NiMnCo粉末触媒合成金刚石的特征分析

采用扫描电子显微镜(SEM)和扫描俄歇微探针(AES)分别对NiMnCo粉末触媒合成金刚石不同阶段的断口组织、合成不同粒度金刚石断口和金刚石的生长界面进行了分析，研究结果表明：NiMnCo粉末触媒具有较宽的适用范围，既可以合成粗颗粒、高强度金刚石，又可以合成细粒度磨料级金刚石；在其合成体系中，碳能够实现三维方向扩散，有利于金刚石的对称长大，提高晶体完整性。     

合成金刚石用水雾化粉末触媒的研究

介绍了合成高品级人选金刚石用水雾化FeNi30粉末触媒的制备方法.采用 100 MPa超高压水雾化制粉技术,选取有机RY缓蚀剂,对水雾化FeNi30粉末进行缓蚀处理,在六面顶压机上进行水雾化触媒的合成人造金刚石的对比实验.结果表明:缓蚀处理后的FeNi30粉末,X-光相分析结果未发现有FeO相及Fe3O4相的存在,粉末自然条件下存放1年,氧含量增量低于100×10-6.该触媒粉末与天然石墨混合,合成的金刚石单产提高,颜色加深,冲击韧性指数TI(Toughness Index),热冲击韧性指数TTI(Thermal Toughness Index)值有较大提高.     

NiMnCo金刚石粉末触媒的特性

采用差热分析 (DAT)研究了NiMnCo粉末触媒熔化和凝固过程中合金的变化规律 ;采用扫描电子显微镜、金相显微镜、X射线衍射分析仪揭示了粉末触媒的微观组织结构 ,并对粉末触媒合成金刚石的合成块断口及合成的金刚石进行了分析 ,从宏观、微观角度评价了合成金刚石用NiMnCo粉末触媒的特性     

大腔体Ni-Mn粉末触媒细颗粒金刚石合成

对Ni-Mn粉末触媒的制备方法及基本特征进行了介绍和研究,在此基础上,采用优化工艺进行了细颗粒金刚石的多批次合成试验,结果表明,Ni-Mn粉末触媒在大腔体内合成细颗粒金刚石单产在3 g以上,粒度峰值处于160～240目之间,具有一定的实用价值。     

化学共沉淀-共还原法制备Fe70Ni27Co3触媒粉末及金刚石合成实验研究

本文介绍了利用化学共沉淀-共还原法制备Fe70Ni27Co3触媒粉末,研究了pH值、金属离子浓度、加料速度、添加剂用量对沉淀物产生和粒度的影响,确定出工艺条件为:pH值为3左右,沉淀物煅烧为450℃×3h,氢气还原工艺为650℃×3h;得到了D50约为9μm,氧含量为0.418%,铁、镍、钴的质量比为68.9∶26.5∶3.57的触媒粉末;进行了金刚石合成实验并与使用气雾化触媒粉末合成效果进行了对比。     

触媒合金组织与合成人造金刚石的关系

利用金相显微技术分析了合成人造金刚石后的Ｎｉ７０Ｍｎ２５Ｃｏ５触媒合金的组织。同时，还研究了合成棒中触媒片正，反面人造金刚石的生长分布状态，并对改善金刚石晶体生长环境的途径作了初步探讨。     

气雾化Ni-Mn-Co合金粉末触媒制备及其合成金刚石特性

采用真空 /惰气雾化方法制备了NiMn2 5Co5合金粉末触媒 ,利用SEM、OM、XRD等手段研究了粉末触媒的特性。结果表明粉末触媒颗粒形貌呈球形 ,流动性好 ,比表面积大 ,成分均匀 ,组织细小 ,具有类似Ni的单一面心立方固溶体结构 ,大于 30 μm的粉末氧含量 <2 0 0× 10 -6。在国产六面顶压机上进行了粉末触媒合成金刚石的批量试验 ,合成的金刚石晶型完整率高 ,晶体纯净 ,包裹体总量不多 ,夹杂物和气泡少 ,测试结果显示合成的金刚石具有较高的抗压强度和良好的冷热冲击强度。采用粉末触媒合成金刚石 ,可大大降低金刚石的生产成本 ,并且不仅能合成高产磨料级金刚石 ,还能够大大提高优质粗颗粒和高品级金刚石的比例 ,将有利促进我国金刚石行业的技术革新和进步     

