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Title: Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

Abstract

Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogicalmore » data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.« less

Authors:
 [1]; ;  [2]
  1. Westinghouse Hanford Co., Richland, WA (United States)
  2. Northwestern Univ., Evanston, IL (United States). Center for Advanced Cement-Based Materials; and others
Publication Date:
Research Org.:
Westinghouse Hanford Co., Richland, WA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
79046
Report Number(s):
WHC-SA-2865
ON: DE95013576; TRN: 95:016449
DOE Contract Number:  
AC06-87RL10930
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Apr 1995
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; LOW-LEVEL RADIOACTIVE WASTES; CONTAINMENT; WASTE FORMS; EVALUATION; PORTLAND CEMENT; FLY ASH; PH VALUE; PHASE STUDIES; PERMEABILITY; ZEOLITES; CHEMICAL COMPOSITION; GROUTING

Citation Formats

Kruger, A A, Olson, R A, and Tennis, P D. Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement. United States: N. p., 1995. Web. doi:10.2172/79046.
Kruger, A A, Olson, R A, & Tennis, P D. Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement. United States. https://doi.org/10.2172/79046
Kruger, A A, Olson, R A, and Tennis, P D. 1995. "Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement". United States. https://doi.org/10.2172/79046. https://www.osti.gov/servlets/purl/79046.
@article{osti_79046,
title = {Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement},
author = {Kruger, A A and Olson, R A and Tennis, P D},
abstractNote = {Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.},
doi = {10.2172/79046},
url = {https://www.osti.gov/biblio/79046}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {4}
}