Novel process for preparing tungsten powder by hydrogen reduction …

The production of tungsten powder was mainly obtained by the hydrogen reduction of tungsten xide [21]. In the reduction, the main factors affecting the reaction process can be attributed to temperature and H 2 O partial pressure [4]. Furthermore, it undergoes a multistage reaction and forms a series of oxides [[22], [23], [24]].

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Eindhoven University of Technology MASTER Reduction of …

Reduction of tungsten oxide using a hydrogen plasma Rasulyaar, Parwez Award date: 2021 Link to publication Disclaimer This document contains a student thesis (bachelor's or master's), as authored by a student at Eindhoven University of Technology. Student theses are made available in the TU/e repository upon obtaining the required degree.

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Preparation of uniform tungsten powder by wet hydrogen …

Uniform tungsten powders were prepared by an improved wet hydrogen reduction method. Explored the relationship between dew point, reduction temperature and particle size …

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(PDF) Mechanism of technical reduction of tungsten: …

Phase transformation of WO3/Y2O3 powder was observed during the hydrogen reduction process in the temperature range of 400–800 °C for up to 5 h. The reduction behavior was investigated by...

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Hydrogen Plasma for Low-Carbon Extractive Metallurgy: Oxides Reduction

This study undertakes a comprehensive review of prior research on the use of hydrogen plasma for metal oxides reduction and reviewing state-of-the-art techniques for its use in extractive metallurgy applications. ... The authors reported that to produce tungsten powder, the hydrogen plasma route consumed 1.5 times less hydrogen and 1.8 times ...

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Unraveling grain growth of metallic tungsten: Investigating the

In the first step of the hydrogen reduction process, the vapor phase product water vapor generated by the combination of hydrogen and oxygen atoms reacts with tungsten oxide, and vapor phase migration deposition is carried out in the form of WO2(OH)2 on the W nucleus, resulting in the abnormal growth of W particles [29–31].

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Environmentally safe fluoride cycle in tungsten technology

A fluoride cycle in tungsten technology is based on three processes: (i) electrochemical decomposition of HF in the KHF 2 + HF melt at 80–100°C with the separate evolution of gaseous fluorine and hydrogen; (ii) fluorination of the tungsten powder with evoluated fluorine at 300–350°C with the condensation of formed WF 6 in a liquid form at t = 2.5–3.0°C, …

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Mechanism of technical reduction of tungsten. Pt. 2. Hydrogen reduction

Hydrogen reduction of tungsten blue oxide to tungsten powder} author = {Haubner, R, Schubert, W D, Hellmer, H, Lassner, E, and Lux, B} abstractNote = {The purpose of this work was to ascertain the mechanism of the hydrogen reduction of tungsten oxide (WO/sub 3/, WOsub(2.9), WOsub(2.72) and WO/sub 2/) to tungsten powder and to clarify ...

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Hydrogen Gas from Praxair in Tungsten Powder …

Buffalo Tungsten creates hydrogen gas through the electrolysis of water in a hydrogen generator. The basic chemical equation for this is. 2 H2O -> 2 H2 + O2. We use the hydrogen gas in the reduction of tungsten oxide. We use the …

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Vapor Deposition of Tungsten by Hydrogen Reduction of Tungsten

An investigation of the variables involved in the deposition of tungsten from a mixture of tungsten hexafluoride and hydrogen has shown that the fastest rate of deposition (about 5 mils thickness in 2 min) was obtained at atmospheric pressure with a hydrogen/tungsten hexafluoride ratio of 1.5 (by volume) at a temperature of 800°–850°C.

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Study of the formation of tungsten powder by hydrogen reduction …

In the present investigation, we have explored the synthesis of tungsten powders by means of annealing treatments and hydrogen reduction of ammonium paratungstate, …

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Novel process for preparing tungsten powder by hydrogen reduction …

A novel process is proposed for the preparation of tungsten powder by the hydrogen reduction of tungsten xide. The process changes the traditional method of flow of hydrogen from the surface ...

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Metals Production and Metal Oxides Reduction Using Hydrogen …

Current commercial tungsten powder is dominantly produced via hydrogen reduction of the tungsten oxides. Carbothermic reduction is not preferred for producing pure …

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Study on the oxidation and reduction of tungsten surface for …

addition to the reduction characteristics of the WO x layer formed on the tungsten line surface using hydrogen plasmas. The surface oxidation of tungsten lines during the mask layer removal process could be minimized by using low-temperature (300K) plasma processing for the removal of the carbon-based material. Using this technique, the ...

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(PDF) Mechanism of technical reduction of tungsten: …

The action of aluminum traces on tungsten reduction by hydrogen is examined. A detailed description of the morphological changes which occur during the reduction of the tungsten oxide to metal ...

