Sulfur Polymer Cement, a Final Waste form for Radioactive and Hazardous Wastes

Because of its unusual properties, sulfur polymer cement (SPC) is a promising solidification and stabilization agent for radioactive and hazardous wastes. SPC accepts no water and requires no activation agents. It always melts at 115°C and pours at 135°C; therefore, economical remediation is offered through remelt and addition of additives or more SPC to meet specifications. Compressive strength upon cooling is approximately 27.6 MPa (4 000 psi). SPC has survived for years in acids and salts that destroy or severely damage hydraulic concretes in months or even weeks. In tests with 5 wt% loading of pure toxic metal oxides in powder form, the U.S. Environmental Protection Agency's the toxicity characteristic leaching procedure shows the maximum leachate concentration of mercury, lead, silver, arsenic, barium, and chromium to be less than their established threshold limits. Tests to determine SPC's expected longevity are being conducted and are encouraging.