Abstract
The extraction of zirconium (IV) from aqueous HCl solution by binary mixture TOA and Cyanex 923 using kerosene as diluent was studied. The effect of parameters like aqueous phase acid concentration, extractant concentration, chloride ion concentration, diverse ion effect, metal loading, nature of diluents and temperature on the extraction of Zr (IV) was investigated. The percentage of extraction of Zr(IV) became 100% with 0.1 M TOA and 0.01 M Cyanex 923 from 7 M HCl and also from 4 M HCl with 0.1 M TOA and 0.02 M Cyanex 923. Benzene was found to be effective diluent for the extraction of Zr(IV) with binary mixture of TOA and Cyanex 923. The positive enthalpy change and positive entropy change in the binary extraction system show endothermic process with increase in randomness. Stripping of Zr (IV) from the loaded organic phase containing mixture of TOA (0.1 M) and Cyanex 923 (0.01 M) indicated that HNO3 and Na2CO3 are the best stripping agents.
Highlights
Zirconium metal is highly desirable as a cladding material for nuclear fuel rods in nuclear power plants, because of its very low absorption cross-section for neutrons [1]
The stoichiometric relation for the extraction of zirconium and hafnium from acid chloride solutions was investigated with Versatic Acid-10 by Lee et al [11]
Extraction of zirconium (IV) from hydrochloric acid solution by tri-octylamine and neutral donors in carbon tetrachloride has been investigated by Biswas et al [16] and they found that higher extraction takes place in case of mixture than by single extractant
Summary
Zirconium metal is highly desirable as a cladding material for nuclear fuel rods in nuclear power plants, because of its very low absorption cross-section for neutrons [1]. According to Mishra et al [18] the presence of thiocyanate ions results in appreciable extraction of Zr(IV) by Aliquat336 from low aqueous HCl acidities. The present authors have already reported the study of extraction of Zr(IV) from HCl medium using binary mixture of TOA and Cyanex 921 in kerosene [20]. There is no report on systematic investigations of extraction of Zr(IV) from HCl medium with binary mixture of TOA and Cyanex 923 in kerosene so far. In the present study, an attempt has been made to know the effect of various parameters such as aqueous phase acid concentration, extractant molarity, chloride ion concentration, temperature, metal loading, diverse ion, nature of diluents on the extraction of Zr(IV) from HCl medium using binary mixture of TOA and Cyanex 923. Nitric acid and Sodium carbonate have been used as the stripping agents for recovery of zirconium from loaded organic phase containing binary mixture of TOA and Cyanex 923 under conditions of maximum extraction
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