scholarly journals STUDY OF CONDITIONS OF TRANSITION OF SILICON INTO ALUMINATE SOLUTION DURING LEACHING OF RAW ALUNITE AND ITS REMOVAL FROM THIS SOLUTION

2021 ◽  
Vol 0 (4) ◽  
pp. 71-76
Author(s):  
G.I. Alyshanly ◽  
Keyword(s):  
Sulfuric Acid ◽  
Liquid Phase ◽  
Silicon Dioxide ◽  
Alkaline Solution ◽  
Room Temperature ◽  
Acid Activation ◽  
High Quality ◽  
Aluminate Solution ◽  
Sorption Ability

When extracting aluminum from the alunite ore of the Zaglik deposit by leaching, silicon, which is part of the alunite, passes into solution in the form of a silicate ion in a small amount. Silicon in solution not only degrades the quality of the produced alumina but also contributes to the clogging of pipes and equipment during its production. In this work, we investigated the dynamics of the distribution of silicon in the liquid phase upon leaching of raw alunite at room temperature and heating in an alkaline solution. A method of extracting silicon from an aluminate solution is proposed to obtain high-quality aluminum hydroxide. Desilication was carried out by recirculating the parent solution. The silicon dioxide sorption ability from the solution of the material, which was obtained as a result of acid activation of alunite mud, was investigated. It was found that alunite mud activated with sulfuric acid, in comparison with non-activated mud, has the ability to separate the silicate ion from the aluminate solution with a higher percentage of yield

Electric and thermoelectric properties of CdTe/PbTe epitaxial nanocomposite

2014 ◽  
Vol 07 (06) ◽  
pp. 1440007
Author(s):  
Michal Szot ◽  
Krzysztof Dybko ◽  
Piotr Dziawa ◽  
Leszek Kowalczyk ◽  
Viktor Domukhovski ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Carrier Mobility ◽  
Room Temperature ◽  
Molecular Beam ◽  
High Quality ◽  
Polycrystalline Solid ◽  
Hall Effect Measurements ◽  
Shubnikov De Haas Oscillations

The electric and thermoelectric properties of novel, CdTe / PbTe layered nanocomposite material are investigated. The molecular beam epitaxy (MBE) method was used for preparation of samples with well controlled distances (from 20 to 70 nm) between the layers of CdTe nanograins embedded in PbTe thermoelectric matrix as well as with number of these layers from 2 to 10. The Hall effect measurements performed in temperature range from 4–300 K revealed that carrier mobility is strongly affected by scattering on CdTe grain boundaries. The observation of Shubnikov-de Haas oscillations confirms high quality of the samples and allows determination of effective mass of conducting electrons m* = 0.04m0. The measurements of the room temperature Seebeck coefficient together with electrical conductivity lead to the power factors which are comparable to those reported in PbTe / CdTe polycrystalline solid solutions.

High Quality Hydrothermal ZnO Crystals

1998 ◽  
Vol 537 ◽  
Author(s):  
M. Suscavage ◽  
M. Harris ◽  
D. Bliss ◽  
P. Yip ◽  
S.-Q. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Liquid Helium ◽  
Room Temperature ◽  
Surface Preparation ◽  
Critical Factor ◽  
High Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Oxide Crystals

AbstractZinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C-) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

scholarly journals An Alternative Process for Leaching Chalcopyrite Concentrate in Nitrate-Acid-Seawater Media with Oxidant Recovery

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 518 ◽  
Author(s):  
César I. Castellón ◽  
Pía C. Hernández ◽  
Lilian Velásquez-Yévenes ◽  
María E. Taboada
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Alkaline Solution ◽  
Sodium Nitrite ◽  
Sodium Nitrate ◽  
Room Temperature ◽  
Leaching Test ◽  
Copper Concentrate ◽  
Leaching Process ◽  
Chalcopyrite Concentrate

An alternative copper concentrate leaching process using sodium nitrate and sulfuric acid diluted in seawater followed by gas scrubbing to recover the sodium nitrate has been evaluated. The work involved leaching test carried out under various condition by varying temperature, leaching time, particle size, and concentrations of NaNO3 and H2SO4. The amount of copper extracted from the chalcopyrite concentrate leached with seawater, 0.5 M of H2SO4 and 0.5 M of NaNO3 increased from 78% at room temperature to 91% at 45 °C in 96 h and 46 h of leaching, respectively. Gas scrubbing with the alkaline solution of NaOH was explored to recover part of the sodium nitrate. The dissolved salts were recovered by evaporation as sodium nitrate and sodium nitrite crystals.

