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A Novel Approach for Separating Iron and Rare Earths from
Complex Polymetallic Ores via Hydrogen-Based Mineral
Phase Transformation: A Pilot-Scale Study
Jilai Ning, Peng Gao, Shuai Yuan, Yuexin Han, Yongsheng Sun, Wenbo Li
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: Bayan Obo low grade iron ore (BOLIO), which has been abandoned for many years due to its
difficult beneficiation. In this pilot -scale study, the hydrogen -based mineral phase transformation (HMPT)
technology and associated equipment were used to successfully separate iron and rare earths from BOLIO,
demonstrating stable operation for 48 hours. Optimal HMPT conditions included a feed rate of 120 kg/h,
HMPT temperature of 500°C, gas flow rate of 3.5 m3/h and gas concentration of 22.5 vol%. After grinding
and flotation, the iron concentrate obtained had a TFe grade of 65.26 wt% with a recovery of 85.29 wt% and
a low F content of 0.28 wt%. Product analysis revealed phase transformations of iron and rare earths during
the HMPT process, which increased the magnetic difference between magnetic and non -magnetic products.
The formation of pores and cracks during the process also facilitated the subsequent separation of iron and rare
earths. This study paves the way for clean, efficient iron and rare earth separation with regional mineral recovery
potential.
Keywords: Hydrogen based mineral phase transformation, Iron ore, Magnetic separation
INTRODUCTION
The iron and steel industry is crucial to the economic and
industrial development of any country. It serves not only
as the foundation of the national industrial system, but
also as a key indicator of a nation’s level of industrializa-
tion and overall national strength (Tang et al., 2021 Wu et
al., 2023). The Bayan Obo region, known for its rich min-
eral resources, particularly its vast reserves of iron ore, rare
earths and fluorite, has become a global focal point (Liu
et al., 2022 She et al., 2021a). The effective development
and utilization of these resources is of great importance in
promoting the growth of the steel industry both regionally
and globally.
As China’s crude steel production continues to grow
steadily, traditional high-grade iron ore resources are gradu-
ally being depleted. This has led the industry to pay more
attention to the development and utilization of low-grade,
difficult-to-process iron ores (Bhaskar et al., 2020 Cheng et
al., 2023). In the Bayan Obo region, more than 20 million
tons of such low-grade and complex iron ores have been
underutilized for a long time (Liu et al., 2020 She et al.,
2021b). This is mainly due to their complex composition,
A Novel Approach for Separating Iron and Rare Earths from
Complex Polymetallic Ores via Hydrogen-Based Mineral
Phase Transformation: A Pilot-Scale Study
Jilai Ning, Peng Gao, Shuai Yuan, Yuexin Han, Yongsheng Sun, Wenbo Li
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: Bayan Obo low grade iron ore (BOLIO), which has been abandoned for many years due to its
difficult beneficiation. In this pilot -scale study, the hydrogen -based mineral phase transformation (HMPT)
technology and associated equipment were used to successfully separate iron and rare earths from BOLIO,
demonstrating stable operation for 48 hours. Optimal HMPT conditions included a feed rate of 120 kg/h,
HMPT temperature of 500°C, gas flow rate of 3.5 m3/h and gas concentration of 22.5 vol%. After grinding
and flotation, the iron concentrate obtained had a TFe grade of 65.26 wt% with a recovery of 85.29 wt% and
a low F content of 0.28 wt%. Product analysis revealed phase transformations of iron and rare earths during
the HMPT process, which increased the magnetic difference between magnetic and non -magnetic products.
The formation of pores and cracks during the process also facilitated the subsequent separation of iron and rare
earths. This study paves the way for clean, efficient iron and rare earth separation with regional mineral recovery
potential.
Keywords: Hydrogen based mineral phase transformation, Iron ore, Magnetic separation
INTRODUCTION
The iron and steel industry is crucial to the economic and
industrial development of any country. It serves not only
as the foundation of the national industrial system, but
also as a key indicator of a nation’s level of industrializa-
tion and overall national strength (Tang et al., 2021 Wu et
al., 2023). The Bayan Obo region, known for its rich min-
eral resources, particularly its vast reserves of iron ore, rare
earths and fluorite, has become a global focal point (Liu
et al., 2022 She et al., 2021a). The effective development
and utilization of these resources is of great importance in
promoting the growth of the steel industry both regionally
and globally.
As China’s crude steel production continues to grow
steadily, traditional high-grade iron ore resources are gradu-
ally being depleted. This has led the industry to pay more
attention to the development and utilization of low-grade,
difficult-to-process iron ores (Bhaskar et al., 2020 Cheng et
al., 2023). In the Bayan Obo region, more than 20 million
tons of such low-grade and complex iron ores have been
underutilized for a long time (Liu et al., 2020 She et al.,
2021b). This is mainly due to their complex composition,
