At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to co...At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La（Ⅲ）,Pr（Ⅲ）, and Nd（Ⅲ） from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid（HLac） and auxiliary agents citric acid（H3 Cit）, acetic acid（HAc）, and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.展开更多
Synergistic solvent extraction of rare earth elements （REEs） from nitrate medium was investigated with mixtures of 8-hydroxyquinoline （HQ） and acidic organophosphorus extractants, bis（2,4,4-trimethylpentyl） dith...Synergistic solvent extraction of rare earth elements （REEs） from nitrate medium was investigated with mixtures of 8-hydroxyquinoline （HQ） and acidic organophosphorus extractants, bis（2,4,4-trimethylpentyl） dithiophosphinic acid （Cyanex 301） and bis（2,4,4-trimethylpentyl） monothiophosphinic acid （Cyanex 302）. The extraction behavior of Cyanex 301/Cyanex 302 and their binary mixtures with HQ towards several lanthanoids （La, Nd, Sm, Tb, Ho, Tm） and yttrium （Y） was investigated. The separation ability of REEs was studied according to the various extraction effects. The extraction mechanisms for yttrium were studied with the methods of slope analysis and constant moles in the synergistic systems. The extracted compounds, the equilibrium constants, and thermodynamic functions were also determined.展开更多
Extraction of vanadium（IV） from sulphate acid solution was studied using organophosphorous-based extractants D2EHPA, EHEHPA and CYANEX 272 in kerosene. The different parameters affecting the extraction of vanadium...Extraction of vanadium（IV） from sulphate acid solution was studied using organophosphorous-based extractants D2EHPA, EHEHPA and CYANEX 272 in kerosene. The different parameters affecting the extraction of vanadium（IV） under equilibrium conditions were separately investigated to elucidate the stoichiometry of the extracted species. The distribution ratio of vanadium increased with increasing equilibrium pH of the aqueous phase, concentration of the extractants and temperature. D2EHPA was found to be a stronger extractant, having greater pH functionality than EHEHPA and CYANEX 272. Extraction of vanadium（IV） by these organophosphorous-based extractants involved cation exchange mechanism, and the extracted species appear to be VOR2（HR）2 in the low equilibrium pH and VOR2 in the higher equilibrium pH, where HR refers to the three acidic extractants.展开更多
The behaviour of vanadium（V） extracted from sulfuric acid solution was investigated using Cyanex 923 as an extractant. The effects of the concentration of Cyanex 923 and the pH of the solution were studied. The extr...The behaviour of vanadium（V） extracted from sulfuric acid solution was investigated using Cyanex 923 as an extractant. The effects of the concentration of Cyanex 923 and the pH of the solution were studied. The extraction of vanadium（V） increases with the increase of Cyanex 923 concentration and shaking time. Cyanex 923 can extract vanadium（V） from sulfuric acid solution at low pH conditions, and the best pH conditions for extraction of vanadium（V） are at pH 1.0-2.0. The species extracted into the organic phase is VO2HSO4 with one molecule of Cyanex 923. Equilibrium studies were used to assess the extraction efficiency of vanadium（V） recovery from the sulfuric acid solution.展开更多
The extraction behavior of bis (2,4,4-trimethylpentyl) dithiophosphinic acid (HBTMPDTP), purified from Cyanex 301, was studied for extracting Am 3+ and trivalent lanthanides (Lns). HBTMPDTP shows very high select...The extraction behavior of bis (2,4,4-trimethylpentyl) dithiophosphinic acid (HBTMPDTP), purified from Cyanex 301, was studied for extracting Am 3+ and trivalent lanthanides (Lns). HBTMPDTP shows very high selectivity for Am. Separation factor (SF) of Am and Eu, SF Am/Eu ,(trace amount) reaches a high value of 5.9×10 3 and SF Am/(Pr+Nd) (macro amount) is about 2×10 3. The mathematical model for the distribution ratios and process parameters calculated for HBTMPDTP extraction was established and the calculated results were verified experimentally. In a five-stage countercurrent process, the extraction rates of Am and Lns were > 99.999% and 0.14%, respectively, to fulfill the separation requirements. The efficiency of this process was also verified in a cross-flow extraction experiment using a genuine Am-FPLns fraction. In the presence of TBP, the extraction of Am and Eu is enhanced, but their separation is reduced to some extent. A fairly good separation was achieved in a fractional extraction process using a mixture of HBTMPDTP and TBP in kerosene at low pH.展开更多
