Solidification of decontamination resin wastes with cement matrix

Abstract

In order to immobilize successfully the decontamination resin wastes the effects of decontaminating agents on the immobilization in ordinary Portland cement(OPC) are examined and suitable cement matrix is developed. Compressive strength and immersion test are conducted on the variables such as curing periods, curing condition, resin depletion, pH of waste stream, and resin loading. Waste forms loaded with EDTA, oxalic acid, and picolinic acid even at 12.4wt\% resin loading have a compressive strength which exceed the minimum criterion in the Technical Position by at least a factor of twenty. And they show no degradation in immersion test. However, it is noticed that the resin waste forms loaded with citric acid show a poor mechanical integrity. To increase the resin loading rate, blending agents such as pulverized fly ash(PFA) and bentonite are considered. Cement matrices blended with PFA do not increase the mechanical strength of resin waste loaded with citric acid to a considerable degree. In case of bentonite, cement matrices which have the 2:8 blends of bentonite and OPC immobilize successfully the waste stream containing up to 30wt\% resin loading. Also in order to investigate the cracking mechanism of waste form in immersion test volumetric changes of ion exchange resin are measured. Cation exchanger, IRN-77, shows no volume change on metal ions. Anion exchanger, IRN-78, shows about-4-10 percent volume change dependent on the type of organic acids.