Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation; Journal of Environmental Radioactivity; Vol. 178-179
| Parent link: | Journal of Environmental Radioactivity Vol. 178-179.— 2017.— [P. 63-76] |
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| Yhteisötekijä: | |
| Muut tekijät: | , , , , , |
| Yhteenveto: | Title screen Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO2 pressure (PCO2, open system) of 10-2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L-1. Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L-1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U3O7 and U4O9). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L-1, but with typical concentrations of up to 10 μg L-1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and PCO2 (low PCO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals). Режим доступа: по договору с организацией-держателем ресурса |
| Kieli: | englanti |
| Julkaistu: |
2017
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| Aiheet: | |
| Linkit: | https://doi.org/10.1016/j.jenvrad.2017.07.016 |
| Aineistotyyppi: | MixedMaterials Elektroninen Kirjan osa |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=664816 |
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| 200 | 1 | |a Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation |f E. M. Dutova, A. N. Nikitenkov, V. D. Pokrovsky [et al.] | |
| 203 | |a Text |c electronic | ||
| 300 | |a Title screen | ||
| 320 | |a [References: 64 tit.] | ||
| 330 | |a Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO2 pressure (PCO2, open system) of 10-2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L-1. Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L-1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U3O7 and U4O9). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L-1, but with typical concentrations of up to 10 μg L-1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and PCO2 (low PCO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals). | ||
| 333 | |a Режим доступа: по договору с организацией-держателем ресурса | ||
| 461 | |t Journal of Environmental Radioactivity | ||
| 463 | |t Vol. 178-179 |v [P. 63-76] |d 2017 | ||
| 610 | 1 | |a электронный ресурс | |
| 610 | 1 | |a труды учёных ТПУ | |
| 610 | 1 | |a groundwater | |
| 610 | 1 | |a hydrochemical modelling | |
| 610 | 1 | |a mineralisation | |
| 610 | 1 | |a natural uranium | |
| 610 | 1 | |a ore | |
| 610 | 1 | |a solubility | |
| 610 | 1 | |a грунтовые воды | |
| 610 | 1 | |a моделирование | |
| 610 | 1 | |a минерализация | |
| 610 | 1 | |a природный уран | |
| 610 | 1 | |a руды | |
| 610 | 1 | |a растворимость | |
| 701 | 1 | |a Dutova |b E. M. |c hydrogeologist |c Professor of Tomsk Polytechnic University, Doctor of geological and mineralogical sciences |f 1956- |g Ekaterina Matveevna |3 (RuTPU)RU\TPU\pers\31021 |9 15251 | |
| 701 | 1 | |a Nikitenkov |b A. N. |c physicist, hydrogeologist |c associate Professor of Tomsk Polytechnic University, candidate of geological and mineralogical Sciences |f 1983- |g Aleksey Nikolaevich |3 (RuTPU)RU\TPU\pers\33263 |9 17008 | |
| 701 | 1 | |a Pokrovsky |b V. D. |c Specialist in the field of higher professional education |c Analyst of the Tomsk Polytechnic University |f 1989- |g Vitaly Dmitrievich |3 (RuTPU)RU\TPU\pers\32204 | |
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