Synthesis, identification and thermal decomposition of double sulfates of La, Ce, Pr or Nd with ethanolammonium

1997 ◽  
Vol 50 (5-6) ◽  
pp. 785-793 ◽  
Author(s):  
V. Jordanovska ◽  
R. Trojko
Keyword(s):  
Thermal Decomposition ◽  
Double Sulfates

scholarly journals Studying of possibility for breakdown of ilmenite concentrate with ammonium sulphate

2020 ◽  
Vol 4 (312) ◽  
pp. 22-30
Author(s):  
G. F. Krysenko ◽  
◽  
D. G. Epov ◽  
M. A. Medkov ◽  
E. B. Merkulov ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Sulfate ◽  
X Ray Diffraction ◽  
Iron Compounds ◽  
Water Leaching ◽  
Ilmenite Concentrate ◽  
Double Salts ◽  
Leaching Solution ◽  
Double Sulfates ◽  
Main Components

The data on investigation of the possibility of breakdown of ilmenite concentrate of the Ariadnensky deposit in Primorsky Krai with ammonium sulfate are presented in the article. For study the ilmenite concentrate and ammonium sulfate interaction, the concentrate and (NH4)2SO4 were mixed based on the formation of sulfates of the main components of the concentrate and then double sulfates of the components of the concentrate and ammonium. The interaction was carried out in glassy carbon crucibles, which were placed in a muffle furnace controller company Nabertherm GmbH (Germany). The weight of sample was 10–40 g. Thermogravimetry, X-ray diffraction and atomic absorption analyses were used in the study. It was found that when the temperature of thermal decomposition of (NH4)2SO4 (3000С) is reached, the interaction of the main components of the concentrate with (NH4)2SO4 begins and proceeds in the temperature range of 300-3600С with the formation of a mixture of double salts well soluble in water - ammonium sulfate and iron compounds (NH4)2Fe2(SO4)3 and NH4Fe(SO4)2 and ammonium sulfate and titanyl of the composition (NH4)2TiO(SO4)2. The interaction at a temperature above 3600С leads to thermal decomposition of the formed double sulfates of ammonium and titanyl and ammonium and iron to sulfates and then oxides. It was shown that water leaching of the product of the interaction of ilmenite concentrate with (NH4)2SO4 at 3600С allows to extract practically all titanium and the bulk of iron to water in the form of well soluble double salts. The conditions for the titanium dioxide separation in the form of anatase from the water leaching solution were found.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

A magnetic super lattice

1987 ◽  
Vol 45 ◽  
pp. 360-361 ◽  
Author(s):  
M.D. Bentzon ◽  
J. v. Wonterghem ◽  
A. Thölén
Keyword(s):  
Thermal Decomposition ◽  
Oleic Acid ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Carbon Film ◽  
Thick Layer ◽  
Amorphous Iron ◽  
Super Lattice ◽  
Carrier Liquid ◽  
Median Diameter

We report on the oxidation of a magnetic fluid. The oxidation results in magnetic super lattice crystals. The “atoms” are hematite (α-Fe2O3) particles with a diameter ø = 6.9 nm and they are covered with a 1-2 nm thick layer of surfactant molecules.Magnetic fluids are homogeneous suspensions of small magnetic particles in a carrier liquid. To prevent agglomeration, the particles are coated with surfactant molecules. The magnetic fluid studied in this work was produced by thermal decomposition of Fe(CO)5 in Declin (carrier liquid) in the presence of oleic acid (surfactant). The magnetic particles consist of an amorphous iron-carbon alloy. For TEM investigation a droplet of the fluid was added to benzine and a carbon film on a copper net was immersed. When exposed to air the sample starts burning. The oxidation and electron irradiation transform the magnetic particles into hematite (α-Fe2O3) particles with a median diameter ø = 6.9 nm.

Supersonic jet spectrometry of chemical species resulting from thermal decomposition of polystyrene and polycarbonate

1992 ◽  
Vol 64 (19) ◽  
pp. 931A-940A ◽  
Author(s):  
Totaro Imasaka ◽  
Masami Hozumi ◽  
Nobuhiko Ishibashi
Keyword(s):  
Thermal Decomposition ◽  
Supersonic Jet ◽  
Chemical Species
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