Structural Controls and Predictive Mapping of Tin, Niobium and Tantalum Mineralization Associated with the Mayo Darlé Stanniferous Granitoids;Contributions of Geostatistics

The aim of this study of the spatial dispersion of tin, niobium and tantalum mineralization associated with the Mayo Darlé granitoids was to produce prospecting guides through predictive maps of Sn, Nb and Ta in the region. It was based on a database (in appendix) obtained after analysis of rock samples (greisens and quartz veins) collected in the field, using a portable X-ray fluorescence (XRF) spectrometer. Two approaches were used: 1) structural studies in the field using the directions of veins and fractures 2) the use of variographic maps, an essential element in geostatistics for determining directional anisotropies. A joint synthesis of the modelling results shows that tin, tantalum and niobium mineralization at Mayo Darlé is concentrated along strike intervals N315E to N320E, with mineralization also occurring along strike N35E for high-grade Sn, medium-grade Ta and low-grade Nb. In short, mineral concentrations disperse progressively in space: positively from east to west for tantalum and niobium, and inversely for tin.

A Review of Niobium-Tantalum Separation in Hydrometallurgy

Niobium and tantalum are chemically similar and are associated with each other in nature which makes it very difficult to separate. For many years, the separation of tantalum from niobium involved the fractional crystallization of potassium heptafluorotantalate away from potassium oxypentafluoroniobate monohydrate, this method has been supplanted by solvent extraction from fluoride-containing solutions by the use of solvent extractants such as Octanol, bis(2-ethylhexyl)phosphoric acid (DEHPA), Alamine 336, methyl isobutyl ketone (MIBK), tri-nbutyl phosphate (TBP) or cyclohexanone. A detailed review of the various processes involved in the breakdown treatment of niobium and tantalum primary sources, extraction and separation and newer processes of extraction as well as the various technique involved were discussed.

Rare Earths, Niobium and Tantalum Minerals in Bayan Obo Ore Deposit and Discussion on Their Genesis

Bayan Obo ore deposit is endowed with and lie hidden in the Proterozoic strata. The localities and occurrences of the minerals in the ore deposit were described. It is obviously that some minerals are strata minerals and some are post strata minerals. The rare earths, niobium and tantalum minerals are exactly the post strata minerals. In these minerals the hydrothermal metasomatic phenomena distinctly reveal their metallogenic characteristics. According to tectonic movement, magma activity, mineral paragenesis, hydrothermal metasomatism, geological age and lasting time scale of metallogenesis, and some other factors, it is supposed that genesis of rare earths, niobium and tantalum minerals in Bayan Obo ore deposit are closely related with hydrothermal metallogenic solution which is differentiated from silica acid and carbonic acid magma and derived from deep seated source, and then intruded into Proterozoic strata and metasomatized. It is recognized that the metallogenesis of Bayan Obo ore deposit is undergoing a long geological period and many episodes.

Blast and tensile properties of tantalum/niobium lined SiC/SiC composite tubes for nuclear cladding

The mechanical performances such as tensile strength and blast property of metal lined SiC/SiC composite cladding tubes were investigated. Nb or Ta was selected as liner material, and the SiC/SiC composite layer was fabricated by winding and different precursor impregnation and pyrolysis(PIP) processes. The tensile strengths of different tube samples were measured at room temperature(RT) and 1200 °C, respectively. The blast property was investigated through the maximum water pressure of tubes. And the fracture microstructures were observed by SEM.The highest tensile strength at RT was 150.7 MPa. The blast strength was enhanced with the PIP process increasing from 1 to 4 cycles and the tube of 4 PIP cycles had the highest water pressure of 34.7 MPa. Compared with the metal tubes, the multi-layer structure improved tensile and blast properties significantly. The different processes such as PIP cycles and pyrolytic carbon(PyC) coating were important factors to enhance the mechanical performances of SiC/SiC-based tubes. However, the retention rate of tensile strength was only 18.5% at 1200 °C.

