ORIGINAL PAPER Solidification of hot real radioactive liquid scintillator waste using cement–clay composite T. A. Bayoumi • H. M. Saleh • S. B. Eskander Received: 21 May 2013 / Accepted: 16 July 2013 / Published online: 16 August 2013 Ó Springer-Verlag Wien 2013 Abstract Cementation of hazardous organic liquid wastes such as radioactive liquid scintillator is receiving increasing importance. Using clay as natural adsorbent to improve the incorporation process of these organic wastes into cement paste was performed. The waste form com- posed of water/cement at the ratio 0.3 with 3 % solid natural clay by the weight of cement and incorporating up to 15 % real spent organic liquid scintillator waste by the weight of cement-based paste was prepared. The temper- ature changes accompanying with the cementation process were followed. The nominated solidified cement–clay composite was also subjected to free falling test at different heights to evaluate its structural stability during unexpected transportation events or disposal site impacts. Scanning electron microscopy and X-ray investigations were used to evaluate the microstructure of the composite. The results revealed that the proposed cement–clay composite could be nominated structurally as a durable matrix for incorporat- ing up to 15 % of liquid scintillator safely. Keywords Solidification  Liquid scintillator  Radioactive waste  Cement–clay composite Introduction Increasing amounts of radioactive wastes are generated from the continuous peaceful applications of nuclear technology in numerous aspects, for instance, in human health, cultivation and irrigation, scientific research, and wide use in industry, and are thus important manners for deep studies. These peacefully applications are growing very quickly; therefore, various sorts of radioactive wastes are produced that must be managed safely and efficiently. Cementitious materials have a long history of use in the nuclear industry for immobilizing and hardening radio- nuclides containing wastes [1–5]. The liquid scintillation counting technique is widely used for quantification of many radiation types, e.g., alpha and beta particles, Auger and conversion electrons, Cerenkov radiation, electron capture, luminescence and fluorescence, and many others. After counting the quantification pro- cesses, the spent liquid scintillators as a dangerous organic waste should be managed safely [6–8]. Large volumes of the spent liquid scintillation are generated each year, which require more elaborate treatment to avoid their hazardous components [9]. However, there are many possible com- bination processes for treating the spent organic liquid scintillator waste (LSW) [10]. The final selection of the process to be used will, of course, be based on the national need and/or availability of resources [11]. These wastes are considered as one of the most problematic wastes due to their radioactive contents as well as their organic nature. Although cementitious materials have been extensively used for a long time in the nuclear industry, especially for solidification and stabilization of low-level and interme- diate-level radioactive wastes, very few articles have described the cementation of spent liquid radioactive scintillator waste [12–14]. To overcome the retarding effect of liquid scintillator waste (LSW) due to its organic nature [15] on the hydration of the cement matrix, and to avoid the fire risk of the immobilized waste form, Eskander and Ghattas [16] stud- ied the pretreatment of liquid scintillation wastes before cementation. Furthermore, strength, mechanical integrity, T. A. Bayoumi  H. M. Saleh (&)  S. B. Eskander Radioisotope Department, Nuclear Research Center, Atomic Energy Authority, Dokki, Giza 12311, Egypt e-mail: hosamsaleh70@yahoo.com 123 Monatsh Chem (2013) 144:1751–1758 DOI 10.1007/s00706-013-1065-9