Microstructures and Magnetic Properties of As-Cast RE（Dy）-Fe-C（B） Alloys

RE2 Fe14 Ccompoundswithtetragonalcrystalstructureareformedforalmostallrareearthelements(RE ) .Theirmagneticpropertiesareveryclosetothoseofthecorrespondingborides[1～ 5] .Formostofthelightrare earthelements ,La ,Ce ,ProrNd ,itisdifficulttoproducetheRE2 Fe14 Cphase[5～ 7] .Thereasonisthefairlylowtemperature (Tt)ofthesolidstatephasetransformationinthesecompounds .TheydecomposeeasilyintoRE2 Fe17Cxcompoundsathighertemperatures[8,9] .Highcoercivitiescanbeobtainedthroughacontrolledtransformat…     

Separation chemistry and clean technique of cerium（IV）： A review

The separation method of changeable valence RE element of cerium(Ce) was reviewed in this paper. Solvent extraction is the most effective and efficient method to separate Ce(IV) from RE(Ⅲ), usually accompanied with fluorine(F) and phosphor(P) from bastnaesite and monazite etc. By roast or wet-air oxidation, Ce(Ⅲ) of bastnaesite and monazite was oxidized into Ce(IV), and Cyanex923 and [A336][P507] have been investigated to co-extract and recover Ce(IV), F and P from H2SO4 leaching liquor, leading to favorable conditions for the subsequent separation of Th(IV) and RE(Ⅲ). The interaction of Ce(IV) and F and/or P enhances the roasting, leaching and extraction of Ce(IV) due to increasing of the stability of Ce(IV), and the formation of CeF3 and CePO4 after reductive stripping will benefit the utilization of F and P. For dealing with RE ores of high-content Ce, the clean process of oxidation roasting and Ce(IV)-F separation for Sichuan bastnaesite highlights the advantages of Ce(IV) based clean technique, which firstly demonstrates the comprehensive utilization of Ce(IV), Th(IV), F and RE(Ⅲ) and prevention of environmental pollution from fountainhead. A preliminary flowsheet of two-step oxidation and extraction of Ce(IV) for Bayan Obo mixed ores was further proposed to process the oxidation and extraction of Ce(IV) in presence of both F and P, indicating the possibility of similar effects with clean process of Sichuan bastnaesite. Ce(IV) separation chemistry and clean technique will open up new realms for light RE resources utilization, meeting "Emission Standards of Pollutants from Rare Earths Industry" promulgated by China's Ministry of Environment Protection(MOP) in 2011.     

Studies on the Complexes of Rare Earth with Organic Ligands Containing Sulphur Atoms Ⅴ.Preparation and Properties of Heavy Rare Earth Piperidinocarbodithioate Complexes

The rare earth piperidinocarbodithioate complexes with the general formulas(PipH_2)[RE(PipCS_2)_4]·xH_2O(Pip=piperidino,RE=Y,Tb～Er,x=2.6)and RE(PipCS_2)Cl_2·2H_2O(RE=Tm,Yb)have been pre-pared by using anhydrous rare earth chloride and piperidinium piperidinocarbodithioate as reactants under drynitrogen atmosphere.They have been characterized by elemental analyses,IR spectra,conductivity measurementand TG-DTA technique.The results show that in the complexes the ligands coordinate to RE ion through twosulphur atoms.     

Adsorption of Ce（ Ⅳ ） Anionic Nitrato Complexes onto Anion Exchangers and Its Application for Ce （Ⅳ） Separation from Rare Earths （ Ⅲ ）

Ceriumis one of the cheapest[1]and most abun-dant rare earths (RE) .However ,high purityis usual-ly required for its utilization in industry , where it isusedfor sulfur control insteels ,pyrophoric alloys ,ce-ramic ,catalyst support ,polishing powders ,etc .In its minerals ,as well as in the spent nuclearfuel ,ceriumis accompanied by other RE.They basi-cally exist in solution as stable RE(Ⅲ) species ,which makes their mutual separation rather difficult .In contrast to other RE, Ce(Ⅲ) can…     

Alleviation Effect of Lanthanum on Cadmium Stress in Seedling Hydroponic Culture of Kidney Bean and Corn

