scholarly journals To flocculant effect on the kinetics of dewatering and washing processes of red muds from low silicon bauxites in alumina production

2019 ◽  
Vol 23 (2) ◽  
pp. 404-414
Author(s):  
Oleg Salamatov ◽  
◽  
Viktor Salamatov ◽  
Keyword(s):  
Alumina Production ◽  
Red Muds ◽  
Kinetics Of

scholarly journals USE OF DUMPED RED MUD OF ALUMINA INDUSTRY AT GRANULATION OF THE MOLTEN SULFUR-CONTAINING BLAST FURNACE SLAG

2019 ◽  
Vol 16 (31) ◽  
pp. 837-845
Author(s):  
Andrey B LEBEDEV ◽  
Vladimir A UTKOV ◽  
Olga A KAYGORODOVA ◽  
Marsel A KADYROV
Keyword(s):  
Blast Furnace ◽  
Red Mud ◽  
Power Plants ◽  
Natural Waters ◽  
Thermal Power ◽  
Alumina Production ◽  
Industrial Gases ◽  
Red Muds ◽  
Alumina Industry ◽  
Sulfur Containing

There is a problem of using waste of alumina production from bauxite red mud. Warehousing of it is fraught with ecological catastrophes. Red muds constantly worsen the environment due to dusting and pollution of natural waters. Red mud is a product of bauxite processing. One ton of alumina accounts for 1 to 2.5 tons of red mud. Currently, it is not being processed, despite the availability of 3,000 publications and patents on this topic. One of them is justified by the ambiguity in the economic effectiveness of its use by consumers. In this paper, the options for economic and environmental efficiency of RM use are presented as substitutes for expensive lime and limestone used for purification of industrial gases emitted to the atmosphere in large quantities with toxic sulfur compounds. Laboratory and industrial tests revealed the sorption properties of red muds. When cleaning gases from sulfur emitted into the atmosphere by furnace gases, thermal power plants, sinter machines, and steelmaking furnaces. In addition, the ecological and technological efficiency of purification of sulfur-containing gases released in the areas of granulation of molten blast-furnace slags is shown.

scholarly journals Kinetics of the Leaching Process of an Australian Gibbsitic Bauxite by Hydrochloric Acid

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Aichun Zhao ◽  
Ting-an Zhang ◽  
Guozhi Lv ◽  
Wenyan Tian
Keyword(s):  
Activation Energy ◽  
Hydrochloric Acid ◽  
Acid Leaching ◽  
Low Grade ◽  
Good Theory ◽  
Alumina Production ◽  
Work Analysis ◽  
Leaching Process ◽  
Hydrochloric Acid Leaching ◽  
Kinetics Of

Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al2O3was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation,ln⁡k=39.44-1.66×104(1/T), with an apparent activation energy of 137.90 kJ/mol, according to the equation ofk=Ae-Ea/RT. This work aims to provide a good theory support for the process control by using a new method of alumina production from the low grade bauxite.

scholarly journals STUDY OF THICKENING AND WASHING KINETICS OF RED MUDS FROM LOW-SILICA BAUXITES

2018 ◽  
Vol 22 (4) ◽  
pp. 191-202
Author(s):  
Viktor Salamatov ◽  
◽  
Oleg Salamatov ◽  
Keyword(s):  
Red Muds ◽  
Kinetics Of

Recovery of Zirconium From Alumina Production Red Muds

2018 ◽  
Vol 118 ◽  
pp. 5-6
Author(s):  
Vladimir Skachkov ◽  
Keyword(s):  
Alumina Production ◽  
Red Muds

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

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