scholarly journals In Situ Observation of the Carbothermic Reduction and Foaming of Slags in Silicomanganese Production

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2020
Author(s):  
Vincent Canaguier ◽  
Merete Tangstad
Keyword(s):  
Carbothermic Reduction ◽  
Sessile Drop ◽  
Raw Materials ◽  
Reduction Reaction ◽  
Furnace Operation ◽  
Graphite Substrate ◽  
In Situ Observation ◽  
High Carbon ◽  
Slag Droplet

The carbothermic reduction of slag in silicomanganese production is accompanied by the release of carbon monoxide. This gas can accumulate as bubbles within the slag, leading to foaming and, potentially, disturbances to furnace operation. This study investigated the reduction in the slag together with its foaming using a sessile drop furnace. Five silicomanganese slags produced from industrial raw materials (Assmang ore, Comilog ore, high-carbon FeMn slag with quartz, and FeS additions) were reduced by a graphite substrate at isothermal conditions (i.e., 1540–1660 °C) under CO atmosphere. The reduction reaction was tracked by photographing the slag droplet, and the cyclic expansion and burst of the droplet were used to estimate the gas evolution. The reacted samples were analyzed by wavelength-dispersive X-ray spectroscopy (WDS) to determine MnO and SiO2 reduction. While no foaming was observed using Comilog ore, extensive retention of CO in the slag phase was observed when using Assmang ore or Assmang with high-carbon FeMn slag. The beginning of foaming was attributed to an increase in the reaction rate; the absence of foaming when using Comilog can be attributed to the acidity of the charge. Addition of sulfur to the Comilog-based charge did not influence the reduction.

In situ Atmospheric Transmission Electron Microscopy of Catalytic Nanomaterials

MRS Advances ◽  
2018 ◽  
Vol 3 (39) ◽  
pp. 2297-2303 ◽  
Author(s):  
Sheng Dai ◽  
Wenpei Gao ◽  
George W. Graham ◽  
Xiaoqing Pan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reduction Reaction ◽  
In Situ Observation ◽  
Atmospheric Transmission ◽  
Free Standing ◽  
Gaseous Reaction ◽  
Transmission Electron ◽  
Catalyst Systems

AbstractSignificant developments in micro-electrical-mechanical systems (MEMS)-based devices for use in transmission electron microscopy (TEM) sample holders have recently led to the commercialization of windowed gas cells that now enable the atomic-resolution visualization of phenomena occurring during gas-solid interactions at atmospheric pressure. In situ atmospheric TEM study provides unique information that is beneficial to correlating the structure-properties relationship of catalytic nanomaterials, particularly under realistic gaseous reaction conditions. In this paper, we illustrate the capability of this novel in situ device as applied to our study of two catalyst systems: (1) In situ kinetic growth of free standing Pt nanowires as active catalysts toward oxygen reduction reaction (ORR); (2) In situ observation of facet-dependent oxidation of another promising ORR catalyst, Pt3Co nanoparticles.

High Temperature In Situ Antioxidation Coating Fabricated by AAC Method

2013 ◽  
Vol 537 ◽  
pp. 42-45
Author(s):  
Zhen Ting Wang ◽  
Gang Liang ◽  
Guo Gang Zhao
Keyword(s):  
High Temperature ◽  
Composite Coating ◽  
Oxygen Diffusion ◽  
Graphite Electrode ◽  
Raw Materials ◽  
Graphite Substrate ◽  
Ceramic Particles ◽  
Cladding Layer

In the surface of graphite electrode, the in-situ synthesized high temperature antioxidation composite coating is prepared, depending on argon arc cladding and the raw materials of Si and B4C powder. The coating consists of SiC and B13C2ceramic particles. The results show that: the reaction generates B2O3and SiO2with high temperature play a role in healing crack and preventing oxygen diffusion; a kind of continuous interface is present between the cladding layer and the graphite substrate, no obvious flaws; burning at 1573 K and 10 h, oxidation weightlessness rate is 0.912%.

