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Assessment of the leaching characteristics of incineration ashes in cement matrix / R.O. Abdel Rahman in Chemical engineering journal, Vol. 155 N° 3 (Decembre 2009) 

Public ISBD [article]  in Chemical engineering journal > Vol. 155 N° 3 (Decembre 2009) . - pp. 698-708 Titre : Assessment of the leaching characteristics of incineration ashes in cement matrix Type de document : texte imprimé Auteurs : R.O. Abdel Rahman, Auteur ; A.A. Zaki, Auteur Année de publication : 2010 Article en page(s) : pp. 698-708 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Radioactive  waste  Incineration  Leaching  mechanisms  Mathematical  models Index. décimale : 660 Résumé : In this work, the effort is directed to assess the feasibility of immobilizing the ash produced from the incineration of solid radioactive wastes. Within this context, the ash was characterized to determine its chemical composition and physical properties. Immobilized cement-ash matrices have been prepared to investigate the influence of waste to cement ratio. To characterize the extent of the solidification process of the immobilized waste matrices, the mechanical strength test was conducted. The standard mass transfer leach test has been employed to test the extent of 137Cs and 60Co stabilization. Non-linear fitting of the experimental leach data to different mathematical models was conducted to evaluate the mechanisms those instigate the leaching phenomena and the leaching parameters were determined. The controlling leaching mechanism and leachability indices were calculated for the studied waste matrices. The results indicated that 137Cs leaching is resulted from first-order reaction between the surface of the waste matrix and the leaching solution followed by diffusion through the studied matrices. The leaching of 60Co was found to be as result of four subsequent mechanisms that include release of loosely bound 60Co followed by first-order reaction the diffusion and finally dissolution. It was found that the studied immobilized waste matrices have acceptable mechanical performance. The values of the leachability indices indicate that the performance of the studied matrices in 137Cs stabilization is not acceptable. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4X5JRBR-2&_user=6 [...] [article] Assessment of the leaching characteristics of incineration ashes in cement matrix [texte imprimé] / R.O. Abdel Rahman, Auteur ; A.A. Zaki, Auteur . - 2010 . - pp. 698-708. Génie Chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 155 N° 3 (Decembre 2009) . - pp. 698-708 Mots-clés : Radioactive  waste  Incineration  Leaching  mechanisms  Mathematical  models Index. décimale : 660 Résumé : In this work, the effort is directed to assess the feasibility of immobilizing the ash produced from the incineration of solid radioactive wastes. Within this context, the ash was characterized to determine its chemical composition and physical properties. Immobilized cement-ash matrices have been prepared to investigate the influence of waste to cement ratio. To characterize the extent of the solidification process of the immobilized waste matrices, the mechanical strength test was conducted. The standard mass transfer leach test has been employed to test the extent of 137Cs and 60Co stabilization. Non-linear fitting of the experimental leach data to different mathematical models was conducted to evaluate the mechanisms those instigate the leaching phenomena and the leaching parameters were determined. The controlling leaching mechanism and leachability indices were calculated for the studied waste matrices. The results indicated that 137Cs leaching is resulted from first-order reaction between the surface of the waste matrix and the leaching solution followed by diffusion through the studied matrices. The leaching of 60Co was found to be as result of four subsequent mechanisms that include release of loosely bound 60Co followed by first-order reaction the diffusion and finally dissolution. It was found that the studied immobilized waste matrices have acceptable mechanical performance. The values of the leachability indices indicate that the performance of the studied matrices in 137Cs stabilization is not acceptable. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4X5JRBR-2&_user=6 [...]