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Sample records for bayleyite

  1. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  2. Kinetic study of time-dependent fixation of U{sup VI} on biochar

    Energy Technology Data Exchange (ETDEWEB)

    Ashry, A. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Radiation Protection Department, Nuclear Research Centre, Egyptian Atomic Energy Authority, Cairo (Egypt); Bailey, E.H., E-mail: liz.bailey@nottingham.ac.uk [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Chenery, S.R.N. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Young, S.D. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom)

    2016-12-15

    Biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of U{sup VI} from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20 °C, including pH, initial concentration of U{sup VI} and contact time. Uranium (U{sup VI}) adsorption was highly dependent on pH but adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH > 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of U{sup VI} within the biochar structure. Desorption experiments showed that U{sup VI} was only sparingly desorbable from the biochar with time and isotopic dilution with {sup 233}U{sup VI} confirmed the low, or time-dependent, lability of adsorbed {sup 238}U{sup VI}. Below pH 7 the adsorption isotherm trend suggested precipitation, rather than true adsorption, may occur. However, across all pH values (4.5-9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and either swartzite, liebigite or bayleyite above pH 6.5.

  3. Kinetic study of time-dependent fixation of UVI on biochar

    International Nuclear Information System (INIS)

    Ashry, A.; Bailey, E.H.; Chenery, S.R.N.; Young, S.D.

    2016-01-01

    Biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of U VI from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20 °C, including pH, initial concentration of U VI and contact time. Uranium (U VI ) adsorption was highly dependent on pH but adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH > 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of U VI within the biochar structure. Desorption experiments showed that U VI was only sparingly desorbable from the biochar with time and isotopic dilution with 233 U VI confirmed the low, or time-dependent, lability of adsorbed 238 U VI . Below pH 7 the adsorption isotherm trend suggested precipitation, rather than true adsorption, may occur. However, across all pH values (4.5-9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and either swartzite, liebigite or bayleyite above pH 6.5.

  4. Mode of occurrence of secondary radionuclide-bearing minerals in natural argillized rocks

    International Nuclear Information System (INIS)

    Rimsaite, J.

    1982-01-01

    Three processes that may be activated by the emplacement of radionuclide-bearing waste in natural argilized rock are described: 1. natural decompositon of rock-forming and associated radioactive ore and accessory minerals, such as uraninite, uranothorite, allanite, pyrochlore, apatite, monazite, xenotime, tourmaline, zircon, sulphides and carbonates; 2. mobilization, migration and redeposition of U, Th, REE, Zr, radiogenic lead and other elements along fractures; 3. neoformation of autunite, torbernite, phosphuranylite, coffinite, boltwoodite, kasolite, uranophane, bayleyite, ruthefordine, liebigite, masuyite, anglesite, wulfenite and complex unidentified U, Th, Pb, REE and Zr compounds in clays and in fractures of hydrated rock-forming minerals. The mobilized radionuclides can be fixed by several processes, namely by adsorption, by reacting with other ions, and by entering and capture in the interlayer of swelling mixed-layer clays and hydrated layer silicates. These observations on the natural behaviour of radioactive and radiogenic materials can be applied in evaluating rock formations and planning preventive measures for the escape of nuclear waste from disposal sites