Effects of niobium on network carbide in high-carbon chromium bearing steel by in situ observation analysis

2020 ◽  
pp. 1-6
Author(s):  
Huan Wang ◽  
Jian Li ◽  
Chaolei Zhang ◽  
Wenjun Wang ◽  
Yazheng Liu
Keyword(s):  
Bearing Steel ◽  
In Situ Observation ◽  
High Carbon

scholarly journals In situ observation of reduction reaction of calcium ferrites by XRD and XAFS

2014 ◽  
Vol 70 (a1) ◽  
pp. C1780-C1780
Author(s):  
Reiko Murao ◽  
Masao Kimura
Keyword(s):  
Induction Period ◽  
Reduction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Calcium Ferrite ◽  
In Situ Observation ◽  
X Ray ◽  
In Situ Xrd ◽  
Gas Atmosphere

The lime-fluxed iron ore sinter is the major iron source in the steelmaking process. Its macroscopic properties, (e.g. strength, reduction-ability and reduction-disintegration) should strongly depend on characteristics, quantity and morphology of the bonding phase. It contains several calcium ferrite phases (CFs) including solid solutions of gang materials. Most of previous studies focused on the relation of micro-texture with properties of the sinter. However, properties of individual CFs, especially, of multi-component CFs have not been clarified yet. In this study, reduction process and rates of various CFs have been investigated by in situ observation using both X-Ray Absorption Fine Structure (XAFS) and X-Ray Diffraction (XRD) methods to clarify influence of CF species on the properties of the sinter. High temperature XAFS measurements were carried out using a synchrotron radiation source at the 9A beam line in Photon Factory (KEK-PF), Japan. Powdered single phase CFs, such as CaFe2O4, Ca2(Fe,Ca)6(Fe,Al,Si)6O20 (SFCA) were diluted with BN. Fe K and Ca K-edge XAFS spectra at 9000C and 7500C in He-H2 gas atmosphere were collected repeatedly by the quick-XAFS method. Absorption variations in normalized XANES spectra were used to calculate the reduction rate constants[1]. XRD patterns of various CFs at 9000C and 7500C were corrected repeatedly at 40-second intervals in N2-H2 gas atmosphere during reduction reaction progressed. Reduction rate of CaFe2O4, determined by XANES analysis was slower than that of Fe2O3. The reduction of Fe in CaFe2O4 was a single first-order reaction, although an induction period was clearly observed at the beginning of the reduction process. In situ XRD observations showed that CaFe2O4 was reduced into Fe and CaO via Fe2+ containing CFs such as CaFe3O5 and CaFe5O7 at 9000C. These may correspond to the induction period observed in the absorption variation. Analysis results for SFCA will be discussed in the presentation.

XRD In Situ Observation of Carbothermic Reduction of Magnetite Powder in Microwave Electric and Magnetic Fields

2013 ◽  
pp. n/a-n/a ◽  
Author(s):  
Nils Sabelström ◽  
Miyuki Hayashi ◽  
Yuki Yokoyama ◽  
Takashi Watanabe ◽  
Kazuhiro Nagata
Keyword(s):  
Magnetic Fields ◽  
Carbothermic Reduction ◽  
In Situ Observation ◽  
Electric And Magnetic Fields

In Situ Observation of Catalyzed Gasification of Graphite by Nickel

1981 ◽  
Vol 39 ◽  
pp. 76-77
Author(s):  
R. T. K. Baker ◽  
R. D. Sherwood
Keyword(s):  
Objective Lens ◽  
In Situ Observation ◽  
Gas Flows ◽  
Catalytic Gasification ◽  
Television Camera ◽  
Viewing Screen ◽  
Fuels And Chemicals ◽  
Gasification Of Carbon ◽  
Transmission Microscope

The catalytic gasification of carbon at high temperature by microscopic size metal particles is of fundamental importance to removal of coke deposits and conversion of refractory hydrocarbons into fuels and chemicals. The reaction of metal/carbon/gas systems can be observed by controlled atmosphere electron microscopy (CAEM) in an 100 KV conventional transmission microscope. In the JEOL gas reaction stage model AGl (Fig. 1) the specimen is positioned over a hole, 200μm diameter, in a platinum heater strip, and is interposed between two apertures, 75μm diameter. The control gas flows across the specimen and exits through these apertures into the specimen chamber. The gas is further confined by two apertures, one in the condenser and one in the objective lens pole pieces, and removed by an auxiliary vacuum pump. The reaction zone is <1 mm thick and is maintained at gas pressure up to 400 Torr and temperature up to 1300<C as measured by a Pt-Pt/Rh 13% thermocouple. Reaction events are observed and recorded on videotape by using a Philips phosphor-television camera located below a hole in the center of the viewing screen. The overall resolution is greater than 2.5 nm.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

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