On Mechanism of The Effect of Rare Earth on Wearability of Nickel Base Self-Fluxing Alloy Spray-Welding Layers

The mechansim of the effect of rare earth(RE)on wearability of spray-welding layers has been investi-gated by adding RE in ppm into Nickel base self-fluxing alloy powder.The test results show that the microalloy-ing effect of RE can refine the structure of spray-welding layers,and change the amount,size,shape and distri-bution of hard phase in spray-welding layers.The wearability of spray-welding layers is increased consequently.     

Monoalkyl Esters of Isoalkylphosphonic Acid as Extractants in Rare Earth Separation

Four monoalkyl esters of isoalkylphosphonic acids have been studied for the chromatographic separation ofrare earths (RE).The relationship between distribution ratios and acid concentration of the eluants forsamarium and ytterbium has been explored.The characteristics of these extractants loaded onto macroreticularpoly (methyl methacrylate) resin beads for the separation of lanthanum,cerium,praseodymium and neodymiumhave been compared.Among the extractants studied,mono(1-methylheptyl) ester of isooctylphosphonic acidwas found to be the best for RE separation.The acidity for separation is lower than any known P-containingextractants for the same purpose.For instance,with 1.73 mol·L~(-1) nitric acid as eluent,thulium,ytterbium andlutetium can be separated quantitatively.The extractant-loaded resins possess high column efficiency with goodkinetic characteristics.The extraction mechanism was also explored.     

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.     

Effect of RE on the Brittleness of Electrolytic Boronization Coating

The electrolytic coatings of boron and RE-boron on medium carbon steel are carried out in molten salt mix-tures respectively.The brittleness of both coatings has been measured by using sound-emission with the methodof three point bending.Results show that the brittleness of electrolytic boronization coating can be obviously de-creased by addition of RE elements.Meanwhile,the shape of crack and the solid solubility of RE in boride andα-Fe phase are determined,and the effect of RE on the lattice constant of Fe_2B is discussed.From these experi-ments,the authors explain the cause of the brittleness decreasing of electrolytic boronization coating.     

THE PRESENT SITUATION OF THE DEVELOPMENT OF RARE EARTHS IN CHINA

1.Rare Earth Resources in China1.1.Reserves and distributionChina is the country which is the richest in the world in rare earth(RE)resources of allavailable varieties of minerals and their deposits are located in vast areas in China.Reserveshave been estimated at a grand total of 36 million ton,which is 80% of the world(RE)de-posits.The majority of these deposits are concentratedly located in Baiyunebo mine of the     

Advances in Rare Earth Application to Semiconductor Materials and Devices

The development of rare earths (RE) applications to semiconductor materials and devices is reviewed. The recent advances in RE doped silicon light emitting diodes (LED) and display materials are described. The various technologies of incorporating RE into semiconductor materials and devices are presented. The RE high dielectric materials, RE silicides and the phase transition of RE materials are also discussed. Finally, the paper describes the prospects of the RE application to semiconductor industry .     

The Characteristics of Adsorption and Desorption of Rare Earth Elements by the Main Types of Soils of China

The adsorption-desorption behavior of the mixed rare earth elements(RE)on the main types ofsoils of China,kaolinite and synthetic oxides was studied.The isothermal adsorption of RE was fitted toLangmuir.Freundlich and Temkin equations.The main factors determining the RE adsorption capacity ofthe soils are the type of clay mineral and the content of amorphous iron oxide in the soils.The above two fac-tors and the pH of soil determine the RE adsorption ability of the soils.The soil and synthetic iron,manga-nese oxides strongly adsorb RE specifically.     

Synthesis and Properties of Rare Earth Complexes with 3-Ferrocenyl-5-Phenyl-Pyrazoline-1-Dithiocarbamate

Sodium 3-ferrocenyl-5-phenyl-pyrazoline-1-dithiocarbamate (FPPD) reacts with anhydrousrare earth chlorides in absolute ethanol to give 14 new complexes.The results of elemental analysis show thatthe compositions of the complexes are RE(FPPD)_3·nH_2O(RE=La,Pr～Lu and Y;n=3).The ligand andits complexes have been characterized by infrared spectroscopy,UV-visible absorptionspectroscopy,~1H-NMR spectra,thermal analysis and molar conductivity measurement.     

Research on Thermal Wear of Cast Hot Forging Die Steel Modified by Rare Earths

Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.     

Study on Rare Earth Electrolyte of Ce0.9 RE0.102－δ （RE=Pr, Nd, Sm,Gd, Dy）

The solid solutions Ce0.9RE0.102-δ(RE=Pr,Nd,Sm,Gd,Dy) were prepared by sol-gel method, The XRD measurement shows that the solid solution is crystallized in cubic fluorite-type structure and the cell volume of Ce0.9RE0.1O2-δ decreases with the increase of atomic number of RE. The ionic conduction for Ce0.9RE0.1O2-δ was measured by impedance spectroscopy and Ce0.9Pr0.1O2-δ has better conductivity. The linear thermal expansion of Ce0.9RE0.1O2-δ decreases with the increase of atomic number of RE.     

Development Status and Research Progress in Rare Earth Hydrometallurgy in China

Characteristic and hydrometallurgy processes for Baotou mixed-type rare earth concentrate, bastnasite, and ionic adsorption deposit in China were reviewed. The R ＆ D circumstance and new progresses in extraction and separation of RE element in China were introduced. Moreover, the development trend of RE hydrometallurgy was predicted. The direction and emphasised fields of research and development are also brought forward as： to R ＆ D high efficient green progresses in hydrometallurgy and separation of RE ore, resolve the waste pollution problem of water, slagand gas, reduce the chemical material consumption and improve comprehensive efficiency of resources; to R ＆ D preparation technology for RE compounds with ultra high-purity and special physical property for extending application fields of RE.     

