Synthesis and Thermal Decomposition Mechanism of Rare Earth Benzoates

Rareearthbenzoatesareakind0fstablecompounds.Theco0rdinationcomP0undsf0rmedbyrareearthandcarboxylicacidshaveunusualstructuresandinterestinglundnesceniProperties.Bymeansoff0rmingc0njugaedcomplexes,rareearthmetalsandcarb0xylicacidscanf0rmnetorlayerp0lymerandchangetheirlundnescentprop-erties.S0merareearthcomplexeshavebeenap-Pliedinagricultureaslight-transfeedngmaeri-al8-Althoughthermaldecompositi0nmechanismofrareearthbenz0ateshasbeenreported,itdealswith0nlys0lidphaseproducts["'1,litdeab0utgasPha…     

Preparation，Structural Characterization and Thermal Decomposition Mechanism of Rare Earth Salts of 3－Nitro－1，2，4－Triazol－5－One

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Thermal Stability of Rare Earth-Rich Phase in High Temperature Titanium Alloy

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稀土在钢中的应用

本文阐述稀土在钢中的作用机理和加入方法,分析了稀土应用的前景。对钢液进行稀土处理是我国发展钢产业的重要技术手段之一。     

稀土电解槽内电解质导热系数的计算

根据混合熔盐导热系数计算原则,通过计算稀土电解槽内电解质单组分熔盐导热系数,从而预测稀土电解槽内三元系电解质熔盐导热系数,为稀土电解槽内温度场的研究提供了一个重要物性参数。     

稀土氧化物对高氯酸铵热分解的作用及机制

采用草酸沉淀法、碳酸氢铵沉淀法和乙二醇溶胶凝胶法制备了多种稀土氧化物,用差热分析技术比较了不同稀土氧化物对高氯酸铵热分解的催化作用。结果表明：所有稀土氧化物均能使高氯酸铵的第一放热峰滞后,而第二放热分解峰提前;随着稀土添加量的增加,两分解峰逐渐靠近,最终合并为一个分解放热峰,分解热也大大提高。不同稀土氧化物种类对高氯酸铵热分解的催化作用有一定的差异,轻稀土镨和钕的氧化物使分解峰表现为前弱后强的两个相连的峰,中稀土钐和钆的氧化物表现为单一的强峰,而重稀土铒和镱的氧化物表现为前强后弱的两个分立的放热峰。对于同一种稀土氧化物,制备方法的不同对催化高氯酸铵的热分解也有差异,这与产物的比表面积有关,随着产物比表面积的增加,催化效果越明显。用能带理论解释了氧化稀土对AP热分解过程的影响,把氧化稀土作为半导体来考虑,正是由于它们储存和释放电子的功能性质导致了AP第一分解峰的滞后和第二分解峰的提前。     

Effect of Rare Earth Elements on Thermal Fatigue of High Ni－Cr Alloy Cast Iron

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混合碳酸稀土热分解过程的研究

用 DTA热分析技术研究混合碳酸稀土焙烧过程中的脱水过程、分解过程 .用 Freeman-Carroll法、Piloyan法和 Kissinger法对其脱水及热分解的动力学参数进行计算 ,并对计算的结果进行比较和验证 ,得到了混合碳酸稀土脱水过程的反应活化能和反应级数分别为 80 6.9J/mol、0 .78,热分解过程的反应活化能和反应级数分别为 8.52 9k J/mol、 0 .95.用 XRD分析方法研究了不同焙烧温度对焙烧产物的影响 ,论证高温下焙烧可能产生 Ce0 .75Nd0 .2 5O1.875相     

包头稀土精矿硫酸低温焙烧分解工艺研究

采用浓硫酸低温焙烧的方法分解包头稀土精矿,考察了矿酸比、焙烧温度、焙烧时间等几个因素对矿分解率及对钍分布的影响。结果水浸渣的放射性总比放符合国家低放渣排放标准,稀土和钍的浸出率均达到95%以上。     

Study on the Formation of Crystalline Rare Earth Carbonates from Rare Earth Ore Leaching Liquors

The crystalline precipitate of rare earth carbonates has been produced by the ammonium bicar-bonate precipitation method in the recovery of RE from the ammonium sulfate leaching liquor of the weath-ered leach-deposited rare earth ore.Various influencing factors such as time,temperature and reagent con-centration have been studied.And chemical analysis,XRD,SEM,IR spectrography,TGA and DTA havebeen used to analyze and examine the crystalline RE carbonates.Good results were obtained.     

