scholarly journals Thermodynamics and Kinetics Research of the Fluorination Process of the Concentrate Rutile

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Vladimir A. Karelin ◽  
Son Hai Le ◽  
Nadezhda V. Karelina ◽  
Alexander N. Strashko ◽  
Alexander V. Sazonov ◽  
...  
Keyword(s):  
Kinetic Equation ◽  
Solid Phase ◽  
Fluorine Content ◽  
Preexponential Factor ◽  
Toxic Waste ◽  
Process Time ◽  
Elemental Fluorine ◽  
Laboratory Setup ◽  
Constant Versus ◽  
Size Distribution Of Particles

The growth in the production of titanium metal and its compounds leads to an increase in the amount of toxic waste. As a result, at the legislative level, emissions of such wastes are limited, which leads to a drop in the production of titanium-containing products and a shortage of titanium in the international market. This paper presents the results of the process of fluorination of rutile concentrate from the Tarsky deposit (Russia, Omsk region) with elemental fluorine using a laboratory setup of a special design. For fluorination, samples of rutile concentrate weighing 0.1–1.0 g were used. The particle size distribution of particles varied from 2 × 10−6 to 2 × 10−5 m. To determine the possibility of carrying out the process, the calculation of the change in the logarithm of the equilibrium constant versus temperature was performed. The influence of the following operating parameters on the fluorination process has been studied: various concentrations of F2 in a fluorinating mixture of fluorine with nitrogen; process time from 0 to 9 min; different ratios of the initial solid phase to fluorine (10 and 50% excess of fluorine and 10 and 50% of its deficiency); fluorination temperature in the range of 300–1800 K. A kinetic equation is selected that most accurately describes the fluorination process. The values of the activation energy and the preexponential factor in the kinetic equation are determined. The obtained results show that with an increase in the fluorine content in the fluorinating gas mixture and the temperature of the process, the fluorination rate increases. Optimal conditions for fluorination: temperature—680 K; time—5 min excess fluorine in the fluorinating mixture—20–25%. The obtained results allow to propose and consider the conditions of process execution on industrial equipment.

scholarly journals Magnetite and Hematite in Advanced Oxidation Processes Application for Cosmetic Wastewater Treatment

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1343 ◽  
Author(s):  
Piotr Marcinowski ◽  
Dominika Bury ◽  
Monika Krupa ◽  
Dominika Ścieżyńska ◽  
Prasanth Prabhu ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
High Efficiency ◽  
Solid Phase ◽  
Oxygen Demand ◽  
Gas Chromatography Mass Spectrometry ◽  
Process Time ◽  
Toc Removal ◽  
Treatment Processes ◽  
Detection And Identification ◽  
Best Fit

Wastewater from a cosmetic factory, with an initial total organic carbon (TOC) of 146.4 mg/L, was treated with Fe2O3/Fe0/H2O2, Fe3O4/Fe0/H2O2, light/Fe2O3/Fe0/H2O2, and light/Fe3O4/Fe0/H2O2 processes. The light-supported processes were more effective than the lightless processes. The fastest TOC removal was observed during the first 15 min of the process. Out of the four tested kinetic models, the best fit was obtained for the modified second-order reaction with respect to the TOC value. The best treatment efficiency was obtained for the light/Fe3O4/Fe0/H2O2 process with 250/750 mg/L Fe3O4/Fe0 reagent doses, a 1:1 hydrogen peroxide to Chemical Oxygen Demand (H2O2/COD) mass ratio, and a 120 min process time. These conditions allowed 75.7% TOC removal to a final TOC of 35.52 mg/L and 90.5% total nitrogen removal to a final content of 4.9 mg/L. The five-day Biochemical Oxygen Demand to Chemical Oxygen Demand (BOD5/COD) ratio was increased slightly from 0.124 to 0.161. Application of Head Space Solid-Phase Microextraction Gas Chromatography Mass Spectrometry (HS-SPME-GC-MS) analysis allows for the detection and identification of 23 compounds contained in the raw wastewater. The identified compounds were eliminated during the applied process. The HS-SPME-GC-MS results confirmed the high efficiency of the treatment processes.

