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  • Author or Editor: M. Eskandari x
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Abstract  

In this study, the effects of various extraction parameters such as extractant types (Cyanex302, Cyanex272, TBP), acid type (nitric, sulfuric, hydrochloric) and their concentrations were studied on the thorium separation efficiency from uranium(VI), titanium(IV), lanthanum(III), iron(III) using Taguchis method. Results showed that, all these variables had significant effects on the selective thorium separation. The optimum separations of thorium from uranium, titanium and iron were achieved by Cyanex302. The aqueous solutions of 0.01 and 1 M nitric acid were found as the best aqueous conditions for separating of thorium from titanium (or iron) and uranium, respectively. The combination of 0.01 M nitric acid and Cyanex272 were found that to be the optimum conditions for the selective separation of thorium from lanthanum. The results also showed that TBP could selectively extract all studied elements into organic phase leaving thorium behind in the aqueous phase. Detailed experiments showed that 0.5 M HNO3 is the optimum acid concentration for separating of thorium from other elements with acidic extractants such as Cyanex272 and Cyanex302. The two-stage process containing TBP-Cyanex302 was proposed for separation thorium and uranium from Zarigan ore leachate.

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Abstract  

Solvent extraction of thorium was studied using Taguchi method. The effect of various parameters such as acid types (sulfuric, nitric, hydrochloric, sulfuric + nitric) and their concentrations from 0.001 to 4 M, initial thorium concentration (0.0001, 0.001, 0.01, 0.1 M) and solvent type (TBP, D2EHPA, Cyanex921, Cyanex272) in the ranges of 0.001 to 1 M on thorium extraction efficiency were investigated. The maximum extraction of thorium was obtained while 0.001 M hydrochloric acid, 0.001 or 0.01 M thorium and Cyanex272 were used. Under these optimum conditions, the extraction percent and distribution coefficient of thorium were 98.7% and 73.8, respectively. Compared with the hydrochloric aqueous solution, the nitric acid system showed less variation in the extraction of thorium. The proposed process has been applied for the separation of Th(IV), U(VI), La(III), and Ce(III) from synthetic solution same as thorium ores (monazite).

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Solanum

(Solanaceae) comprises cultivated and wild plants with 1400 species in the world and 14 species in Iran. Solanum is a taxonomically complex genus due to morphological similarities, phenotypic plasticity and hybridisation. Limited studies were done on anatomical features of this important genus. In this project, 10 native and exotic species of Solanum in Iran belonging to two subgenera were examined anatomically. Leaf mesophyll and midrib and indumentum were analysed using light microscope. Hand-made cross section method and Toluidine blue as colouring agent were used. Characters as length and width of main vascular bundle, thickness of collenchyma, trichome density, thickness of parenchyma strand, thickness of lamina and length and shape of midrib were diagnostic features among species studied. In UPGMA tree and PCA ordination, species of two subgenera were separated from each other. Results of this study confirmed the taxonomic importance of anatomical characters in Solanum species studied.

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