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The monazite sand is attacked with sodium hydroxide transforming the mineral into water-soluble trisodium phosphate and mixed hydroxides of the rare earth elements and of thorium. ... A representative analysis of the thorium oxide prepared via peroxide and directly firing at 800°C is following (Table 2): If the precipitation pH is rigorously ...
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The structure of K 3 Th 2 (PO 4) 3 F 2 contains a nine coordinate thorium atom and two orthophosphate tetrahedra which combine to form a novel thorium phosphate network. A similar network can be found in the ATh 2 (PO 4) 3 family of compounds, where A = Na, K, Rb, and Cs [].The potassium analogue of ATh 2 (PO 4) 3 …
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synthesized for several x values from a mixture of thorium, tetravalent neptunium (or plutonium) nitrate and concentrated phosphoric acid solutions. For thorium-uranium (IV) phosphate-diphosphate solid solutions (TUPD), solutions were prepared in hydrochloric acid in order to avoid the oxidization of U4+ into U02+.
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The prepared. solution was diluted with distilled water. The. experiment was carried out in a temperature- ... rare earth, phosphate, and thorium during leaching. after 250 °C bake. A thorium ...
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Phosphate-modified zeolite was prepared by mixing 100 g of the natural zeolite ... In this study, the impact of pH on the adsorption of thorium onto Phosphate-modified zeolite (PZ) was examined ...
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The thorium phosphate hydrogen-phosphate hydrate (TPHPH) sample was prepared by wet chemical synthesis [17]; 3.63 g of the prepared thorium nitrate solution (C Th = 5.52 × 10 −4 mol·g −1) were mixed with 612 μL of a 5 mol·L −1 phosphoric acid solution in a Teflon container (30 mL). The mole ratio of Th/P was close to 2/3, …
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Process for the preparation of thorium phosphate/diphosphate of formula Th 4 (PO 4) 4 P 2 O 7, wherein a product based on thorium(IV) phosphate is prepared by carrying out the process according to claim 1 using, in stage a), a solution comprising thorium and phosphoric acid and wherein the product based on thorium(IV) phosphate is subjected …
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The preparation of thorium phosphate-diphosphate (Th4(PO4)4P2O7, TPD) was developed through the precipitation of thorium phosphate-hydrogenphosphate hydrate (Th2(PO4)2(HPO4)·H2O, TPHPH) at 150 ...
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Sintered pellets were prepared using a two-step procedure (involving an uniaxial pressing at room temperature followed by a heat treatment at 1250 ... β-thorium phosphate diphosphate ceramic (β-TPD), β-Th 4 (PO 4) 4 P 2 O 7, was proposed as a potential actinide-bearing phase for nuclear waste storage. Self-irradiation by α-decays, …
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Thorium occurs inside 30 minerals in acceptable amounts, including oxides 50%, silicates 27%, uranate 17% and phosphate 6%. 2 One of the most important minerals containing thorium is thorite. ... The mineralogical studies of the Choghart thorium deposit showed that the thorium content in the prepared sample (radiometric sorting …
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Since uranium (IV) can be easily oxidized into the molecular uranyl ion UO 2 2+, UV-visible spectrum was recorded in order to check that uranium was only present in the tetrapositive oxidation state in the obtained phosphate.All the bands were assigned to the transition levels of the tetravalent uranium [33]: 3 P 1 multiplets (500–560 nm), 1 G 4, 1 D …
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The preparation of thorium phosphate-diphosphate (Th 4 (PO 4) 4 P 2 O 7, TPD) was developed through the precipitation of thorium phosphate-hydrogenphosphate hydrate (Th 2 (PO 4) 2 (HPO 4)·H 2 O, TPHPH) at 150–160 °C in closed PTFE container or in autoclaves. From EPMA analyses and SEM observations, the initial precipitate was …
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Several compositions of thorium–uranium (IV) phosphate–hydrogenphosphate hydrate (U x/2 Th 2−x/2 (PO 4) 2 (HPO 4) · H 2 O, …
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Thorium (Th 4+) and cerium (Ce 4+) phosphonates have been synthesized by the sol–gel method using various phosphonic acids and analyzed using elemental and …
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Efficient separation and enrichment of thorium from aqueous solutions is an important subject in the field of energy and ecological environment. In this study, a novel polymer-based xerogel was prepared by a crosslinking reaction of 2-carboxyethyl phosphonic acid functionalized chitosan(CCS-TCEP) and was applied to the adsorption …
