Waste solidification

Historically, ferrous sulfamate, Fe(NH2S02)2, was added to the HNO scmbbing solution in sufficient excess to ensure the destmction of nitrite ions and the resulting reduction of the Pu to the less extractable Pu . However, the sulfate ion is undesirable because sulfate complexes with the plutonium to compHcate the subsequent plutonium purification step, adds to corrosion problems, and as SO2 is an off-gas pollutant during any subsequent high temperature waste solidification operations. The associated ferric ion contributes significantly to the solidified waste volume. 

Technology Description Waste solidification techniques based on lime products usually depiend on the reaction of lime with a fine-grained silica... 

L.W. Jones, "Interference Mechanism in Waste Solidification/ Stabilization Processes, EPA-600/S-89/067 (NTIS No. PB90-156209/AS), USEPA, Risk Reduction Engineering Laboratory, Cincinati, OH, 1989. 

T0192 CURE International, Inc., CURE Electrocoagulation Wastewater Treatment System T0214 DuPont/Oberlin, Microfiltration Technology T0230 EET Corporation, Microwaste Waste Solidification T0232 Eichrom Industries, Inc., Diphonix... 

T0229 Edenspace Systems Corporation, Hyperaccumulation of Metals T0230 EET Corporation, Microwaste Waste Solidification T0231 EFX Systems, Inc., Granular Activated Carbon-Fluidized-Bed Reactor (GAC FBR) Process... 

Demine, A. V., Krylova, N. V., Poluektov, P. P., Shestoperov, I. N., Smelova, T. V., Gorn, V. F. Medvedev, G. M. 2001. High level liquid waste solidification using a cold crucible induction melter. Materials Research Society Symposium Proceedings, 663, 27-34. 

Saidl, J. Ralko v A, J. 1966. Radioactive waste solidification by means of melting with basalt. Atomic Energy, 10, 285-289 (in Russian). 

Another reaction of the titanate which has an important effect in waste solidification is the reaction with hydrogen ion, as in the hydrolysis reaction shown in Eq. 3 ... 

The use of ion exchange resins and natural or synthetic inorganic exchange materials in the nuclear industry is well documented ( ). In the waste solidification application, the titanates or niobates offer no unique sorption properties. They do, however, provide a relatively high overall sorption capacity for a variety of nuclides in materials which can be converted into a stable ceramic host for the sorbed ions. After the sorption process, the column bed must be consolidated to reduce surface area. The project emphasis was directed toward a stable waste form and a considerable effort was devoted to producing and characterizing a highly dense form with favorable physical, chemical and thermal properties (l ). 

The work on hi level waste solidification has led to applications of the same materials to other areas of waste management. These include decontamination of defense wastes currently in tank storage at Richland, WA, selective separation of Cs for beneficial uses, and development of a process flowsheet for conversion of Zircaloy fuel cladding hulls to sodium zirconate for use in waste stabilization. Each is briefly described below. 

Lynch, R.W., Dosch, R.G., Kenna, B.T., Johnstone, J.K., and Nowak, E.J., "The Sandia Solidification Process - A Broad Range Aqueous Waste Solidification Method," Proc. IAEA Symposium on the Management of Radioactive Wastes," IAEA - SM 207/155 Vienna, Austria, March 22-26 (1976). 

Dosch, R.G., "Ceramics from Ion Exchangers An Approach to Nuclear Waste Solidification," Trans. Amer. Nucl. Soc., 22,... 

Binder In site remediation and waste treatment, binders refer to cement, clays, or other cohesive solid materials that encapsulate and immobilize solid and even liquid wastes. Binders are key components in waste solidification/stabilization. 

Major categories of industrial waste solidification/stabilization systems are cement-based processes, pozzolanic processes (not including cement), thermoplastic trohniques, organic polymer techniques, surface encapsulation techniques, and self-cementing techniques (for high calcium sulfate sludges). Vitrification (discussed previously) can also be considered a solidification process. 

Advanced waste form work is also being carried out in the Ceramics and Graphite Section at PNL, where high temperature gas-cooled reactor fuel technology is applied to waste solidification. Waste particles are coated with pyrolytic carbon followed by a cover coat of silicon carbide. These coated particles would then be placed in a matrix of inert material contained in a canister of yet another material. 

G. L., McKee, R. W., Blasewitz, A. G., Waste Solidification Program Summary Report, Vol. II, Evaluation of WSEP High-Level Waste Solidification Process, BNWL-1667, July 1972. 

The americium and curium isotopes formed during irradiation of nuclear reactor fuels are diverted into the high-level waste (HLW) stream during fuel reprocessing. The HLW is thus the biggest potential source for these elements, and R+D activities to develop a process for the recovery of Am and Cm from HLW were started in 1967. A major condition was that the process to be developed must not essentially increase the waste amount to be processed further, must not use strongly corrosive reagents, and must be compatible with the final waste solidification procedure. 

---