Solidification of Acidic, High Nitrate Nuclear Wastes by Grouting or Absorption on Silica Gel
The use of grout and silica gel were explored for the solidification of four types of acidic, high nitrate radioactive wastes. Two methods of grouting were tested: direct grouting and pre-neutralization. Two methods of absorption on silica gel were also tested: direct absorption and rotary spray drying. The waste simulant acidity varied between 1 N and 12 N. The waste simulant was neutralized by pre-blending calcium hydroxide with Portland cement and blast furnace slag powders prior to mixing with the simulant for grout solidification. Liquid sodium hydroxide was used to partially neutralize the simulant to a pH above 2 and then it was absorbed for silica gel solidification. Formulations for each of these methods are presented along with waste form characteristics and properties. Compositional variation maps for grout formulations are presented which help determine the optimum "recipe" for a particular waste stream. These maps provide a method to determine the proportions of waste, calcium hydroxide, Portland cement, and blast furnace slag that provide a waste form that meets the disposal acceptance criteria. The maps guide researchers in selecting areas to study and provide an operational envelop that produces acceptable waste forms. The grouts both solidify and stabilize the wastes, while absorption on silica gel produces a solid waste that will not pass standard leaching procedures (TCLP) if required. Silica gel wastes can be made to pass most leach tests if heated to 600ºC.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- DOE - EM
- DOE Contract Number:
- DE-AC07-99ID-13727
- OSTI ID:
- 910783
- Report Number(s):
- INEEL/CON-03-01393; TRN: US0800535
- Resource Relation:
- Conference: Alternative Nuclear Waste Forms Conference,Girdwood, Alaska,01/18/2004,01/23/2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
BLAST FURNACES
CALCIUM HYDROXIDES
GROUTING
NITRATES
PH VALUE
PORTLAND CEMENT
RADIOACTIVE WASTES
SILICA GEL
SODIUM HYDROXIDES
SOLID WASTES
SOLIDIFICATION
SPRAY DRYING
WASTE FORMS
WASTES
acidic
high nitrate
grout
silica gel
solidification