Kinetics of the reaction between magnesium oxide and ammonium chloride solution

1988 ◽  
Vol 53 (8) ◽  
pp. 1711-1717 ◽  
Author(s):  
Vladimír Glaser ◽  
Jan Vídenský ◽  
Miroslav Kužela
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Equation ◽  
Magnesium Oxide ◽  
Ammonium Chloride ◽  
Chloride Solution ◽  
Solid Phase ◽  
Batch Reactor ◽  
Ammonium Chloride Solution ◽  
Kinetics Of ◽  
Rate Controlling Step

The kinetics of the reaction between magnesium oxide and ammonium chloride solution in a well-stirred batch reactor have been investigated. The results have shown that the rate-controlling step is the dissolution of the solid phase. A kinetic equation has been derived for this variant of reaction mechanism.

Selective Titanium Silicide for Industrial Applications

1995 ◽  
Vol 402 ◽  
Author(s):  
D. Maury ◽  
J. L. Regolini ◽  
P. Gayet
Keyword(s):  
Solid Phase ◽  
Stoichiometric Composition ◽  
Industrial Applications ◽  
Titanium Silicide ◽  
Design Rule ◽  
Process Time ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Silicon Epitaxy ◽  
Si Epitaxy

AbstractThe possibilities of using TiSi2 for contacts and interconnects in 0.25 μm and below design rule ICs are at present being investigated using the standard solid phase reaction (salicide) technique. Some problems still remain, such as phase transformation or dewettability over narrow lines. Over the last few years we have developed a TiSi2 selective CVD technique which is being used for 200 mm wafers in an industrial integrated cluster reactor. The system consists of two reaction chambers: one for Si epitaxy (and related alloys) and the other for TiSi2 deposition. The process sequence involves three main steps: (i) a wet chemical wafer cleaning, (ii) a selective silicon epitaxy for elevated source/drains to obtain minimum substrate consumption and (iii) the deposition of TiSi2 using the H2/SiH4 (or DCS)/TiCl4 gas system in the 650–750°C temperature range. The whole process time per wafer is shorter than 4 min. Selectivity, stoichiometric composition and resistivity of around 16 μmΩcm are obtained. The growth rate, uniformity, grain size and doping effects have been studied on single, polycrystalline, doped and undoped silicon. Device wafers have been used to compare the two processes, standard and CVD, obtaining electrical results such as lower series resistances, and a linewidth independent sheet resistance of down to 0.20 μm.

Kinetics of ammonia recovery from soda-plant liquor by burnt magnesite

1988 ◽  
Vol 53 (8) ◽  
pp. 1718-1724 ◽  
Author(s):  
Vladimír Glaser ◽  
Jan Vídenský
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Kinetic Equation ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Chemical Engineering ◽  
Solid Phase ◽  
Test Evaluation ◽  
Ammonia Recovery ◽  
Kinetics Of

The kinetics of the reaction of a soda-plant liquor containing ammonium chloride and sodium chloride with softly burnt magnesite have been investigated using a modified distillation test. Evaluation of the kinetic data has shown that the reaction rate is controlled by the dissolution of the solid phase. The kinetic equation for this variant of reaction mechanism has been modified to obtain a form suitable for chemical engineering calculations. A procedure of determining the adjustable parameters of this equation is illustrated by treating the obtained experimental data.

scholarly journals Mechanochemical Activation and Reaction Capacity of SHS-Systems on the Base of Quartz

2011 ◽  
Vol 13 (3-4) ◽  
pp. 125 ◽  
Author(s):  
Z.A. Mansurov ◽  
N.N. Mofa
Keyword(s):  
Phase Composition ◽  
Heat Dissipation ◽  
Mechanochemical Activation ◽  
Solid Phase ◽  
Energy State ◽  
Combustion Process ◽  
Process Time ◽  
Composite Formation ◽  
Reaction Capacity ◽  
Different Characteristics

The influence of different characteristics of mechanochemical activation on changes of structure and energy characteristics of silicon dioxide (quartz) is considered in this work. It is shown that after treatment in mill in the presence of different modificators, the quartz samples are complex composite formation, composed of crystalline, amorphous and polymeric component, and also contain inclusions of iron and carbon. Polymerized surface layer provides the encapsulation of the energy state of activated particle. Particularities of the technological combustion systems with active and modified quartz are investigated. The using of modifying agents leads to increasing of maximum combustion temperature, increasing of combustion process time as well as the change of phase composition of synthesis products. It is shown that alteration the sizes of synthesized sample (products) we can change the heat dissipation conditions, kinetic of reaction development and temperature in combustion wave. “The process scale” of solid phase combustion at material synthesis appears in change of the phase composition of obtained materials.

