Sustainable tuff-based geopolymers for encapsulation of radioactive solid organic waste

The broad range of nuclear applications makes the generated radioactive waste very different in terms of physical and chemical forms, activity concentrations, and types of contamination. Such a variety results in an equally wide spectrum of waste management strategies, which must be carefully addressed in virtue of waste-inherent hazards. Among all, radioactive solid organic waste is particularly challenging to manage because of its nature, which typically exhibits flammability, dispersivity, and swelling. Such features are incompatiblw with common encapsulation matrices. In the recent years, geopolymers, mainly based on metakaolin, emerged as a promising class of materials. In this work, alkaline geopolymerization of highly zeolitized volcanic tuff and some industrial by-products has been investigated at laboratory scale as an economically and environmentally sustainable process for the conditioning of radioactive solid organic waste