论文信息 - A new method of synthesis of boltwoodite and of formation of sodium boltwoodite, uranophane, sklodowskite and kasolite from boltwoodite

A new method of synthesis of boltwoodite and of formation of sodium boltwoodite, uranophane, sklodowskite and kasolite from boltwoodite

Boltwoodite has been syntlesized at 185"C (1.3 MPa) from quartz, KCI and uranyl nitrate by a new method avoiding local supersatmation of silicat€ species in solution. Sodium boltwoodite, uranophane, sklodowskite and kasolite were synthesized from boltwoodite. Unit-cell paramet€n and space groups were determined from the X-ray powder-diffraction data. Infrared spectra have intense absorptionbands at 3458 and 3377 cm-l, which conespondto OH-stretching vibrations. Bands at 1384 cm-l indicate the presence of SiO:OH groups in the structures. Luminescence spoctra and solubility data are reported.

[1] R. J. Silva,et al. Standard Gibbs free energies of formation at the temperature 303.15 K of four uranyl silicates: soddyite, uranophane, sodium boltwoodite, and sodium weeksite , 1992 .

[2] B. Scheetz,et al. Infrared vibrational characterization and synthesis of a family of hydrous alkali uranyl silicates and hydrous uranyl silicate minerals , 1992 .

[3] Lars Eriksson,et al. TREOR, a semi-exhaustive trial-and-error powder indexing program for all symmetries , 1985 .

[4] Y. I. Ryskin. The Vibrations of Protons in Minerals: hydroxyl, water and ammonium , 1974 .

[5] Michael Rinne,et al. A least-squares method for the identification of resonant groups from NMR powder spectra. Identification of oxonium and hydroxyl ions in hydrated uranates , 1973 .

[6] R. M. Honea. New data on boltwoodite, an alkali uranyl silicate , 1961 .