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Various samples of polyvinyl alcohol Th(IV) phosphate hybrid cation exchanger electrospun fibers were obtained by using slurries of inorganic precipitates of thorium phosphate prepared by mixing (0.1 M Th(NO 3).5H 2 O and 2 M H 3 PO 4 in 1:3 ratio) and varying amounts of polyvinyl alcohol (4, 5 and 6 g) under 16 kV of applied …
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The values of the standard enthalpy of formation and the standard molar entropy of TPHPH are equal to: Δ f H ∘ ( TPHPH) = - ( 5640.5 ± 16.0) kJ · mol - 1 and …
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Thus, marketable pure thorium and uranium products were prepared in addition to rare earth concentrate. Introduction. Demands for uranium and thorium are increasingly crucial in Egypt today. ... Modified acidic leaching for selective separation of thorium, phosphate and rare earth concentrates from Egyptian crude monazite. …
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The functional composition was confirmed using an FTIR-8400S FTIR spectrophotometer from Shimadzu. To record the IR spectrum in the wave numbers of 1600–400 cm −1 and the studied samples were prepared in the form of tablets with KBr [].IR spectra were recorded with an accuracy of determining the absorption of maxima of ± …
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In this paper, we are moving in the knowledge of both structural and morphological features of the ammonium-thorium(IV) bis(phosphate) monohydrate and …
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Several compositions of thorium–uranium (IV) phosphate–hydrogenphosphate hydrate (U x/2 Th 2−x/2 (PO 4) 2 (HPO 4) · H 2 O, TUPHPH) were prepating from actinides chloride solutions and concentrated phosphoric acid. The experimental synthesis parameters were optimized in order to get …
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This paper describes the synthesis of some thorium phosphate compounds with different Th/P ratio (1/2, 2/3 and 3/4) by a spray pyrolysis technique. The so-prepared rough compounds were annealed at different temperatures for 2 h and then analyzed by mainly X-ray diffraction on powder and infrared spectroscopy.Every rough compound is …
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This paper describes the synthesis of some thorium phosphate compounds with different Th/P ratio (1/2, 2/3 and 3/4) by a spray pyrolysis technique. The so-prepared rough compounds were annealed at different temperatures for 2 h and then analyzed by mainly X-ray diffraction on powder and infrared spectroscopy.
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The structure of K 3 Th 2 (PO 4) 3 F 2 contains a nine coordinate thorium atom and two orthophosphate tetrahedra which combine to form a novel thorium …
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Solutions of thorium nitrate were prepared in 1 M HNO 3 while those of acrylamide were prepared in deionized water. The 2 M solutions of orthophosphoric acid were prepared in deionized water. 1000 mg/L stock solution of lead (II) was prepared by dissolving 1.5985 g of Pb(NO 3) 2 in 1 LCharacterization of polyacrylamide thorium (IV) …
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72 NA 72 NA NA NA Recycling: None. Import Sources (2016–19): Monazite: Canada, . Thorium compounds: India, 82%; France, 17%; and the United Kingdom, 1%. Tariff: Item …
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Section snippets Preparation and characterization of the β-TUPD sintered samples. β-TUPD sintered samples with several x values were prepared by wet chemistry methods [23] from low-temperature crystallized precursors through a two-step procedure including an uniaxial pressing at room temperature (200–500 MPa) then a heat treatment …
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The natural zeolite has been modified with sulphate and phosphate. The adsorption of thorium from the aqueous solutions by using the natural and modified zeolites has been investigated via a batch method. The adsorbent samples were characterized by X-ray Diffraction (XRD), N2 adsorption–desorption (BET), Fourier transform infrared (FTIR), …
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Some thorium phosphates have been synthesised: caesium–thorium phosphate, barium–thorium phosphate, thorium fluoride phosphate, thorium sulphate phosphate, and thorium silicate phosphate, starting from aqueous solutions.
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So, a polyacrylonitrile thorium (IV) phosphate has been prepared, which possesses a fibrous structure with high mechanical strength and a good ion exchange capacity. Thorium phosphate has been selected because of its fibrous nature already reported earlier [2], [3]. Following pages summarize the synthesis, ion exchange …
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