Φ23腔体Ni—Mn粉末触媒优质金刚石合成研究

对Ｎｉ－Ｍｎ粉末触媒的制备方法及基本特征进行了介绍和研究。在此基础上，采用优化工艺进行了优质金刚石的多批次合成试验，结果表明：采用二步升压法优化工艺，Ｎｉ－Ｍｎ粉末触媒在Φ２３腔体内合成金刚石单产在１０克拉以上，粒度峰值处于６０目￣８０目之间，具有一定的实用价值。     

触媒合金的热处理对合成金刚石强度的影响

本文研究了Ｎｉ７０Ｍｎ２５Ｃｏ５触媒合金的热处理对合成金刚石的形核，长大及金刚石强度的影响，提出了合成金刚石用Ｎｉ７０Ｍｎ２５Ｃｏ５触媒合金的最佳热处理制度。     

超音速气雾化制备FeNi30触媒粉末的表征

利用自行研制的超音速气雾化设备制备了FeNi30触媒粉末,对其粒度分布、形貌及晶体结构等进行了表征.结果表明,粉末平均粒度约为26 μm,微分分布曲线呈单峰且接近正态分布.粉末颗粒大部分呈球形或近球形,粒度大的粉末表面相对较为粗糙,有少量卫星球和凹坑,粒度小的粉末表面较为光滑;粉末内部主要有胞状晶、胞状树枝晶和柱状树枝晶等凝固组织,粒度大的粉末主要由胞状晶组成,有少量不发达的枝晶,粒度小的粉末具有较为发达的枝晶,并伴有少量胞状晶;各粒度粉末的晶粒尺寸均较小,基本在1-10 μm之间;各粒度粉末均由面心立方结构的FeNi固溶相组成,晶格常数为(0.3586±0.0001) nm,与金刚石的晶格常数接近.     

Effect of rare earths on corrosion resistance of Cu-30Ni alloys in simulated seawater

Cu-30Ni-xRE(x=0-0.213 wt.%) alloy was prepared by adding rare earths(RE) in melted Cu-30Ni alloy using metal mould casting method.The effects of RE on corrosion resistance of the alloy in simulated seawater were investigated using optical microscope,scanning electronic microscope with energy-dispersive spectrometer and electrochemical measurement system.The results showed that the corrosion resistance of Cu-30Ni alloy was greatly improved by adding proper amount of RE,whereas excess addition of RE worsened ...     

Recovery of rare earths from ion-absorbed rare earths ore with MgSO4-ascorbic acid compound leaching agent

The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO_4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO_4 and environmentally friendly leaching.     

Extractive metallurgy of rare earths

Abstract

A short account is given on the extraction of rare earths from monazite sand, bastnasite ore, and phosphate rock of igneous origin. This includes mineral beneficiation, leaching methods, fractional crystallisation [of historical interest], ion exchange, solvent extraction, precipitation from solution, and reduction to metals.

On donne un bref compte-rendu de l’extraction des terres rares à partir de sable monazité, de minerai de bastnaésite et de roche phosphatée d’origine ignée. Ceci inclut l’enrichissement du minéral, les méthodes de lixiviation, la cristallisation fractionnelle (d’intérêt historique), l’échange d’ion, l’extraction par solvant, la précipitation à partir de solution et la réduction en métaux.     

Thermodynamics of rare earths in steelmaking

The standard free energies of formation of the oxides, sulfides and oxysulfides of cerium and lanthanum under steelmaking conditions have been calculated and used to predict the behavior of rare earths in steelmaking. Deoxidation and desulfurization constants, expressed in terms of Henrian activities, have been used to construct a precipitation diagram which indicates the sequence of rare earth inclusion formation. An enrichment of lanthanum in (RE)-oxysulfide and cerium in (RE)-sulfide is predicted. It is also predicted that rare earths should be able to reduce the soluble oxygen and sulfur contents of liquid steel well below the contents presently found in most industrial and laboratory practices. A simple method of calculating steelmaking additions for complete rare earth control of inclusion composition is presented. Formerly a Research Engineer at McMaster University     

Effects of transparent inorganic pigment on spectral properties of spectrum-fingerprint anti-counterfeiting fiber containing rare earths