Since1970s,rare earths(RE)have been exten-sively used as micro-fertilizers for crops in China.Ithas already been proved that REcani mprove the pro-duction and quality of crops.However,there havebeen a fewinvestigations about using RE as regulatorin pollution ecology.For example,An et al[1]studiedthe effects of O3on wheat growth and the protectiveeffect of RE.Yan and Zhou et al[2,3]discussed theprotective effect of RE on plants under acid rainstress.Jia et al[4]and Hu et al[5]reported th…     

Ternary Complexes of Rare Earth Nitrate with B-15-C-5 and 4-Picoline N-Oxide

A series of ternary complexes of rare earth(Ⅲ)nitrate with benzo-15-crown-5 and 4-picoline N-oxidehave been prepared.They have the general formula of RE(NO_3)_3·2(4-picNO)·3H_2O·(1/2)(B-15-C-5)(RE=La～Tm).Their physico-chemical properties have also been studied with conductance,thermal analysisand IR absorption spectroscopy.     

Toxicity of Lanthanum to Pathogenic Fungi and Its Morphological Characteristics

Rare earth (RE) ,a kind of natural mineral hasbeen used as a beneficial element to crops for quite alongti me . Withthe solution of a series of keytechnolo-gies such as extraction,separation of radioactive ingre-dients ,sanitary toxicology,and environmental safety,China became the first countryto apply commercial REproducts asfertilizer or growthsti mulatorin agriculture ,which produced considerable economic and social ben-efits[1 ,2].RE has been found to have some controllingeffects on many…     

Investigation of Tribological Behavior of Lanthanum-Based Thin Films Deposited on Sulfonated Self-Assembled Monolayer

3-mercaptopropyl trimethoxysilane （MPTS） was prepared on glass substrate so as to form a two-dimensional self-assembled monolayer （SAM）, and the terminal - SH group in the film was in situ oxidized to - SO3H group to confer good chemisorption ability to the film. Thus, lanthanum-based thin films were deposited on oxidized MPTS-SAM, making use of the chemisorption ability of -SOaH group. Atomic force microscopy （AFM） and X-ray photoelectron spectrometry （XPS） and contact angle measurements were used to characterize the thin films. The tribological properties of the as-prepared thin films sliding against a steel ball were evaluated on a friction and wear tester. Tribological experiment shows that the friction coefficient of glass substrate decreases from 0.8 to 0.08 after the rare earth （RE） self-assembled films （SAMs） are formed on its surface. And the RE self-assembled films have longer wear life （500 sliding passes）. It is demonstrated that RE self-assembled film exhibits good wear-resistant property. The marked decrease in friction and the longer wear life of RE films are attributed to the excellent adhesion of the film to the substrate and to the special characteristics of the RE elements. The frictional behaviors of RE thin-films-coated silicon surface were sensitive to the applied load and the sliding velocity of the steel ball.     

Synthesis and fluorescence properties of Eu（Ⅲ）, Tb（Ⅲ） and Sm（Ⅲ） with β-diketone and 2,2＇- bipyridine

Three new rare earth ternary complexes,RE(PPP)3bpy(RE=Sm 3+ ,Eu 3+ ,Tb 3+ ),were synthesized by the reaction of 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP)and 2,2′-bipyridine(bpy)with rare earth chloride RECl3,respectively,in alcohol solution. The compositions were characterized by means of infrared(IR)spectra,chemical analysis,elemental analysis,and thermodynamic analysis.Luminescent properties of the three complexes were studied.At room temperature,under UV light excitation,the Sm 3+ ,Eu 3+ and Tb 3+ complexes exhibited characteristic emission of the central ions.The fluorescence spectra showed that the fluorescence emission intensity of Eu 3+ complex was the strongest.The narrow strongest emission band of Eu 3+ complex was considered to be a valuable material with bright red fluorescence.     

