共查询到17条相似文献,搜索用时 62 毫秒
1.
1 IntroductionAsakindofseparationtechnique ,solventextractioniswidelyapplied .More over ,insynergisticsystemtheextracingpowerofthemixtureexceedsobviouslythesumeffectoftheextractingpowersofitscomponents .Theenhancedextractionhasbeenobservedinmanymetalextra… 相似文献
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Extraction Behavior of Rare Earths with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 Using Solid-liquid Extraction Technique 总被引:1,自引:0,他引:1
The extraction behavior of rare earths was studied by using paraffin with ceresin as a diluent containing1-phenyl-3-methyl-4-benzoyl-pyrazolone-5.In solid phase,the composition of complexes is REP_3.The equilib-rium extraction constants and pH_(1/2) values of solid-liquid extraction are higher than those of normalliquid-liquid extraction.The extraction efficiency tends to maximum when the ratio of phases is 1:1.When theextraction temperature is higher than the melting point of paraffin and the extraction time is over 10 min,theextraction efficiency keeps constant.Moreover,the relationship among separation factor,equilibrium extrac-tion constant,pH_(1/2) value and atomic number was obtained.The mechanism of solid-liquid extraction isanalogous to that of liquid-liquid extraction. 相似文献
3.
A method is proposed for the extraction and separation of trivalent gallium, indium and thallium from their corre-sponding aqueous solutions at 65°C with 2, 6-bis-(l'-phenyl-3'-methyl-5'-oxopyrazole-4') pyridineacyl (H2PMBPPor H2A)using molten paraffin wax as a diluent. The values of pH 1/2 for extraction of gallium, indium and thallium are 2.62, 4.32 and4.93, respectively. Gallium can be extracted by H2PMBPP at a lower acid medium. The effect of solvent and the composi-tion of the extracted species are reported. And the thermodynamic data of the extraction are also obtained. 相似文献
4.
The oxidation resistance of Ti–50Al intermetallics is improved bypreoxidation for 1, 4, or 16 hours in high-pressure, pure oxygen(3.9 atm) at 900°C. Specimens preoxidized for 1 hr exhibit betteroxidation resistance than others. Prolonged preoxidation time candeteriorate the oxidation resistance and reduce the parabolic-lineartransition time during subsequent cyclic oxidation in 800°C air. Theoxide-mound occurrence is an important factor for evaluating theeffectiveness of the preoxidation treatment in oxygen. The formationmechanism of Z-phase (Ti5Al3O2) in the Al-depleted layer beneath theflat oxide scale and that beneath the oxide mound are also proposed inthis study. 相似文献
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Synthesis and electrochemical properties of nanocrystalline Li[Li1/3Ti5/3O4] by complex sol-gel method 总被引:1,自引:0,他引:1
1 INTRODUCTIONSpinelLi[Li1/3Ti5/3O4 ]isaveryattractiveelec trodematerialforitsexcellentcyclelifeandpromisingchargingrateinrechargeableenergystoragecells .Duringelectrochemicalreactionsconsistingofelectronandlithiumioninsertionintoorextractionfromit,itslatticeconstantchangesveryslightly ,soitiscon sidereda“zero strain”insertioncompound[13] .Thismaterialwassuccessfullyusedasanodecoupledwithhighpotentialcathodematerials (LiMn2 O4 ,LiCoO2oractivecarbonfiber)toprovideacellorhybridsu perc… 相似文献
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1 IntroductionBecauseoftheimportanceofrareearths,asimple ,rapidandhighlysensi tivemethodfortheirdeterminationswasre quired .Theelectrochemicalstudiesformeasurementoftraceytterbiumhavebeenreported[1~ 6].Inthepreviouspaper[7]wehavereportedtheabsorptivewaveabout… 相似文献
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The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
8.
GAO Jinzhang DENG Qiliang PENG Bo and GUO XiaojunChemistry & Chemical Engineering College Northwest Normal University Lanzhou China 《稀有金属(英文版)》2003,(2)
A method is proposed for the extraction and separation of trivalent gallium, indium and thallium from their corresponding aqueous solutions at 65 ! with 2, 6-bis-(1'-phenyl-3'-methyl-5'-oxopyrazole-4') pyridineacyl (H2PMBPPor H2A) using molten paraffin wax as a diluent. The values of pH1/2for extraction of gallium, indium and thallium are 2.62,4.32 and 4.93, respectively. Gallium can be extracted by H2PMBPP at a lower acid medium. The effect of solvent and the composition of the extracted species are reported. And the thermodynamic data of the extraction are also obtained. 相似文献
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This paper describes the quantitative determination of rare-earth elements cerium, dysprosium andnon-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxidereference material by isotope dilution spark source mass spectrometry (ID-SSMS). The sensitivity of the meth-od is l0~(-5)~10~(-7%). The precision is better than 6%. The accuracy is better than 5%. The interferences of thespectra and the optimum amount of the spike added to the sample are discussed. The choice of the conductingmaterial for the sample electrodes is studied. 相似文献
10.
