Structure of barium chloride-oxide tellurite glasses

Abstract This paper describes the on-going pilot scale development of a new treatment process designed to remove radium-226 from uranium milling effluents. Presently, decants from Canadian uranium mining and milling tailings areas are treated with barium chloride to remove radium-226 prior to discharge into the environment. This is usually accomplished in large natural or man-made ponds which provide an opportunity for a (Ba,Ra)SO4 precipitate to form and subsequently settle. Sand filtration is sometimes used as a polishing step. This new process differs from conventional and other experimental processes in that it involves the use of a fluidized bed to facilitate the deposition of a (Ba,Ra)SO4 precipitate on a granular medium of high surface area. As a stand-alone treatment process, the new process is consistently able to reduce incoming radium-226 activity levels by 90-99%. Effluent levels of 10 pCi/L (0.370 Bq/L) or less have been achieved, depending on the influent activity levels. Recent testing of the process as a polishing step has demonstrated radium removal efficiencies up to 60% when the process influent was already less than 5 pCi/L (0.185 Bq/L). The process has been operated at temperatures ranging from 26°C down to 0.3°C with no reduction in efficiency. In contrast to treatment times in the order of days for conventional settling pond systems and hours for mechanical stirred tank/filtration systems, the new process is able to achieve these radium removal efficiencies in times on the order of one minute.

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The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

Materials ◽

10.3390/ma14143913 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3913

Author(s):

Aljawhara H. Almuqrin ◽

Mohamed Hanfi ◽

K. G. Mahmoud ◽

M. I. Sayyed ◽

Hanan Al-Ghamdi ◽

...

Keyword(s):

Monte Carlo Simulation ◽

Theoretical Study ◽

Radiation Shielding ◽

Photon Flux ◽

Transmission Factor ◽

Tellurite Glasses ◽

Attenuation Coefficients ◽

Binary Glass ◽

Buildup Factors

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.

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