Preparation and Mechanical Properties of Misch Metal Based Bulk Metallic Glasses

Bulk metallic glasses(BMGs)have been devel-oped in many alloy systems during past decade.Among these systems,rare-earth(RE)metal-basedBMGs are ones of those found earliest and with betterglass forming ability(GFA).For example,La-basedBMGs were the first a…     

Degradation of Extraction from Seaweed and Its Complex with Rare Earths for Organophosphorous Pesticides

On the basis of several experiments carried out in China, it was proved that both seaweed liquid fertilizer and rare earth （RE） could promote the growth of crops and increase their yield. The effects of extraction from seaweed and its complex with RE on the degradation of organophosphorous pesticides and the yield of vegetables were investigated. The resuits showed that the extract and its complex with RE could degrade organophosphorous pesticides in neutral solvent. The residues of the pesticides treated by the extract decreased by 96.88 %, 52.30%, 49.52%, and 22.88 %, respectively, for chlorpyrifos, dichlorvos, omethoate, and dimethoate, and those by the complex decreased by 95.99%, 54.23%, 48.79%, and 25.66%, respectively, when compared with the control. The residues of chlorpyrifos and dimethoate in spinach sprayed with the complex were decreased by 90.64% and 76.56%, respectively, compared with those in spinach from control plots when the interval between spraying and sampling was 8 d. The fresh weight of brassica chinensis and cabbage increased by 28.62% and 18.72%, and their dry weight increased by 44.49% and 14.74%, respectively, compared with those of the controls. The chlorpyrifos and dimethoate residues in brasscia chinese were decreased by 36.36% and 50.00%, respectively, and their rate of decrease in cabbage was 40.00% and 75.00%, respectively, on 5th day after spraying with the complex, when compared with those in the vegetable from control. These results suggest that this complex can increase the agricultural productivity and reduce the use of pesticide residues in the production of vegetables.     

Effect of Rare Earths on Composition and Activities of Rare Earth Elements Binding Glycoprotein in Tea

Ｔｅａｐｏｌｙｓａｃｃｈｒｉｄｅｃｏｍｐｌｅｘ ,ｏｎｅｏｆｔｈｅｂａｓｉｃｍａｃｒｏｍｏｌｅｃｕｌｅｓｉｎｔｅａ ,ｈａｓｍａｎｙｐｈａｒ ｍａｃｅｕｔｉｃａｌｅｆｆｅｃｔｓａｎｄｉｓｅａｓｙｔｏｄｉｓｓｏｌｖｅｉｎｔｅａｉｎｆｕｓｉｏｎ[1] .Ｚｈｏｎｇｅｔａｌ .[2 ] ｄｉｓｃｏｖｅｒｅｄｔｈａｔｔｈｅｒｅｉｓａＲＥｂｉｎｄｉｎｇｐｏｌｙｓａｃｃｈａｒｉｄｅｉｎｌｅａｖｅｓｏｆｔｅａｐｌａｎｔ (ＣａｍｅｌｌｉａＳｉｎｅｎｓｉｓＬＯ .Ｋｕｎｔｚｅ) .Ｉｎｔｈｉｓｐａｐｅｒ ,ｔｈｅｓｔｕｄｙｏｎｔｈｅｃｏ…     

Wear-Resistance Performance of ZA-27 Alloys Reinforced by Rare Earth Compounds

In order to further improve wear-resistanceof the ZA-27 alloy and widen its applieationfields, St phase is added in the alloy[' '21. ButSt phase seriously cuts apart the alloy matrix.It not only decreases high toughness of the alloy, but also is harmful to its wear-resistance.On the basis of the researches in foregoing periodical on Zn-based alloy reinforced by Stphase and the inLfluence of RE on the high temperature mechanical properties of the ZA-27 alloy["'j, this paper deals with the e…     

Effect of Ce-Mg-Si and Y-Mg-Si nodulizers on the microstructures and mechanical properties of heavy section ductile iron

Effect of Ce-Mg-Si （light RE） and Y-Mg-Si （heavy RE） nodulizers on the microstructures and mechanical properties of heavy section ductile iron was investigated to develop the material of spent-nuclear-fuel containers. Two as-casts were treated by the same quality percentage of light RE and heavy RE, respectively. Four positions were chosen to stand for different solidification cool-ing rates of specimens. The tensile strength, elongation and impact toughness of specimens treated by heavy RE were all higher than those of the specimens treated by light RE. With the decrease of cooling rate, the mechanical properties of two specimens decreased, and the fracture morphology changed from ductile fracture to brittle fracture. The improving effect of mechanical properties between heavy RE and light RE was obvious due to the better anti-degradation property of heavy RE. While the solidification process lasted for more than 250 min, the improving effect was not obvious due to serious spheroidalization decaying.     