In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef-fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-RareEarth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium andyttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationshipsfor the induced effects between yttrium and neodymium as well as between gadolinium and neodymium havebeen determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured byalizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration mayoccur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometricdetermination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi-tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention mustbe paid to this area in the photometric determination of certain metals. 相似文献
11.
TOPO has been applied to tiranium separation[l]. Some fundamental investigations for uranium extraction have also been well done [2, 3].However little data have been reported for theextraction of lanthanides with TOPO. Ceccoine[4] reported the lanthanides extraction withTOPO in chloroform at 25 C. Other authors stUdied the synergistic extraction of lanthanides byusing TOPO as a neutral adducts [5].For the past decade, the method using themolten paraffin wax as a diluent for the lanthan… 相似文献
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13.
1 IntroductionAluminium lithiumalloysarebeingdevelopedasadvancedstructuralmaterialsforaerospacetechnologyowingtotheirlowdensity ,highstrengthandspecificrigiditycomparedwithconventionalaluminumal loys ,buttherestillexistsomedisadvan tages ,suchaslowplastic… 相似文献
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This study has focused on the morphology and distribution of inclusions and precipitates modified by rare earth (RE) elements, which has a decisive influence on microstructure, corrosion properties and impact behaviors in Q355 low alloy steel. Characterized by the method of electrolytic extraction and ASPEX-scanning electron microscopy (ASPEX-SEM), small-sized spherical RE inclusions have been modified to replace elongated MnS and large-sized Al2O3. Q355RE steel after RE alloying has lower corrosion rate and higher value of α/γ, due to the formation of stable and dense rust layers. Q355RE steel also exhibits better resistance to fracture at low temperature, owing to the presence of RE modification to inclusions and its effects on reducing crack initiation and propagation. Nano-scale RE precipitates containing sulfur and phosphorus is observed along grain boundaries by transmission electron microscopy (TEM). The purification of grain boundaries by RE is beneficial to the improvement of corrosion and impact properties. 相似文献
15.
Y2O3-CeO2稀土氧化物对激光熔覆生物陶瓷涂层中HA的影响 总被引:2,自引:2,他引:0
为降低激光熔覆过程中基材与生物陶瓷涂层之间的热应力,提高涂层与基材的结合强度,选用宽带激光熔覆方法,在TC4合金表面制备一层含HA和β-TCP的梯度活性生物陶瓷涂层。通过金相显微镜、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对在体外模拟体液中浸泡14d后的涂层进行形貌和相组成的研究。结果表明:当Y2O3质量分数为0.6%,CeO2质量分数分别为0%,0.2%,0.4%和0.6%时,生物陶瓷涂层在SBF中浸泡14d后,基材与涂层之间呈良好的冶金结合;涂层表面都有白色球状颗粒生成;且涂层当中HA的生成量各不相同。当CeO2质量分数为0%时几乎不生成HA,为0.2%时HA的生成量最大,而后随着CeO2的含量增加HA生成量减少。说明当Y2O3质量分数为0.6%,CeO2的含量为0.2%时,生物陶瓷涂层具有较好的生物活性。 相似文献
16.
冶炼和铸造了不同稀土镁含量的W6Mo5Cr4V2高速钢,并对铸态钢材进行退火及锻打,检测了不同状态下的显微组织,并用Gleeble模拟了钢材的高温性能。结果表明:稀土镁能使铸态W6Mo5Cr4V2钢中网状碳化物组织断裂;随着钢中稀土镁含量的增加和锻打压下量的增大,碳化物粒化度提升;热模拟表明W6Mo5Cr4V2钢的第I高温脆性区为熔点到1180℃,第Ⅱ高温脆性区为950~800℃;综合高温塑性区极窄,为1170~1190℃。 相似文献
17.
Hrudananda Jena K. V. Govindan Kutty T. R. N. Kutty 《Journal of Alloys and Compounds》2003,350(1-2):102-112
Structural transformation and ionic transport properties are investigated on wet-chemically synthesized La1−xMnO3 (x=0.0–0.18) compositions. Powders annealed in oxygen/air at 1000–1080 K exhibit cubic symmetry and transform to rhombohedral on annealing at 1173–1573 K in air/oxygen. Annealing above 1773 K in air or in argon/helium at 1473 K stabilized distorted rhombohedral or orthorhombic symmetry. Structural transformations are confirmed from XRD and TEM studies. The total conductivity of sintered disks, measured by four-probe technique, ranges from 5 S cm−1 at 298 K to 105 S cm−1 at 1273 K. The ionic conductivity measured by blocking electrode technique ranges from 1.0×10−6 S cm−1 at 700 K to 2.0×10−3 S cm−1 at 1273 K. The ionic transference number of these compositions ranges from 3.0×10−5 to 5.0×10−5 at 1273 K. The activation energy deduced from experimental data for ionic conduction and ionic migration is 1.03–1.10 and 0.80–1.00 eV, respectively. The activation energy of formation, association and migration of vacancies ranges from 1.07 to 1.44 eV. 相似文献