Preparation of Niobium Metal Powder by Two-Stage Magnesium Vapor Reduction of Niobium Pentoxide

Direct electrochemical reduction of iron ore in concentrated NaOH electrolyte has been proposed as a potential route to substantially reducing the global steel industry’s CO2 emissions. Here, we report the solid-state electro-reduction of sintered pellets formed from titanomagnetite ironsand. This commercial iron ore contains ∼4 wt.% Ti which is directly incorporated within the magnetite lattice. At 110 °C, these pellets are electrochemically reduced and exhibit a well-defined reaction front which moves into the pellet as the reaction progresses. The electro-reduction process selectively produces iron metal, whilst the Ti content is not reduced. Instead, Ti becomes enriched in segregated oxide inclusions, which are subsequently transformed to a sodium iron titanate phase through taking up Na+ from the electrolyte. These inclusions adopt an elongated shape and appear to exhibit locally preferential alignment. This suggests that they may nucleate from the microscopic titanohematite lamellae which naturally occur within the original ironsand particles. The expulsion of contaminant Ti-oxides from the final reduced metal matrix has implications for the potential to development of an industrial electrochemical iron-making process utilising titanomagnetite ore. © 2020 The Author(s). Published by IOP Publishing Ltd.

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Characterization of the ultrafine and fine particles formed during laser cladding with the Inconel 718 metal powder by means of X-ray spectroscopic techniques

Spectrochimica Acta Part B Atomic Spectroscopy ◽

10.1016/j.sab.2021.106110 ◽

2021 ◽

Vol 177 ◽

pp. 106110

Author(s):

Szilvia Kugler ◽

Attila Nagy ◽

János Osán ◽

László Péter ◽

Veronika Groma ◽

...

Keyword(s):

Metal Powder ◽

Laser Cladding ◽

Inconel 718 ◽

Fine Particles ◽

Spectroscopic Techniques ◽

X Ray

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Fate of titanium in alkaline electro-reduction of sintered titanomagnetite

10.26686/wgtn.14331635.v1 ◽

2021 ◽

Author(s):

O Bjareborn ◽

Tanzeel Arif ◽

B Monaghan ◽

Christopher Bumby

Keyword(s):

Reaction Front ◽

Iron Ore ◽

Reduction Process ◽

Ti Oxides ◽

Iron Metal ◽

Reduction Of Iron ◽

Iron Titanate ◽

Commercial Iron ◽

Ti Content ◽

Preferential Alignment

Direct electrochemical reduction of iron ore in concentrated NaOH electrolyte has been proposed as a potential route to substantially reducing the global steel industry’s CO2 emissions. Here, we report the solid-state electro-reduction of sintered pellets formed from titanomagnetite ironsand. This commercial iron ore contains ∼4 wt.% Ti which is directly incorporated within the magnetite lattice. At 110 °C, these pellets are electrochemically reduced and exhibit a well-defined reaction front which moves into the pellet as the reaction progresses. The electro-reduction process selectively produces iron metal, whilst the Ti content is not reduced. Instead, Ti becomes enriched in segregated oxide inclusions, which are subsequently transformed to a sodium iron titanate phase through taking up Na+ from the electrolyte. These inclusions adopt an elongated shape and appear to exhibit locally preferential alignment. This suggests that they may nucleate from the microscopic titanohematite lamellae which naturally occur within the original ironsand particles. The expulsion of contaminant Ti-oxides from the final reduced metal matrix has implications for the potential to development of an industrial electrochemical iron-making process utilising titanomagnetite ore. © 2020 The Author(s). Published by IOP Publishing Ltd.