氟碳铈与独居石混合型稀土精矿热分解机理研究

用X射线衍射分析和TG－DTA热分析技术研究了氟碳铈矿、独居石及混合型稀土精矿在空气中的热分解过程。独居石在900℃以下无明显分解反应，当CaO存在时REPO4在620℃以上可分解成RE2O3。氟碳铈矿的热分解过程中有CaO时在725℃以上REOF完全分解为RE2O3，并发生CaF2。混合型稀土精矿中氟碳铈矿在473℃开始分解，在700℃以上时分解产物主要是REOF、RE2O3和Ca5F(PO4)3。     

Mechanism of Wool Whitening in the Rare Earth Assistant Dyeing Process

The keratins of wool underwent Photooxidation to form a weaker luminophor in visible blue region(λ_(max)=420nm),that reacts with cerium ion to produce an enhanced luminophor complex (λ_(max)=426 nm),itmakes wool white obviously.     

CaO-NaCl体系焙烧混合稀土精矿的研究

采用TG-DTA热分析技术研究CaO-NaCl体系焙烧混合稀土精矿的分解过程。结果表明:添加CaO-NaCl后,混合稀土精矿的分解过程分为两个阶段,第一阶段在405℃～498℃区间主要是氟碳铈矿的分解,第二阶段在670℃～730℃区间主要是CaO和矿物中的CaCO3分解独居石和稀土氟氧化物。并选择了焙烧温度、CaO加入量、NaCl加入量为影响因素,用二次正交回归实验设计方法研究了混合稀土精矿分解率随三因素而变化的规律,得出了相应的回归方程。通过分析讨论,得到了CaO-NaCl体系焙烧混合稀土精矿的合理工艺条件:温度780℃、CaO加入量15%(质量分数)、NaCl加入量10%(质量分数)。     

Morphology and Forming Mechanism of Rare Earth Inclusions During Solidification of Steel

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黑色风化物的物理化学性质及稀土配分研究

某稀土矿产生的黑色风化物，是一种稀土以胶态相赋存的新稀土资源。黑色风化物主要由锰、铁，稀土和铅组成，形成锰铁氧化物非晶质的高聚合度无机高分子。黑色风化物强烈地选择铈族轻稀土，与矿区产的矿石和氟碳铈矿稀土配分相近，但黑色风化物含中重稀土最高，矿石次之，氟碳铈矿最低。     

含肼稀土草酸盐热分解制备大比表面积稀土氧化物

利用肼 (或肼盐 )易分解同时释放大量的热和气体这一特点 ,将肼 (或肼盐 )添加到草酸稀土中去 ,热分解含肼稀土草酸盐可制得比表面积较常法制备的大得多的稀土氧化物。     

Syntheses and Infrared Spectra of Rare Earth Complexes with Diethyl Phosphate

The title complexes Ln(DEP),(Ln=La,Sm,Eu,Ho and Yb)were synthesized by reaction of triethylphosphate with trivalent rare earth chlorides.The mechanism of thermo-decomposition of the complexes hasbeen studied.According to their IR spectra,the residues of the thermo-decomposition of the complexes wereidentified as Ln(PO_3)_3.Their IR spectra were measured and principal IR bands were assigned.The experimentalresults of the IR spectra of the complexes show that the title complexes have the same coordination form and mo-lecular configuration as rare earth,e.g.Sm,complex with dimethyl phosphate(Sm(DMP)_3).Each of the rareearth ion links three rare earth ions nearby through double“O-P-O”bridges to form a special network ofrings-linking-rings,each of which consists of twenty-four atoms.The Ln-O bond is principally ionic.     

Preparing Process of Cerium Acetate and Rare Earth Acetate

Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.     

包头稀土精矿浓硫酸焙烧反应机理研究

采用新的低温焙烧分解工艺,浓硫酸不分解,放射性钍形成硫酸钍进入水浸液中,废渣成为低放渣。在确立较佳工艺条件后,用热重-差热法分析硫酸分解稀土精矿的反应动力学行为,推断其反应机理,计算反应活化能、反应级数、频率因子等。     

The Rare Earth Aluminium Alloys in China

The development and application of rare earth aluminium alloys began in the 1960s in China.The represen-tative work was the usage of rare earth metals in alumino-silicon alloys for piston.In the 1970s,its initial stage.rare earths were used in enhanced AIMgSi alloy transmission line and FeCr Al alloy electric heating wire.Duringits developing period(from 1980 to 1985),in the field of smelting,after the electrolytic preparation of RE-Almaster alloys at relatively low temperature,a new technique was invented that rare earth compounds were addedto commercial aluminium electrowinning cell to produce RE-Al alloys directly.It opened the way for the appli-cation of rare earths in industry on a large scale.In the field of application,it was found that the addition ofrare earths could improve the conductivity and processing property of aluminium alloys.The application of rareearths to aluminium conductors and products had made a breakthrough progress.Since 1986,its golden age,thestudy,production and application of aluminium alloys containing rare earths have been developing at an amazingspeed,running neck and neck with the application of RE in agriculture,textile dyeing,and cast iron.