The extraction and stripping of Cu and Ni ions from synthetic and industrial solutions of Sarcheshmeh Copper Mine containing Cu(770 mg/L),Ni(3200 mg/L),Fe(800 mg/L)and Zn(200 mg/L)were comprehensively investigated usi...The extraction and stripping of Cu and Ni ions from synthetic and industrial solutions of Sarcheshmeh Copper Mine containing Cu(770 mg/L),Ni(3200 mg/L),Fe(800 mg/L)and Zn(200 mg/L)were comprehensively investigated using D2 EHPA,LIX 984,Cyanex 302,Chemorex CP 150 and Acorga 5774 diluted in kerosene.The influential parameters such as mixing speed and time,concentration of extractant,p H and temperature were considered in extraction stage.Furthermore,stripping of Cu and Ni was examined using different inorganic and organic acids(sulfuric,hydrochloric,nitric and citric acids)with different concentrations.The results indicated that the highest extractions of Cu and Ni occurred within 3 min,with the mixing speed of 500 r/min,28℃and A/O ratio of 1:1.Moreover,Cu was extracted by LIX 984 at the concentration of 10%(v/v),whereas Ni was extracted by Cyanex 302 at the concentration of 30%(v/v),efficiently.The optimal p H for Cu and Ni extraction is in ranges of 2-3 and 4-5,respectively.Cu and Ni were selectively extracted with the recoveries of 85%,93%and 77%,82%from synthetic and industrial solutions containing Ni,Cu,Zn and Fe ions,respectively.The results of optimal condition showed that 96%of Ni and 93%of Cu were stripped from the synthetic and industrial solutions.Finally,four elements Zn,Fe,Cu and Ni were extracted in three stages with D2 EHPA,LIX 984 and Cyanex 302 extractants respectively with the least impurities.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
Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial ads...Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial adsorption properties of purified Cyanex 923-heptane-0.20mol/L (H, Na)NO3 were studied at 298K. The experimental results show that the mass transfer is controlled by diffusion and the chemical reactions are carried out in the interfacial zone. The extraction rates of yttrium were measured at different chemical compositions by varying ionic strength, pH values and the purified Cyanex 923 concentrations. The initial extraction rate equations were obtained.展开更多
The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitr...The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitrate medium was investigated.On the basis of slope analysis data,the composition of the extracted species was determined as(M(NO3)3?2CY923),CY923 refers to Cyanex 923.The values of the equilibrium constants and the separation factors were calculated.The effect of the diluents on the metal extracti...展开更多
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 and stripping characteristics of Versatic 10 and its mixtures with Cyanex 301 were investigated for the recovery of cobalt and nickel from sulfate solutions containing magnesium and calcium. The optimum...The extraction and stripping characteristics of Versatic 10 and its mixtures with Cyanex 301 were investigated for the recovery of cobalt and nickel from sulfate solutions containing magnesium and calcium. The optimum extraction factors of Versatic 10 were initial pH of 2.5, O/A ratio of 1/3, and saponification rate of 60%. The loaded Versatic 10 was stripped by using 2 mol/L H2SO4 at O/A ratio of 1/1. The optimum volume ratio of Versatic 10 to Cyanex301 was 7/3 in the mixtures, which could effectively reduce the equilibrium pH to 3.50. And the loaded mixtures were stripped by using 2 mol/L H2SO4at O/A ratio of 1/2. The reaction principle of Versatic10 and metal ions is an ion exchange reaction. However, in the extraction reaction of and metal ions, besides the ion exchange reaction, the strong coordination effect between Cyanex 301 and metal ions also exists, which is much weakened in the extraction reaction of the mixtures and metal ions.展开更多
The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous ac...The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous acidity on extraction of La 3+ using Cyanex 302 in different diluents was discussed. The effects of extractant concentration and chloride ion on the extraction reaction were also studied. Stoichiometry of the extraction reactions and the nature of metal complexes formed were determined using slope analysis technique and IR measurement.展开更多
Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the...Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the contribution of diffusion to the measured rate of reaction was minimized. Cerium extraction rate was measured at different chemical composition by varying the concentrations of hydrogen ion, sulphate and Cyanex923. A cerium Cyanex923(B) extractive is formed at the interface. The data were analyszed in terms of pseudo first order constants and a reaction mechanism was developed.展开更多
In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex ...In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.展开更多
The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were re...The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were removed by precipitation method and solvent extraction was used to extract/separate Zn, Mn, Co and Ni. The nickel laterite leach liquor which was obtained from bioleaching of chromite overburden samples contained 3.72 g/L Fe, 2.08 g/L Al, 0.44 g/L Ni, 0.02 g/L Co, 0.13 g/L Mn, 0.14 g/L Zn and 0.22 g/L Cr. From this leach liquor, 100% Fe, 96.98% Al and 70.42% Cr were removed by precipitation with Ca CO_3 at pH 4.4 followed by precipitation of remaining Al and Cr with 50% ammonia at p H 5.4. After precipitation, the extraction of Zn from the Fe, Al and Cr free leach liquor was carried out with 0.1 mol/L TOPS-99 followed by Mn extraction with 0.04 mol/L Na TOPS-99. The yields of Zn and Mn were 97.77% and 95.63%, respectively. After Mn extraction, cobalt was removed from the leach liquor using 0.0125 mol/L Na Cyanex 272 and finally nickel extraction was carried out using 0.12 mol/L Na TOPS-99 with 99.84% yield. The stripping of loaded organic（LO） phases were achieved with dilute H_2SO_4.展开更多
基金Project supported by Anguran Lead and Zinc Company(55/G/93)
文摘At present, the use of rare earth elements（REEs） has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La（Ⅲ）,Pr（Ⅲ）, and Nd（Ⅲ） from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid（HLac） and auxiliary agents citric acid（H3 Cit）, acetic acid（HAc）, and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.
基金supported by National 973 Program of China(2012CBA01206)National Natural Science Foundation of China(51222404)the financial support from State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry(RERU2011006)
文摘Synergistic solvent extraction of rare earth elements （REEs） from nitrate medium was investigated with mixtures of 8-hydroxyquinoline （HQ） and acidic organophosphorus extractants, bis（2,4,4-trimethylpentyl） dithiophosphinic acid （Cyanex 301） and bis（2,4,4-trimethylpentyl） monothiophosphinic acid （Cyanex 302）. The extraction behavior of Cyanex 301/Cyanex 302 and their binary mixtures with HQ towards several lanthanoids （La, Nd, Sm, Tb, Ho, Tm） and yttrium （Y） was investigated. The separation ability of REEs was studied according to the various extraction effects. The extraction mechanisms for yttrium were studied with the methods of slope analysis and constant moles in the synergistic systems. The extracted compounds, the equilibrium constants, and thermodynamic functions were also determined.
基金Project (2009AA06Z106) supported by the High-tech Research and Development Program of ChinaProject (51174104) supported by the National Natural Science Foundation of ChinaProject (20115314110001) supported by the Doctoral Fund of Ministry of Education of China
文摘Extraction of vanadium（IV） from sulphate acid solution was studied using organophosphorous-based extractants D2EHPA, EHEHPA and CYANEX 272 in kerosene. The different parameters affecting the extraction of vanadium（IV） under equilibrium conditions were separately investigated to elucidate the stoichiometry of the extracted species. The distribution ratio of vanadium increased with increasing equilibrium pH of the aqueous phase, concentration of the extractants and temperature. D2EHPA was found to be a stronger extractant, having greater pH functionality than EHEHPA and CYANEX 272. Extraction of vanadium（IV） by these organophosphorous-based extractants involved cation exchange mechanism, and the extracted species appear to be VOR2（HR）2 in the low equilibrium pH and VOR2 in the higher equilibrium pH, where HR refers to the three acidic extractants.