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Phase transformation involved in the reduction process of magnesium oxide in calcined dolomite by ferrosilicon with additive of aluminum

Green Processing and Synthesis ◽

10.1515/gps-2020-0017 ◽

2020 ◽

Vol 9 (1) ◽

pp. 164-170

Author(s):

Hongzhou Ma ◽

Zhixian Wang ◽

Yaoning Wang ◽

Dingding Wang

Keyword(s):

Phase Transformation ◽

Magnesium Oxide ◽

Calcium Oxide ◽

Silicon Oxide ◽

Reduction Process ◽

Magnesium Vapor ◽

Oxide Reduction ◽

Internal Mechanism ◽

Heating Up ◽

Reaction Speed

AbstractMetal magnesium is mainly produced from the calcined dolomite by the silicothermic production. However, in this process, the reduction temperature is higher while the reaction speed is slow, which results in higher energy consumption and serious environmental problems. In this paper, adding aluminum into the ferrosilicon reducing agent is expected to lower the reaction temperature so as to solve the problems above. The phase transition involved in the whole reduction process including with and without aluminum addition were investigated in details by theoretical calculation and experimental research. The influence of aluminum on the magnesium oxide reduction path was analysis to clarify the internal mechanism. The results show that aluminum added into the ferrosilicon would first react with magnesium oxide to form magnesium vapor and alumina under vacuum pressure of 10 Pa when the temperature rises to 720°C. Then, calcium aluminate would be formed by the reaction of aluminum oxide and calcium oxide. Once the temperature reaches 1150°C, silicon begins to reduce the magnesium oxide to create the silicon oxide that will finally react with calcium oxide to form calcium silicate. When the temperature rises above 1150°C, both the aluminum and silicon will participate in the reduction of magnesium oxide. In the process of heating up, the mixture of aluminum, ferrosilicon and calcined dolomite forms Mg2Al4Si5O18 and Ca3Al2(OH)12 phase with the components in calcined dolomite. Mg2Al4Si5O18 and Ca3Al2(OH)12 phase finally form Ca12Al14O33 phase. The interaction between aluminum and ferrosilicon in the mixture is less; the mixture of aluminum and ferrosilicon first forms Al3FeSi2 phase, and finally has the trend of forming Al4.5FeSi phase. There is a great difference between the phase transformation of aluminum in the mixture of aluminum, ferrosilicon and calcined dolomite and that of aluminum in the mixture of aluminum and ferrosilicon.

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Coal-Based Reduction on Flotation Middling from Iron Ore Containing Carbonate at Donganshan

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.826.20 ◽

2013 ◽

Vol 826 ◽

pp. 20-24

Author(s):

Duo Zhen Ren ◽

Hui Wen Zhou ◽

Peng Gao ◽

Yue Xin Han

Keyword(s):

Chemical Analysis ◽

Layer Thickness ◽

Iron Ore ◽

Fine Particles ◽

Reduction Process ◽

Reduction Temperature ◽

Iron Recovery ◽

Low Intensity ◽

Three Stages ◽

Optimal Reduction

In this paper, coal-based reduction on flotation middling from iron ore containing carbonate at donganshan was studied, during which the effect of reduction temperature, reduction time, C/O mole ratio and feed layer thickness on reduction process were carried out. The results showed that the optimal reduction conditions required a temperature of 1250°C,a duration of 70min, a C/O mole ratio of 2.0 and a feed layer thickness of 25mm, and the iron powder containing 90.27% Fe with iron recovery of 93.36% was obtained after three stages low intensity magnetic separation, which could be used to make steel. According to the chemical analysis, most of the iron minerals were reduced to metallic iron. Coal-based reduction proved to be an alternative and promising process to conduct the fine particles and powders.

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Hf metal powder synthesis via a chemically activated combustion-reduction process

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2021.124417 ◽

2021 ◽

Vol 263 ◽

pp. 124417

Author(s):

Hayk Nersisyan ◽

Hwa Young Woo ◽

Vladislav Ri ◽

Huynh Thanh-Nam ◽

Frank Moon ◽

...

