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 250â¯Â°C
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The solubility and speciation of Th in Cl-bearing solutions saturated in ThO2 was investigated experimentally at 150, 175, 200, 225 and 250â¯Â°C, and saturated water vapor pressure. At these experimental conditions (pH25°Câ¯<â¯3.8, mNaClâ¯<â¯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-âTh(OH)22+ and Th4++4OH-âTh(OH)40. The logarithms of the formation constants determined for the first reaction are 23.91â¯Â±â¯0.05, 24.79â¯Â±â¯0.07, 25.78â¯Â±â¯0.05, and 25.85â¯Â±â¯0.05 for 175, 200, 225 and 250â¯Â°C, respectively, and 42.18â¯Â±â¯0.06, 43.50â¯Â±â¯0.07, 43.17â¯Â±â¯0.08, and 43.74â¯Â±â¯0.11 for the second reaction at the same temperatures. Formation constants could not be determined reliably for 150â¯Â°C. Extrapolations of our formation constants to 25â¯Â°C are in excellent agreement with the values determined at 25â¯Â°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
Journal: Geochimica et Cosmochimica Acta - Volume 239, 15 October 2018, Pages 363-373
نویسندگان
H. Nisbet, A. Migdisov, H. Xu, X. Guo, V. van Hinsberg, A.E. Williams-Jones, H. Boukhalfa, R. Roback,