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Hydrogen reduction of tungsten oxides: Alkali additions, their …

This investigation shows how alkali compounds act during the reduction of doped tungsten oxides, making their effects "visible" in XRD and SEM investigations by using both heterogeneous and homogeneous additions. Alkali metals react at the very beginning of …

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Reduction of Oxide Minerals by Hydrogen Plasma: An Overview

The process of reduction of tungsten oxide in hydrogen arc plasma using linear plasmatron (300 kW) and a direct-flow reactor has been developed on semi-industrial scale (INET, VNIITS, VNIIETO, USSR) . By rapid cooling (quenching) metallic tungsten powder as globular particulates with a specific surface of 10–12 m 2 /g was produced. After ...

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Deep decarburization of molybdenum and tungsten powders by wet hydrogen

The control of residual carbon content is an urgent problem to be solved for the preparations of molybdenum and tungsten powders by method of carbothermic reduction of their oxides.In this paper, finer Mo (W) powder with a low residual carbon content was prepared by a two-step reduction process consisting of carbothermal pre-reduction of MoO 3 (WO 3) at 1050 …

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MECHANISM OF TECHNICAL REDUCTION OF TUNGSTEN: PART …

The industrial production of tungsten powder is carried out by the reduction of tungsten oxide powder via hydrogen. In this process, the size of the W particles is limited to particle sizes larger ...

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Sequential oxidation and reduction of tungsten/tungsten oxide

The reduction of oxide films on the surface of tungsten was studied. The oxide films were created by briefly exposing smooth W foils to oxygen plasma generated using a microwave discharge at 500 W and an oxygen pressure of 40 Pa. Oxidation resulted in the formation of a WO 3 film with a thickness of approximately 1700 nm. The oxidised samples …

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Operando Unveiling of Hydrogen Spillover Mechanisms on …

This study focuses on the operando unveiling of platinum-induced hydrogen spillover on monoclinic tungsten xide (γ-WO 3), employing ambient pressure X-ray photoelectron …

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Deposition of tungsten by reduction of its hexafluoride with hydrogen

Tungsten fabricated by hydrogen reduction of WF6 and thermolysis of WCl6 has 100 -preferred columnar microstructures. However, the latter exhibits larger columnar grains and preferred 100 less. ...

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A new pathway for preparing ultrafine tungsten powder via non …

Ultrafine tungsten (W) powder was prepared by a non-contact carbon reduction followed by hydrogen reduction method. In this process, WO 3 and activated carbon were separated by a porous plate and the reduction of tungsten oxide was achieved by carbon atoms diffusion at high temperature. This method can stably prepare violet tungsten oxide powder …

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Effect of Water Vapor Partial Pressure on the Structure of Blue

A novel process is proposed for the preparation of tungsten powder by the hydrogen reduction of tungsten xide. The process changes the traditional method of flow of hydrogen from the surface ...

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Deposition of tungsten by reduction of its hexafluoride with hydrogen

The reduction of WF 6 with hydrogen on a heated surface under atmospheric pressure, temperatures of 500–600°C, and a stoichiometric ratio of components with the subsequent additional reduction of tungsten hexafluoride at t = 800°C and condensation of formed HF is described. The method of calculation of the completeness (α) of reduction of WF 6 and …

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Crystal growth of tungsten during hydrogen reduction of tungsten …

On the other hand, WO 2 and H 2 O can form volatile tungsten oxide-hydroxide during reduction, and then the tungsten grain grows through CVT (chemical vapour transport) reaction [13, 15]: 222 H3)g(OH)(WO O(g)H4W(s) 2 (1) When the p H 2 O /p H 2 in hydrogen atmosphere is high, the nucleation is limited; tungsten grain grows; and coarse-grain ...

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High-pressure hydrogen annealing for resistivity reduction of …

High-pressure hydrogen annealing for resistivity reduction of ultrathin tungsten electrodes. Author links open overlay panel Seunghyun Park a, Sungjun Kim b, Changyu Park a, Hyoungsub Kim a. Show more. Add to Mendeley. ... Reduction of tungsten oxides with hydrogen. Ind. Eng. Chem., 48 (1956), p. 318, 10.1021/ie50554a042. Google Scholar

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Hydrogen Reduction of Tungsten Oxides

PREVIOUS work1 has shown that hydrogen reduction of tungsten xide gave the β-oxide (W20O58)2, which was then apparently reduced both to β-tungsten (a = 5.04 A.) and to tungsten dioxide or ...

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Recent progress on tungsten oxide-based materials for the hydrogen …

With a high N 2 plasma flux, the W-N bond can be formed on the tungsten oxide surface, which contributes to the promotion of the hydrogen evolution reaction (HER) activity, and an overpotential of 93 mV @ 10 mA cm −2 in 1.0 M KOH is exhibited, and the Tafel slope largely reduced to 76 mV dec-1. Such a facile strategy provides an engineering ...

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(PDF) Hydrogen as a reducing agent: State-of-the-art …

The reduction of tungsten yellow oxide (WO 3) or tungsten blue oxide (WO 3-x) can be controlled by temperature and. ... Hydrogen reduction of model steam reforming catalysts, comprising about 10 ...

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