Niobium–tantalum oxide minerals in alluvial placer deposits from the Ngoura area,East-Cameroon

This work presents a preliminary mineralogical characterization of Nb-Ta oxide minerals from alluvial placers located in the Ngoura area,eastern Cameroon.The heavy minerals are characteristic of short hydromechanical transport and highlight the stability of Nb-Ta oxides during the weathering and transport.Nb-Ta mineralization in placer deposits from the Ngoura area may derive from local sedimentation.The assemblage of Nb-Ta oxides in the studied placers consists of tapiolite-(Fe)and tantalite-(Mn).Tapiolite-(Fe)exhibits high concentrations in Ta2O5(78.07-80.46 wt%)and FeO(12.18-13.66 wt%)and plots within a narrow range of Ta*(0.900-0.933)and Mn*(0.037-0.119),which correspond to the ranges typically observed in tapiolite-(Fe)worldwide.Tantalite-(Mn)shows Ta2O5 contents ranging from 62.17 to 69.45 wt%,Nb2O5 from 12.09 to 17.37 wt%,MnO from 7.63 to 12.49 wt%and FeO from 1.48 to 6.62 wt%.It is also characterized by a wider range of Mn<sup>*(0.538-0.891)and relatively homogeneous Ta/(Ta+Nb)(0.683-0.779)ratios.Texturally,the studied Nb-Ta minerals exhibit oscillatory zoning characterized by bright Ta-rich zones alternating with dark Nb-rich zones.This oscillatory zoning is progressive in some minerals and the alternating bands may appear regular to wavy with gradual transitions.Oscillatory zoning in Nb-Ta oxides from the Ngoura placers is considered to be a primary magmatic feature and is tentatively explained as a result of magmas mixing,rapid cooling or degassing/decompression of the igneous system.The geomorphology and the tropical humid climate of the eastern region offer suitable conditions for the deposition of alluvial placers.Therefore,niobium-tantalum minerals from the Ngoura placers must have been sourced from the weathering and erosion of alkaline granites and pegmatites widespread in the study area.

Potash Breakdown of Poly-Mineralized Niobium-Tantalum-Lanthanides Ore Material

The potentiality of the alkali breakdown of the poly mineralized ore material south Gabal El-A’urf area, central Eastern Desert, Egypt is investigated. It includes the multiple oxide mineral tanteuxenite, monazite, bastnasite, anatase, as well as zircon. This ore material assaying lanthanides (RE2O3 1.9%), niobium (Nb2O5 1.25%) as well as titanium and zirconium (TiO2 and ZrO2 1.23% and 1.12%) respectively besides tantalum (Ta2O5 0.13%), were used for the present work. This sample has thus been subjected to two alkali breakdown techniques using potash;namely agitation leaching and fusion. The latter technique was found to be preferred as it gives higher leaching efficiency. The optimum leaching conditions are weight ratio of the ore/potassium hydroxide 1/2 at 400°C for 1 h. The realized leaching efficiencies attained 95.0% and 93.7% for Nb and Ta respectively as well as 96% for lanthanides and 75% for Ti while that for Zr did not exceed 10%.

Separation and purification of tantalum from plumbomicrolite of amazonite deposit in Kola Peninsula by acid leaching and solvent extraction

A plumbomicrolite concentrate(PMC)was leached with the mixture of HF and H2SO4,HF and HNO3 acids,respectively.Optimal conditions ensuring high recovery of tantalum and niobium(up to 99%)into solution,and radionuclides into insoluble residue were determined.Fluoride-sulfuric acid and fluoride-nitric acid schemes were proposed for PMC leaching by an extractive separation of tantalum form niobium,lead and impurities,and production of high-purity tantalum compounds.Octanol-1 was used as an extractant.Optimal conditions for production of high-purity tantalum strip solutions were defined for all stages(extraction-scrubbing-stripping).Produced tantalum compounds,such as tantalum pentoxide and potassium heptafluotanthalate,comply with the norms for high-purity substances in terms of impurities content.Final choice of the PMC processing scheme is determined by its profitability.

Sulfuric acid leaching of low-grade refractory tantalum–niobium and associated rare earths minerals in Panxi area of China

By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.