Solid-phase immunoelectron microscopy for rapid diagnosis of enteroviruses

1984 ◽  
Vol 42 ◽  
pp. 226-227 ◽  
Author(s):  
K. Pegg-Feige ◽  
F. W. Doane
Keyword(s):  
Electron Microscopy ◽  
Cell Culture ◽  
Immunoelectron Microscopy ◽  
Detection Method ◽  
Solid Phase ◽  
Protein A ◽  
Plant Viruses ◽  
Rapid Diagnosis ◽  
Virus Diagnosis ◽  
Antiviral Antibody

Immunoelectron microscopy (IEM) applied to rapid virus diagnosis offers a more sensitive detection method than direct electron microscopy (DEM), and can also be used to serotype viruses. One of several IEM techniques is that introduced by Derrick in 1972, in which antiviral antibody is attached to the support film of an EM specimen grid. Originally developed for plant viruses, it has recently been applied to several animal viruses, especially rotaviruses. We have investigated the use of this solid phase IEM technique (SPIEM) in detecting and identifying enteroviruses (in the form of crude cell culture isolates), and have compared it with a modified “SPIEM-SPA” method in which grids are coated with protein A from Staphylococcus aureus prior to exposure to antiserum.

Application of solid-phase immune electron microscopy to study physical and stability characteristics of enterically transmitted non-a, non-b hepatitis virus

1988 ◽  
Vol 46 ◽  
pp. 80-81
Author(s):  
Charles D. Humphrey ◽  
E. H. Cook ◽  
Karen A. McCaustland ◽  
Daniel W. Bradley
Keyword(s):  
Electron Microscopy ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Etiologic Agent ◽  
World Health ◽  
Health Concern ◽  
Morphological Identification ◽  
Immune Electron Microscopy

Enterically transmitted non-A, non-B hepatitis (ET-NANBH) is a type of hepatitis which is increasingly becoming a significant world health concern. As with hepatitis A virus (HAV), spread is by the fecal-oral mode of transmission. Until recently, the etiologic agent had not been isolated and identified. We have succeeded in the isolation and preliminary characterization of this virus and demonstrating that this agent can cause hepatic disease and seroconversion in experimental primates. Our characterization of this virus was facilitated by immune (IEM) and solid phase immune electron microscopic (SPIEM) methodologies.Many immune electron microscopy methodologies have been used for morphological identification and characterization of viruses. We have previously reported a highly effective solid phase immune electron microscopy procedure which facilitated identification of hepatitis A virus (HAV) in crude cell culture extracts. More recently we have reported utilization of the method for identification of an etiologic agent responsible for (ET-NANBH).

Identification of hepatitis a virus in cell cultures by solid phase immune electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 238-239
Author(s):  
C.D. Humphrey ◽  
T.L. Cromeans ◽  
E.H. Cook ◽  
D.W. Bradley
Keyword(s):  
Electron Microscopy ◽  
Liquid Phase ◽  
Cell Cultures ◽  
Rapid Detection ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Immune Electron Microscopy ◽  
Detection And Identification

There is a variety of methods available for the rapid detection and identification of viruses by electron microscopy as described in several reviews. The predominant techniques are classified as direct electron microscopy (DEM), immune electron microscopy (IEM), liquid phase immune electron microscopy (LPIEM) and solid phase immune electron microscopy (SPIEM). Each technique has inherent strengths and weaknesses. However, in recent years, the most progress for identifying viruses has been realized by the utilization of SPIEM.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Sign in / Sign up

Export Citation Format

Share Document