基金supported by the Science Foundation of Central South University (No. 76112037) the Postdoctoral Science Foundation of Central South University
文摘The behaviour of vanadium（V） extracted from sulfuric acid solution was investigated using Cyanex 923 as an extractant. The effects of the concentration of Cyanex 923 and the pH of the solution were studied. The extraction of vanadium（V） increases with the increase of Cyanex 923 concentration and shaking time. Cyanex 923 can extract vanadium（V） from sulfuric acid solution at low pH conditions, and the best pH conditions for extraction of vanadium（V） are at pH 1.0-2.0. The species extracted into the organic phase is VO2HSO4 with one molecule of Cyanex 923. Equilibrium studies were used to assess the extraction efficiency of vanadium（V） recovery from the sulfuric acid solution.
文摘The extraction behavior of bis (2,4,4-trimethylpentyl) dithiophosphinic acid (HBTMPDTP), purified from Cyanex 301, was studied for extracting Am 3+ and trivalent lanthanides (Lns). HBTMPDTP shows very high selectivity for Am. Separation factor (SF) of Am and Eu, SF Am/Eu ,(trace amount) reaches a high value of 5.9×10 3 and SF Am/(Pr+Nd) (macro amount) is about 2×10 3. The mathematical model for the distribution ratios and process parameters calculated for HBTMPDTP extraction was established and the calculated results were verified experimentally. In a five-stage countercurrent process, the extraction rates of Am and Lns were > 99.999% and 0.14%, respectively, to fulfill the separation requirements. The efficiency of this process was also verified in a cross-flow extraction experiment using a genuine Am-FPLns fraction. In the presence of TBP, the extraction of Am and Eu is enhanced, but their separation is reduced to some extent. A fairly good separation was achieved in a fractional extraction process using a mixture of HBTMPDTP and TBP in kerosene at low pH.
文摘The extraction and stripping of Cu and Ni ions from synthetic and industrial solutions of Sarcheshmeh Copper Mine containing Cu(770 mg/L),Ni(3200 mg/L),Fe(800 mg/L)and Zn(200 mg/L)were comprehensively investigated using D2 EHPA,LIX 984,Cyanex 302,Chemorex CP 150 and Acorga 5774 diluted in kerosene.The influential parameters such as mixing speed and time,concentration of extractant,p H and temperature were considered in extraction stage.Furthermore,stripping of Cu and Ni was examined using different inorganic and organic acids(sulfuric,hydrochloric,nitric and citric acids)with different concentrations.The results indicated that the highest extractions of Cu and Ni occurred within 3 min,with the mixing speed of 500 r/min,28℃and A/O ratio of 1:1.Moreover,Cu was extracted by LIX 984 at the concentration of 10%(v/v),whereas Ni was extracted by Cyanex 302 at the concentration of 30%(v/v),efficiently.The optimal p H for Cu and Ni extraction is in ranges of 2-3 and 4-5,respectively.Cu and Ni were selectively extracted with the recoveries of 85%,93%and 77%,82%from synthetic and industrial solutions containing Ni,Cu,Zn and Fe ions,respectively.The results of optimal condition showed that 96%of Ni and 93%of Cu were stripped from the synthetic and industrial solutions.Finally,four elements Zn,Fe,Cu and Ni were extracted in three stages with D2 EHPA,LIX 984 and Cyanex 302 extractants respectively with the least impurities.
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.
文摘Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial adsorption properties of purified Cyanex 923-heptane-0.20mol/L (H, Na)NO3 were studied at 298K. The experimental results show that the mass transfer is controlled by diffusion and the chemical reactions are carried out in the interfacial zone. The extraction rates of yttrium were measured at different chemical compositions by varying ionic strength, pH values and the purified Cyanex 923 concentrations. The initial extraction rate equations were obtained.