钽铌清洁冶金与纯化技术研究进展与探讨

钽铌是至关重要的战略性金属。随着高端制造业对先进材料的需求不断增加,以及绿色发展理念的深刻践行,产品纯化精制和过程清洁循环已成为钽铌湿法冶金的重要转型目标。本文概述了我国钽铌原生资源及二次资源的特点与利用现状,系统介绍了钽铌原料绿色分解技术、钽铌溶液分离与纯化技术、钽铌冶金废水增值利用技术的新进展,结合工业实际对比分析了各技术优缺点,并从资源保障、技术发展方向及污染物全面治理等方面提出了展望和建议,以期为钽铌冶金工业的可持续高质量发展提供支持。

湘东北白沙窝稀有金属矿床电性特征与找矿预测研究

花岗伟晶岩型稀有金属矿床是最重要的稀有金属矿床类型之一。连云山东部新发现了白沙窝伟晶岩型矿床,初步评估白沙窝矿床深部稀有金属资源潜力巨大,但该矿床的矿产开采程度很低,围绕深部隐伏花岗伟晶岩脉的研究程度不高。通过研究白沙窝伟晶岩型矿床的深部电性结构特征,探讨稀有金属成矿模型及赋矿载体的空间分布,阐明矿脉就位关系,旨为稀有金属找矿预测提供依据。通过可控源音频大地电磁法(CSAMT)在白沙窝岩体东南方向开展深部隐伏岩(矿)体的探测工作,采用共轭梯度法反演实测3条探测剖面数据,探测深部隐伏岩(矿)体,并结合钻孔信息和元素地球化学异常特征信息进行综合分析,揭示隐伏岩脉的分布及成矿特征。研究结果表明,隐伏伟晶岩脉主要位于冷家溪群中,集中分布在花岗岩体顶部及构造裂隙周围,埋深在50~300 m;伟晶岩脉的成矿地球物理标志为深部高阻体侵入浅部低阻体中的高阻脉状地质体。研究成果为白沙窝矿床后续勘查工作提供了科学依据,揭示了伟晶岩脉的形成机理,并为湘东北及华南地区的稀有金属勘查提供了可靠的物探预测技术和经验。

X荧光测定铌钽原矿中铌和钽及不确定度评定

本文建立了X射线荧光熔片法测定铌钽原矿中铌和钽的分析方法。采用低稀释比(Li2B4O7:LiNO3:样品=4:0.6:1)制备熔融玻璃片,以光谱纯SiO2、Al2O3和Fe2O3混合物为基体,添加Nb、Ta标准溶液及少量干扰元素Rb、Y、Mo、Zr、W、Ce制备校准曲线所用标准样品。使用Rh靶compton散射线为内标线校正基体效应对Nb元素的影响;Ta元素则外加HfO2,并用Hf Lβ3为内标线。本文讨论了复杂铌钽原矿和本实验试剂中含有的Br、Rb、Y、Mo、Zr、Nb、W、Hf和Ta各元素之间的光谱干扰。对于Br、Rb、Y、Nb及Hf和Ta之间的谱线重叠干扰,采用干扰系数法逐级扣除;而Mo Kα和Zr Kα背景对Nb Kα的影响及W Lα背景对Ta Lα的影响,则分别通过选取40.000°和70.500°公共背景点来避免,最后得到分析元素Nb Kα和Ta Lα谱线净强度。本文选用钽矿石成分分析标准物质(GBW07155)作为方法验证样品,并对Nb、Ta测量结果不确定度进行评定。最终本方法报出结果:w(Nb_(2)O_(5))=(0.044±0.002)%(k=2);w(Ta2O5)=(0.069±0.002)%(k=2)。

碱熔-电感耦合等离子体质谱法测定铌钽矿中铌钽锂铍

这是一篇矿物分析测试领域的论文。建立了碱熔-电感耦合等离子体质谱法同时测定铌钽矿中铌钽锂铍的快速测定方法。采用过氧化钠:氢氧化钠=1:1的混合熔剂分解样品,水提取使铌钽等元素完全形成沉淀,与液体分离,采用10%硫酸+10%过氧化氢溶液25 mL转化沉淀和溶液后用电感耦合等离子体质谱仪测定样品中铌、钽、锂、铍元素的含量。采用该方法测定国家一级标准物质GBW 07153、GBW 07155、GBW 07185,各元素的测定值与认定值基本一致,相对误差为0.50%~4.77%,相对标准偏差(n=6)为-0.009%~0.008%,适用于铌钽精矿、难分解或复杂样品中铌钽等元素的测定,并在生产实践中进行了应用。

