کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8910581 1637918 2018 32 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
An experimental study of the solubility and speciation of thorium in chloride-bearing aqueous solutions at temperatures up to 250 °C
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
An experimental study of the solubility and speciation of thorium in chloride-bearing aqueous solutions at temperatures up to 250 °C
چکیده انگلیسی
The solubility and speciation of Th in Cl-bearing solutions saturated in ThO2 was investigated experimentally at 150, 175, 200, 225 and 250 °C, and saturated water vapor pressure. At these experimental conditions (pH25°C < 3.8, mNaCl < 2.5), Th-chloride complexation is insignificant, and the solubility of Th is controlled by hydrolysis. The two main species in solution were identified as Th(OH)22+ and Th(OH)4° and formed via the reactions Th4++2OH-↔Th(OH)22+ and Th4++4OH-↔Th(OH)40. The logarithms of the formation constants determined for the first reaction are 23.91 ± 0.05, 24.79 ± 0.07, 25.78 ± 0.05, and 25.85 ± 0.05 for 175, 200, 225 and 250 °C, respectively, and 42.18 ± 0.06, 43.50 ± 0.07, 43.17 ± 0.08, and 43.74 ± 0.11 for the second reaction at the same temperatures. Formation constants could not be determined reliably for 150 °C. Extrapolations of our formation constants to 25 °C are in excellent agreement with the values determined at 25 °C by Neck and Kim (2001) and Ekberg et al. (2000). For natural systems buffered by thorianite (ThO2), the solubility determined in our study likely reflects a minimum, as the presence of additional ligands would lead to higher solubility.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 239, 15 October 2018, Pages 363-373
نویسندگان
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