J R, Xu F, et al. Application progress
of preconcentration and discarding technology[J].
Conservation and utilization of mineral resources, 2021,
41 (04): 157–163.
[8] Wang L, Teng X D, Wang S, et al. Experimental study
of dry preconcentration on ultralow-grade magnetite
ores [J]. China Mining Magazine, 2016, 25 (01):
115–117.
[9] Wang D Z.The research of Ultra-poor magnetite wet
coarse particles and sorting process[J]. China Mining
Magazine,2013,22(3):91–94.

1976 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
the raw material, ethanol as the solvent, and chloroacetic
acid as the etherification agent to prepare carboxymethyl
chitosan. According to the experimental results, when the
volume fraction of ethanol is 90%, the yield of carboxy-
methyl chitosan is the highest. Li et al. [11] proposed a
new process of selective dispersion-flocculation-magnetic
separation. The process involves using the reagent YL-1
for selective flocculation of iron tailings from the Yunnan
Shangchang factory, followed by high-gradient magnetic
separation. Ultimately, a concentrate with an iron grade of
59.63% and an iron recovery rate of 50.41% was obtained.
This article explores the development of modified
agents based on starch flocculants to enhance the mag-
netic separation efficiency of fine-grained iron minerals.
Through flocculation-magnetic separation experiments
on fine-grained specularite, the study investigates the
enhanced recovery effects of carboxymethyl corn starch
and carboxymethyl cassava starch with different degrees of
substitution on single minerals. The objective is to identify
the polymer flocculant with the optimal flocculation effect.
Additionally, the article employs electron microscopy, Zeta
potential measurements, and FTIR analysis to observe and
analyze the selectivity of modified agents and the interac-
tion mechanisms between the agents and minerals.
MATERIALS AND METHODS
Samples and Reagents
Chemical composition analysis was conducted on a specu-
larite sample taken from Brazil, and the result is presented
in Table 1. The sample’s total iron (TFe) content is 68.95%,
including 0.16% of FeO. The impurity SiO2 content is
1.31%, followed by small amounts of CaO and Al2O3. The
harmful elements S and P are present in concentrations less
than 0.1%. XRD was employed to determine the mineral
composition of the specularite sample, and the results are
depicted in Figure 1a. In Figure 1a, it is evident that the
predominant iron mineral in the sample is hematite. After
grinding, a specularite single mineral was prepared with
–12.5 μm particle size by hydraulic analysis method, and
its particle size characteristic is shown in Figure 2a. From
Figure 2a, the average particle size of the specularite single
mineral is 8.29 μm, and the particle size distribution of
each particle grade is uniform, meeting the experimental
requirements.
The procedure involved the use of a ceramic ball mill for
the fine grinding of quartz powder ore. Subsequently, the
quartz was soaked in hydrochloric acid with a concentration
of 10%, followed by repeated washing with deionized water
Table 1. Chemical composition analysis of samples (wt%)
Composition of Specularite TFe FeO SiO
2 Al
2 O
3 S P
Content 68.95 0.16 1.31 0.20 0.005 0.01
Composition of Quartz SiO2 Al2O3 MgO CaO Na2O K2O
Content 99.11 0.18 0.18 0.05 0.05 0.01
Figure 1. XRD pattern of specularite (a) and quartz (b)

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Extracted Text (may have errors)

1976 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
the raw material, ethanol as the solvent, and chloroacetic
acid as the etherification agent to prepare carboxymethyl
chitosan. According to the experimental results, when the
volume fraction of ethanol is 90%, the yield of carboxy-
methyl chitosan is the highest. Li et al. [11] proposed a
new process of selective dispersion-flocculation-magnetic
separation. The process involves using the reagent YL-1
for selective flocculation of iron tailings from the Yunnan
Shangchang factory, followed by high-gradient magnetic
separation. Ultimately, a concentrate with an iron grade of
59.63% and an iron recovery rate of 50.41% was obtained.
This article explores the development of modified
agents based on starch flocculants to enhance the mag-
netic separation efficiency of fine-grained iron minerals.
Through flocculation-magnetic separation experiments
on fine-grained specularite, the study investigates the
enhanced recovery effects of carboxymethyl corn starch
and carboxymethyl cassava starch with different degrees of
substitution on single minerals. The objective is to identify
the polymer flocculant with the optimal flocculation effect.
Additionally, the article employs electron microscopy, Zeta
potential measurements, and FTIR analysis to observe and
analyze the selectivity of modified agents and the interac-
tion mechanisms between the agents and minerals.
MATERIALS AND METHODS
Samples and Reagents
Chemical composition analysis was conducted on a specu-
larite sample taken from Brazil, and the result is presented
in Table 1. The sample’s total iron (TFe) content is 68.95%,
including 0.16% of FeO. The impurity SiO2 content is
1.31%, followed by small amounts of CaO and Al2O3. The
harmful elements S and P are present in concentrations less
than 0.1%. XRD was employed to determine the mineral
composition of the specularite sample, and the results are
depicted in Figure 1a. In Figure 1a, it is evident that the
predominant iron mineral in the sample is hematite. After
grinding, a specularite single mineral was prepared with
–12.5 μm particle size by hydraulic analysis method, and
its particle size characteristic is shown in Figure 2a. From
Figure 2a, the average particle size of the specularite single
mineral is 8.29 μm, and the particle size distribution of
each particle grade is uniform, meeting the experimental
requirements.
The procedure involved the use of a ceramic ball mill for
the fine grinding of quartz powder ore. Subsequently, the
quartz was soaked in hydrochloric acid with a concentration
of 10%, followed by repeated washing with deionized water
Table 1. Chemical composition analysis of samples (wt%)
Composition of Specularite TFe FeO SiO
2 Al
2 O
3 S P
Content 68.95 0.16 1.31 0.20 0.005 0.01
Composition of Quartz SiO2 Al2O3 MgO CaO Na2O K2O
Content 99.11 0.18 0.18 0.05 0.05 0.01
Figure 1. XRD pattern of specularite (a) and quartz (b)