Reactions between cement components and U(VI) oxide
Reactions between cement components and U(VI) oxide
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水泥组分与 U(VI) 氧化物之间的反应
DOI：
10.1016/0956-053x(95)00022-r
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发表时间：
1995
期刊：
影响因子：
8.1
通讯作者：
F. Glasser
中科院分区：
文献类型：
--
作者：
L. Moroni;F. Glasser
在85°C的水悬浮液中，研究了CaO和SiO2（代表水泥的主要成分）与软钾镁矾（UO 3·2 H2O）之间的反应，以评估铀在高pH值下的溶解度，这是固定电位的主要控制因素。还报道了使用预形成的C z.sbnd;S z.sbnd;H（硅酸钙水凝胶）的补充实验。U负载量在10-80摩尔%的范围内。46个组合物的反应产物的研究导致相相容性区域的识别。描述了几种溶解度限制但迄今为止尚未表征的CaO z.sbnd; UO 3 z.sbnd;SiO2 z.sbnd;H2O相;给出了它们的X射线粉末衍射数据。合成阶段与天然类似物进行比较，并得出结论，存在相似之处：weeksite和贝可石样结构可能是在合成开发。随着晶相的形成，铀的溶解度下降到108-10− 9 mol/l。溶解度与所观察到的相容性区域有很好的相关性，在含铀相之间获得最低的溶解度，这也与C z.sbnd;S z.sbnd;H凝胶相容。可能会发生一些轻微的U吸附到凝胶中，并假定在55-85°C下抑制其结晶。的溶解度值，在一般情况下，小于在以前的研究中，通过省略SiO2从模拟物和使用相对较短的反应时间，未能实现的特征固定化潜力。
Reactions between CaO and SiO2, representing the principal components of cement, and schoepite, UO3·2H2O, have been studied in aqueous suspensions at 85°C to evaluate the solubility of uranium at high pH, which is a principal control of the immobilisation potential. Supplementary experiments with preformed Cz.sbnd;Sz.sbnd;H (calcium silicate hydrogel) are also reported. U loadings are in the range 10–80 mol%. Study of the reaction products of 46 compositions has led to the identification of phase compatibility regions. Several solubility-limiting but hitherto uncharacterised CaOz.sbnd;UO3z.sbnd;SiO2z.sbnd;H2O phases are described; their X-ray powder diffraction data are given. The synthetic phases are compared with natural analogues and it is concluded that similarities exist: weeksite- and becquerelite-like structures are probably developed in the synthetics. With formation of crystalline phases, U solubilities decline to 108-10−9mol/l. Solubilities correlate well with the observed compatibility regions, with lowest solubilities obtained among the uranium-containing phases which are also compatible with Cz.sbnd;Sz.sbnd;H gel. Some slight U sorption into the gel may occur and is postulated to inhibit its crystallisation at 55–85°C. The solubility values are, in general, less than in previous studies which, by omitting SiO2from simulants and using relatively brief reaction times, fail to achieve the characteristic immobilisation potential.