Reduction of water content in calcium aluminate cement with/out phosphate modification for alternative cementation technique
Reduction of water content in calcium aluminate cement with/out phosphate modification for alternative cementation technique
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DOI：
10.1016/j.cemconres.2018.04.019
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发表时间：
2018-07-01
影响因子：
11.4
通讯作者：
Kinoshita, Hajime
中科院分区：
文献类型：
--
作者：
Garcia-Lodeiro, Ines;Irisawa, Keita;Kinoshita, Hajime
由于TEPCO福岛第一核电站的二次含水废物含有大量的锶和放射性，因此其胶结具有挑战性，从而导致通过水含量的辐射分解产生氢气的潜在风险。本文研究了在未加磷酸盐改性的铝酸钙水泥（CAC）固化过程中通过热处理降低其含水量的方法。发现CAC中水的减少受到结晶水合相的快速形成的限制，而磷酸盐改性的系统允许水的逐渐减少，在95 ℃下实现60%的水含量的减少。在60-95 ℃下固化也消除了磷酸盐体系中在35 ℃下发现的显著裂纹。无定形产物的可能差异，即35 ℃下的NaCaPO 4中心点nH（2）O型和60-95 ℃下的Ca（HPO 4）中心点xH（2）O型，可能有助于改善微观结构以及孔径分布的变化。
Cementation of the secondary aqueous wastes from TEPCO Fukushima Daiichi Nuclear Power Plant is challenging due to the significant strontium content and radioactivity, leading to a potential risk of hydrogen gas generation via radiolysis of water content. The present study investigates the reduction of water content in calcium aluminate cement (CAC) with/out phosphate modification by a heat-treatment during the solidification. The reduction of water in the CAC was found restricted by the rapid formation of crystalline hydration phases, whereas the phosphate-modified system allowed the gradual reduction of water, achieving the reduction of 60% water content at 95 degrees C. Curing at 60-95 degrees C also eliminated the significant cracks found at 35 degrees C in the phosphate system. The possible difference in the amorphous products, NaCaPO4 center dot nH(2)O type at 35 degrees C and Ca(HPO4)center dot xH(2)O type at 60-95 degrees C, may have contributed to the improvement in the microstructure together with the change in the pore size distribution.