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- Author or Editor: M. Aly x
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Abstract
Sodiumlignosulphonate was added to sulphate resisting cement as chemical additive to modify its physical and chemical properties for conditioning hazardous and radioactive wastes for long term disposal. The effect of some organic and inorganic chemicals on sulphate resisting cement was investigated. The physical properties such as density, porosity percent and absorption percent for all the studied samples as well as the compressive strength values and the leaching properties were also determined. The thermal stability and the radiation stability were also investigated.
Thermodynamics of dinonylnaphthalene sulfonic acid (HD)
Extraction of trivalent americium, curium and californium
Abstract
The effect of temperature on the extraction of the trivalent actinides Am3+, Cm3+ and Cf3+ with the liquid cation exchanger dinonylnaphthalenesulphonic acid (HD) in toluene is studied. The different thermodynamic functions of this system are determined from the experimental results. It is found that the free energy variation for the extraction of these metal ions by HD is mainly determined by the entropic terms arising from the hydration-dehydration process of the exchanged ions.
Abstract
A rapid method for fluorimetric estimation of uranium in silicate rocks is described. The fluorescence of uranyl complex is induced by laser beam in the ultraviolet region provided by nitrogen laser tube. The emission spectrum is quite intense and relatively persistent. For direct estimation of uranium in geological silicate materials without prior extraction, the interference of certain cations and anions that might be present in silicate rocks on uranium determination was studied. The limit of detection is 0.5 ppb.
Abstract
The solid-state thermal reactions of 2,6-diamino-4-chloropyrimidine, 3,3-dimethoxybenzidine and of thiosemicarbazide with each of 2-hydroxy-1-naphthaldehyde and 2,4-dihydroxybenzaldehyde in a mole ratio of 1∶1 produced (1+1) condensation products (‘half units’). These solid state reactions have been studied by means of differential thermal analysis (DTA). The products of the reactions were identified using elemental analysis and IR spectroscopy. Some kinetic parameters such as orders and activation energies of the reactions were evaluated form the DTA curves.
Abstract
Different nitrogen fertilizers produced in Egypt were analyzed mass-spectrometrically for their15N content. The results indicate that nitrate fertilizers are relatively enriched in15N compared with ammonium fertilizers. The isotopic fractionation of nitrogen encountered in the production processes of fertilizers are discussed.
Abstract
The thermodynamic functions for the extraction of Sc3+ by liquid cation exchangers HD and HDEHP are determined radiometrically by the temperature coefficient method. The role of diluent dielectric constant on the extraction of Sc3+ by HD is also studied. The thermodynamic parameters determined indicated that the free energy variation for the extraction of Sc3+ by HD is mainly determined by the entropic terms arising from the hydration—dehydration process of the exchanged ions. In the case of HDEHP as extractant, the free energy variations are determined mainly by the entalpic terms of the system.
Abstract
Zirconyl tungstate ceramic-supported membranes were developed and characterized. The transport process of Cs(I), Sr(II) and La(III) from the anode compartment to the cathode was investigated. The cationic fluxes for Cs(I), Sr(II) and La(III) were found to be 9·10–10, 2.7·10–9 and 2.4·10–9 g·eq·cm–2·s–1, respectively. The transport numbers of these cations were found to be 0.12, 0.07 and 0.09, respectively. Separation of Cs(I), Sr(II) and La(III) was achieved using EDTA as a chelating agent in the anode compartment. Cs(I) was successfully separated with a decontamination factor of 97% from simulated intermediate level liquid waste (ILLW) containing Cs(I) and Sr(II).
Abstract
The electrical conductivity of pure and Co-doped MgAl2O4 spinels was measured at 700–1100 K. The results of both pure and doped spinels were found to be fitted with an exponential expression with two different activation-energy parameters, in two ranges of temperature. The effect of 
-irradiation on the electrical conductivity of pure and doped spinels was also studied. The kinetic parameters of the isothermal annealing of the induced irradiation damages in the spinels were determined. All the results were found to be consistent with the ionic conduction which was suggested to be due to the motion of the cation vacancy.
Abstract
Fission-produced 131I and 103Ru radionuclides have been separated sequentially by distillation from H2SO4 of controlled chemical composition. The thermal-neutron irradiated uranium trioxide targets were digested in 2M NaOH solution and then, the supernatant solution was acidified to 20% H2SO4 with addition of a few drops of H2O2 solution. On boiling for 3.5 hours, ≥99.99%131I was volatilized, passed through 3M H2SO4 traps, and then collected in 0.1M NaOH + 0.01% Na2S2O3 solution with a recovery yield of 73.6%. The product radionuclide had high radiochemical and radionuclidic purities. After separation of 131I, the fission-product solution was acidified to 40% H2SO4 acid containing KMnO4 as an oxidant and boiled for 40 minutes. Ruthenium nuclides were volatilized and collected in 0.1M NaOH solution. Gamma-ray spectrometry showed that the separation and the recovery yields of 103Ru were ≥99.99 and 65%, respectively, with ~92% radionuclidic purity, measured immediately after separation. The radionuclides of 132I and 106Rh were the main contaminants detected in the obtained 103Ru product solution.
