Solvent extraction of iron (III) from the HCl leach liquor of low grade iron ore tailings was studied with Aliquat 336, a quaternary amine in kerosene. p-Nonyl phenol was used as the third phase ...modifier. The effect of different parameters such as equilibration time, HCl concentration, H
+ concentration, Cl
− concentration and extractant concentration on extraction of iron was studied. The effect of different diluents such as xylene, benzene, toluene, diphenyl ether, diethyl ether, cyclohexane, hexanol, cyclohexanol and butanol on extraction of iron was investigated. The effect of various salts such as NaCl, NaNO
3, Na
2SO
4, NaOOCCH
3, and Na
3C
6H
5O
7·2H
2O in the feed solution within the concentrations of 0.5 to 2.5
M on extraction of iron was studied. It was observed that extraction of iron increased from 51.82 to 97.52% and from 5.81 to 97.19% with increase in HCl and extractant concentrations from 1.67 to 9.7
M and from 0.025 to 0.4
M, respectively. From the slope analysis study, the number of moles of H
+, Cl
− and Aliquat 336 associated with the extracted species was determined and the extracted species was found to be R
3NCH
3
·FeCl
4. The McCabe–Thiele plot for extraction of iron with 0.2
M Aliquat 336 illustrated 2-stages at 1:1 phase ratio and the loaded organic contained 0.338
M (18.8496
kg/m
3) iron indicating 98.57% extraction. The stripping of iron from the loaded organic carried out with distilled water showed quantitative stripping in 3-stages at O:A ratio of 2:1.
► Study on Fe extraction from low grade Fe ore tailing leach liquor with Aliquat 336. ► Extraction increased with increase of HCl and Aliquat 336 concentration. ► Diluent and salt effects are studied and thermodynamic data generated. ► Extraction of Fe in 2 stages at O:A
=
1:1, stripping of LO in 3 stages at O:A
=
2:1. ► Extracted species is R
3NCH
3·FeCl
4.
A comparative study on extraction of Fe(III) from the HCl leach liquor of low grade iron ore tailings has been carried out using Tri-n-butyl phosphate (TBP), Cyanex 921 and Cyanex 923 in distilled ...kerosene. The percentage extraction of iron increased with increasing HCl and extractant concentrations. The extracted species in each case was found to be HFeCl
4·S. The extraction isotherms for the above extractants indicated quantitative extraction of Fe(III) in 3-stages at O:A ratio of 3:2 with TBP, and in 2-stages at O:A ratio of 1:1 with Cyanex 921 and Cyanex 923. The stripping studies of the loaded organic phases were carried out with 0.4
M HCl. The stripping isotherms indicated 2-stages at O:A ratio of 5:2 for TBP, and 3-stages at O:A ratio of 2:3 for Cyanex 921 and Cyanex 923. From the extraction studies, the extraction efficiency of the extractants for Fe(III) was in the order TBP
<
Cyanex 921
<
Cyanex 923. Although Cyanex 923 was found to be the best extractant, the percentage stripping of Fe from the loaded Cyanex 923 was the least. The stripping of Cyanex 923 was 94.9%, but with TBP and Cyanex 921, it was 99.8% and >
99.9%, respectively.
►Iron was extracted from HCl media using TBP, Cyanex 921 and Cyanex 923. ► The order of efficiency of the extractants: TBP
<
Cyanex 921
<
Cyanex 923. ► Extraction with TBP: 3-stage, O:A
=
1.5 ; Cyanex 921, Cyanex 923: 2-stage, O:A
=
1. ► Quantitative stripping of Fe-LO was achieved with 0.4 M HCl. ► The extracted species for TBP, Cyanex 921 and Cyanex 923 were HFeCl4.Solvent.
The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted ...metal ions were removed by precipitation method and solvent extraction was used to extract/separate Zn, Mn, Co and Ni. The nickel laterite leach liquor which was obtained from bioleaching of chromite overburden samples contained 3.72 g/L Fe, 2.08 g/L Al, 0.44 g/L Ni, 0.02 g/L Co, 0.13 g/L Mn, 0.14 g/L Zn and 0.22 g/L Cr. From this leach liquor, 100% Fe, 96.98% Al and 70.42% Cr were removed by precipitation with CaCO3 at pH 4.4 followed by precipitation of remaining Al and Cr with 50% ammonia at pH 5.4. After precipitation, the extraction of Zn from the Fe, Al and Cr free leach liquor was carried out with 0.1 mol/L TOPS-99 followed by Mn extraction with 0.04 mol/L NaTOPS-99. The yields of Zn and Mn were 97.77% and 95.63%, respectively. After Mn extraction, cobalt was removed from the leach liquor using 0.0125 mol/L NaCyanex 272 and finally nickel extraction was carried out using 0.12 mol/L NaTOPS-99 with 99.84% yield. The stripping of loaded organic (LO) phases were achieved with dilute H2SO4.
Measurements of fusion cross-sections of 7Li and 12C with 198Pt at deep sub-barrier energies are reported to unravel the role of the entrance channel in the occurrence of fusion hindrance. The onset ...of fusion hindrance has been clearly observed in C12+Pt198 system but not in Li7+Pt198 system, within the measured energy range. Emergence of the hindrance, moving from lighter (6,7Li) to heavier (12C, 16O) projectiles is explained employing a model that considers a gradual transition from a sudden to adiabatic regime at low energies. The model calculation reveals a weak effect of the damping of coupling to collective motion for the present systems as compared to that obtained for systems with heavier projectiles.
