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Journal articles on the topic 'Uranium Thorium'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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1

Anggraini, Mutia, Budi Sarono, Sugeng Waluyo, Rusydi Rusydi, and Sujono Sujono. "Pengendapan Uranium dan Thorium Hasil Pelarutan Slag II." EKSPLORIUM 36, no. 2 (November 30, 2015): 125. http://dx.doi.org/10.17146/eksplorium.2015.36.2.2776.

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Proses peleburan timah menghasilkan limbah berupa slag II dalam jumlah besar. Slag II sebagai terak pada proses peleburan timah masih mengandung beberapa unsur utama antara lain 0,0619% uranium, 0,530% thorium, 0,179% P2O5, dan 6,194% logam tanah jarang (LTJ) oksida total. Berdasarkan fakta tersebut, maka sangat menarik untuk meneliti pengolahan slag II, terutama untuk memisahkan uranium dan thorium yang terkandung di dalamnya. Uranium dan thorium dilarutkan dengan pelarut asam (H2SO4). Recovery pelarutan slag II dari hasil peleburan timah pada kondisi optimum adalah 98,52% uranium, 83,16% thorium, 97,22% fosfat, dan 69,62% LTJ. Uranium, thorium, LTJ, dan fosfat yang telah terlarut diendapkan agar masing-masing unsur terpisah. Faktor yang mempengaruhi kesempurnaan reaksi pada pengendapan antara lain reagen yang digunakan, pH reaksi, suhu, dan waktu. NH4OH digunakan sebagai reagen pengendapan dengan kondisi optimum proses pada pH 4. Suhu dan waktu reaksi tidak mempengaruhi proses. Recovery pengendapan yang dihasilkan adalah 93,84% uranium dan 84,33% thorium. Tin smelting process produces waste in the form of large amount of slag II. Slag II still consist of major elements such as 0.0619% uranium, 0.530% thorium, 0.179% P2O5 and 6.194% RE total oxide. Based on that fact, the processing of slag II is interesting to be researched, particularly in separating uranium and thorium which contained in slag II. Uranium and thorium dissolved using acid reagent (H2SO4). Percentage recovery of uranium, thorium, phosphate and RE oxides by dissolution method are 98.52%, 83.16%, 97.22%, and 69.62% respectively. Dissolved uranium, thorium, phosphat, and RE were each precipitated. The factors which considerable affect the precipitation process are reagent, pH, temperature, and time. NH4OH is used as precipitation reagent, optimum condition are pH 4. Temperature and time reaction did not influence this reaction. Percentage recovery of this precipitation process at optimum condition are 93.84% uranium and 84.33% thorium.

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2

Lidman, F., C. M. Mörth, and H. Laudon. "Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands." Biogeosciences Discussions 9, no. 3 (March 13, 2012): 2823–49. http://dx.doi.org/10.5194/bgd-9-2823-2012.

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Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, but could not explain the variability in the export. Instead, the extent of lakes and mires within each subcatchment was found to be a stronger predictor for the transport of uranium and thorium. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal mires. Approximately 65–80 % of uranium and 55–65 % of thorium entering a mire is estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands is estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40 %. The atmospheric deposition of uranium and thorium was also quantified and its contribution to boreal streams was found to be low compared to weathering.

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3

Lidman, F., C. M. Mörth, and H. Laudon. "Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands." Biogeosciences 9, no. 11 (November 23, 2012): 4773–85. http://dx.doi.org/10.5194/bg-9-4773-2012.

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Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2) up to a fourth-order stream (67 km2). Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, suggesting that the concentrations of uranium and thorium in mineral soils are similar throughout the catchment. The fluxes of uranium and thorium were compared to a wide range of parameters characterising the investigated catchments and the chemistry of the stream water, e.g. soil concentrations of these elements, pH, TOC (total organic carbon), Al, Si and hydrogen carbonate, but it was concluded that the spatial variabilities in the fluxes of both uranium and thorium mainly were controlled by wetlands. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal wetlands that is large enough to control the transport of these elements. On the landscape scale approximately 65–80% of uranium and 55–65% of thorium entering a wetland were estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands was estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40%, indicating that wetlands play an important role for the biogeochemical cycling of uranium and thorium in the boreal forest landscape. The atmospheric deposition of uranium and thorium was also quantified, and its contribution to boreal streams was found to be low compared to weathering.

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4

Islami rad, Seyedeh Zahra, and Reza Gholipour Peyvandi. "Determination of uranium and thorium concentrations in thorium ore sample using artificial neural network and comparison with net area peak method." Radiochimica Acta 106, no. 8 (August 28, 2018): 669–74. http://dx.doi.org/10.1515/ract-2017-2880.

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Abstract In order to determine favorable and different elements in soil, the rapid and accurate methods are required. In this research, simultaneous prediction of thorium and uranium in soil samples was performed via gamma spectrometry. Then, the acquired data were analyzed with artificial neural network (ANN) and net area peak (NAP). Natural soil samples obtained from thorium ore consisting of thorium and uranium were used to train models (ANN and NAP). The techniques were evaluated with respect to prediction ability of uranium and thorium concentrations and robustness. Using proposed ANN and NAP methods, the thorium concentration was predicted with mean relative error percentage less than 8.27% and 9.30%, respectively. Also, uranium concentration just was determined with ANN because the NAP method cannot measure uranium concentration. The performance of the neural network model and NAP technique were compared with the acquired empirical data. The results showed that the neural network can more accurately predict the thorium and uranium concentrations in soil samples.

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5

Ridantami, Vemi, Bangun Wasito, and Prayitno Prayitno. "PENGARUH TEGANGAN DAN WAKTU PADA PENGOLAHAN LIMBAH RADIOAKTIF URANIUM DAN THORIUM DENGAN PROSES ELEKTROKOAGULASI." Jurnal Forum Nuklir 10, no. 2 (June 8, 2017): 102. http://dx.doi.org/10.17146/jfn.2016.10.2.3494.

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PENGARUH TEGANGAN DAN WAKTU PADA PENGOLAHAN LIMBAH RADIOAKTIF URANIUM DAN THORIUM DENGAN PROSES ELEKTROKOAGULASI. Metode pengolahan limbah radioaktif dengan metode fisika dan kimia yang telah dilakukan dinilai kurang efektif, memerlukan waktu yang lama dan biaya yang mahal. Untuk itu perlu dilakukan pengolahan limbah uranium dan thorium dengan proses elektokoagulasi untuk memisahkan uranium dan thorium dalam limbah cair. Limbah yang digunakan memiliki kadar kontaminan Uranium dan Thorium 500 mg/liter. Pengolahan dilakukan dengan tegangan 10V, 12,5V, dan 15 volt dengan waktu 10,20,30,40,50,dan 60 menit dengan elektroda alumunium. Hasil penelitian menunjukkan effisiensi penurunan kontaminan terbaik pada pengolahan ini diperoleh pada kondisi 12,5V dan waktu 60 menit untuk uranium, dengan efisiensi sebesar sebesar 97,2 %, dan thorium pada 12,5 V waktu 30 menit dengan efisiensi penurunan sebesar 99,6 % .