文摘The solvent extraction of Pr(Ⅲ) and Sm(Ⅲ) with trialkyl phosphine oxide(Cyanex 923) in chloroform,carbon tetrachloride,n-octane,cyclohexane,1,2-dichloroethane,benzene,toluene,xylene and nitrobenzene from acidic nitrate medium was investigated.On the basis of slope analysis data,the composition of the extracted species was determined as(M(NO3)3?2CY923),CY923 refers to Cyanex 923.The values of the equilibrium constants and the separation factors were calculated.The effect of the diluents on the metal extracti...
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.
基金Project(2012BAB07B05)supported by the National Key Technology R&D Programs from the Ministry of Science and Technology of ChinaProject(B14034)supported by the Program of Introducing Talents of Discipline to Universities,China
文摘The extraction and stripping characteristics of Versatic 10 and its mixtures with Cyanex 301 were investigated for the recovery of cobalt and nickel from sulfate solutions containing magnesium and calcium. The optimum extraction factors of Versatic 10 were initial pH of 2.5, O/A ratio of 1/3, and saponification rate of 60%. The loaded Versatic 10 was stripped by using 2 mol/L H2SO4 at O/A ratio of 1/1. The optimum volume ratio of Versatic 10 to Cyanex301 was 7/3 in the mixtures, which could effectively reduce the equilibrium pH to 3.50. And the loaded mixtures were stripped by using 2 mol/L H2SO4at O/A ratio of 1/2. The reaction principle of Versatic10 and metal ions is an ion exchange reaction. However, in the extraction reaction of and metal ions, besides the ion exchange reaction, the strong coordination effect between Cyanex 301 and metal ions also exists, which is much weakened in the extraction reaction of the mixtures and metal ions.
文摘The solvent extraction of La 3+ from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of equilibrium of aqueous acidity on extraction of La 3+ using Cyanex 302 in different diluents was discussed. The effects of extractant concentration and chloride ion on the extraction reaction were also studied. Stoichiometry of the extraction reactions and the nature of metal complexes formed were determined using slope analysis technique and IR measurement.
文摘Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the contribution of diffusion to the measured rate of reaction was minimized. Cerium extraction rate was measured at different chemical composition by varying the concentrations of hydrogen ion, sulphate and Cyanex923. A cerium Cyanex923(B) extractive is formed at the interface. The data were analyszed in terms of pseudo first order constants and a reaction mechanism was developed.
基金Project supported by the National Key Research and Development Project of China(2022YFC2905201)the Science and Technology Service Network Initiative Program of the Chinese Academy of Sciences(KFJ-STSQYZD-2021-18-001)+3 种基金the Research Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055C002)Jiangxi"Double Thous and Plan"(jxsq.2020101005)Jiangxi Province Natural Science Foundation(20212BAB213033)Ganzhou Science and Technology Program(2022CXRC9671)。
文摘In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.
文摘The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were removed by precipitation method and solvent extraction was used to extract/separate Zn, Mn, Co and Ni. The nickel laterite leach liquor which was obtained from bioleaching of chromite overburden samples contained 3.72 g/L Fe, 2.08 g/L Al, 0.44 g/L Ni, 0.02 g/L Co, 0.13 g/L Mn, 0.14 g/L Zn and 0.22 g/L Cr. From this leach liquor, 100% Fe, 96.98% Al and 70.42% Cr were removed by precipitation with Ca CO_3 at pH 4.4 followed by precipitation of remaining Al and Cr with 50% ammonia at p H 5.4. After precipitation, the extraction of Zn from the Fe, Al and Cr free leach liquor was carried out with 0.1 mol/L TOPS-99 followed by Mn extraction with 0.04 mol/L Na TOPS-99. The yields of Zn and Mn were 97.77% and 95.63%, respectively. After Mn extraction, cobalt was removed from the leach liquor using 0.0125 mol/L Na Cyanex 272 and finally nickel extraction was carried out using 0.12 mol/L Na TOPS-99 with 99.84% yield. The stripping of loaded organic（LO） phases were achieved with dilute H_2SO_4.
