Yang Yong-Hui

Extraction of uranium(VI) from sulfuric acid solution with TOPO

The extraction of uranium(VI) from sulfuric acid medium with tri-octylphosphine oxide (TOPO) in n-heptane was studied. Accompanied with the increase in the concentration of H2SO4, the distribution coefficient of uranium(VI) increased in the region of dilute sulfuric acid. When the concentration of H2SO4 surpassed 3.5 mol·dm−3, the distribution coefficient of uranium(VI) was at maximum. This result was due to the competition extraction between uranium(VI) and H2SO4. From the data, the composition of extracted species and the equilibrium constant of extraction reaction have been evaluated, which were (TOPOH)2UO2(SO4)2 (TOPO) and 107.6±0.15, respectively.

INTERFACIAL ACTIVITY OF HDEHP AND KINETICS OF NICKEL EXTRACTION IN VARIOUS DILUENTS

ABSTRACT The interfacial behavior of HDEHP at various diluents/0.05M (H2,Na2)SO4 interfaces was examined using the Drop Volume Method. Different adsorption isotherms such as the Gibbs and Szyszkowski were found as fits well to the experimental interfacial tension isotherms. The values of surface excess at saturated interface,calculated according to them by using the concentration of individual species (e.g. organic monomeric species),increase in the order: MIBK<chloroform <benzene∼toluene∼xylene<CCl4 <n-hexane∼n-heptane The interfacial activity data were used to discuss the mechanism and kinetics of nickel extraction. It was shown that the interfacial mechanism is very probable and the extraction limiting step is the reaction between HDEHP molecules present near the interface and the intermediate 1:2 complex just as following Ni(H2O) 4A2(int,0) +2H2A2(int,0) =Ni(H2O) 2A2˙2H2A2(int,0) +2H2O(int,0) The investigation of the influence of diluent on the extraction rate supports the mechanism suggested.

The effect of diluents on extraction of uranium(VI) with petroleum-sulfoxides (PSO)

The effect of diluents on the extraction of uranium(VI) with petroleum sulfoxides (PSO) was studied. The decreasing order of extraction ability of PSO is as follows: benzene, toluene, cyclohexane, heptane, kerosene, carbon tetrachloride and chloroform. The effect of temperature on the extraction equilibrium was also investigated and enthalpy of the extraction was obtained. The relationship between the extraction equilibrium constantsKex and the physical parameters of diluents can be derived.

Extraction of uranium(VI) through reversed micelle by primary amine N1923

A study on extraction of uranium(VI) from sulfuric acid media by the primary amine N1923 in chloroform is described. Extraction coefficients of uranium(VI) as a function of aqueous H2SO4 concentration, extractant concentration and temperature have been studied. From the data, the compositions of extracted species, equilibrium constants and enthalpies of extraction reaction have been evaluated. A new extraction mechanism of amine has been suggested, that is the formation of reversed micelle as a result of the aggregation of ammonium salt in the organic phase of the extraction. This assumption may be used for interpreting extraction data satisfactorily, which can not be explained by the slope analysis method.

Extraction of uranium(VI) with bis(octylsulfinyl)methane

The liquid-liquid extraction of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)methane (BOSM) has been studied over a wide range of conditions. The extracted species appear to be UO2(NO3)2·2BOSM. It was found that the extraction increased with increasing nitric acid concentration up to 8.5 mol/l and then descreased. Extraction also increased with increasing extractant concentration. The influence of temperature and salting-out agent concentration on the extraction equilibrium has also been investigated, and the enthalpy of the extraction reaction was estimated.

Extraction of sulfuric acid with TOPO

A study on solvent extraction of sulfuric acid by tri-octylphosphine oxide (TOPO) in n-heptane has been made. Extraction coefficients of H2SO4 as a function of H2SO4 concentration in aqueous phase, and extractant concentrations in organic phase have been studied. The composition of extracted species, equilibrium constants of extraction reaction have been evaluated. These results are important for interpreting extraction equilibrium data of uranium(VI) or other metal ions with TOPO in sulfuric acid media.

SYNERGISTIC EXTRACTION OF URANIUM(VI) WITH PRIMARY AMINE N1923 AND TOPO

The synergistic extraction of uranium(VI) from sulfuric acid solution with primary amine N1923 and tri-octylphosphine oxide (TOPO) inn-heptane was studied. When the mole ratio of primary amine N1923 and TOPO is about 2∶1, the distribution coefficient will be the maximum. This result shows that primary amine N1923 and TOPO could exhibit the distinct synergistic effect for extraction of uranium(VI) from sulfuric acid solution. From the results of the extraction, it was suggested that the composition of synergistic extraction species is (RNH3)UO2(SO4)2·TOPO. The equilibrium constant (K12) of synergistic extraction reaction has been evaluated, to be 1.07·109. In addition, the integration phenomenon of N1923 and TOPO have been discussed, the integration constant (K3) is 1.60·102.

Liquid-liquid extraction of uranium(VI) from nitric acid solutions with bis(octylsulfinyl)ethane (BOSE)

The liquid-liquid extraction behavior of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)ethane (BOSE) in 1,1,2,2-tetrachloroethane has been studied over a wide range of conditions. The extracted species appears to be UO2(NO3)2·2BOSE. It was found that the extraction increases with increasing nitric acid concentration up to 7 mol/l and then decreased. Extraction also increases with increasing extractant concentration. The influence of temperature and salting-out agent concentration on the extraction equilibrium and stripping of uranium(VI) was also investigated and the enthalpy of the extraction reaction was obtained.

The Synergic Extraction of Uranium(VI) with Bis(octylsulfinyl)ethane (BOSE) and Petroleum Sulfoxides (PSO)

The synergic extraction of uranium(VI) from nitric acid solution with a mixture of bis(octylsulfinyl)ethane (BOSE) and petroleum sulfoxides (PSO) in 1,1,2,2- tetrachloroethane has been studied. The composition of the complex of the synergic extraction is UO2(NO3)2·BOSE·PSO. The formation constant of the complex is KPT = 4.44±0.23. The effect of extractant concentration, nitric acid concentration, salting-out agent concentration and temperature on the extraction equilibrium of uranium(VI) is also studied and the enthalpy of the extraction reaction is calculated. It has been found that the maximum synergic extraction effect occurs if the molar ratio of PSO to BOSE is one to one.

Study on the synergic extraction of uranium(VI) with petroleum sulfoxides (PSO) and tri-n-butyl phosphate (TBP) mixture

The synergic extraction of uranium(VI) from nitric acid solution with petroleum sulfoxides (PSO) and tri-n-butyl phosphate (TBP) mixture has been studied. It has been found that maximum synergic extraction effect occurs if the molar ratio of PSO to TBP is two to three. The composition of the complex of synergic extraction is UO2(NO3)2·TBP·PSO. The formation constant of the complex isKPT=8.19. The effect of extractant concentration, nitric acid concentration, salting-out agent concentration and temperature on the extraction equilibrium of uranium(VI) was also studied.