大松装比氟化钕的研制

讨论了原料氟化钕的起始松装比、氢氟酸的加入量、二次煅烧工艺对提高氟化钕最终松装比的影响.通过最佳工艺条件,生产出了松装比大于2.5g/cm3的氟化钕产品,满足了生产高性能稀土磁性材料的要求.     

无水氟化钕的制取方法研究

本文对无水氟化钕的各种制取方法进行了分析,比较,认为氢氟酸沉淀法是最好的方法。给出了氢氟酸沉淀法的最佳工艺条件。此法可成功地制取无水氟化钕,氧含量可降至0.16。     

稀土动态

赣州有色冶金研究所针对氟化物体系熔盐电解氧化物制取金属钕工艺存在的问题。进行试验研究,在小型试验基础上。我所与寻乌稀土矿共同开展了“从离子交换解吸氟化钕溶液开始制取金属钕”的全流程扩大试验。试验结果表明,全流程可行;用氟化剂直接制备氟化钕的工艺简便,较好地解决了熔盐电解质制备氟化钕沉淀过滤洗涤的困难,可以大量生产。采用混合沉淀剂代替草酸,工艺合理、成本低。在电解金属钕工艺中有所创新,具有电弧升温熔化,阴极保护,小电流自热电解和金属取出等特点,有实用价值。     

氟化镨钕制备方法研究比较

文章用氢氟酸法、氟化氢铵法、氟化氢气体法三种方法制备氟化镨钕工艺进行了研究对比,分别对氟化镨钕在生产中的使用效果、成本、质量、环保等方面进行了讨论,给生产和使用厂家提供参考建议。     

HF气体制备氟化(镨)钕产业化研究

自行设计了工业化HF气体法氟化炉,并对用HF气体法生产氟化(镨)钕工艺进行了研究,研究结果表明,该炉型具有产量大、氟化效果好、成本低、质量好等特点,已实现工业化生产。     

金属钕工业生产中氧化钕利用率的探讨

在氟化体系氧化物电解金属钕的工业生产中,采用调整熔盐配比和适当提高氧化钕利用率的方法,可改善金属钕产品的质量.     

金属钕工业生产中氧化钕利用率的探讨

在氟化体系氧化物电解金属钕的工业生产中,采用调整熔盐酯比和适应提高氧化钕利用率的方法,可改善金属钕产品的质量。     

熔盐电解法制备镨钕铈合金的研究

利用500A规模电解槽,在氟化锂-氟化镨钕-氟化铈熔盐体系中,以氧化铈与氧化镨钕混合物为电解原料,制备了不同金属配分的镨钕铈合金。研究了不同电解质组成、电解温度(980～1 060℃)以及加料速度对电解过程的影响。研究表明,电解质组成是控制合金中金属配分的关键因素,同时电解温度对金属配分的影响不大。但电解温度偏低或者加料速度偏慢会使电解质液面上升,导致"熔盐外溢"现象的发生。     

熔盐电解法制备镨钕镝合金的研究

利用4000 A电解槽,在氟化锂-氟化镨钕-氟化镝熔盐体系中,通过电解氧化镝与氧化镨钕的方法,制备了成分稳定的镨钕镝合金,金属直收率大于96%,电流效率大于75%。讨论了电解质组元、温度、阴极电流密度、加料速度对电解过程的影响。同时与钙热法生产金属镝、自耗阴极制备镝铁合金工艺进行综合性对比分析,结果表明,熔盐电解法在成本、工艺稳定、产品质量等方面具有绝对的优势。     

氧化钕和氟化钕粉尘对作业人员血液学指标及炎性细胞因子表达的影响

随机抽取某稀土厂接触氧化钕、氟化钕粉尘的32名作业工人作为暴露组,不接尘的43名人员为对照组,采集静脉血,检测血液中钕及其化合物含量,血常规、血生化指标及血清中炎性因子(IL-6、IL-10、TNF-α、CC16、SP-D)水平。暴露组血液中钕及其化合物浓度高于对照组,红细胞均值(RBC)高于对照组,谷丙转氨酶(ALT)、谷草转氨酶(AST)高于对照组,血清中克细胞白介素6(IL-6)含量高于对照组,差异均有统计学意义(p0.05)。氧化钕、氟化钕粉尘经呼吸道进入人体,对作业人员肝脏、呼吸系统有影响。     

氢氧化镧湿法氟化法合成氟化镧工艺研究

采用了氢氟酸直接氟化氢氧化镧浆液的制备工艺，考察了工艺的可行性。研究了氢氟酸浓度、用量、反应温度、反应时间等因素对产物含氧量、氟化率和制备过程中过滤、洗涤的影响。通过差热分析、扫描电镜、X射线衍射等手段对产品的组成、形貌、结构等进行了研究。制备工艺为固液反应，工艺简单，产品分散性好，易过滤洗涤，质量稳定，工业可操作性强，流程短。     