湖北某低品位铌钽矿选矿工艺试验研究

针对湖北某花岗伟晶岩型铌钽矿进行了选矿试验研究,确定了重磁粗选—粗精矿浮选—酸化焙烧、浸出—萃取、反萃—磁选尾矿浮选分离长石、石英的联合选矿工艺流程。试验获得的铌钽精矿产品中Nb2O5品位53.96%、Ta2O5品位21.33%,Nb2O5回收率63.48%、Ta2O5回收率53.05%。其中,在重磁粗选阶段通过粗磨分级—摇床工艺,考察了磨矿细度和磁场强度对铌钽预富集的影响,试验得到产率9.47%,可工业应用的一级绢云母产品;针对强磁精矿进行浮选,考察了捕收剂种类对浮选效果的影响,在苯乙烯膦酸与正辛醇用量比4︰1、药剂用量1500g/t的条件下进行两次精选,获得Nb2O5品位为10.578%、Ta2O5品位为4.753%的浮选精矿;在纯硫酸体系下对浮选精矿产品进行了酸化焙烧浸出试验研究,铌钽分解液在低酸条件下采用甲基异丁基甲酮(MIBK)萃取钽、在高酸条件下采用磷酸三丁酯(TBP)萃取铌,萃取液均采用纯水进行反萃,反萃后的铌、钽液用氨水沉淀后焙烧,得到高纯Nb2O5和Ta2O5产品;对磁选尾矿进行浮选获得可工业利用的长石精矿和石英精矿。试验对绝大部分有用矿物实现了富集,高效富集铌钽的同时实现了伴生矿物的综合回收。

磁-重联合工艺从钽铌尾矿中分选钽的实验研究

钽铌矿组分结构复杂,嵌布粒度细,品位较低,选矿工艺比较复杂。针对宜春钽铌尾矿中钽铌含量少,难以回收利用的问题,采用高梯度磁选机和摇床对钽铌尾矿进行分选。针对Ta_(2)O_(5)品位0.0134%、Nb_(2)O_(5)品位0.0078%的钽铌尾矿,采用“磁选-重选”联合工艺流程对其进行富集,分别得到Ta_(2)O_(5)品位为11.286%、回收率为40.74%、Nb_(2)O_(5)品位为6.633%、回收率为40.74%的钽铌精矿产品,试验指标良好。Ta_(2)O_(5)、Nb_(2)O_(5)得到了较好的综合回收,证明了“磁选-重选”联合工艺的可行性,并且该工艺提供了环保绿色的回收钽铌矿的方法,为钽铌矿及同类资源的综合回收提供了的技术支持。

新疆某锂钽铌铍多金属矿选矿试验研究

对新疆某锂品位0.68%的锂钽铌铍多金属矿进行了选矿试验研究。工艺矿物学研究结果表明,该矿石中锂矿物以锂辉石为主,钽铌矿物含量较低。采用磁选-重选回收钽铌、浮选回收锂的工艺流程,可得到Ta_(2)O_(5)品位17.110%、Nb_(2)O_(5)品位19.670%,回收率分别为41.69%、42.63%的钽铌精矿和Li2O品位5.12%、Li2O回收率75.21%的锂精矿。

