THE POLYMORPHISM OF A NUMBER OF RARE EARTH OXIDES AND THEIR INTERACTION WITH WATER (in Russian)
Journal Article
·
· At. Energ. (USSR)
OSTI ID:4664741
Pure Sm/sub 2/O/sub 3/ (99.83%), Eu/sub 2/O/sub 3/ (99.70%), and Gd/sub 2/O/su b 3/ (99.80%) were dissolved in dilute HCl, and precipitated with ammonia. The hydroxides were calcined at 700 to 750 deg C for 2 hours. X-ray analysis showed that these oxides consisted of a single phase witu a body-centered, cubic lattice. The appearance of the stable, high-temperature, monoclinic modification was determined by calcining rare oxide pellets for 8 hours at a temperature of 800 to 1700 deg C in intervals of 100 deg C. X-ray analysis showed that the conversion of tue cubic modification to the monoclinic form takes place at 900 to 1000 deg C for Sm/sub 2/O/sub 3/, at 900 to 1100 deg C for Eu/sub 2/O/sub 3/, and at 1000 to 1800 deg C for Gd/sub 2/O/sub 3/. The conversion is slow, but the rate increases witu increasing temperature. The reverse transformation is so slow that none of the rare earth oxides showed an appreciable conversion of the monoclinic form into the cubic form. Rare earth oxide pellets were calcined for 8 hours at temperatures of 800, solubility in boiling water. After 10 to 20 hours boiling in water, the dissolution of rare eartu oxide was 2 to 30% for a calcining temperature of 800 to 1100 deg C. Colloidal solutions were formed. The least solubility was observed at calcining temperatures of 1200 to 1650 deg C. All the pellets containing the high-temperature modifications of Gd/sub 2/O/sub 3/ , Eu/sub 2/O/sub 3/, and Sm/sub 2/O/sub 3/ were unstable, and disintegrated completely after tue first 10 hours of boiling in water. (TTT)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-032058
- OSTI ID:
- 4664741
- Journal Information:
- At. Energ. (USSR), Journal Name: At. Energ. (USSR) Vol. Vol: 14
- Country of Publication:
- Country unknown/Code not available
- Language:
- Russian
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