Keyword(s):

Metal Powder ◽

Reduction Process ◽

Powder Synthesis

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Magnesium Vapor Reduction of Structured Silica for Lithium Ion Battery Applications

MRS Proceedings ◽

10.1557/opl.2014.289 ◽

2014 ◽

Vol 1643 ◽

Author(s):

Rob Cook ◽

Matthew Schrandt ◽

Praveen Kolla ◽

Wendell Rhine ◽

Ranjit Koodali ◽

...

Keyword(s):

Lithium Ion Battery ◽

Reduction Process ◽

Lithium Ion ◽

Thermal Reduction ◽

Morphological Properties ◽

Magnesium Vapor ◽

X Ray Diffraction ◽

Silicon Nanostructure ◽

Magnesium Thermal Reduction ◽

By Products

ABSTRACTThree types of silica materials with different morphology, specifically SiO2 hollow microspheres, mesoporous silica, and silica aerogel were tested as potential precursors for synthesis of silicon nano- and meso-structures that resemble the original morphology of the precursors. In the optimized magnesium thermal reduction process, magnesium vapor was delivered to silica surface through a stainless steel mesh placed on top of a zirconia boat filled with silica precursor. This approach allowed for better control of silicon nanostructure formation by minimizing reaction by-products that can affect performance of lithium ion battery anode. Material morphological properties of the reduced silica precursors are discussed in terms of X-ray diffraction, BET, BJH pore size distribution, Raman spectroscopy, and TGA.

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Synthesis of Vanadium Powder by Magnesiothermic Reduction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.509 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 509-514 ◽

Cited By ~ 1

Author(s):

Dong Won Lee ◽

Hak Sung Lee ◽

Jung Yeul Yun ◽

Young Ho Kim ◽

Jei Pil Wang

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Chemical Composition ◽

Fine Particles ◽

Reduction Process ◽

Hydrogen Gas ◽

Raw Material ◽

Magnesiothermic Reduction ◽

Vanadium Metal ◽

Scanning Electron

Vanadium metal powder was successfully synthesized by combination reduction process with hydrogen gas and liquid magnesium. V2O5 as a raw material was first reduced by hydrogen gas to produce V2O3 at 873K for 3 hours and then it was reduced by liquid magnesium at 1,073K for 48 hours to become final vanadium powder. The microstructure and chemical composition of pure vanadium powder fabricated were examined by SEM(Scanning Electron Microscopy) and EDX(energy dispersive spectroscopy), respectively. The oxygen content of vanadium powder was finally found to be 0.5 wt.% showing the structure loosely agglomerated with fine particles of about 1~2μm.

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Phase Transformation of Diatomite during Magnesiothermic Reduction Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.833.230 ◽

2013 ◽

Vol 833 ◽

pp. 230-233

Author(s):

Shu Yue Liu ◽

Ming Hao Fang ◽

Zhao Hui Huang ◽

Hai Peng Ji ◽

Xin Min ◽

...

Keyword(s):

Phase Transformation ◽

Phase Behavior ◽

Reduction Process ◽

Molar Ratio ◽

Magnesiothermic Reduction ◽

Magnesium Vapor ◽

Reaction Products ◽

Low Reaction Temperature ◽

Hcl Solution ◽

Reduction Effectiveness

In this study the phase behavior of diatomite during magnesiothermic reduction process was investigated. Two packing routes were adopted to estimate the reduction effectiveness at a low reaction temperature of 650 °C for 2h. The phase and microstructure evolution of diatomite were investigated by XRD, SEM, EDS. The results show that diatomite was sucessessfully reduced by the magnesium vapor and reaction products were Si, MgO, and Mg2Si when the raw diatomite was blended with Mg powder. Mg2Si and MgO were alternatively and incompletely dissolved after being immersed in a 1 M HCl solution for 6 h. Meanwhile, the reactant molar ratio had an important influence on products when the raw diatomite was separated with the Mg powder. A small amount of diatomite was reacted to generate MgO and Mg2Si as the molar ratio of Mg and diatomite was 2:1. By contrast, with the molar ratio increasing to be 10:1, diatomite was completely reacted to be Mg2Si and MgO.

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