Transparent inorganic pigment is the color-filler material for manufacturing spectrum-fingerprint anti-counterfeiting fiber, and has great effects on the emission spectral characteristics of the fiber. In order to explain the change mechanism of the emission spectral characteristics of spectrum-fingerprint anti-counterfeiting fiber and to promote the development of the fiber, several kinds of spectrum-fingerprint fiber samples were prepared by using rare-earth strontium aluminate and polyethylene terephthalate (PET) as raw materials and by adding different kinds of transparent inorganic pigments respectively in this research. The effect of transparent inorganic pigment on the spectral characteristics of the fiber was analyzed in detail by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and fluorescence spectrometer. The results showed that transparent inorganic pigment had no effect on the dispersion state and phase structure of rare-earth luminescent material in spectrum-fingerprint fiber and the microscopic morphology of the fiber. However, transparent inorganic pigment did affect the excitation and emission process of spectrum-fingerprint fiber so as to decrease its excitation and emission efficiency. The change of both the type and content of transparent inorganic pigment exerted great effects on the excitation and emission spectra of the fiber. Therefore, it was a feasible way to control the emission spectrum of spectrum-fingerprint fiber through changing the type and content of transparent inorganic pigment.     

稀土铌钴合金粉末材料研究与应用

研究应用稀土铌钴合金粉末材料提高内燃机气门锥面材料的综合性能。通过对稀土铌钴合金粉末材料显微组织分析，抗磨性能、抗高温燃气腐蚀性能、抗热冲击性能试验以及应用等工作，表明该材料具有良好的涂敷烧结性能和优异的综合性能等特点。     

Reduction leaching of rare earth from ion-adsorption type rare earths ore with ferrous sulfate

The practice of in-situ leaching of the ion-adsorption type rare earths ore with ammonium sulfate could only leach most of rare earth in ion-exchangeable phase,but not the colloidal sediment phase.Therefore,the reduction leaching of rare earth from the ion-adsorption type rare earths ore with ferrous sulfate was innovatively put forward.The soak leaching process and the column leaching process were investigated in the present study.It was determined that ion-exchangeable phase could be released,and part of colloidal sediment phase rare earth could be reduction leached by the cations with reduction properties.The mechanism of reduction leaching was discussed with the Eh-pH diagram of cerium.Moreover,the stronger reduction of reductive ions,the greater acidity of leaching agent solution,and the higher reductive ion concentration,could result in the higher rare earth efficiency and the bigger cerium partition in the leaching liquor.In the ferrous sulfate column leaching process,the rare earth leaching rate and the rare earth efficiency were a little higher than with(NH_4)_2SO_4 agent,and the rare earth efficiency and the partitioning of cerium in leaching liquor could be about 102% and 5.31%,respectively.However,the ferrous sulfate leaching process revealed some problems,so compound leaching with magnesium sulfate and a small amount of ferrous sulfate was proposed to an excellent alternative leaching agent for further studies,which may realize efficiency extraction and be environment-friendly.     

表面活性剂对稀土与偶氮氯膦-mK显色反应的影响及其应用

研究了溴化十六烷基三甲基铵、十二烷基磺酸钠、吐温 80、乳化剂OP和聚乙烯醇 5种表面活性剂对稀土与偶氮氯膦 mK显色反应的影响。结果表明 :乳化剂OP、吐温 80和聚乙烯醇对显色反应有增敏作用 ,其中吐温 80效果最为显著。在 0. 0 2～ 0.0 8mol/L硫酸介质中和吐温 80存在下 ,Ce 与偶氮氯膦 mK生成稳定的蓝绿色络合物 ,最大吸收波长为 668nm ,表观摩尔吸光系数ε =9.1× 10 4 。用此显色体系测定低合金钢中稀土 ,结果满意     

稀土资源收储专项储备量的确定

文中梳理了定性确定稀土资源储备规模的文献资料,利用现实可提供储备量与预测趋势可提供储备量的波动关系以及储备量模拟模型,定量化计算了稀土资源收储储备量,以2000-2011年的稀土资源产、销、存数据为例,设计了稀土资源可提供储备量波动范围分别为0%、5%和10%的3个方案,模拟计算了3个方案的年最大储备量、最小储备量、专项储备量和绝对储备量,初步确定了2012年中国稀土资源收储的专项储备量.国家储备进行储备决策时,可以根据国家财政状况、国内外经济景气状况和稀土产业发展状况,选择实施高度储备、中度储备还是低度储备,并在不同储备思路指导下动态调节专项储备量.