Synthesis of minerals and polymineral matrixes for immobilization of radioactive wastes elements

For the development of methods for the disposal of radioactive waste in the rocks of the earths crust, the concept of phase and chemical correspondence in the system of matrix material ― host rock has been proposed. This principle allows directional synthesis of certain mineral matrices. Matrix materials were experimentally synthesized ― solid solutions of minerals for immobilization of alkaline, alkaline-earth, rare-earth elements ― radionuclides. The properties of a number of solid solutions of minerals are investigated. The possibilities of processing graphite into stable matrices are studied. Methods of fixation and separation of noble metals (components of radioactive waste) and halides (Br, I) have been developed. The problems of processing glass matrix minerals (borosilicate and aluminophosphate glasses) into stable crystalline matrix materials are considered. Methods for processing glass matrices into mineral matrix materials are presented.

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An Analysis on the Tensile Strength of Hybridized Reinforcement Filament Yarns by Commingling Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.974 ◽

2007 ◽

Vol 539-543 ◽

pp. 974-978

Author(s):

Chathura Nalendra Herath ◽

Beong Bok Hwang ◽

B.S. Ham ◽

Jung Min Seo ◽

Bok Choon Kang

Keyword(s):

Mechanical Properties ◽

Glass Matrix ◽

High Performance ◽

Glass Fibers ◽

Tensile Force ◽

Matrix Material ◽

General Purpose ◽

Practical Applications ◽

Advantages And Disadvantages ◽

Glass Matrices

Carbon, aramid and glass fibers are inherently superior to conventional textile fibers in terms of mechanical properties as well as other chemical characteristics. Because of inherent advantages and disadvantages associated with each material, it is generally better to hybridize them to fully benefit of their high performance in many practical applications. In this paper, the possibility of hybridizing Carbon/Aramid-, Carbon/Glass- and Aramid/Glass- matrices has been investigated through the commingling process. In the experiment, several process parameters were selected and they include pressure, yarn oversupply-rate and different nozzle types. As a result of experiments, it was concluded that the hybridized materials has shown better performance than individual reinforced filament yarns in terms of mechanical properties. For small tensile forces, the Carbon/Glass/matrix combination turned out to be good enough for general purpose applications. However, for high tensile applications, Carbon/Aramid or Aramid/Glass with matrix combinations was better than the other material combinations. The hybridization process was also investigated under an air pressure of 5 bar, a yarn oversupply-rate of 1.5% for reinforced filaments, and 3.5% to 6% for matrix materials, respectively. It was also shown from the experimental results that Carbon/Glass/matrix combination may be desirable for small tensile force applications and Carbon/Aramid/matrix and Glass/Aramid/matrix combinations most suitable for heavy tensile force applications, respectively. As a matrix material, polypropylene and polyester have shown better performance than polyether-ether-keeton in terms of tensile property.

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Mechanochemical synthesis, structure, and properties of solid solutions of alkaline earth metal fluorides: Ma−MbF2 (M: Ca, Sr, Ba)

Solid State Sciences ◽

10.1016/j.solidstatesciences.2016.08.004 ◽

2016 ◽

Vol 60 ◽

pp. 65-74 ◽

Cited By ~ 17

Author(s):

M. Heise ◽

G. Scholz ◽

A. Düvel ◽

P. Heitjans ◽

E. Kemnitz

Keyword(s):

Solid Solutions ◽

Mechanochemical Synthesis ◽

Alkaline Earth ◽

Earth Metal ◽

Alkaline Earth Metal ◽

Structure And Properties ◽

Metal Fluorides

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Vapour Phase Hydration of Blended Oxide - Magnox Waste Glasses

MRS Proceedings ◽

10.1557/proc-807-181 ◽

2003 ◽

Vol 807 ◽

Cited By ~ 2

Author(s):

Neil C. Hyatt ◽

William E. Lee ◽

Russell J. Hand ◽

Paul K. Abraitis ◽

Charlie R. Scales

Keyword(s):

Glass Matrix ◽

Alkaline Earth ◽

Vapour Phase ◽

Waste Glass ◽

High Level Waste ◽

Zirconium Silicate ◽

Constant Rate ◽

Surface Alteration ◽

High Level ◽

Short Incubation Time

ABSTRACTVapour phase hydration studies of a blended Oxide / Magnox simulant high level waste glass were undertaken at 200°C, over a period of 5 – 25 days. The alteration of this simulant waste glass is characterised by a short incubation time of less than 5 days, leading to the formation of an alteration layer several microns thick. Following the incubation period, the alteration proceeds at a constant rate of 0.15(1)μmd−1. The distribution of key glass matrix (Si, Na) and waste (Cs, Zr, Nd, Mo) elements was found to vary significantly across the alteration layer. Vapour phase hydration leads to formation of surface alteration products, identified as smectite, zirconium silicate and alkaline-earth molybdate phases.

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