Testing Stabilization/solidification Processes for Mixed Waste

Stabilization/Solidification technologies reduce the mobility of hazardous and radioactive contaminants in the environment through both physical and chemical processes. Four stabilization/solidification (S/S) processes were used to solidify three sample matrices contaminated with arsenic, chromium (VI), lead, cesium and strontium. These sample matrices were Idaho National Engineering and Environmental Laboratory (INEEL) soil, synthetic soil, and synthetic sludge. The four S/S processes, calcium sulfo-aluminate (CSA) based cement stabilization, magnesium phosphate (MP) based cement stabilization, Orthophthalic Polyester (OPE) Resin Encapsulation, and Epoxy Vinyl Ester (EVE) Resin Encapsulation were then evaluated, using leachability and durability tests. The purpose of this project was to assess various stabilization/solidification processes. The CSA and MP cement processes resulted in significant variability retention of arsenic, chromium and lead (largely due to failures in pretreatment), poor retention of cesium and strontium, generally poor durability in the treated waste forms, and low to moderate strengths. The OPE and EVE processes resulted in generally good retention of metals, good durability, and exceptional strength in most cases.