Papers by Keyword: Dysprosium

Abstract: The separation process of Dysprosium (Dy) from other Rare Earth Elements (REE) in monazite was carried out considering various applications of Dy in high purity. The Dy elements can be used as a dopant in Thermoluminescence Detector (TLD) crystals to monitor the personnel dose of radiation workers. The separation process of Dy is hard to do due to the similarity of the physical and chemical properties of all REE. This research was conducted to separate Dy by a precipitation process at a certain pH. The feed used is Rare Earth Hydroxide (REOH) concentrate from a monazite processing. The variation of the precipitation used was pH 4.5 to pH 8.5 with 0.5 intervals. The highest precipitation of Dy with an efficiency of 24.47% was obtained at pH 8. Other REEs precipitated at pH 8.5, while the Dy was found the most in the filtrate.

Abstract: The luminescence properties Dy³⁺, Eu³⁺ and Sm³⁺ doped magnesium sodium borate glasses were investigated. The glasses samples containing the composition 30MgO-70Na2B4O7.10H2O-xRE₂O₃ (where RE = Dy³⁺, Eu³⁺, and Sm³⁺, x = 0.1, 0.5, and 1.0 mol %) are prepared by the conventional melt quenching technique. The optical properties have been evaluated using Ultraviolet-Visible Spectroscopy and Photoluminescence Spectroscopy. The X-ray Diffraction pattern was studied to confirm the amorphous nature of the prepared glass. The absorption spectra yield the most intense absorption bands and transition energy levels for Dy³⁺, Eu³⁺, and Sm³⁺ located at 347 nm (⁶H_15/2 → ⁶P_7/2), 393 nm (⁷F₀ → ⁵L₆), and 403 nm (⁶H_5/2 →⁶P_5/2) respectively. The emission spectra demonstrate the highest emission intensity centered at 463 nm (⁴F_9/2 → ⁶F_11/2 + ⁶H_9/2), 612 nm (⁵D₀ → ⁷F_J), and 599 nm (⁴G_5/2 → ⁶H_7/2) for Dy³⁺, Eu³⁺, and Sm³⁺ respectively. Dy³⁺ emits combination of blue, yellow, and red light, Eu³⁺ emits red light and Sm³⁺ emits orange to red light. The higher the content of Dy³⁺, Eu³⁺, and Sm³⁺, the higher the spectral or peak intensity for both absorption and emission. The findings could be useful for development of laser, light emitting diode (LED), and color displays applications. KEY WORDS: Luminescence, Borax glass, Magnesium, Dysprosium, Europium, Samarium.

Abstract: Similarity of chemical and physical properties between rare-earth elements (REEs) and Dy is the main concern in order to get Dy with high purity, which it is necessary to do separation by extraction process. The purpose of this research is to obtain the optimum condition of operation (stirring time and rate, concentration of nitric acid, feed, and solvent) and determine the distribution constant, separation factor, and extraction efficiency of Dy using Aliquat 336. This research was conducted by varying stirring time (10, 15, 20, 30, 40 minutes), stirring rate (100, 150, 200, 250, 300 rpm), nitric acid concentration (2, 3, 4, 5, 6 N), feed concentration (25,000; 50,000; 100,000; 150,000; 200,000 ppm) and solvent concentration (10, 20, 30, 40, 50 % v/v). The optimum result is achieved when operation is carried out at stirring 100 rpm about 15 minutes in nitric acid 3 N with 100,000 ppm of feed concentration using 30% solvent concentration (v/v) which extract more Dy element than Yttrium (Y) and Godolinium (Gd). The highest distribution constant of Dy is 0.427, separation factor of Dy-Y is 6.831, separation factor of Dy-Gd is 1.799, and extraction efficiency of Dy is 31.604%.

Abstract: Five distinguish glass samples were prepared by melt quenching technique of the composition (81-x)H₃BO₃-19BaCO₃-xDy₂O₃ with x = 0, 0.2, 0.4, 0.6 and 0.8 mol%. The effect of Dy³⁺ to the barium borate glass can be investigated in terms of their physical properties such as density, molar volume and oxygen packing density. The structural properties were analyzed by X-Ray Diffraction (XRD) technique and Fourier Transform Infrared Spectroscopy (FTIR). The result revealed that the increment of mol% of Dy³⁺ in the compound generally will increases the density and molar volume of the glass samples. The amorphous nature of the glass system was verified from the XRD spectra pattern. Meanwhile, the FTIR spectra shown the presence of Ba²⁺, BO₃, BO₄, B-O-B linkage, H-O-H and isolated borate in the glass network.

Abstract: The new ternary silicide Dy₃Ni_11.83(1)Si_3.98(1) was synthesized from the elements by arc-melting and its crystal structure was determined by X-ray single-crystal diffraction. The compound crystallizes in a Sc₃Ni₁₁Ge₄-type structure: Pearson symbol hP38, space group P6₃/mmc (No. 194), a = 8.1990(7), c = 8.6840(7) Å, Z = 2; R = 0.0222, wR = 0.0284 for 365 reflections. The structure belongs to a large family of structures related to the EuMg_5.2 type, with representatives among ternary aluminides, silicides, germanides, etc.