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6

Ngadenin, Ngadenin, and Adhika Junara Karunianto. "Identifikasi Keterdapatan Mineral Radioaktif pada Granit Muncung Sebagai Tahap Awal untuk Penilaian Prospek Uranium dan Thorium di Pulau Singkep." EKSPLORIUM 37, no. 2 (December 19, 2016): 63. http://dx.doi.org/10.17146/eksplorium.2016.37.2.3101.

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ABSTRAKPulau Singkep adalah bagian dari jalur timah Asia Tenggara, yang salah satu litologinya tersusun oleh granit Muncung. Keberadaan granit tersebut memungkinkan adanya cebakan mineral radioaktif yang prospek terhadap uranium dan thorium. Penelitian ini bertujuan untuk mengidentifikasi keterdapatan mineral radioaktif pada granit Muncung sebagai tahap awal untuk penilaian prospek uranium dan thorium di Pulau Singkep. Metoda yang digunakan adalah pengambilan sampel batuan granit, analisis petrografi sampel granit Muncung, analisis kadar uranium dan thorium serta analisis butir sampel konsentrat dulang yang diambil di wilayah granit Muncung. Mineral radioaktif pada granit Muncung adalah monasit dan zirkon sedangkan pada konsentrat dulang adalah monasit, zirkon, dan senotim. Persentase monasit dalam konsentrat dulang adalah 1,1 – 59,53 %, zirkon 0,68 –55,07 % dan senotim 0,39 – 3,54 %. Kadar uranium dalam konsentrat dulang adalah 30 – 1.346 ppm dan kadar thorium 557 – 13.200 ppm. Disimpulkan bahwa daerah di sekitar granit Muncung dianggap cukup prospek uranium dan thorium dan dapat dikembangkan ke tahapan eksplorasi lebih detail. ABSTRACTSingkep Island is part of Southeast Asia tin belt, which is one of the lithologies, composed of granite Muncung. Existence of granite allows formed deposits of radioactive minerals that prospect of the uranium and thorium. This research goal is to identify radioactive minerals occurrences on granit Muncung in the initial stage for prospect assessment of uranium and thorium in Singkep Island. The Methodologies are granite sampling, petrography analysis of Muncung granite samples, uranium and thorium content analysis and grain size analysis of pan concentrate samples. Radioactive minerals in Muncung granite are monazite and zircon, while in pan concentrate they are monazite, zircon, and xenotime. The percentage of monazite, zircon, and xenotime in the pan concentrate are 1.1–59.53 %, 0.68–55.07 %, and 0.3–3.54 % respectively. The uranium and thorium content in the pan concentrate are 30–1,346 ppm and 557–13,200 ppm respectively. It concluded that the area around the Muncung granite considered prospect for uranium and thorium, and possibly developed into more detailed exploration stage.

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7

Omnia M., Ali, El-Kashif H.H., Sayed S.A., and Shalabi M.E.H. "The Removal of Uranium and Thorium from Aqueous Solutions Onto by-pass Cement Dust (BCD)." Eurasian Chemico-Technological Journal 11, no. 2 (April 6, 2016): 105. http://dx.doi.org/10.18321/ectj303.

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<p>The adsorption behavior of uranium and thorium from aqueous solutions by By-pass cement dust (BCD) has been investigated by a batch technique. The uranium and thorium adsorption on BCD was studied as a function of initial concentration, weight of BCD, pH, shaking time and temperature. The uptake of uranium and thorium at the determined optimum conditions follows Freundlich isotherm. The adsorption control of both thorium and uranium are first order and uptake energy of activation E<sub>a</sub> =10 and 15 kJ/mol for thorium and uranium respectively. Thermodynamic parameters such as ΔH<sup>o</sup>, ΔS<sup>o</sup> and ΔG<sup>o</sup> were also investigated.</p>

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8

Mintz Testa, Bridget. "Thunder on the Horizon." Mechanical Engineering 139, no. 02 (February 1, 2017): 38–43. http://dx.doi.org/10.1115/1.2017-feb-2.

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This article discusses the advantageous usage of thorium-based breeder reactors in the nuclear industry. Since thorium is more abundant than uranium and can be turned into fuel without the enrichment process needed to concentrate U-235, experts believe that the thorium fuel cycle could be more sustainable than the uranium cycle. The addition of thorium to the fluid salt helps reduce uranium consumption. ThorCon, a Florida-based nuclear power startup, has developed the ThorCon reactor that will be breeding some of its own fuel by irradiating thorium. Thorium is about three times more abundant than uranium, and all of it can be used to create a fuel source for nuclear reactors. Thor Energy is developing two different families of thorium-based fuels with both U-235 and Pu-239 as the fissile driver material. The interest in thorium suggests that it is going to take an unconventional approach to lead to the much-anticipated Nuclear Renaissance.

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9

Reda, Sonia M., Ibrahim M. Gomaa, Ibrahim I. Bashter, and Esmat A. Amin. "Neutronic Performance of the VVER-1000 Reactor Using Thorium Fuel with ENDF Library." Science and Technology of Nuclear Installations 2021 (April 14, 2021): 1–9. http://dx.doi.org/10.1155/2021/8838097.

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In this paper, neutronic calculations and the core analysis of the VVER-1000 reactor were performed using MCNP6 code together with both ENDF/B-VII.1 and ENDF/B-VIII libraries. The effect of thorium introduction on the neutronic parameters of the VVER-1000 reactor was discussed. The reference core was initially filled with enriched uranium oxide fuel and then fueled with uranium-thorium fuel. The calculations determine the delayed neutron fraction βeff, the temperature reactivity coefficients, the fuel consumption, and the production of the transuranic elements during reactor operation. βeff and the Doppler coefficient (DC) are found to be in agreement with the design values. It is found that the core loaded with uranium and thorium has lower delayed neutron fraction than the uranium oxide core. The moderator temperature coefficients of the uranium-thorium core are found to be higher than those of the uranium core. Results indicated that thorium has lower production of minor actinides (MAs) and transuranic elements (mainly plutonium isotopes) compared with the relatively large amounts produced from the uranium-based fuel UO2.

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10

Said, Moch Iqbal Nur, Mutia Anggraini, Mohammad Zaki Mubarok, and Kurnia Setiawan Widana. "Studi Ekstraksi Bijih Thorit dengan Metode Digesti Asam dan Pemisahan Thorium dari Logam Tanah Jarang dengan Metode Oksidasi-Presipitasi Selektif." EKSPLORIUM 38, no. 2 (November 30, 2017): 109. http://dx.doi.org/10.17146/eksplorium.2017.38.2.3930.