Behaviors of Rare Earths during Fluid-Rock Interaction and Its Significance of Geochemistry

Ｒａｒｅｅａｒｔｈｓ (ＲＥ)ａｒｅｐｏｗｅｒｆｕｌｔｒａｃｅｒｓｉｎｔｈｅｓｔｕｄｙｏｆｅｖｏｌｕｔｉｏｎｏｆｇｅｏｃｈｅｍｉｃａｌｓｙｓｔｅｍｓ .Ｔｈｅｙｈａｖｅｂｅｅｎｕｓｅｄｏｖｅｒｔｈｅｐａｓｔ 3 0ｙｅａｒｓａｓａｔｏｏｌｆｏｒｓｏｌｖｉｎｇｖａｒｉｏｕｓｇｅｏｌｏｇｉｃａｌｐｒｏｂｌｅｍｓ .ＴｈｅａｐｐｌｉｃａｔｉｏｎｏｆＲＥａｂｕｎｄａｎｃｅｓｔｏｐｅｔｒｏｇｅ ｎｅｔｉｃｐｒｏｂｌｅｍｓｈａｓｃｅｎｔｅｒｅｄｓｏｆａｒｏｎｔｈｅｅｖｏ ｌｕｔｉｏｎｏｆｉｇｎｅｏｕｓｒｏｃｋｓ ,ｗｈｅ…     

Synthesis, Characterization and Vulcanizing Properties of Rare Earth Complexes with 2-Mercaptobenthiazole

2 ｍｅｒｃａｐｔｏｂｅｎｚｏｔｈｉａｚｏｌｅｗａｓｆｉｒｓｔｒｅｐｏｒｔｅｄｂｙＨｏｆｍａｎｎ[1 ] ｉｎ 1 887.Ｉｔｈａｓｂｅｅｎｕｓｅｄａｓａｎａｃｃｅｌｅｒａｔｏｒｉｎｔｈｅｖｕｌｃａｎｉｚａｔｉｏｎｏｆｒｕｂｂｅｒｆｏｒｍａｎｙｙｅａｒｓ .Ｔｏｄａｙｉｔｉｓｓｔｉｌｌｂｅｉｎｇｕｓｅｄａｓａｍａｉｎａｃｉｄｉｃａｃｃｅｌｅｒａｔｏｒｉｎｒｕｂｂｅｒｉｎｄｕｓｔｒｙ .Ｂｕｔｉｔｈａｓｄｉｓａｄｖａｎｔａｇｅｓｏｆｖｕｌｃａｎｉｚａｔｉｏｎｒｅｖｅｒｓｉｏｎａｎｄｅａｓｙｓｃｏｒｃｈ[2 ] ｗｈｅ…     

MATLAB simulation of preparation of Sm-loaded extractant directly from HEH（EHP）

Computer simulation of the preparation process loading rare earth(RE)directly from acidic extractant and RE chloride was established using MATLAB software.The mechanism of the extraction reaction was assumed,and then an experiment was conducted to confirm the mechanism and the apparent equilibrium constant of the reaction was determined as well.Owing to the involvement of H+ ion in the reaction between acidic extractant and RE chloride,the computer simulation of the process was more complicated than that of the extraction only between different rare earths.In the present work,MATLAB software was therefore introduced to handle the resolution of the complicated processing equation,and the simulation was performed by varying some key parameters including feed composition and phase ratio,etc.Consequently this work presented a simple method to simulate the H+ ion involved countercurrent extraction process of rare earths and also provided the practical references for the relative process designing.     

Modification Behavior of Trace Rare Earth on Impurity Phases in Commercial Purity Aluminum

Modifying effect and mechanism of trace rare earth on Fe(Si)-rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce-rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe-rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (A1FeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0.07% (mass fraction).     

Effects of Light and Heavy Rare Earths on Anti-Degradation of Nodular Cast Iron

The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%（mass fraction）, the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% （mass fraction）. Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.