我国氟盐体系氧化钕电解制备金属钕

本文论述了我国氟化物熔盐体系,电解氧化钕制备金属钕工艺技术及装备的现状、最新进展。并就大型电解槽工艺技术及装备的研究进行了探讨。     

氟化氢铵氟化法制备稀土氟化物工艺研究

采用正交试验法,研究了用氟化氢铵作氟化剂直接与稀土氧化物(Gd2O3)反应,制备稀土氟化物的工艺,确定了氟化的最佳工艺条件,并进行了分析讨论。     

PrF3-NdF3-DyF3-LiF electrolyte system for preparation of Pr-Nd-Dy alloy by electrolysis

The application of Pr-Nd-Dy alloy in the field of high-performance Nd-Fe-B permanent magnet materials has great potential. The composition of the PrF₃-NdF₃-DyF₃-LiF (PND-LiF) electrolyte system used in the production of Pr-Nd-Dy alloys, the distribution of F, Li, RE and other elements in the electrolyte and their occurrence state were studied in this paper. The effect of temperature and lithium fluoride addition on electrolyte conductivity was revealed using the continuous conductivity cell constant (CVCC) method. The thermal analysis method was used to study the influence of lithium fluoride addition on the electrolyte's liquidus temperature and the optimal process conditions for the production of Pr-Nd-Dy alloy were determined. The results show that the overall distribution of praseodymium neodymium fluoride and lithium fluoride is uniform in the electrolyte and dysprosium fluoride is distributed between praseodymium-neodymium fluoride and lithium fluoride. Praseodymium-neodymium oxide is embedded in praseodymium neodymium fluoride in spotty pattern. The electrolyte's conductivity is increased as the temperature and lithium fluoride addition are going up, while the liquidus temperature is going down with increasing lithium fluoride addition. The best electrolysis process conditions for the PND-LiF system to produce praseodymium neodymium dysprosium alloy are as follows: temperature 1050 °C and 15.56 wt% PrF₃-62.22 wt% NdF₃-11.11 wt% DyF₃-11.11 wt% LiF.     

在氟盐体系中钕离子阴极过程的研究

采用循环伏安法和计时电流法研究了ＬｉＦ－ＫＦ熔盐体系中钕离子在钼电极上的还原过程。结果表明,在本实验条件下,钕离子的电化学反应是一步还原,阴极过程受扩散控制。且在沉积的初级阶段是三维半球形瞬时成核,而后是扩散控制下的晶核长大过程     

电解质组成对10 kA熔盐电解金属钕的影响

通过工业实践,考察了氟盐体系熔盐的配比对10 kA稀土电解槽钕电解的电流效率、电解槽槽龄与电解产品的碳含量等的影响;指出氟盐体系熔盐的配比是整个工艺的基础,并直接影响主要工艺技术经济指标;在长期的工业生产中,保持了高达80%～82%的电流效率.     

Molten salt synthesis of neodynium oxyfluoride in various fluoride media with different fluoride ion activities

Neodymium oxyfluoride has received much attention in the fields of anionic solid electrolytes, luminescent, catalytic and magnetic materials because of its structure combined advantages of rare-earth cations with F^– and O^2– anions. In this work, neodynium oxyfluoride was synthesized by the reaction between neodymium oxide and four fluoride media with different fluoride ion activities. The synthesis processes in molten LiF–CaF₂–NdF₃, LiF–NdF₃, NaF–CaF₂-NdF₃ and NaF–KF–NdF₃ are observed in situ by a confocal scanning laser microscope. The expansion of neodymium oxide particle is observed in the LiF–CaF₂–NdF₃, LiF–NdF₃, and NaF–KF–NdF₃ melts, and the growth of needle crystals on neodymium oxide particle is clearly observed in molten NaF–CaF₂–NdF₃. Based on scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses of products, neodynium oxyfluoride was successfully synthesized in the four fluoride media. The neodynium oxyfluoride generated in the LiF–CaF₂–NdF₃, LiF–NdF₃, and NaF–KF–NdF₃ melts is a tetragonal structure. However, in molten NaF–CaF₂–NdF₃, neodynium oxyfluoride with a rhombohedral structure is formed. It is suggested that the substitution of Na(I) and Ca(II) for Nd(III) can transform NdOF from tetragonal structure to rhombohedral structure. The growth rate of needle crystals generated in molten NaF–CaF₂–NdF₃ was calculated based on the result of a confocal scanning laser microscope, and it is found that the reaction kinetics of crystal formation is zero-order reaction. The effect of fluoride media on the structure and morphology of formed NdOF were evaluated by XRD, X-ray photoelectron spectroscopy (XPS) and SEM. The neodymium oxyfluoride prepared in the fluoride media with high fluoride ion activity has low binding energy of F 1s. The ratio of adsorbed oxygen to lattice oxygen for neodymium oxyfluoride prepared in molten LiF-NdF₃ is larger than those in the other three fluoride media, so it can have better catalytic performance.     

氟化氢铵与稀土氧化物氟化反应机理研究

通过系统的实验及化学分析、X射线结构分析,研究了氟化氢铵与稀土氧化物(Gd2O3)氟化反应制备稀土氟化物的化学反应机理,得出了氟化反应和脱胺反应的化学反应方程式、总反应方程式及副反应式。