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AbstrakThorium (Th) merupakan logam radioaktif yang dapat terbentuk bersama uranium dan logam tanah jarang (LTJ). Mineral-mineral yang mengandung unsur radioaktif diantaranya monasit ((Ce,La,Y,U/Th)PO4), thorianit ((Th,U)O2), dan thorit (ThSiO4). Daerah Mamuju, Sulawesi Barat diketahui mengandung mineral radioaktif, salah satunya adalah thorit. Untuk memisahkan LTJ dari unsur radioaktif dapat dilakukan dengan cara mengekstraksi thorium dari bijih thorit dengan metode digesti asam menggunakan asam sulfat (H2SO4), kemudian diikuti pelindian dalam air dan rekoveri thorium dalam bentuk thorium hidroksida dengan metode presipitasi kimia menggunakan ammonium hidroksida (NH4OH). Hasil percobaan menunjukkan bahwa kondisi optimum digesti asam yang memberikan persentase ekstraksi paling tinggi didapatkan pada rasio padat/cair 1:2 (g/mL) selama 60 menit dengan persentase ekstraksi Th, besi (Fe), dan LTJ masing-masing sebesar 82,47%, 80,08%, dan 83,31%. Persentase presipitasi Th tertinggi sebesar 95,47% diperoleh pada pH 4,5 dalam suhu ruangan (26±1°C). Pada temperatur yang lebih tinggi, (70°C), diperoleh persentase presipitasi thorium yang lebih rendah sebesar 83,69%. Pre-oksidasi dengan menggunakan larutan H2O2sebanyak dua kali stoikiometri selama 1,5 jam pada suhu kamar meningkatkan persentase presipitasi Fe dari 93,08% menjadi 99,93%. AbstractThorium (Th) is a radioactive metal that can be formed along with uranumand rare earth metals (REM). Minerals contain radioactive elements are monazite ((Ce,La,Y,U/Th)PO4), thorianite ((Th,U)O2), and thorite (ThSiO4). Mamuju Area is containing radioactive minerals, thorite is one of them. To separate REM from radioactive elements can be conducted by exctracting thorium from thorite ore by acid digestion method using sulphuric acid (H2SO4), followed by leaching and thorium recovery in the form of thorium hydroxide by chemical precipitation using ammonium hydroxide (NH4OH). The experimental results showed that the optimum conditions of acid digestion that give the highest Th extraction percentage on solid to liquid ratio are obtained at 1:2 (g/mL) in 60 minutes with extraction percentages of Th, iron (Fe) and REM are 82.47%, 80.08%, and 83.31% respectively. The highest thorium precipitation percentage, as much as 95.47% , was obtained at pH 4.5 on room temperature (26 ± 1°C). At higher temperature (70°C), a lower percentage of thorium precipitation is obtained, as much as 83.69%. Pre-oxidation by using H2O2 solution with two times stoichiometry for 1.5 hours at room temperature is increasing Fe precipitation percentage from 93.08% to 99.93%.

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11

Pradhan, Susanta Kumar, and Balram Ambade. "Determination of trace uranium in thorium matrix by laser induced fluorimetry after separation of thorium by its fluoride precipitation using NH4HF2." Radiochimica Acta 109, no. 3 (January 26, 2021): 195–203. http://dx.doi.org/10.1515/ract-2020-0050.

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Abstract Thorium, a major element in thorium matrix, quenches uranium fluorescence when it is present above the ratio (Th/U) of 2000 in conventional pellet fluorimetry determination of uranium. A single step ‘sample digestion cum thorium fluoride precipitation’ with NH4HF2 has been developed for separation of bulk thorium as hydrated thorium fluoride precipitates. Uranium in aqueous solution is extracted into ethyl acetate and stripped into pyrophosphate medium (pH ∼ 7), prior to its laser induced fluorimetry determination. Optimizations of certain parameters such as the effects of fluoride flux, mineral acid, temperature and time, stripping solution, diverse ions etc. are discussed in detail. The method has been validated by analyzing a set of synthetic mixtures and certified reference materials of rock samples such as SY-2, SY-3, GSP-2, NKT-1 and CG-2 doped with a large excess of thorium. This method has been applied for the determination of microgram to nanogram uranium in thorium rich rocks and synthetic nuclear grade ThO2 with high degree of accuracy and precision. This is the improvement of the existing method which involves two liquid-liquid solvent extraction separation of thorium and uranium using the chelating agent 2,3-dihydroxynaphthalene at the different pH, compared to one solvent extraction separation of uranium in the present method, because separation of thorium by precipitation as its fluoride has already been carried out during sample digestion step itself. The proposed method involving ammonium hydrogen fluoride in combination with laser induced fluorimetry is simple, rapid, cost effective and more eco-friendly.

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Singh, N. P. "The Role of Thorium in Endomyocardial Fibrosis." Human & Experimental Toxicology 9, no. 2 (March 1990): 79–82. http://dx.doi.org/10.1177/096032719000900203.

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The behaviour of thorium in animals exposed through injection, ingestion and inhalation, as well as in uranium miners, millers and the general population suggests that thorium . accumulates primarily in the lung, tracheobronchial lymph nodes and skeleton; or in the liver if injected with polymeric thorium. Epidemiological studies on uranium miners, Thorotrast studies in man and animal, and studies on the toxic effects of thorium in animals suggest that there is no apparent heart diseases due to exposure to thorium in man and animal.

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Ferliana, Rida, Bangun Wasito, and Riesna Prassanti. "EKSTRAKSI DAN STRIPPING THORIUM DARI RAFINAT HASIL EKSTRAKSI URANIUM MONASIT BANGKA." Jurnal Forum Nuklir 10, no. 1 (June 7, 2017): 26. http://dx.doi.org/10.17146/jfn.2016.10.1.3488.

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EKSTRAKSI DAN STRIPPING THORIUM DARI RAFINAT HASIL EKSTRAKSI URANIUM MONASIT BANGKA. Pusat Teknologi Bahan Galian Nuklir – Badan Tenaga Nuklir Nasional (PTBGN- BATAN) yang bekerja sama dengan PT Timah mengimplementasikan penelitian pengolahan monasit menjadi logam tanah jarang ke dalam skala pilot plant 50 kg/hari. Kegiatan tersebut menghasilkan limbah berupa unsur radioaktif seperti uranium dan thorium. Thorium merupakan alternatif pengganti bahan bakar uranium. Agar dapat dijadikan bahan bakar nuklir maka perlu dilakukan pemisahan thorium. Salah satu metode pemisahan adalah ekstraksi-stripping. Ekstraksi-stripping thorium dilakukan menggunakan rafinat ekstraksi uranium pada limbah pengolahan monasit. Solven yang digunakan dalam ekstraksi yaitu TBP dan dalam stripping yaitu HNO3 encer. Berdasarkan penelitian tersebut diperoleh bahwa semakin tinggi keasaman umpan maka rekoveri dan koefisien distribusi thorium semakin meningkat serta semakin tinggi konsentrasi HNO3 maka rekoveri semakin menurun dan koefisien distribusi thorium semakin meningkat. Ekstraksi pada waktu 15 menit, pH umpan 0,09, TBP/kerosin 50/50, dan perbandingan A/O = 1/1 memberikan koefisien distribusi sebesar 13,80 dengan rekoveri ekstraksi sebesar 93%. Stripping pada waktu 15 menit, konsentrasi HNO3 0,1 N, dan perbandingan A/O = 1/1 memberikan koefisien distribusi 1,57 dengan rekoveri sebesar 38,92%. Jika rekoveri thorium ingin ditingkatkan menjadi 95% maka dibutuhkan 2 stage ekstraksi pada perbandingan A/O 1/1, 8 stage stripping pada perbandingan A/O 2/1, dan 5 stage stripping pada perbandingan A/O = 3/1.