Microstructure and growth of joins in melt-textured YBa2Cu3O7−δ

2001 ◽  
Vol 16 (8) ◽  
pp. 2298-2305 ◽  
Author(s):  
A. D. Bradley ◽  
W. Lo ◽  
M. Mironova ◽  
N. H. Babu ◽  
D. A. Cardwell ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Liquid Phase ◽  
Grain Boundary ◽  
Electron Probe ◽  
High Quality ◽  
Strongly Coupled ◽  
External Agent ◽  
Transmission Electron

Joining of melt-textured YBa2Cu3O7-δ (Y123) grains has been achieved without use of an external agent. The technique uses barium-cuprate liquid phase released from platelet boundaries to mediate the growth of Y123 at the interface between two grains. The epitaxial nature and high quality of the growth was determined by optical and transmission electron microscopy. The composition of Ba–Cu–O phases found in some parts of the joins was determined by electron probe microanalysis. A clean low-angle join was found to consist of a grain boundary with dislocation networks and facets. Transport critical current measurements on this type of join revealed strongly coupled behavior. The technique shows promise for the joining of melt-textured material for power engineering applications.

scholarly journals Квантовые каскадные лазеры с длиной волны излучения 4.8 mum, работающие при комнатной температуре

2018 ◽  
Vol 44 (18) ◽  
pp. 17
Author(s):  
В.В. Мамутин ◽  
А.П. Васильев ◽  
А.В. Лютецкий ◽  
Н.Д. Ильинская ◽  
А.А. Усикова ◽  
...  
Keyword(s):  
Indium Phosphide ◽  
Room Temperature ◽  
Molecular Beam ◽  
High Accuracy ◽  
High Quality ◽  
Quantum Cascade ◽  
Laser Heterostructures ◽  
Inp Substrate ◽  
Lattice Matched

AbstractWe report on room-temperature generation at the 4.8-μm wavelength in a lattice-matched structure of a quantum cascade laser (QCL) grown on indium phosphide (InP) substrate. Laser heterostructures grown by molecular beam epitaxy (MBE) comprised 30 cascades and were designed to generate at the 4.80 μm wavelength corresponding to an atmospheric transparency window. Experiments demonstrated effective lasing at temperatures from 80 to 300 K on a wavelength coinciding with the calculated value, which confirmed the high quality of interfaces, high precision of layer thicknesses, and high accuracy of active region doping.

High quality of IWO films prepared at room temperature by reactive plasma deposition for photovoltaic devices

2013 ◽  
Vol 46 (7) ◽  
pp. 075103 ◽  
Author(s):  
Zhongdan Lu ◽  
Fanying Meng ◽  
Yanfeng Cui ◽  
Jianhua Shi ◽  
Zhiqiang Feng ◽  
...  
Keyword(s):  
Room Temperature ◽  
Plasma Deposition ◽  
Photovoltaic Devices ◽  
High Quality ◽  
Reactive Plasma

Epitaxial Layers Si: (Sn,Yb) Produced by the Crystallization From the Melt-Solution on the Basis of Sn.

1993 ◽  
Vol 298 ◽  
Author(s):  
D.I. Brinkevich ◽  
N.M. Kazuchits ◽  
V.V. Petrov
Keyword(s):  
Liquid Phase ◽  
Optical Microscopy ◽  
Liquid Phase Epitaxy ◽  
Epitaxial Layers ◽  
High Quality ◽  
Low Concentration ◽  
Crystallization From The Melt

AbstractEpitaxial layers (EL) Si:Sn doped with Yb in the process of liquid phase epitaxy were studied by optical microscopy and photoluminescence (PL) methods.At low concentration of lanthanoid (0,01 < Nyb > 0,1 weight %) the good planarity of the interface and high quality of the surface are detected. At NYb > 0,1 weight % microirregularities are presented.In EL Si:(Sn, Yb) irradiated by 4,5 MeV-electrons the suppression of the generation of radiaton defects, responsible for G– and C-lines of PL, has been found. This effect has been explainedwithin the score of the model takeng into the consideration gettering propering ofYb in reference to the impurities of 0 and C as deformation fields, attributed to the presence of Sn atoms.

scholarly journals High Quality Hydrothermal ZnO Crystals

1999 ◽  
Vol 4 (S1) ◽  
pp. 287-292 ◽  
Author(s):  
M. Suscavage ◽  
M. Harris ◽  
D. Bliss ◽  
P. Yip ◽  
S.-Q. Wang ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Liquid Helium ◽  
Room Temperature ◽  
Surface Preparation ◽  
Critical Factor ◽  
High Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Oxide Crystals

Zinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C−) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

Sign in / Sign up

Export Citation Format

Share Document