Sökning: "Physical chemistry bentonite"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Physical chemistry bentonite.

1. 1. Generation, stability and migration of montmorillonite colloids in aqueous systems

   Författare :Sandra García García; Mats Jonsson; Tiziana Missana; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Bentonite; montmorillonite; colloid stability; colloid migration; geological disposal; nuclear waste; granitic fractures; ; Environmental chemistry; Miljökemi; Environmental toxicology; Miljötoxikologi; Surface and colloid chemistry; Yt- och kolloidkemi; Nuclear chemistry; Kärnkemi;

   Sammanfattning : In Sweden the encapsulated nuclear waste will be surrounded by compacted bentonite in the granitic host rock. In contact with water-bearing fractures the bentonite barrier may release montmorillonite colloids that may be further transported in groundwater. LÄS MER

3. 2. Experimental studies of radiation-induced dissolution of UO2 : The effect of intrinsic solid phase properties and external factors

   Författare :Alexandre Barreiro Fidalgo; Mats Jonsson; David Shoesmith; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Oxidation; dissolution; uranium dioxide; gadolinium; bentonite; sulfide; hydrogen; gamma radiation; radiolysis; hydrogen peroxide; hydroxyl radical; repository; Kemi; Chemistry;

   Sammanfattning : Dissolution of the UO2 matrix is one of the potential routes for radionuclide release in a future deep geological repository for spent nuclear fuel. This doctoral thesis focuses on interfacial reactions of relevance in radiation-induced dissolution of UO2 and is divided in two parts:In the first part, we sought to explore the effects of solid phase composition:The impact of surface stoichiometry on the reactivity of UO2 towards aqueous radiolytic oxidants was studied. LÄS MER

4. 3. Interaction of magnetite with soluble silicates and bentonite : implications for wet agglomeration of magnetite concentrate

   Författare :Xiaofang Yang; James McQuillan; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical Chemistry; Fysikalisk kemi; Chemistry of Interfaces; Gränsytors kemi;

   Sammanfattning : Iron ore green pellets are produced by agglomeration of moist magnetite concentrates. The quality of green pellets is essential for the transportability and metallurgical benefits of the final product. LÄS MER

5. 4. Nuclear magnetic resonance studies on bentonite in complex mixed systems

   Författare :Alexander S. Goryan; Willis Forsling; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bentonite; montmorillonite; 23Na; 31P; 29Si NMR; interaction; ion exchange; sorption; Chemistry of Interfaces; Gränsytors kemi;

   Sammanfattning : In this work 23Na MAS NMR was validated as a successful quantitative method for studies of exchanging sodium in bentonites useful, in particular, for studies of ion-exchange kinetics. Na-enriched bentonites equilibrated in a re-circulated process water at iron-oxide pelletizing plants may acquire properties of Ca-bentonites after already 20 minutes of the equilibration time, since >50 % of sodium ions will be exchanged by calcium ions during first minutes of bentonite placed in contact with the process water. LÄS MER

7. 5. Stability and sorption capacity of montmorillonite colloids : Investigation of size fractional differences and effects of γ-irradiation

   Författare :Karin Norrfors; Susanna Wold; Daniel Kaplan; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; montmorillonite; colloids; size effect; γ-irradiation; sorption; colloid stability; radionuclides; montmorillonit; kolloider; storlekseffekt; γ-bestrålning; sorption; kollodial stabilitet; radionuklider; Kemi; Chemistry;

   Sammanfattning : Bentonite clay is intended to form one of the barriers in most repositories of spent nuclear fuel located in granite. One important function of the bentonite barrier is to retard transport of radionuclides in the event of waste canister failure. Bentonite has a high sorption capacity of cations and its main constituent is montmorillonite. LÄS MER