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Abstract

During the extraction of nuclear raw materials, rare earths and other elements from ores containing uranium and thorium, various types of radioactive waste and some recovery tailings are generated. Mining and ore processing residues, i.e. waste and tailings, present a variety of problems related to waste management. Their bulky structure prevents their disposal underground, and their long radioactive half-life causes various problems with regard to their long-term storage. As a matter of fact, the secondary presence of nuclear raw materials together with other minerals requires compliance with hazardous waste procedures in the storage of waste containing nuclear raw materials after the recovery of these main minerals. It may be possible in the future to recover these nuclear raw materials from stockpiles of stored mine waste. The prospect of imbalances in the global uranium supply and demand increases the importance of secondary sources contributing to the global uranium supply. The increasing importance of secondary sources of nuclear raw materials suggests that more attention should be paid to the recovery of these resources together with primary minerals than in the past. In world literature, there is no review article that describes and discusses the waste management of nuclear raw materials in mining and mineral processing together with the opportunities and obstacles for their recovery. Considering this deficiency in the literature, in this study, the properties of waste and tailings resulting from mining and ore preparation activities of nuclear raw materials are explained, the difficulties encountered are mentioned, and solution suggestions are presented by making use of the literature on the recovery of tailings and waste management.
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Authors and Affiliations

Taşkın Deniz Yıldız
1
ORCID: ORCID
Tuğba Deniz Tombal-Kara
1
ORCID: ORCID

  1. Adana Alparslan Türkeş Science and Technology University, Department of Mining Engineering, Turkey
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Abstract

This study is devoted to synthesis and characterization of uranium dioxide microspheres (Ø < 100 µm) and pellets by application of powder-free process called the Complex Sol-Gel Process. The precursors of prepared sols were ascorbic acid solution with dissolved a freshly precipitated ammonium diuranate. The microspheres of uranyl-ascorbate gel were obtained using the ICHTJ Process. The pellets were formed by pressing and sintering of uranium dioxide powder. Studies allowed determining an optimal heat treatment of calcination, reduction and sintering processes at temperatures of 700°C, 900°C and 1300°C, respectively. The main parameters which play a key role in the process of synthesis method and features of the pellets and microspheres of uranium dioxide are described in this article.

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Authors and Affiliations

M. Brykala
M. Rogowski
D. Wawszczak
T. Olczak
T. Smolinski
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Abstract

Uranium concentrations in groundwater taken from private drilled wells have been never determined in Poland, implying a lack of available data to quantify the human exposure to U through drinking water consumption, especially in rural areas influenced by mining activities. The main aim of the study was the assessment of human health risk related to the consumption of well waters containing U, collected from selected rural areas of the Lower Silesian region (Poland). The random daytime (RDT) sampling method was applied to the collection of well waters from three control study areas (CSA): Mniszków (CSA-A), Stara Kamienica/M. Kamienica/Kopaniec (CSA-B) and Kletno (CSA-C). The analyses of RDT samples were performed by validated method based on inductively coupled plasma mass spectrometry (ICP-MS). Uranium concentration ranges in well waters and the estimated geometric means for individual control study areas were: 0.005-1.03 μg/L and 0.052 μg/L (CSA-A), 0.027-10.6 μg/L and 0.40 μg/L (CSA-B), and 0.006-27.1 μg/L and 0.38 μg/L (CSA-C). The average and individual chronic daily intakes (CDI) of U by drinking water pathway (adults/children) were in the ranges of: 0.0017-0.013/0.0052-0.040 μg · kg-1 · day-1 and 0.0002-0.90/0.0005-2.71 μg · kg-1 · day-1. The average %TDI and ranges of individual %TDI (adults/children) were: 0.17%/0.52% and 0.02-3.4%/0.05-10.3% (CSA-A), 1.3%/4.0% and 0.09-35%/0.27-106% (CSA-B), and 1.3%/3.8% and 0.02-90%/0.06-271% (CSA-C). The estimated average CDI values of U through well water are significantly lower than the TDI (1 μg · kg-1 · day-1), while for individual CDI values the contribution to the TDI can reach even 90% (adults) and 271% (children), indicating essential human health risk for children consuming well water from private drilled wells located in CSA-B and CSA-C (5.3% of total number of samples collected).

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Authors and Affiliations

Sławomir Garboś
Dorota Święcicka

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