Effect of Manganese Ions on Spectroscopic and Insulating Properties of Aluminophosphate Glasses

The melt-quenching technique was used to produce 39CdO–10Al2O3-(51-x) P2O5: xMnO glasses (x = 0, 0.1, 0.2, 0.3, and 0.4 wt.%). Various stability factors were calculated and presented from DTA analysis. The stability of the glass network appears to increase with the increase of MnO concentration, according to the findings. IR spectral analysis of these glasses exhibited several symmetrical and asymmetrical bands due to phosphate groups. The observed change in these band intensities with the rise in MnO concentrations, ranging from 0.1 wt.% to 0.4 wt.%, shows an increase in the stability of the glass network. Optical absorption analyses of these glasses revealed an absorption band that shifted from 500 to 488 nm as the concentration of manganese oxide (MnO) increased from 0.1 wt.% to 0.4 wt.%, indicating that Mn2+ ions were gradually converted into Mn3+ ions. EPR spectra of these glasses were characterized by two signals due to Mn2+ and Mn3+ ions. Observations on these signal intensity variations revealed an increase in stability of the glass network with the increase of MnO concentration from 0.1 wt.% to 0.4 wt.%. Parameters, which describe the insulating characteristics, for example, dielectric constant, ε, dielectric loss, tan δ, and AC conductivity σac, were determined in relation to frequency (103 Hz to 105 Hz) and temperature (20°C to 400°C) and presented in the dielectric analysis of these glasses.

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.