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14

Okamoto, H. "Th-U (Thorium-Uranium)." Journal of Phase Equilibria and Diffusion 33, no. 2 (January 31, 2012): 157. http://dx.doi.org/10.1007/s11669-012-9991-5.

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Naumov, Valery S. "Conceptual potential of a pyroelectrochemical technology for the thorium engagement in the fast neutron fuel cycle." Nuclear Energy and Technology 5, no. 1 (March 20, 2019): 17–22. http://dx.doi.org/10.3897/nucet.5.33977.

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The use of thorium in combination with plutonium in nuclear power generation offers a solution to the problem of reducing the accumulation of long-lived transplutonium nuclides. Along with this, the existing uranium fuel cycle (UFC) has such disadvantage as the vulnerability to unauthorized use of nuclear materials. The thorium fuel cycle (TFC) is devoid of these drawbacks. The engagement of thorium in nuclear power is possible provided the availability of an appropriate technology for reprocessing irradiated thorium. A fuel cycle based on thorium oxide may not differ in principle from the already developed pyrochemical fuel cycle involving uranium and plutonium oxides. Thorium oxide is most commonly obtained in compact state by electrolysis of molten salts from thorium-containing electrolytes. The most thorough studies of physical and chemical and electrochemical behavior of thorium in molten haloids of alkali and alkaline-earth metals were conducted in the 1960ies and the 1970ies. Since extensive experimental material has been accumulated by now for justification of the use of pyroelectrochemical and chemical processes for regeneration of fuel in molten salts, then it has also been proposed that technologies for fuel reprocessing in molten chlorides of alkali metals should be applied resulting in a crystalline product that can be used for the fuel element fabrication. Unlike uranium and plutonium, thorium behavior in molten salt environments is less complex. In molten salts, thorium exists predominantly in the form of Th4+, and the mixture of uranium and thorium dioxides with ThO2 content reaching up to 50 % can be obtained by electrolysis of molten salts. Therefore, the existing amount of knowledge about the chemistry of thorium allows regarding the use of pyrochemical processes in production of thorium oxide as highly promising, and the available data on the physical and chemical properties of thorium and its compounds in high-temperature molten salts makes it possible to state that the pyroelectrochemical technology can be potentially used in production and reprocessing of thorium fuel.

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Meor Sulaiman, Meor Yusoff, Nursaidatul Syafadillah Kamaruzaman, and Ahmad Khairulikram Zahari. "Standardless EDXRF Analysis Methods of U and Th in Malaysian Tin Slag Waste." Materials Science Forum 840 (January 2016): 410–15. http://dx.doi.org/10.4028/www.scientific.net/msf.840.410.

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Accurate quantification of uranium and thorium elements was performed in the absence of standards for the XRF analysis. This quantification method uses standard addition method. The standard addition method was first established by performing a micofocus XRF onto a sample. In the calibration graphs of uranium, the R2 was 0.9997 white the R2 value for thorium was 0.9915. Once the baseline quantity of both uranium and thorium were obtained, they were used to normalize all the quantification of other samples prepared by grab and vibratory methods. It was found out that the vibratory method gives more accurate results.

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Zhang, Yao, Xianzhang Shao, Liangliang Yin, and Yanqin Ji. "Estimation of Inhaled Effective Doses of Uranium and Thorium for Workers in Bayan Obo Ore and the Surrounding Public, Inner Mongolia, China." International Journal of Environmental Research and Public Health 18, no. 3 (January 22, 2021): 987. http://dx.doi.org/10.3390/ijerph18030987.

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Uranium and thorium are two common natural radioactive elements with high concentrations in Earth’s crust. The main aim of this study is to estimate the inhaled effective dose of uranium and thorium caused by a typical radioactive rare earth ore to the occupational population and the surrounding public. The particulate matter (PM) concentrations in the atmosphere of four typical workplaces and one surrounding living area were obtained by a high-flow sampling equipment with a natural cellulose filter membrane. The critical parameter for the inhaled effective dose estimation—the activity median aerodynamic diameter (AMAD)—was determined. The AMAD values of uranium and thorium in the atmosphere PM were 3.36 and 3.64 μm, respectively. The estimated median effective dose caused by inhalation thorium among the occupational population ranged from 15.3 to 269.0 μSv/a, and the corresponding value for the surrounding public was 2.3 μSv/a. All values for the effective dose caused by the inhalation of uranium were in the nSv magnitude.

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Sahoo, Sarata, Kenzo Fujimoto, Igor Celikovic, Predrag Ujic, and Zora Zunic. "Distribution of uranium, thorium, and isotopic composition of uranium in soil samples of south Serbia: Evidence of depleted uranium." Nuclear Technology and Radiation Protection 19, no. 1 (2004): 26–30. http://dx.doi.org/10.2298/ntrp0401026s.

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Inductively coupled plasma mass spectrometry and thermal ionization mass spectrom - etry were used to measure concentration of uranium and thorium as well as isotopic composition of uranium respectively in soil samples collected around south Serbia. An analytical method was established for a routine sample preparation procedure for uranium and thorium. Uranium was chemically separated and purified from soil samples by anion exchange resin and UTEVA extraction chromatography and its isotopic composition was measured using a thermal ionization mass spectrometry. There was a little deviation of U/Th ratio from the average values in some soil samples. Presence of 236U as well as depleted uranium was observed in 235U/238U ratio measurement in the same soil sample.

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Guitouni, Mohamed. "Determination of Uranium and Thorium in the Industrial Phosphoric Acid Using X-Ray Fluorescence Spectrometry with Wavelength Dispersive (WDXRF)." International Journal of Chemistry 8, no. 4 (August 31, 2016): 15. http://dx.doi.org/10.5539/ijc.v8n4p15.

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<p>The method of determination for uranium and thorium in the industrial phosphoric acid by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) responds positively to all the validation tests and can be adopted for the dosage for these elements. It is clear that the procedure of the proposed method is simple and requires less time to complete the analysis. The concentration for uranium and thorium in the Tunisian phosphoric acid is in the order of 22 ppm for uranium with a coefficient of variation of 0.77% and of about 4 ppm for thorium with a coefficient of variation of 1.37%.</p>

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20

TAKAHASHI, Y., H. YAMAZAKI, K. ISHII, S. MATSUYAMA, T. SATO, H. ORIHARA, and G. C. JON. "PIXE Analysis for Drainage from a Radioisotope Laboratory." International Journal of PIXE 08, no. 01 (January 1998): 57–67. http://dx.doi.org/10.1142/s0129083598000078.

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PIXE technique has been applied to quantitative analysis of thorium and uranium ions in drainage from a radioisotope laboratory of Tohoku University. Two kinds of targets were prepared and analyzed with an in-air vertical PIXE system of 3 MeV protons. The concentrations of thorium and uranium higher than 40 ppb were easily determined by 3-μC irradiation on targets which are made from a 0.12-ml solution containing Ga-internal standard evaporated on a hand-made polycarbonate film. Uranium(VI) ions in a 25-ml sample were preconcentrated into a thin uniform target containing Zr or Pd as an internal standard by means of dibenzyldithiocarbamate complexation with subsequent condensation into dibenzylidene-D-sorbitol gels, and low concentration of 10 ppb was precisely determined by PIXE measurement. This method does not work for concentrating thorium ions. The PIXE analysis for these two kinds of targets has good sensitivity and precision enough to determine concentrations of thorium and uranium lower than their permissible concentration limits in drainage from a radioisotope laboratory.

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21

Shamanin, Igor, Sergey Bedenko, Ildar Gubaydulin, and Nataliya Novikova. "Materials of New Generation in Nuclear Power Industry." Advanced Materials Research 1040 (September 2014): 74–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.74.

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The results providing advantages of thorium-232 as a reproducing nuclide in comparison with uranium-238 as a part of nuclear fuel of new generation reactors are presented. The explanation of the effects which were found earlier in numerical simulation of parameters of open thorium - plutonium nuclear fuel cycle is offered. Scientific and technical solutions allow considering the possibility of including thorium-232 in the fuel of nuclear reactors, which are based on existing design solutions, and beginning the design of new generation materials: a new generation of fuel rods and fuel assemblies, where the isotope uranium-238 will be completely replaced with thorium-232.

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Salah, Gaber, and Kandil. "The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite." Minerals 9, no. 10 (October 11, 2019): 626. http://dx.doi.org/10.3390/min9100626.

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The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

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23

Devi, V. S. Anasuya, and V. Krishna Reddy. "2-Hydroxy-1-naphthaldehyde-P-hydroxybenzoichydrazone: A New Chromogenic Reagent for the Determination of Thorium(IV) and Uranium(VI)." Journal of Chemistry 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/697379.

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Simple, sensitive, selective, direct, derivative, and simultaneous spectrophotometric methods are developed for the determination of uranium and thorium individually and simultaneously. The methods are based on the reaction of 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH) with thorium(IV) and uranium(VI). HNAHBH reacts with thorium and uranium at pH 6.0 forming stable yellow and reddish brown coloured complexes, respectively. [Th(IV)-HNAHBH] complex shows maximum absorbance at 415 nm. Beer’s law is obeyed over the concentration range 0.464–6.961 μg mL−1with a detection limit of 0.01 μg mL−1and molar absorptivity,ε, 3.5 × 104 L mol−1 cm−1. Maximum absorbance shown by [U(VI)-HNAHBH] complex is at 410 nm with Beer’s law range 0.476–7.140 μg mL−1, detection limit 0.139 μg mL−1and molar absorptivity,ε, 1.78 × 104 L mol−1 cm−1. Highly sensitive and selective second-order derivative methods are reported for the direct and simultaneous determination of Th(IV) and U(VI) using HNAHBH. The applicability of the developed methods is tested by analyzing water, ore, fertilizer, and gas mantle samples for thorium and uranium content.

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24

Raghuwanshi, S. S., B. K. Bhaumik, and S. G. Tewari. "A direct method for determining the altitude variation of the uranium stripping ratio in airborne gamma‐ray surveys." GEOPHYSICS 54, no. 10 (October 1989): 1350–53. http://dx.doi.org/10.1190/1.1442597.

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In airborne gamma‐ray spectrometric surveys, it is essential to calculate the net counts in the thorium, uranium, and potassium channels for quantitative analysis. The net uranium, thorium, and potassium counts are given by [Formula: see text], (1a) [Formula: see text] (1b) and [Formula: see text], (1c) where [Formula: see text], [Formula: see text], and [Formula: see text] are the background corrected counts per second for uranium, thorium, and potassium channels, respectively; α and β are the Compton contributions of thorium gamma rays in the uranium and potassium windows, respectively; and γ is the contribution of uranium gamma rays in the potassium window. In some countries, such as the U.S., Canada, and India, it is common practice to compute the stripping ratios by taking measurements over a set of calibration pads with known and varying amounts of uranium, thorium, and potassium (Grasty and Darnley, 1971; Grasty, 1975; Lovborg, 1984). These factors are determined by keeping the detector system inside the survey aircraft over the calibration pads. The stripping coefficients do not have fixed values but vary with source‐detector distance. Because most airborne surveys are conducted at about 120 m above ground level, the stripping ratios measured over the pads should be corrected for variations with ground clearance. In practice, the ground clearance in airborne gamma‐ray surveys may vary from about 40 m to 200 m depending upon the topography of the area flown. It is, therefore, necessary to know the values of the stripping coefficients as a function of ground clearance at least within the range of investigations. If this is known, it is possible to apply proper corrections while converting all data to a uniform datum of 122 m.

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Cheng, H., R. Lawrence Edwards, M. T. Murrell, and T. M. Benjamin. "Uranium-thorium-protactinium dating systematics." Geochimica et Cosmochimica Acta 62, no. 21-22 (November 1998): 3437–52. http://dx.doi.org/10.1016/s0016-7037(98)00255-5.

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Krishnamurty, K. V. S., and B. H. S. V. Raghava Rao. "Separation of thorium from uranium." Recueil des Travaux Chimiques des Pays-Bas 70, no. 5 (September 2, 2010): 421–24. http://dx.doi.org/10.1002/recl.19510700507.

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27

Elewady, Y. A. "Electrodeposition of uranium and thorium." Journal of Radioanalytical and Nuclear Chemistry Letters 103, no. 4 (February 1986): 205–12. http://dx.doi.org/10.1007/bf02165601.

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Wendt, Kathleen A., Xianglei Li, and R. Lawrence Edwards. "Uranium–Thorium Dating of Speleothems." Elements 17, no. 2 (April 1, 2021): 87–92. http://dx.doi.org/10.2138/gselements.17.2.87.

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Speleothems are important timekeepers of Earth’s climate history. A key advantage of speleothems is that they can be dated using U–Th techniques. Mass spectrometric methods for measuring U and Th isotopes has led to vast improvements in measurement precision and a dramatic reduction in sample size. As a result, the timing of past climate, environment, and Earth system changes can be investigated at exceptional temporal precision. In this review, we summarize the principles and history of U–Th dating of speleothems. Finally, we highlight three studies that use U–Th dated speleothems to investigate past changes to the Asian monsoon, constrain the timing of sociopolitical change in ancient civilizations, and develop a speleothem-based calibration of the 14C timescale.

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29

Misra, N. L., M. K. Tiwari, S. Sanjay Kumar, Sangita Dhara, Ajit Kumar Singh, G. S. Lodha, S. K. Deb, P. D. Gupta, and S. K. Aggarwal. "Synchrotron-induced EDXRF determination of uranium and thorium in mixed uranium-thorium oxide pellets." X-Ray Spectrometry 42, no. 1 (September 18, 2012): 4–7. http://dx.doi.org/10.1002/xrs.2421.

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30

Løvborg, Leif, and Erik Mose. "Counting statistics in radioelement assaying with a portable spectrometer." GEOPHYSICS 52, no. 4 (April 1987): 555–63. http://dx.doi.org/10.1190/1.1442324.

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Counting performed with a portable gamma‐ray spectrometer to assay the concentrations of potassium, uranium, and thorium in the ground normally lasts between 1 and 10 minutes. The statistical uncertainties of the count rates measured in the energy windows are taken into consideration by ascribing standard deviations to the calculated assay values. Such a standard deviation is primarily governed by the counts recorded in two neighboring energy windows. A potassium standard deviation, for example, depends not only on the counts in the potassium window, but is also affected by the mixed uranium‐thorium counts recorded in the uranium window. Counting times of 1, 2, 4, and 10 minutes are normally appropriate in assaying uranium concentrations of 10 to 13, 5 to 7, ∼3, and ∼1.5 ppm eU. By counting for 10 minutes, it may be possible to detect unusually small radioelement concentrations of 0.5 ppm eTh, 0.3 ppm eU, and 0.04 percent K. However, the smallest concentrations that can be measured with a precision of 10 percent amount to about 2 ppm eTh, 1 ppm eU, and 0.15 percent K. Low‐grade uranium ore with whole‐rock concentrations of 100 to 800 ppm eU must contain at least 20 to 100 ppm eTh before reliable thorium assay values can be provided by counting for 1 minute. The corresponding uranium determination limits on thorium mineralizations carrying from 400 to 1 600 ppm eTh are from about 100 to almost 200 ppm eU. Usable potassium assay values are generally not obtained from a ground that contains more than 200 ppm eU or 400 ppm eTh.

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31

Green, A. A. "Leveling airborne gamma‐radiation data using between‐channel correlation information." GEOPHYSICS 52, no. 11 (November 1987): 1557–62. http://dx.doi.org/10.1190/1.1442272.

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A procedure for estimating background‐correction terms for the uranium channel of an airborne gamma‐ray survey has been developed. The residuals obtained from a multiple linear regression of flight‐line means for the uranium channel on the means for thorium and potassium are used to correct the uranium channel for each line. The procedure assumes that, were it not for these background errors, the uranium flight‐line means would be a linear function of the means for potassium and thorium. It also assumes that the background correction is the same for the whole of each line. In spite of these limitations, the method produces good background estimates consistent with those found by more sophisticated methods.

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Anggraini, Mutia, Fuad Wafa Nawawi, and Kurnia Setiawan Widana. "Penentuan Kondisi Optimum Proses Ekstraksi Uranium dan Torium dari Terak II Timah dengan Metode Pelindian Asam Sulfat dan Solvent Extraction Trioctylamine (TOA)." EKSPLORIUM 40, no. 1 (July 31, 2019): 11. http://dx.doi.org/10.17146/eksplorium.2019.40.1.5378.

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ABSTRAKTerak II timah merupakan produk hasil samping dari peleburan timah tahap kedua. Terak II timah ini mengandung unsur bernilai ekonomi tinggi berupa unsur radioaktif (uranium dan torium) dan logam tanah jarang (rare earth element). Unsur-unsur tersebut dapat dimanfaatkan apabila telah terpisah satu dengan lainnya. Proses pemisahan unsur radioaktif dan unsur logam tanah jarang telah dilakukan dengan metode pelindian asam sulfat. Hasil proses ini adalah endapan yang mengandung logam tanah jarang dan filtrat yang mengandung unsur radioaktif berupa uranium dan torium sulfat. Penelitian terkait pemisahan uranium dan torium hasil pengolahan terak II timah hanya sedikit dipublikasikan. Paper ini bertujuan untuk mengetahui efektifitas proses pemisahan uranium dan torium dengan metode solvent extraction menggunakan trioctylamine (TOA). Proses solvent extraction dilakukan dengan memvariasikan konsentrasi TOA yang digunakan, perbandingan fase aqueous dan fase organik (A/O) dan variasi waktu ekstraksi. Pada penelitian ini diperoleh kondisi optimum proses yaitu konsentrasi TOA 4%, perbandingan A/O 1 : 1, dan waktu pencampuran aqueous dan organik selama 2 menit. Pada kondisi ini uranium dan torium yang terekstrak masing-masing sebanyak 67% dan 0,84%. ABSTRACTTin slag II is a by-product of the second stage of tin smelting. The tin slag II contains high economic value elements in the form of radioactive elements (uranium and thorium) and rare earth elements. These elements can be utilized if they are separated from each other. The process of separating radioactive elements and rare earth elements has been carried out by leaching sulfuric acid method. The results of this process are residue containing rare earth elements and filtrates containing radioactive elements in the form of uranium and thorium sulfate. Research related to the separation of uranium and thorium sulfate in tin slag processing is only slightly published. This paper aims to determine the effectiveness of the uranium and thorium separating process by the solvent extraction method using trioctylamine (TOA). The solvent extraction process is carried out by varying the concentration of TOA used, comparison of the aqueous and organic phase (A/O) and variations in extraction time. In this study, the optimum conditions for the process were obtained at 4% of TOA concentration, 1 : 1 of A/O ratio, and mixing time of aqueous and organic phase for 2 minutes. In this condition, uranium and thorium which extracted were 67% and 0.84% respectively.

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Du Toit, Marina, and Sunil Chirayath. "Proposal for improved nuclear fuel utilisation and economic performance by utilising thorium." Journal of Energy in Southern Africa 26, no. 2 (April 13, 2017): 11. http://dx.doi.org/10.17159/2413-3051/2015/v26i2a2191.