从出口税收政策的变化探讨我国稀土资源可持续发展的策略

出口税是近年来各国贸易政策中最常用的一种出口限制措施,各国在贸易管理政策中常常运用出口税来实现一定的贸易目标.稀土是一种不可再生的宝贵战略资源,我国不论是在稀土的储量、还是在产销量上都是世界大国.近年来随着稀土资源的无节制开采、无序竞争及低价出口,造成了我国稀土资源的紧缺.我国政府对稀土出口进行战略性调整,从鼓励稀土出口到逐步下调税率到取消出口退税,目前正不断加征稀土出口关税.文中从我国稀土产品出口税收政策的变化,深入细致地分析了我国稀土产品出口价格、出口数量等方面因此而产生的变化,指出目前我国稀土资源可持续发展的问题所在,并提出相应的对策建议.      

稀土功能材料现状与分析

对我国稀土材料产品进行了概述，并与世界水平进行了对比，叙述了稀土永磁材料，汽车尾气稀土净化催化剂、稀土荧光粉，稀土钨电极的现状及国内外发展状况和存在问题，对发展稀土新材料进行了分析。     

Application and Demonstration of a Series of Rare Earth Drought Resistant Materials in Western Area of China

The application and effects for a series of rare earth (RE) drought resistant materials used in arid, salina,hungriness, wind defending and sand fixing matter, withdraw farming and return to grass and forest in western of China were reported.The important discussion was technological innovation within two years: such as seed clothing agent,RE liquid field film, RE grass and woods transplant living agent, and RE complex pesticide development and application.     

Strategy of Development of Rare Earth Industry in China

This work introduced the current situation of the development of domestic and foreign rare earths (RE) industry, discussed the strategic position of RE industry in China, analyzed the problems existing in the course of RE industry development, made strategic thought about the transference from resource advantage to economic advantage, and put forward strategic suggestions about the development of RE industry in our country.     

稀土分析检测方法标准述评

从稀土矿、稀土精矿、稀土金属及其氧化物、稀土深加工产品等方面概述我国稀土分析国家标准体系.其中稀土配分、三氧化二铝、稀土总量、水分、灼减量等参数的检测,是稀土交易和萃取分离工艺过程中重要的技术指标;而钕铁硼、灯用稀土三基色荧光粉、稀土硅铁合金等分析标准,对于稀土磁性材料、稀土发光材料、稀土合金等稀土深加工产品的生产都有重要的指导意义;稀土产品及分析方法的建立,完善了稀土国家标准体系,满足了稀土生产和贸易的需要,促进了稀土行业持续健康发展.      

稀土镁合金的发展、应用及开发

叙述了国内外稀土镁合金的发展状况，对稀土镁合金的性能及应用作了较为详细的阐述。在对稀土镁中间合金的制备工艺进行比较的基础上，针对性地介绍了目前采用的新工艺。同时，就我国稀土镁合金的发展提出了具体看法。     

Status of Rare Earths for Agriculture in China

Rare Earths (RE) for agriculture is a very typical application and has already brought good economic benefit to Chinese agriculture and farmers.In this paper, the origin, development, status and the future of RE for agriculture in China were discussed.Firstly, through the researches of RE in the fields of physiological activity, physiological and biochemical mechanism, sanitation toxicology and environment security in 1980's, RE has been extended more widely in agriculture, such as crops, vegetables, forest, wood grass and stock breeding, such as cattle, fish and chicken.Secondly, with using of new techniques that were developed in the "State Ninth Five-Year Plan", the utilization area of RE was expanded to broad agricultural space, such as sunlight converting plastic film, RE fertilizer, RE drought resistant and RE water saving materials and new RE top dressing fertilizer.Thirdly, with the development of the nanometer materials, the techniques and process of nanometer RE materials were focused.Around these kinds of materials, the new seed cover matters, new seed mixed matter and new nanometer fertilizer will appear in the near future, and will produce many updated techniques and improve a new round RE application in agriculture.     

我国熔盐电解法制备稀土金属及其合金工艺技术进展

介绍了我国熔盐电解法制备稀土金属及其合金工艺技术的发展历程、现状与发展趋势.经过近60年的发展,氟化物体系氧化物电解工艺已经成为当今生产稀土金属及其合金的最重要的和最主要的生产工艺,我国已经基本形成了完整的、具有完全知识产权的熔盐电解工业技术体系和创新体系;分析总结了当前稀土熔盐电解工艺技术的特点及存在的问题,指出造成目前稀土电解高能耗、高排放的最根本的原因是电解槽型即平行上插阴阳极结构决定的,提出开发节能、环保、大型、高效的稀土电解新技术及设备是稀土电解发展的方向;认为液态下阴极电解制备稀土金属及合金新技术由于阴阳极距可减小至6～7cm,阴、阳极电流密度较小,电解槽压可降低至5～6V,可降低能耗、减少含氟气体排放,具有突出的节能减排潜力,是下一代工业化生产稀土金属及合金的新型电解槽,也是今后稀土电解新技术研究领域的重点发展方向;此外,熔盐电解法制备重稀土中间合金由于具备突出的节能减排效果和成本优势,也是当前的重要开发领域.     

Research and Development of Rare Earth Advanced Materials in China

ＲｅｓｅａｒｃｈａｎｄＤｅｖｅｌｏｐｍｅｎｔｏｆＲａｒｅＥａｒｔｈＡｄｖａｎｃｅｄＭａｔｅｒｉａｌｓｉｎＣｈｉｎａＷａｎｇＤｉａｎｚｕｏ（王淀佐），ＷａｎＱｕｎ（万群），ＹａｎｇＹｕｃｈｕｎ（杨遇春）（ＧｅｎｅｒａｌＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅ...