Immobilization index of liquid low-level waste in cementitious grouts
The ability of grouts formulated from mixtures of cementitious materials and attapulgite clay to immobilize various chemical species in the projected off-gas waste stream from vitrification of Hanford low level tank wastes was studied. Three different solid blends were evaluated, with cement:fly ash: slag:clay weight ratios of 3:3:3:1, 3:0:6:1, and 0:0:9:1. The blended solids were mixed with a simulated low level liquid waste solution containing Na{sup +}, NO{sub 2}{sup {minus}}, NO{sub 3}{sup {minus}}, PO{sub 4}{sup 3{minus}} and OH{sup {minus}} ions, in the proportion of 1 liter of solution to 1 kg of solid blend, and were cured either at 22 C (room temperature), 50 C or 90 C. Pore solutions were expressed at various ages and were analyzed to determine the reductions in concentrations of the individual ionic species. The results were expressed in the form of immobilization index (I) calculated for each species. The immobilization indices for Na{sup +} (I Na{sup +}) and for OH{sup {minus}} (I OH{sup {minus}}) were similar in each case, and were found to be highest when only slag and clay was present (blend 0:0:9:1). The immobilization index for phosphate, I PO{sub 4}{sup 3{minus}}, was 1 in all cases, i.e. phosphate was completely removed from solution. On the other hand removal of NO{sub 2}{sup {minus}} and NO{sub 3}{sup {minus}} ions was generally ineffective.
- Research Organization:
- Westinghouse Hanford Co., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-87RL10930
- OSTI ID:
- 195643
- Report Number(s):
- WHC-SA-2906; CONF-951155-31; ON: DE96005199; TRN: AHC29605%%18
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 27 Nov - 1 Dec 1995; Other Information: PBD: Dec 1995
- Country of Publication:
- United States
- Language:
- English
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Pore solution chemistry of simulated low level liquid waste incorporated cement grouts
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Related Subjects
LOW-LEVEL RADIOACTIVE WASTES
CEMENTING
SOLIDIFICATION
LIQUID WASTES
CEMENTS
MATERIALS TESTING
CLASSIFICATION
FLY ASH
SLAGS
CLAYS
SODIUM
NITRITES
NITRATES
PHOSPHATES
HYDROXIDES
HYDRATION
OFF-GAS SYSTEMS
CONDENSATES
RADIOACTIVE WASTE FACILITIES
CONCENTRATION RATIO
WASTE FORMS
PERFORMANCE