Versatile Monazite: Resolving geological records and solving challenges in materials science. Monazite as a promising long-term radioactive waste matrix: Benefits of high-structural flexibility and chemical durability
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Abstract
Monazite (Ln3+PO4) and related solid solutions are a well-known source of rare earth elements on earth. They may also accommodate large amounts of thorium and uranium without sustaining damage to the structure by self-irradiation. Such observations led to monazite-type structures being proposed as a potential host matrix for sequestering long-lived radionuclides produced during the nuclear fuel cycle and/or plutonium and americium from dismantled nuclear weapons. Monazite has two main advantages as a matrix for the containment of radioactive waste (or “radwaste”). The first is a highly flexible structure that permits accommodation of high concentrations of actinides. The incorporation of trivalent elements may be achieved by direct synthesis of An3+PO4 (An3+ = plutonium, Pu to einsteinium, Es), while tetravalent cation incorporation requires coupled substitutions, either on the anionic site (leading to monazite-huttonite solid solution) or on the cationic site (monazite-cheralite solid solution). Various methods developed for the preparation of such compounds are summarized here, as well as the experimental conditions required for the production of sintered pellets, with a particular focus on plutonium-bearing compositions. The second highly favorable property of monazite is its high chemical durability. Several experimental procedures developed to determine normalized leaching rates are reviewed, as well as results obtained from natural and synthetic monazite. Potential phases formed during dissolution were considered because they also partially control the concentration of actinides in the media. A preliminary list for such phases of interest, as well as corresponding thermodynamic data, is presented.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Review: Versatile Monazite: resolving geological records and solving challenges in materials science. Generalizations about monazite: Implications for geochronologic studies
- Versatile Monazite: Resolving geological records and solving challenges in materials science. Monazite as a promising long-term radioactive waste matrix: Benefits of high-structural flexibility and chemical durability
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- Kangite, (Sc,Ti,Al,Zr,Mg,Ca,⃞)2O3, a new ultra-refractory scandia mineral from the Allende meteorite: Synchrotron micro-Laue diffraction and electron backscatter diffraction
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- Solidification of trapped liquid in rocks and crystals
- Using the chemical composition of carbonate rocks on Mars as a record of secondary interaction with liquid water
- Multinuclear NMR study of Cs-bearing geyserites of the Targejia hot spring cesium deposit in Tibet
- Clay minerals as geo-thermometer: A comparative study based on high spatial resolution analyses of illite and chlorite in Gulf Coast sandstones (Texas, U.S.A.)
- Incorporation of Zn in the destabilization products of muscovite at 1175 °C under disequilibrium conditions, and implications for heavy metal sequestration
- H/D methane isotopologues dissolved in magmatic fluids: Stable hydrogen isotope fractionations in the Earth’s interior
- Ca-Sr fractionation between zoisite, lawsonite, and aqueous fluids: An experimental study at 2.0 and 4.0 GPa/400 to 800 °C
- The infrared vibrational spectrum of andradite-grossular solid solutions: A quantum mechanical simulation
- Occurrence of silica polymorphs nanocrystals in tuffaceous rocks, Province of the Mesa Central, Mexico, and their formation from subcritical Si-rich fluids
- Pressure-induced Pbca-P21/c phase transition of natural orthoenstatite: Compositional effect and its geophysical implications
- High-pressure and high-temperature equation of state of cobalt oxide: Implications for redox relations in Earth’s mantle
- Synthesis and characterization of kanemite from fluoride-containing media: Influence of the alkali cation
- Structure of prismatic halloysite
- Fluorophlogopite from Piano delle Concazze (Mt. Etna, Italy): Crystal chemistry and implications for the crystallization conditions
- Analysis of hydrogen and fluorine in pyroxenes: I. Orthopyroxene
- Analysis of hydrogen and fluorine in pyroxenes: II. Clinopyroxene
- Letter. A carbonate-fluoride defect model for carbonate-rich fluorapatite
- Letter. Kumdykolite, a high-temperature feldspar from an enstatite chondrite
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Artikel in diesem Heft
- Review: Versatile Monazite: resolving geological records and solving challenges in materials science. Generalizations about monazite: Implications for geochronologic studies
- Versatile Monazite: Resolving geological records and solving challenges in materials science. Monazite as a promising long-term radioactive waste matrix: Benefits of high-structural flexibility and chemical durability
- Incorporation of Ge in ferrihydrite: Implications for the structure of ferrihydrite
- The pressures and temperatures of meteorite impact: Evidence from micro-Raman mapping of mineral phases in the strongly shocked Taiban ordinary chondrite
- Kangite, (Sc,Ti,Al,Zr,Mg,Ca,⃞)2O3, a new ultra-refractory scandia mineral from the Allende meteorite: Synchrotron micro-Laue diffraction and electron backscatter diffraction
- New insights into the formation of diagenetic illite from TEM studies
- Solidification of trapped liquid in rocks and crystals
- Using the chemical composition of carbonate rocks on Mars as a record of secondary interaction with liquid water
- Multinuclear NMR study of Cs-bearing geyserites of the Targejia hot spring cesium deposit in Tibet
- Clay minerals as geo-thermometer: A comparative study based on high spatial resolution analyses of illite and chlorite in Gulf Coast sandstones (Texas, U.S.A.)
- Incorporation of Zn in the destabilization products of muscovite at 1175 °C under disequilibrium conditions, and implications for heavy metal sequestration
- H/D methane isotopologues dissolved in magmatic fluids: Stable hydrogen isotope fractionations in the Earth’s interior
- Ca-Sr fractionation between zoisite, lawsonite, and aqueous fluids: An experimental study at 2.0 and 4.0 GPa/400 to 800 °C
- The infrared vibrational spectrum of andradite-grossular solid solutions: A quantum mechanical simulation
- Occurrence of silica polymorphs nanocrystals in tuffaceous rocks, Province of the Mesa Central, Mexico, and their formation from subcritical Si-rich fluids
- Pressure-induced Pbca-P21/c phase transition of natural orthoenstatite: Compositional effect and its geophysical implications
- High-pressure and high-temperature equation of state of cobalt oxide: Implications for redox relations in Earth’s mantle
- Synthesis and characterization of kanemite from fluoride-containing media: Influence of the alkali cation
- Structure of prismatic halloysite
- Fluorophlogopite from Piano delle Concazze (Mt. Etna, Italy): Crystal chemistry and implications for the crystallization conditions
- Analysis of hydrogen and fluorine in pyroxenes: I. Orthopyroxene
- Analysis of hydrogen and fluorine in pyroxenes: II. Clinopyroxene
- Letter. A carbonate-fluoride defect model for carbonate-rich fluorapatite
- Letter. Kumdykolite, a high-temperature feldspar from an enstatite chondrite
- Letter. High-pressure aragonite phenocrysts in carbonatite and carbonated syenite xenoliths within an alkali basalt