Abstract: The crystal structure of the binary compound DyGa₃ at 600°C belongs to the structure type Ta (Rh_0.33Pd_0.67)₃ (Pearson symbol hP40, space group P6₃/mmc: a = 6.1617(3), c = 23.0365(18) Å). Progressive substitution of Ge atoms for Ga atoms in DyGa₃ at 600°C led to the formation of two ternary compounds: DyGa_2.92-2.52Ge_0.08-0.48 (structure type Mg₃In, hR48, R3m, a = 6.1707(3)-6.22374(10), c = 27.7297(15)-28.1185(5) Å) and DyGa_2.32-2.20Ge_0.68-0.80 (PuAl₃, hP24, P6₃/mmc, a = 6.0970(3)-6.1091(6), c = 14.3153(8)-14.3528(14) Å). Both structure types belong to the family of close-packed structures, and the increase of the Ge content in the system DyGa_3-xGe_x is accompanied by a decrease of the hexagonality of the close-packing. Both ternary compounds exhibit metallic type of electrical conductivity.

Abstract: In this work, the optical and luminescence properties of Dy₂O₃ doped barium phosphate glass with different alkaline earth oxides (MgO, CaO and SrO) have been investigated. The glass samples were prepared by the melt-quenching technique at the melting temperature of 1200 °C. The absorption spectra of glasses were recorded in the ultraviolet, visible and near infrared (UV-Vis-NIR) region. The absorption bands centered at 385, 424, 452, 472, 754, 803, 901, 1093, 1273 and 1683 nm, respectively have been observed. The emission spectra of glass samples centered at 482, 574, 662 and 751 nm, respectively have been observed with 350 nm excitation wavelength. The result of radioluminescence spectra were slightly different with photoluminescence spectra. The coordinate of emitting color (x, y) for 350 excitation wavelength is 0.3781 and 0.4252, respectively which is located in white light region of CIE diagram.

Abstract: In this study, the effect of zinc bismuth borate (ZBB) glass and bismuth borate glass (BB) doped with trivalent dysprosium ion were investigated. Glass were prepared by the conventional melt quenching technique, with the chemical composition of (60-x) B₂O₃: 30Bi₂O₃: 10ZnO: xDy₂O₃ and (70-x) B₂O₃: 30Bi₂O₃: xDy₂O₃ where x = 1.0 mol %. The results show the densities of glasses are 3.91 g/cm³(ZBB) and 4.24 g/cm³ (BB), respectively. The absorption spectra consists of six absorption bands that are located at 752, 796, 902, 1096, 1276 and 1681 nm, and are assigned to ⁶H_15/2 to ⁶F_3/2, ⁶F_5/2, ⁶F_7/2, ⁶H_7/2+⁶F_9/2, ⁶F_11/2+⁶H_9/2 and ⁶H_11/2 transitions. The emission spectra exhibited three emission bands corresponding to the ⁴F_9/2 → ⁶H_15/2 (483 nm; blue), ⁴F_9/2 → ⁶H_13/2 (575 nm; yellow) and ⁴F_9/2 → ⁶H_11/2 (664 nm; red) transitions. The lifetime for ⁴F_9/2 → ⁶H_13/2 transition are 0.178 ms (ZBB) and 0.420 ms (BB). Both of Dy³⁺ in ZBB and BB glasses have been show white emission and illustrated by CIE 1931 chromaticity coordinates.

Abstract: Dy³⁺-doped phosphate glasses of the compositions 20Gd₂O₃ : 10CaO : (70-x)P₂O₅ : xDy₂O₃, where x = 0.05, 0.10, 0.50, 1.00 and 1.50 mol% have been prepared by melt quenching technique and characterized by optical absorption, emission spectra and decay curve analysis. All the transitions in the absorption spectra are originated from the ⁶H_15/2 ground level to the various excited states and these are intra configuration (f-f) transitions. The observed twelve absorption bands centered at 349, 362, 387, 425, 451, 473, 750, 800, 895, 1089, 1266 and 1676 nm are assigned to ⁶P_7/2, ⁴P_3/2, ⁴F_7/2, ⁴G_11/2, ⁴I_15/2, ⁴F_9/2, ⁶F_3/2, ⁶F_5/2, ⁶F_7/2, ⁶F_9/2, ⁶H_9/2 and ⁶H_11/2 transitions, respectively. The absorption spectra of glasses increase with increase in Dy³⁺ ion concentrations. The emission spectra of Dy³⁺-doped glasses are observed to be centered at 483, 573, 662 and 752 nm originated from the ⁴F_9/2→⁶H_15/2, ⁴F_9/2→⁶H_13/2, ⁴F_9/2→⁶H_11/2 and ⁴F_9/2→⁶H_9/2 transitions, respectively under excitation at 349 nm. The highest emission intensity of Dy³⁺-doped glass is 0.50 mol% due to concentration quenching effect. The experimental lifetimes are found to decrease when Dy³⁺ ion concentrations increased due to energy transfer process between Dy³⁺ ions.

Abstract: Dysprosium doped lithium lanthanum borate glasses (LiLaB:Dy³⁺) were prepared by the melt quenching technique, varying the Dy₂O₃ doped concentration from 0.00 to 1.50 mol%. The absorption spectra showed that LiLaB:Dy³⁺ glass absorbed photon in visible light and near infrared region. From the excitation of 388 nm, this glass emitted the photon with 483, 575, 664 and 753 nm wavelength. The intensity of emission increased with increasing of Dy₂O₃ concentration until 1.0 mol%, after that it decreased. The Judd-Ofelt (J-O) analysis was applied to 1.0 mol% doped glass to investigate the J-O parameter, radiative transition possibility and stimulated emission cross section. These values were interpreted to the ability of laser gain medium.