Immobilisation of Fe floc: Part 2, encapsulation of floc in composite cement

Setting and hardening process of a wollastonite-based brushite cement

“…(ii) Neutralization of the waste causes the precipitation of flocs of metallic hydroxide (aluminum, iron, zinc, uranium…). A significant amount of water can be bound to the floc particles and is unavailable to contribute to workability, explaining why a floc / cement paste can be highly viscous despite its high water content (Collier, 2009). (iii) When the pre-treatment reagent is a concentrated sodium or potassium hydroxide, significant amounts of alkalis are added to the waste, and thus to the cement-waste forms, with possible deleterious effects in the long term (such as the formation of a gel-like product due to alkaliaggregate reaction (Stanton, 1940)).…”

The suitability of a supersulfated cement for nuclear waste immobilisation

“…The historical composite cement formulations developed have proved suitable for immobilising ILW arising from fuel reprocessing and large numbers of drums are currently curing in storage awaiting ultimate disposal [10][11][12][13][14]. These systems have advantageous properties such as a high pH pore water which is reported to provide an environment in which the solubility of many heavy metal oxides, carbonates and hydroxides is reduced, limiting their migration through the porous microstructure of the hardened cement paste [15].…”

Phase development of hydrated cement pastes with SCMs under delayed heating conditions below 100 °C

“…Finally, the hydrogarnet phase (also called Katoite) partially detectable by XRD became slightly stable as the temperature rose. This phase becomes stable at high temperatures according studies [20,27,[70][71][72][73].…”