Performance of geopolymers for direct immobilization of solvent extraction liquids: Metakaolin/LIX-84 formulations

El-Naggar, M.; El-Sherief, Eman A.; Mekhemar, Hamida S.

doi:10.1016/j.jhazmat.2018.08.057

Cited by 16 publications

(5 citation statements)

References 30 publications

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“…Bayoumi [8] found that the optimal w/c ratio was 0.35 to achieve acceptable workability and compressive strength. According to his measurements, the optimum SC concentration of the cement paste was found to be 10% with the addition of 0.15 w% surfactant, which gave a compressive strength of 14.2 MPa, but the leaching property of 14 C significantly deteriorated upon solidification of 15% SC. In our case, the recommended w/c ratio [8] of 0.35 did not allow achieving proper workability of the cement paste, certainly due to the water uptake of Metaver N type metakaolin.…”

Section: Methodsmentioning

confidence: 99%

“…Based on the study of El-Naggar et al [14], we first added SC and SCW to metakaolin, then mixed with deionized water. Then CEM I 42.5 N type cement was added to prepare a homogeneous cement paste.…”

Section: Methodsmentioning

confidence: 99%

“…These materials are able to absorb multiple times of their weight, but they are mechanically vulnerable; and due to their consistency and leaching properties, it is necessary to provide secondary packaging. Embedding this type of waste in a cementitious or geopolymer matrix may be a safer and less costly treatment option for long-term storage [7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Preliminarily Experiments of Liquid Scintillation Cocktail Waste Solidification

Baranyi

Kopecskó

2022

Period. Polytech. Civil Eng.

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Liquid scintillation spectroscopy (LSC) is a widely used laboratory method for measuring radioactive especially low-energy alpha and beta emitter isotopes in solutions. Since the scintillation cocktails (SCs) contain large amounts of aromatic hydrocarbon compounds after the LSC measurement, the sample usually becomes organic radioactive waste, which is challenging to manage and dispose of. The most common and effective waste treatment method is incineration, a costly and cumbersome solution. Another simpler and less expensive way is the immobilization the organic liquids by embedding in cement or geopolymer matrix.The aim of our experiments is to find a universal mix design to solidify and immobilize scintillation cocktail wastes (SCWs) of unknown composition. During the measurement, we assumed that the SCWs could contain Ultima Gold, Ultima Gold LLT, InstaGel Plus and ProSafe FC type scintillation cocktails in pure form or mixed with unknown quantities of water. Therefore, we performed experiments with inactive pure SCs as surrogates to mimic the SCWs. Since the water content determination of the organic solutions is difficult, the mix design must be independent of the water content of SCWs.During our experiments, we found an appropriate mix design to solidify all available SCs up to 5% using CEM I 42.5 N type cement, Metaver N type metakaolin and sodium hydroxide. We could solidify our tested SCW with this mix, and this product meets the waste acceptance criteria of all Hungarian radioactive waste repositories.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preliminarily Experiments of Liquid Scintillation Cocktail Waste Solidification

Baranyi

Kopecskó

2022

Period. Polytech. Civil Eng.

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“…Then, the binder was activated by adding the alkaline solution. 8% waste loading was achieved with acceptable stabilization performance [128].…”

mentioning

confidence: 92%

“…A recent review summarized the progress of the incorporation of organic liquid in geopolymers, classifying the incorporation process into three classes similar to those used in conventional cementitious matrices [125]. Examples on the application of these classes in recent research to immobilize different organic liquid wastes include [126][127][128]:…”

mentioning

confidence: 99%

Toward Sustainable Cementitious Radioactive Waste Forms: Immobilization of Problematic Operational Wastes

Rahman

Ojovan

2021

Sustainability

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Developing effective radioactive waste management practices is essential for ensuring the sustainability of the nuclear industry. The immobilization of radioactive wastes is one of the main activities conducted during the management of these wastes; it aims to produce a durable waste form that has sustainable performance over long periods of time. In this work, the challenges that face the design of durable cementitious waste forms are addressed for problematic operational wastes. In this respect, the problematic characteristics of evaporator concentrates, spent ion exchangers, and organic liquid wastes are overviewed, and the factors that affect the durability of their cementitious waste forms are identified. A summary of potential conventional and innovative cementitious matrices is presented by reviewing the cementation practices in national programs and recent research devoted to developing durable matrices. Finally, a guide to optimize the mix design of these waste forms was proposed that includes the selection of the testing procedure, factors that affect the waste form performance, and the optimization technique. This guide was presented with special focus on leaching tests, which are a means to test the stabilization performance of nuclear waste forms.

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