This article reports the extraction of zirconium （IV） from aqueous HC1 solution by tri-octyl amine （TOA）, Cyanex 921, and their binary mixture using kerosene as the diluent. The effect of some parameters on the ex...This article reports the extraction of zirconium （IV） from aqueous HC1 solution by tri-octyl amine （TOA）, Cyanex 921, and their binary mixture using kerosene as the diluent. The effect of some parameters on the extraction of Zr（IV） was investigated such as equilibration time, aqueous phase acidity, extractant molarity, chloride ion concentration, nature of diluents, and temperature. The extraction of Zr（IV） was found to be 99% from 7.5 M HC1 using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene. Kerosene was found to be the effective diluent for the extraction of Zr（IV） with the binary mixture of TOA and Cyanex 921. The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy. Stripping of Zr（IV） from the loaded organic phase containing the mixture of TOA （0.1 M） and Cyanex 921 （0.02 M） indicates that HNO3 and Na2CO3 are the best stripping agents.展开更多
The extraction of neodymium（III） from acidic nitrate medium was investigated using Cyanex 921 as extractant in kerosene. The metal concentration in the aqueous phase before and after extraction was determined spectr...The extraction of neodymium（III） from acidic nitrate medium was investigated using Cyanex 921 as extractant in kerosene. The metal concentration in the aqueous phase before and after extraction was determined spectrophotometrically by Arsenazo III method. The complete equilibration was achieved in 15 rain. The effects of shaking time, nitric acid concentration, nitrate concentration, extractant concen- tration, and temperature on the extraction were studied. The extraction of Nd（III） was found to increase very slowly with increase in concen- tration of HNO3 in the range of 0.001-3.008 mol/L and then decreased when 0.01 mol/L HNO3 was used. The percentage of extraction was increased with increase in nitrate concentration from 0.01M）.45 mol/L and then decreased when nitrate concentration increased to 0.5 mol/L. Quantitative extraction of Nd（III） （98%） was obtained from the aqueous phase containing 0.001 mol/L HNO3 and 0.1 mol/L KNO3 using 0.5 mol/L Cyanex 921. On the basis of slope analysis, the extracted complex in the organic phase was proposed to be Nd（NO3）3.2Cyanex 921. The extraction of Nd（III） was found to increase with increase in concentration of metal ion in the range of 0.0014）.05 mol/L from 0.001 mol/L HNO3 and 0.1 mol/L KNO3 with 0.1 mol/L Cyanex 921. The percentage of extraction of neodymium was found to decrease with in- crease in temperature. From temperature variation studies, the negative value of AH indicated the extraction reaction to be exothermic and the negative value of AS indicated the formation of a stable complex, Almost 100% Nd（III） was recovered from the fully loaded organic phase using 0.002 mol/L H2SO4 and 0.01 mol/L HCl.展开更多
文摘This article reports the extraction of zirconium （IV） from aqueous HC1 solution by tri-octyl amine （TOA）, Cyanex 921, and their binary mixture using kerosene as the diluent. The effect of some parameters on the extraction of Zr（IV） was investigated such as equilibration time, aqueous phase acidity, extractant molarity, chloride ion concentration, nature of diluents, and temperature. The extraction of Zr（IV） was found to be 99% from 7.5 M HC1 using the mixture of extractants containing 0.1 M TOA and 0.02 M Cyanex 921 in kerosene. Kerosene was found to be the effective diluent for the extraction of Zr（IV） with the binary mixture of TOA and Cyanex 921. The positive enthalpy change and positive entropy change in the binary extraction system show the endothermic process with an increase in entropy. Stripping of Zr（IV） from the loaded organic phase containing the mixture of TOA （0.1 M） and Cyanex 921 （0.02 M） indicates that HNO3 and Na2CO3 are the best stripping agents.
文摘The extraction of neodymium（III） from acidic nitrate medium was investigated using Cyanex 921 as extractant in kerosene. The metal concentration in the aqueous phase before and after extraction was determined spectrophotometrically by Arsenazo III method. The complete equilibration was achieved in 15 rain. The effects of shaking time, nitric acid concentration, nitrate concentration, extractant concen- tration, and temperature on the extraction were studied. The extraction of Nd（III） was found to increase very slowly with increase in concen- tration of HNO3 in the range of 0.001-3.008 mol/L and then decreased when 0.01 mol/L HNO3 was used. The percentage of extraction was increased with increase in nitrate concentration from 0.01M）.45 mol/L and then decreased when nitrate concentration increased to 0.5 mol/L. Quantitative extraction of Nd（III） （98%） was obtained from the aqueous phase containing 0.001 mol/L HNO3 and 0.1 mol/L KNO3 using 0.5 mol/L Cyanex 921. On the basis of slope analysis, the extracted complex in the organic phase was proposed to be Nd（NO3）3.2Cyanex 921. The extraction of Nd（III） was found to increase with increase in concentration of metal ion in the range of 0.0014）.05 mol/L from 0.001 mol/L HNO3 and 0.1 mol/L KNO3 with 0.1 mol/L Cyanex 921. The percentage of extraction of neodymium was found to decrease with in- crease in temperature. From temperature variation studies, the negative value of AH indicated the extraction reaction to be exothermic and the negative value of AS indicated the formation of a stable complex, Almost 100% Nd（III） was recovered from the fully loaded organic phase using 0.002 mol/L H2SO4 and 0.01 mol/L HCl.