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A systematic and strategic nuclear power reactor deployment roadmap has been developed for South Africa within the national strategic plan, utilizing thorium-based fuel. The roadmap was developed through analysis of economical, strategic and historical aspects. The accumulated advantages of thorium-based fuels are summarized, which could form the initiative to implement thorium-based nuclear fuels in South Africa. A timeline (which forms the basis of the roadmap) was constructed and consists of three different phases. Phase 1 starts in 2015 and extends to 2030. Phase 2 starts in 2031 and ends in 2044 whilst Phase 3 is from 2045 to 2060. Each phase is discussed with regard to construction, implementation and research activities. This roadmap starts at current pressurized water reactors (PWRs) and advances to future reactor technologies, using an evolutionary approach. In addition to the results reported in this paper, the economic advantages to introducing thorium as a fertile component in PWR fuels as compared to once-through conventional uranium-only cycles is explored (Du Toit & Cilliers, 2014). The economic evaluation compares uranium fuel to thorium-uranium fuel in terms of the fuel cycle costs, reactor downtime costs due to refuelling and income derived from electricity sales.

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Marisi, Dany Poltak, Suprihatin Suprihatin, and Andes Ismayana. "Penurunan Kadar Torium dan Radioaktivitas dalam Limbah Cair Proses Pengolahan Monasit PLUTHO Menggunakan Koagulan FeSO4." EKSPLORIUM 39, no. 1 (July 10, 2018): 39. http://dx.doi.org/10.17146/eksplorium.2018.39.1.4276.

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Pemisahan unsur radioaktif dan logam tanah jarang yang dilakukan di PLUTHO menghasilkan limbah yang masih mengandung torium dan uranium. Limbah yang dihasilkan memerlukan pengolahan lanjutan agar ramah lingkungan. Tujuan penelitian adalah menurunkan kadar torium dan radioaktivitas dalam limbah cair proses pengolahan monasit pilot plant PLUTHO menggunakan koagulan fero sulfat. Pilot Plant PLUTHO merupakan suatu fasilitas yang didirikan untuk untuk memisahkan uranium, torium, dan logam tanah jarang (LTJ) dari mineral monasit dan mineral lainnya dalam skala pilot. Perlakuan variasi yang dilakukan pada penelitian adalah dosis koagulan dan pH. Pengukuran kadar torium dilakukan dengan metode Spektrofotometer UV-Vis, sedangkan pengukuran radioaktivitas dilakukan dengan alat ukur radiasi Ludlum Model 1000 Scaler. Hasil penelitian menunjukkan kondisi optimum koagulasi pada pH 8,0 dengan dosis koagulan FeSO4 225 mg/L yang dapat menurunkan kadar torium sebesar 45,20 % dan menurunkan radioaktivitas sebesar 100 % dari kadar torium dan radioaktivitas awal yaitu 0,73 mg/L dan 1,35 Bq/g. The separation of radioactive and rare earth mineral carried out in PLUTHO produces waste that still contains thorium and uranium. The resulting waste requires further processing to be environmentally friendly. The purpose of study is to reduce thorium content and radioactivity in liquid waste of PLUTHO monazite treatment process using ferro sulphate coagulant. PLUTHO Pilot Plant is one of facility that built to dissociate uranium, thorium and light rare earth from mineral of monazite. Variations of treatments applied in the research are coagulant dosage and pH. Thorium content is measured by Spectrophotometer UV-Vis method, whereas radioactivity is measured by radiation counting meter Ludlum Model 1000 Scaler. The result shows that the optimum condition of coagulation is in pH 8,0 with concentration of ferro sulphate 225 mg/L which may reduce thorium content up to 45,20 % and reduce radioactivity to 100 % out of its initial thorium content and radioactivity as much as 0,73 mg/L and 1,35 Bq/g, respectively.

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35

Karmanov, Anatoliy Petrovich, Al'bert Vladimirovich Kanarsky, Lyudmila Sergeyevna Kocheva, Zosia Al'bertovna Kanarskaya, Venera Maratovna Gematdinova, Nikolay Ivanovich Bogdanovich, Ol'ga Andreyevna Patova, and Natal'ya Geliyevna Rachkova. "BIOSORBENTS BASED ON POLYSACCHARIDES. EVALUATION OF SORPTION CAPACITY IN RELATION TO URANIUM AND THORIUM." chemistry of plant raw material, no. 4 (December 27, 2019): 431–40. http://dx.doi.org/10.14258/jcprm.2019045210.

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Study of sorption of heavy natural radionuclide’s uranium and thorium from water by β-gluсancontaining sorbents obtained from biomass of yeast Saccharomyces Cerevisiae and bran of oat Avena sativa was carried out. It is shown that the content of mobile (water-soluble, exchange and acid-soluble) and fixed forms of uranium on investigated β-glucans vary considerably. It is found that the extent of irreversible sorption of uranium does not exceed 58.6%. For the first time shown that β-glucans have high sorption capacity in ratio of thorium. In the conditions of the experiments it was retrieved more than 99% of thorium from the water. The content of fixed form of thorium reaches 94% of the sorbed. Characteristics of surface and capillary-porous structure of samples were defined. The correlation relationships between rates of adsorption and specific surface of preparations were installed. An analysis of the relationship between sorption capacity and various properties of glucans leads to the conclusion that the most important role for the implementation of a strong adsorption of heavy radionuclides belongs to chemisorptions mechanisms, while the contribution of surface physical phenomena is not essential. It is shown that the highest strong adsorption of thorium is characterized by a sample representing the cell walls of yeast Saccharomyces cerevisiae. The findings suggest of β-glucans prospects in practical terms and their use as polyfunctional enterosorbеnts.

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36

Duport, P., R. Robertson, K. Ho, and F. Horvath. "Flow-Through Dissolution of Uranium-Thorium Ore Dust, Uranium Concentrate, Uranium Dioxide, and Thorium Alloy in Simulated Lung Fluid." Radiation Protection Dosimetry 38, no. 1-3 (September 1, 1991): 121–33. http://dx.doi.org/10.1093/rpd/38.1-3.121.

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37

Duport, P., R. Robertson, K. Ho, and F. Horvath. "Flow-Through Dissolution of Uranium-Thorium Ore Dust, Uranium Concentrate, Uranium Dioxide, and Thorium Alloy in Simulated Lung Fluid." Radiation Protection Dosimetry 38, no. 1-3 (September 1, 1991): 121–33. http://dx.doi.org/10.1093/oxfordjournals.rpd.a081080.

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38

Wei, Chunlin, Xiuan Shi, Yongwei Yang, and Zhiwei Zhou. "ICONE19-43519 Preliminary Research on Thorium-Uranium Fuel Cycle Characteristic in PWR." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_209.

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39

McCafferty, Anne E., Douglas B. Stoeser, and Bradley S. Van Gosen. "Geophysical interpretation of U, Th, and rare earth element mineralization of the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeast Alaska." Interpretation 2, no. 4 (November 1, 2014): SJ47—SJ63. http://dx.doi.org/10.1190/int-2014-0010.1.

