1853
Fluidized Reduction Behaviors of Boron-bearing Iron
Concentrate Using Hydrogen as Reductant
Jianwen Yu, Yuexin Han, Peng Gao
School of Resources and Civil Engineering, Northeastern University, Shenyang, P.R. China
State Key Laboratory of Rolling and Automation, Shenyang, China
National-local Joint Engineering Research Center of High-Efficient Exploitation Technology for
Refractory Iron Ore Resources, Shenyang, P.R. China
Peiyu Li, Yanjun Li
School of Resources and Civil Engineering, Northeastern University, Shenyang, P.R. China
National-local Joint Engineering Research Center of High-Efficient Exploitation Technology for
Refractory Iron Ore Resources, Shenyang, P.R. China
ABSTRACT: A novel method for the efficient and clean reduction of boron-bearing iron concentrate using
hydrogen as reductant under fluidized bed conditions was proposed, and the reduction process of boron-bearing
iron concentrate within 500–850 °C was discussed. At 500–550 °C, the magnetite was directly reduced to
porous metallic iron. Above 600°C, magnetite was first reduced to wüstite, and then to dense metallic iron,
resulting in a rapid drop in metallization degree at 600–650 °C. Further increasing the reduction temperature
to 700 °C, the metallization degree gradually increased due to the formation of cracks and the gradual reduction
of ludwigite. Under the optimal reduction temperature of 800 °C, H2 concentration of 80% and reduction time
of 40 min, the roasted product with a metallization degree of 82.95% was obtained, providing high-quality raw
materials for smelting or magnetic separation of boron and iron.
INTRODUCTION
In Liaoning Province, China, there are about 280 million
tons of ludwigite ore, with an average composition of B2O3
7%, TFe 30%, MgO 24% and SiO2 15%, accounting for
58% of China’s boron reserves (Fu et al., 2018 Liu et al.,
2006 Sui et al., 1999). Traditional ore dressing methods
(stage grinding- stage magnetic separation- hydro cyclone
separation) only separate initially and obtain qualified
boron concentrate (B2O3≥12 wt %)(Chu et al., 2016
Han et al., 2016 You et al., 2022). However, the con-
tent of B2O3 and TFe in boron tailings reaches 4–6% and
50%–55%, respectively (Li and Han, 2015). The boron-
bearing iron concentrate is only used as blending ores for
blast furnace sintering and pelletizing, and this portion of
boron cannot be recovered once it enters the slag, resulting
in a waste of boron resources (An and Xue, 2014 Guo et
al., 2014).
Currently, the mainstream process of secondary sepa-
ration of boron and iron is the pyrometallurgical process,
including direct reduction -electric arc furnace (EAF) melt-
ing or magnetic separation, sodium roasting -water leach-
ing, etc. (Li et al., 2014 Liang et al., 2017 Wang et al.,
Fluidized Reduction Behaviors of Boron-bearing Iron
Concentrate Using Hydrogen as Reductant
Jianwen Yu, Yuexin Han, Peng Gao
School of Resources and Civil Engineering, Northeastern University, Shenyang, P.R. China
State Key Laboratory of Rolling and Automation, Shenyang, China
National-local Joint Engineering Research Center of High-Efficient Exploitation Technology for
Refractory Iron Ore Resources, Shenyang, P.R. China
Peiyu Li, Yanjun Li
School of Resources and Civil Engineering, Northeastern University, Shenyang, P.R. China
National-local Joint Engineering Research Center of High-Efficient Exploitation Technology for
Refractory Iron Ore Resources, Shenyang, P.R. China
ABSTRACT: A novel method for the efficient and clean reduction of boron-bearing iron concentrate using
hydrogen as reductant under fluidized bed conditions was proposed, and the reduction process of boron-bearing
iron concentrate within 500–850 °C was discussed. At 500–550 °C, the magnetite was directly reduced to
porous metallic iron. Above 600°C, magnetite was first reduced to wüstite, and then to dense metallic iron,
resulting in a rapid drop in metallization degree at 600–650 °C. Further increasing the reduction temperature
to 700 °C, the metallization degree gradually increased due to the formation of cracks and the gradual reduction
of ludwigite. Under the optimal reduction temperature of 800 °C, H2 concentration of 80% and reduction time
of 40 min, the roasted product with a metallization degree of 82.95% was obtained, providing high-quality raw
materials for smelting or magnetic separation of boron and iron.
INTRODUCTION
In Liaoning Province, China, there are about 280 million
tons of ludwigite ore, with an average composition of B2O3
7%, TFe 30%, MgO 24% and SiO2 15%, accounting for
58% of China’s boron reserves (Fu et al., 2018 Liu et al.,
2006 Sui et al., 1999). Traditional ore dressing methods
(stage grinding- stage magnetic separation- hydro cyclone
separation) only separate initially and obtain qualified
boron concentrate (B2O3≥12 wt %)(Chu et al., 2016
Han et al., 2016 You et al., 2022). However, the con-
tent of B2O3 and TFe in boron tailings reaches 4–6% and
50%–55%, respectively (Li and Han, 2015). The boron-
bearing iron concentrate is only used as blending ores for
blast furnace sintering and pelletizing, and this portion of
boron cannot be recovered once it enters the slag, resulting
in a waste of boron resources (An and Xue, 2014 Guo et
al., 2014).
Currently, the mainstream process of secondary sepa-
ration of boron and iron is the pyrometallurgical process,
including direct reduction -electric arc furnace (EAF) melt-
ing or magnetic separation, sodium roasting -water leach-
ing, etc. (Li et al., 2014 Liang et al., 2017 Wang et al.,