Controlled reduction of red mud by H2 followed by magnetic separation

Samouhos, Michail; Taxiarchou, Maria; Pilatos, G.; Tsakiridis, P.E.; Devlin, E.; Pissas, M.

doi:10.1016/j.mineng.2017.01.004

Cited by 69 publications

(20 citation statements)

References 16 publications

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“…With the increasing consumption of good-quality iron ores, the poor, fine, and complex domestic iron ore resources cannot meet the huge demand of the iron and steel industry in China. Thus, it is important to utilize low grade iron resources efficiently [2], such as high-aluminum iron resources including high-aluminum limonite and red mud, which is a residue generated after the clarification of bauxite [3].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore

Zhou

Luo

Chen

et al. 2018

Metals

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How to utilize low grade complex iron resources is an issue that has attracted much attention due to the continuous and huge consumption of iron ores in China. High-aluminum iron ore is a refractory resource and is difficult to upgrade by separating iron and alumina. An innovative technology involving synergistic reducing and synergistic smelting a high-aluminum iron ore containing 41.92% Fetotal, 13.74% Al2O3, and 13.96% SiO2 with a high-manganese iron ore assaying 9.24% Mntotal is proposed. The synergistic reduction process is presented and its enhancing mechanism is discussed. The results show that the generation of hercynite (FeAl2O4) and fayalite (Fe2SiO4) leads to a low metallization degree of 66.49% of the high-aluminum iron ore. Over 90% of the metallization degree is obtained by synergistic reducing with 60% of the high-manganese iron ore. The mechanism of synergistic reduction can be described as follows: MnO from the high-manganese ore chemically combines with Fe2SiO4 and FeAl2O4 to generate Mn2SiO4, MnAl2O4 and FeO, resulting in higher activity of FeO, which can be reduced to Fe in a CO atmosphere. The main products of the synergistic reduction process consist of Fe, Mn2SiO4, and MnAl2O4.

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Section: Introductionmentioning

confidence: 99%

Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore

Zhou

Luo

Chen

et al. 2018

Metals

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“…Parhi et al [11] reported the application of hydrogen for the reduction of the bauxite mineral, and found that only the iron oxide present in bauxite was reduced to iron, while other oxides remain unreduced. Samouhos et al [12] reported the reduction of red mud by H 2 , and found that the maximum conversion degree of hematite to magnetite that was achieved was above 87% at 480 • C. However, the formation amount of metallic iron is very insignificant (≤3 wt %). It is worth noting that natural gas is very scarce in China, and a gas-based direct reduction process (such as MIDREX, HYL-III, FINMET) is not likely to be the main direct reduced process in China [13,14].…”

Section: Of 16mentioning

confidence: 99%

Semi-Smelting Reduction and Magnetic Separation for the Recovery of Iron and Alumina Slag from Iron Rich Bauxite

Gao

Zhao

et al. 2019

Minerals

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This work presents a semi-smelting reduction and magnetic separation process for the recovery of iron and alumina slag from iron rich bauxite ore. The effect of the process parameters on the recovery rate of iron, maximum particle size of the iron nugget, and the Al2O3 content of the alumina slag was investigated and optimized. The results show that the iron nuggets and alumina slag can be obtained in a short time through a semi-smelting reduction and magnetic separation process. The maximum particle size of iron nugget is about 15 mm, and the recovery rate of the iron and Al2O3 grade of the alumina slag are 96.84 wt % and 43.98 wt %, respectively. The alumina slag consisted mainly of alumina (α-Al2O3), calcium hexaluminate (CaAl12O19), gehlenite (Ca2Al2SiO7), and small amounts of hercynite (FeAl4O7), and metallic iron (M.Fe).

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“…Therefore, both Na + and H + attached on P-200 surface in Zn 2+ adsorption. Zn 2+ was divalent-charged, which showed higher affinity to ≡SO − than monovalent Na + and H + [46], and the surface-bound Na + or H + were subsequently replaced (Equations (13) and (14)). The pH of the solution was equilibrated to 6.3, in which Zn was predominated in the form of Zn 2+ and ZnOH + [47].…”

Section: Adsorptionmentioning

confidence: 99%

“…The Fe oxides in red mud can be converted into magnetic magnetite after roasting under addition of pyrite [12], coal [13], or by injecting H 2 [14] and methane [15]. Liu et al [12] reported that part of the Fe oxides in red mud was converted into magnetite with pyrite as exogenous ferrous and reducing regent after calcination at 600 • C. Samouhos et al [14] reported that 87% of the hematite (Fe 2 O 3 ) in red mud was transformed into magnetite after roasting at 480 • C using H 2 as reductant. However, high temperatures were applied in these methods to promote the breakdown of the Fe-O-Si or Fe-O-Al bonds into the form of Fe-O-Fe linkage [16].…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Conversion of Red Mud into Magnetic Adsorbent for Effective Adsorption of Zn(II) in Water

et al. 2019

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Red mud, a Fe-rich waste generated from the aluminum industry, was recovered as an adsorbent for wastewater treatment. The separation process of red mud from water after adsorption, including centrifugation and filtration, was complicated. This study demonstrated an alternative option to recycle red mud for preparing magnetic adsorbent via a facile hydrothermal route using ascorbic acid as reductant. Red mud is weakly magnetized and consists of andradite, muscovite, hematite, and cancrinite. After hydrothermal treatment, andradite in red mud was reductively dissolved by ascorbic acid, and transformed into magnetite and morimotoite. With increasing hydrothermal temperature, the dissolution of andradite accelerated, and the crystallite size of magnetite increased. When the hydrothermal temperature reached 200 °C, the prepared adsorbent P-200 showed a desirable saturation magnetization of 4.1 Am2/kg, and could be easily magnetically separated from water after adsorption. The maximum adsorption capacity of P-200 for Zn2+ was 89.6 mg/g, which is eight-fold higher than that of the raw red mud. The adsorption of Zn2+ by P-200 fitted the Langmuir model, where cation exchange was the main adsorption mechanism. The average distribution coefficient of Zn2+ at low ppm level was 16.81 L/g for P-200, higher than those of the red mud (0.3 L/g) and the prepared P-120 (1.48 L/g) and P-270 (5.48 L/g), demonstrating that P-200 had the best adsorption capacity for Zn2+ and can be served as a practical adsorbent for real-world applications. To our knowledge, this is the first study to report the conversion of red mud into a magnetic adsorbent under mild conditions.

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Controlled reduction of red mud by H2 followed by magnetic separation

Cited by 69 publications

References 16 publications

Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore

Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore

Semi-Smelting Reduction and Magnetic Separation for the Recovery of Iron and Alumina Slag from Iron Rich Bauxite

Hydrothermal Conversion of Red Mud into Magnetic Adsorbent for Effective Adsorption of Zn(II) in Water

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