Ion exchange and dehydration experimental studies of clinoptilolite: Implications to zeolite dating

Technical Report · Wed Feb 01 04:00:00 EST 1995

DOI:https://doi.org/10.2172/25016· OSTI ID:25016

WoldeGabriel, G

Variable effects were noted on the argon (Ar) and potassium (K) contents of clinoptilolite fractions used in ion-exchange and dehydration experiments. The K contents of clinoptilolite fractions were differently affected during cation exchange with Ca-, Cs-, K-, and Na-chloride solutions. Ar was generally less affected during these experiments, except for a Na-clinoptitolite fraction exchanged for five days. Loss of Ar during organic heavy-liquid treatment and cleaning using acetone and deionized water does occur, as indicated by comparing the amounts of radiogenic Ar of treated and untreated fractions. Moreover, a regular decrease in radiogenic Ar contents was noted in clinoptilolite fractions during dehydration experiments at different temperatures for 16 hours. Comparable losses do not occur from saturated samples that were heated in 100 C for more than five months. Water appears to play a vital role in stabilizing the clinoptilolite framework structure and in the retention of Ar. The radiogenic Ar depletion pattern noted in clinoptilolite fractions dehydrated in unsaturated environment at different temperatures is similar to variations in the amount of radiogenic Ar observed in clinoptilolite samples from the unsaturated zone of an altered tuff. These results can be used to evaluate the extent of zeolitic water (and hence Ar) retention in unsaturated geologic settings. The utility of alkali zeolites (e.g., phillipsite, clinoptilolite, and mordenite) from low-temperature, open-hydrologic alteration as potential dateable minerals was evaluated using the K/Ar method as part of the Yucca Mountain Site Characterization Project, which is evaluating Yucca Mountain, Nevada, as a potential high-level radioactive waste repository site.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 25016
• Report Number(s): LA--12894-MS; ON: DE95007726
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
ARGON 40
CALCIUM
CESIUM
CLINOPTILOLITE
DIAGENESIS
EXPERIMENTAL DATA
HYDRATION
ION EXCHANGE
ISOTOPE DATING
MITIGATION
POTASSIUM 40
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
RADIONUCLIDE MIGRATION
SITE CHARACTERIZATION
SODIUM
SORPTIVE PROPERTIES
YUCCA MOUNTAIN
Yucca Mountain Project
ZEOLITES