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A prospectivity map for rare earth element (REE) mineralization at the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeastern Alaska, was calculated from high-resolution airborne gamma-ray data. The map displays areas with similar radioelement concentrations as those over the Dotson REE-vein-dike system, which is characterized by moderately high %K, eU, and eTh (%K, percent potassium; eU, equivalent parts per million uranium; and eTh, equivalent parts per million thorium). Gamma-ray concentrations of rocks that share a similar range as those over the Dotson zone are inferred to locate high concentrations of REE-bearing minerals. An approximately 1300-m-long prospective tract corresponds to shallowly exposed locations of the Dotson zone. Prospective areas of REE mineralization also occur in continuous swaths along the outer edge of the pluton, over known but undeveloped REE occurrences, and within discrete regions in the older Paleozoic country rocks. Detailed mineralogical examinations of samples from the Dotson zone provide a means to understand the possible causes of the airborne Th and U anomalies and their relation to REE minerals. Thorium is sited primarily in thorite. Uranium also occurs in thorite and in a complex suite of [Formula: see text] oxide minerals, which include fergusonite, polycrase, and aeschynite. These oxides, along with Y-silicates, are the chief heavy REE (HREE)-bearing minerals. Hence, the eU anomalies, in particular, may indicate other occurrences of similar HREE-enrichment. Uranium and Th chemistry along the Dotson zone showed elevated U and total REEs east of the Camp Creek fault, which suggested the potential for increased HREEs based on their association with U-oxide minerals. A uranium prospectivity map, based on signatures present over the Ross-Adams mine area, was characterized by extremely high radioelement values. Known uranium deposits were identified in the U-prospectivity map, but the largest tract occurs over a radioelement-rich granite phase within the pluton that is likely not related to mineralization. Neither mineralization type displays a well-defined airborne magnetic signature.

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Réant, Benjamin L. L., Victoria E. J. Berryman, John A. Seed, Annabel R. Basford, Alasdair Formanuik, Ashley J. Wooles, Nikolas Kaltsoyannis, Stephen T. Liddle, and David P. Mills. "Polarised covalent thorium(iv)– and uranium(iv)–silicon bonds." Chemical Communications 56, no. 83 (2020): 12620–23. http://dx.doi.org/10.1039/d0cc06044e.

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41

Soesoo, Alvar, Johannes Vind, and Sigrid Hade. "Uranium and Thorium Resources of Estonia." Minerals 10, no. 9 (September 9, 2020): 798. http://dx.doi.org/10.3390/min10090798.

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We provide a compilation of geology of uranium and thorium potential resources in the Ordovician black shale (graptolite argillite), Cambrian–Ordovician shelly phosphorite and in the secondary resources (tailings) of Estonia. Historical and new geological, XRF and ICP-MS geochemical data and ArcGIS modeling results of elemental distribution and tonnages are presented. The Estonian black shale contains 5.666 million tons of U, 16.533 Mt Zn, 12.762 Mt Mo, 47.754 Mt V and 0.213–0.254 Mt of Th. The Estonian phosphate resources, altogether about 3 billion metric tons of phosphate ore, contain about 147,000 to 175,000 tons of U. Rare earth element concentrations in the phosphorite ore average at 1200–1500 ppm of ΣREE. Thorium can also be a possible co-product. The mining waste dump at the Maardu contains at least 3650 tons of U and 730 tons of Th. The Sillamäe radioactive waste depository contains about 1200 tons of U and 800 tons of Th. Due to the neighboring geological positions, as well as environmental constraints and mining technologies, the black shale and phosphorite can be treated as a complex multi-resource, possibly at the continental scale, which needs to be extracted together.

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Hazen, R. M., R. C. Ewing, and D. A. Sverjensky. "Evolution of uranium and thorium minerals." American Mineralogist 94, no. 10 (October 1, 2009): 1293–311. http://dx.doi.org/10.2138/am.2009.3208.

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43

Van Orman, James A., Timothy L. Grove, and Nobumichi Shimizu. "Uranium and thorium diffusion in diopside." Earth and Planetary Science Letters 160, no. 3-4 (August 1998): 505–19. http://dx.doi.org/10.1016/s0012-821x(98)00107-1.

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44

Rungthanaphatsophon, Pokpong, O. Jonathan Fajen, Steven P. Kelley, and Justin R. Walensky. "Thorium(IV) and Uranium(IV) Phosphaazaallenes." Inorganics 7, no. 9 (August 21, 2019): 105. http://dx.doi.org/10.3390/inorganics7090105.

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The synthesis of tetravalent thorium and uranium complexes with the phosphaazaallene moiety, [N(tBu)C=P(C6H5)]2−, is described. The reaction of the bis(phosphido) complexes, (C5Me5)2An[P(C6H5)(SiMe3)]2, An = Th, U, with two equivalents of tBuNC produces (C5Me5)2An(CNtBu)[η2-(N,C)-N(tBu)C=P(C6H5)] with concomitant formation of P(SiMe3)2(C6H5) via silyl migration. These complexes are characterized by NMR and IR spectroscopy, as well as structurally determined using X-ray crystallography.

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Dulong, Florian, Jacky Pouessel, Pierre Thuéry, Jean-Claude Berthet, Michel Ephritikhine, and Thibault Cantat. "Nitrite complexes of uranium and thorium." Chemical Communications 49, no. 24 (2013): 2412. http://dx.doi.org/10.1039/c3cc39163a.

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David, Sylvain, Élisabeth Huffer, and Hervé Nifenecker. "La filière nucléaire thorium-uranium revisitée." Bulletin de la Société Française de Physique, no. 152 (December 2005): 26–29. http://dx.doi.org/10.1051/refdp/200515204.

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GUSTAVSSON, JOHN E., and S. A. CHRISTER HÖGBERG. "Uranium/thorium dating of Quaternary carbonates." Boreas 1, no. 4 (January 16, 2008): 247–74. http://dx.doi.org/10.1111/j.1502-3885.1972.tb00004.x.

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Peterson, D. E. "The Th-U (Thorium-Uranium) system." Bulletin of Alloy Phase Diagrams 6, no. 5 (October 1985): 443–45. http://dx.doi.org/10.1007/bf02869507.

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Kmak, Kelly N., Dawn A. Shaughnessy, and Jasmina Vujic. "Separation of thorium from uranium ore." Journal of Radioanalytical and Nuclear Chemistry 323, no. 2 (December 7, 2019): 931–45. http://dx.doi.org/10.1007/s10967-019-06980-1.

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Allègre, Claude J., Bernard Dupré, and Eric Lewin. "Thorium/uranium ratio of the Earth." Chemical Geology 56, no. 3-4 (October 1986): 219–27. http://dx.doi.org/10.1016/0009-2541(86)90005-7.

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