HIGH-TEMPERATURE STUDIES OF METALLURGICAL PROCESSES: PART I. THE THERMAL REDUCTION OF MAGNESIUM OXIDE WITH SILICON

1961 ◽  
Vol 39 (3) ◽  
pp. 540-547 ◽  
Author(s):  
J. M. Toguri ◽  
L. M. Pidgeon
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Excess Weight Loss ◽  
High Vacuum ◽  
Thermal Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rate Of Reaction ◽  
Intimate Mixture ◽  
Metallurgical Processes

The rate of reaction (a) has been studied over the temperature range 1140–1460 °C, by following the loss in weight of the reactants in high vacuum.[Formula: see text]The loss in weight of the reactants was found to be greater than that which can be accounted for by the above reaction. The excess weight loss was found to be due to a brownish, glassy deposit which appeared outside the reaction zone. This material was analyzed by X-ray diffraction and found to be an intimate mixture of Mg2SiO4 and Si. Experiments conducted showed that both of these materials are not appreciably volatile at 1350 °C. This transfer of silicon and silicate is postulated to occur by the formation of gaseous SiO formed from the reaction mixture. Based on this assumption a possible mechanism for this reaction is postulated.

HIGH-TEMPERATURE STUDIES OF METALLURGICAL PROCESSES: PART II. THE THERMAL REDUCTION OF CALCINED DOLOMITE WITH SILICON

1962 ◽  
Vol 40 (9) ◽  
pp. 1769-1776 ◽  
Author(s):  
J. M. Toguri ◽  
L. M. Pidgeon
Keyword(s):  
Weight Loss ◽  
Particle Size ◽  
High Temperature ◽  
Direct Relationship ◽  
Thermal Reduction ◽  
Rate Of Reaction ◽  
Metallurgical Processes ◽  
Continuous Weight ◽  
Silicon Activity ◽  
Continuous Weight Loss

The production of magnesium by the following reaction has been studied:[Formula: see text]The rate of reaction (a) was followed by continuous weight loss measurements of the reactants. Keeping the particle size of the reactants and size and shape of the charge constant, the following factors which affect the yield of magnesium were investigated: (1) temperature, from 1050–1560 °C; (2) pressure, from less than 1 µ to 261 mm of Hg; (3) catalysts, CaF2, BaF2, and MgF2; and (4) ferrosilicon grade, from 18.7% to 96.7% Si.It was found that the yield increased by a factor 1.55 for a 50° increase in temperature over the temperature range investigated. At temperatures below 1300 °C the yield falls linearly with increase in pressure, while at temperatures above 1300 °C the yield remains relatively constant until the pressure exceeds the equilibrium magnesium pressure. All fluoride additions were found to increase the yield, CaF2 being the most effective. The rate of the reaction was also found to have a direct relationship with the silicon activity.

scholarly journals High temperature X-ray diffraction and thermo-gravimetrical analysis of the cubic perovskite Ba0.5Sr0.5Co0.8Fe0.2O3−δ under different atmospheres

2015 ◽  
Vol 44 (23) ◽  
pp. 10875-10881 ◽  
Author(s):  
M. G. Sahini ◽  
J. R. Tolchard ◽  
K. Wiik ◽  
T. Grande
Keyword(s):  
High Temperature ◽  
Hexagonal Phase ◽  
Thermal Reduction ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray

Unit cell and non-stoichiometry of Ba0.5Sr0.5Co0.8Fe0.2O3−δ in O2, demonstrating oxidation followed by thermal reduction and formation of a hexagonal phase is reported.

High temperature spectroscopic and X-ray diffraction studies of californium tribromide: Proof of thermal reduction to californium(II)

1975 ◽  
Vol 37 (12) ◽  
pp. 2497-2501 ◽  
Author(s):  
J.P. Young ◽  
K.L. Vander Sluis ◽  
G.K. Werner ◽  
J.R. Peterson ◽  
M. Noé
Keyword(s):  
High Temperature ◽  
Thermal Reduction ◽  
X Ray Diffraction ◽  
X Ray

High temperature X-ray diffraction investigation of an aluminium-silicon-corundum system

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 369-374 ◽  
Author(s):  
D. Garipoli ◽  
P. Bergese ◽  
E. Bontempi ◽  
M. Minicucci ◽  
A. Di Cicco ◽  
...  
Keyword(s):  
High Temperature ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals High-pressure synthesis and crystal structure of the mixed-cation borate Ga4In4B15O33(OH)3

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Mixed Cation ◽  
High Pressure High Temperature ◽  
Pressure Synthesis

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
K. S. Kumar ◽  
S. K. Mannan
Keyword(s):  
High Temperature ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Room Temperature ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

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