Immobilization of Radionuclide 133Cs by Magnesium Silicate Hydrate Cement

Abstract

The radionuclide cesium (Cs) was solidified using magnesium silicate hydrate (M–S–H) cement. The influence of Cs+ on the reaction of the M–S–H gel system was evaluated by measuring the compressive strength and microscopic properties of the solidified body. By testing the impact resistance, leaching resistance and freeze–thaw resistance of the solidified body, the immobilizing ability of Cs+ by the M–S–H cement was analyzed. Results indicate that Cs+ only slightly affects the reaction process of the M–S–H gel system, and only slows down the transformation rate of Mg(OH)2 into the M–S–H gel to a certain extent. The M–S–H cement exhibits superior performance in solidifying Cs+. Both the leaching rate and cumulative leach fraction at 42 d were considerably lower than the national requirements and better than the ordinary Portland cement-solidified body. The curing effect of the M–S–H cement on Cs+ is mainly physical encapsulation and chemisorption of hydration products.

Effect of Aluminum Incorporation on the Reaction Process and Reaction Products of Hydrated Magnesium Silicate

“…The M-S-H has a similar structure with sepiolite: it has a large specific surface area and there are unique nano-scale pores in molecular structure, and it has the ability to adsorb heavy metals (Ji et al, 2014;Jia et al, 2017b;Jia et al, 2019;Liu et al, 2021). Magnesium silicate hydrate (M-S-H) phases can be considered as a potential cementitious material for nuclear waste immobilization (Walling et al, 2015) owing to its moderate pH value (varying from ∼9.5 to ∼10.5) and the Radionuclide (Cs, Sr) sorption potential (Li et al, 2014;Zhang et al, 2020).…”

Characterizing Steel Corrosion in Different Alkali-Activated Mortars

“…These materials are not considered to be able to totally replace of OPC-based concretes, nor do they offer a one-size-fits-all solution. The wide range of combinations available, however, allows for the formation of materials with various advanced properties, including resistance to acid and heat [ 6 ], high strength [ 7 ], and radionuclide immobilization [ 8 ]. The sustainability of these materials primarily depends on the local availability of the precursors used, as well as selection of the correct type and dose of alkali activator [ 9 ].…”

Inorganic Waste Forms for Efficient Immobilization of Radionuclides

“…PC is the most common type of CMs used in radioactive waste immobilization. ,,, Joseph Aspdin coined this term in 1824 because it resembled Portland stone. − The immobilization capacity of the PC concerns both physical and chemical processes. Physically, it can act as a suitable barrier, and chemically, it can act as a selective binder for various radioactive wastes.…”