We report on the observation of room temperature ferromagnetism as well as optical limiting in V2O5 nanoflower structures synthesized by a simple and novel cost-effective low-temperature method. The ...flowers are characterized thoroughly by various analytical techniques to ascertain their structure and composition and to confirm the absence of any impurities. The samples exhibit ferromagnetic properties at 300, 200, and 100 K observed from a hysteresis loop. Coercivity for room temperature synthesized V2O5 flowers is 566 Oe at 300 K and is enhanced at 200 and 100 K. We propose a growth mechanism of the flowers and attribute the origin of ferromagnetism to the introduction of oxygen vacancies in accordance with theoretical predictions available on other oxide nanomaterials. The samples also show optical limiting behavior arising from an effective three photon absorption mechanism as demonstrated by a Z-scan experiment for characterization of optical nonlinearity.
We have successfully deposited epitaxial thin films of the Heusler alloy Co2FeSi on (1 0 0) cut SrTiO3 single crystal substrates by pulsed laser deposition. X-ray diffraction reveals the L21 cubic ...crystal structure for the films grown at 400 and 600 degree C, with a better crystallographic quality at the higher growth temperature. The magnetic moment in saturation of the 600 degree C grown film is 5.0 mu B/fu at 5 K with the easy axis of magnetization in the (1 0 0) plane. Inplane hysteresis measurements suggest a soft magnetic state with a coercive field HC 250 Oe at 5 K for the 600 degree C film which decreases on lowering the growth temperature. The normalized magnetization of thin films follows the well-known Bloch T3/2 law due to spin wave excitation. Electrical resistivity measurements on the films with the L21 crystal structure show a pronounced metallic behaviour down to the lowest temperature of measurement (5 K), and enhanced metallicity in the 600 degree C film as indicated by its lower residual resistivity (0.16 mu Delta *W cm) and higher residual resistivity ratio (RRR 1280). These results suggest that films grown at the higher temperature may be better suited for the fabrication of magnetic tunnel junctions.
Fission fragment mass distribution of 187Ir Dhuri, Sangeeta; Mahata, K.; Shrivastava, A. ...
Journal of physics. Conference series,
09/2023, Letnik:
2586, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The fission fragment mass and total kinetic energy (TKE) distributions were studied for 187Ir populated using 12C + 175Lu reaction at excitation energies 24.8, 23.3, 20.8, and 16.7 MeV above the ...saddle point. Fission fragments (FF) were detected using position sensitive MWPC’s kept at a folding angle. The mass of the fragment was calculated using Time-of-Flight (TOF) difference method. The multi Gaussian fit to the extracted mass distributions shows the presence of narrower microscopic components corresponding to Z = 38 and 45 in addition to the liquid drop component at lower excitation energies. The GEF model predicts significant asymmetric components at all the measured energies. The TKE distribution investigations suggest the dominance of macroscopic liquid drop components at all energies.
Conventional liquid scintillator (BC501A) and pulse shape discrimination capable plastic scintillator (EJ-299-33A) based detector of dimension; 5 inch diameter and 5 inch long, have been used to ...study pulse height response for quasi-monoenergetic neutrons of energy in the range 3 to 15 MeV generated using 7Li(p,n)7Be reaction. Scintillation light output of plastic scintillator having pulse shape discrimination property is found to be 75% of the liquid scintillator at neutron energy (maximum recoil proton energy) of 3 MeV which improves with the increase in energy. Functional dependence of the scintillation light output in terms of recoil protons energy has been determined for the liquid and the plastic scintillator detectors for neutron energy in the range 3 to 15 MeV. This functional dependences were used in the Geant4 simulation to calculate the pulse height responses at several neutron energies.
•Direct leaching followed by baking–leaching of spent Cu-Cr catalyst was carried out using H2SO4 solution.•Copper and chromium leaching was maximized up to 67.25% and 2.3%, respectively, at optimum ...direct leaching condition.•Baking–leaching route was found to be very effective on selective and quantitative (99.9%) dissolution of copper at ambient temperature condition.•Phase transformation taking place during baking and after baking–leaching was ascertained by XRD and Fe-SEM study.•Fe-SEM-Edax results further assured on phase transformation as well as elemental essay of corresponding analyzed samples.
The selective leaching of copper from the spent Cu-Cr catalyst was carried out with H2SO4. The effect of different parameters such as acid concentration, pulp density, temperature and particle size on leaching was investigated. The maximum extraction of copper and chromium was 67.25 and 2.3%, respectively at particle size 45–53μm, pulp density 2.5%, temperature 90°C, time 180min. Therefore, baking followed by leaching approach was adopted for dissolution of spent copper-chromium catalyst using H2SO4 to enhance the metal leaching efficiency. At the optimum baking–leaching condition i.e. baking time 2h, baking temperature 300°C, baking acid concentration 0.5M, leaching temperature 35°C, time 60min, H2SO4 4%, P.D. 2.5%, the extraction of copper and chromium was 99.9% and 1.2%, respectively, ensuring the selective dissolution of copper. The XRD and Fe-SEM-Edax characterization analysis of typical samples (original, baked mass and typical residue) were compared and reported. The XRD and Fe-SEM-Edax analysis of the baked mass indicated the complete sulfation of copper and chromium by H2SO4 yielding CuSO4 (H2O) and (Cr)2(SO4)3, respectively in solid phase. The absence of XRD peaks corresponding to CuSO4·H2O in the final typical leach residue (obtained at optimum baking–leaching condition) confirmed the complete dissolution of copper from Cu-Cr catalyst.
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