Incorporation and phase separation of Cl in alkaline earth aluminosilicate glasses

JOURNAL OF NUCLEAR MATERIALS

卷:507

Article

Tan, Shengheng¹  Hand, Russell J.¹ 

[1] Univ Sheffield, Dept Mat Sci & Engn, ISL, Sir Robert Hadfield Bldg,Mappin St, Sheffield S1 3JD, S Yorkshire, England

关键词: Chlorine;    Aluminosilicate;    Glass;    Phase separation;   

DOI  :  10.1016/j.jnucmat.2018.04.044

来源: Elsevier

【 摘 要 】

Pyrochemical reprocessing of spent nuclear fuels may lead to the generation of chloride containing wastes. Cl-36 wastes may also arise from the treatment of irradiated graphite. Such wastes will have limited solubility in the borosilicates currently used for waste vitrification. Despite requiring higher processing temperatures aluminosilicate glasses show promise for this application. In a series of alkaline earth aluminosilicate glasses we demonstrate that chloride solubility is related to the alkaline earth species as follows Sr > Sr + Ba > Ba > Ca > Mg, with the strontium aluminosilicate glass accommodating up to 5.92 at% Cl. Typical chloride retention rates are similar to 80% of the batched chloride content at 1400 degrees C. It has also been observed that, when Cl is present in the glass in excess, phase separation firstly occurs as formation of non-Cl crystals (mainly alkaline earth aluminosilicates, with a minority of aluminates); a segregated chloride layer is only formed at higher chlorine loadings. This indicates that chlorine solu-bility in glass is not only controlled by the capacity of glass network to accommodate Cl- but also by the stability of glass network after incorporation. In addition, increased incorporation of Cl- in glass results in steadily decreased glass densities and glass transition temperatures. (C) 2018 Elsevier B.V. All rights reserved.

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