碱熔-二次沉淀分离-电感耦合等离子体质谱法测定贵州古陆相沉积型稀土矿中16种稀土元素及铌、钽、锆、铪的含量

贵州古陆相沉积型稀土矿样品主要含锐钛矿、高岭石、赤铁矿等副矿物,难以被微波消解法完全分解。通过优化样品分解、浸取方法,提出了题示方法。取0.1 g样品于刚玉坩埚中,加入约2.5 g过氧化钠,混匀后再铺上约0.5 g过氧化钠,于750℃熔融15 min。置于盛有50 mL含5 g·L^(-1)硫酸镁和5 g·L^(-1)氯化铵的热溶液中浸取10 min,加热煮沸1~2 min。加入5 mL 50%(体积分数,下同)氨水溶液,搅匀后静置60 min。用滤纸过滤,沉淀用40 mL热的50%(体积分数,下同)硝酸溶液分次溶解,将所得溶液加热煮沸1~2 min,用50%氨水溶液调节溶液酸度至p H 8~10,用滤纸过滤,沉淀用40 mL热的50%硝酸溶液分次溶解,用2 g·L^(-1)酒石酸溶液稀释至200 mL,在动能歧视(KED)模式下用电感耦合等离子体质谱仪分析。结果显示:采用含硫酸镁和氯化铵的热溶液加热浸取有助于碱性溶液中铌、钽形成铌酸镁和钽酸镁沉淀析出;氨水-铵盐体系中可将铌、钽、锆、铪以及稀土元素定量沉淀;用氨水调节酸度进行二次沉淀分离提纯,能除去大部分基体元素与试剂引入的盐类;采用KED模式以及在线内标校正能降低质谱干扰,尤其对于钪元素。在优化的试验条件下,20种分析元素的质量浓度均在1.00~1000μg·L^(-1)内和内标103Rh校正后的质谱强度呈线性关系,检出限为0.010~1.66μg·g^(-1);用一级国家标准物质进行验证,所得各分析元素测定值的相对误差为0.030%~16%,相对标准偏差(n=7)为2.1%~14%。

全球铌钽资源开发利用格局及对策建议

铌钽是发展现代化产业体系、加快发展新质生产力的关键原材料之一,是我国紧缺战略性矿产,更是大国博弈竞争的重点领域之一。本文研究梳理了全球铌钽资源储量分布、生产供应格局、国际贸易情况等,分析了我国铌钽资源产业发展存在的问题,提出了增强国内资源供应能力、提升全球治理水平、促进产业高质量发展等对策建议。

九岭地区东槽细晶岩型铌钽矿床年代学、岩石地球化学特征及其地质意义

近些年在赣西北九岭地区南部新预测了潭山-上富Nb-Ta-Li-Be成矿远景区,成矿类型包括花岗岩型和细晶岩型两类,对其进行形成时代和成因机制的研究是认识九岭地区铌、钽、锂等稀有金属富集成矿的关键。对东槽矿床含铌钽细晶岩开展了铌铁矿族矿物U-Pb年代学、岩相学和岩石地球化学研究,确定了其成岩成矿年龄、岩石成因和源区特征,并浅析其成矿潜力。结果显示,铌钽铁矿LA-ICP-MS U-Pb年龄为142±1 Ma,表明含铌钽细晶岩的成岩、成矿时代均在燕山早期(早白垩世)。含铌钽细晶岩以斜长细晶岩为主,具有富硅、富碱、富铝、低钛、贫稀土元素、Rb/Sr值变化大,富集铌、钽、锂、铷以及CaO/(K_(2)O+Na_(2)O)≤0.10、Al_(2)O_(3)/TiO_(2)>160和高的分异指数(DI≥90)等特征,其稀土元素配分曲线呈弱右倾“海鸥型”,微量元素蛛网图左侧隆起和右侧平缓,表明该细晶岩与强过铝质高分异S型花岗岩特征相似。综合分析认为,东槽细晶岩是九岭地区新元古界双桥山群变泥质岩在构造应力场由挤压向伸展演变的背景下发生部分熔融,并经历高程度结晶分异演化的产物。东槽含铌钽细晶岩与南岭含铌钽花岗岩、大湖塘含铌钽花岗斑岩具有相似的地球化学特征,铌、钽、锂等元素含量高,是潭山-上富成矿远景区重要的成矿地质体。

基于多道伽马能谱测量的离子吸附型稀土矿放射性勘查方法研究——以攀西德昌地区为例

冕宁—德昌稀土成矿带资源潜力大,以往的找矿方向集中在寻找与喜马拉雅期碱性杂岩有关的硬岩型稀土矿,对离子吸附型稀土矿的研究程度较浅。为探究区内广泛分布的花岗岩风化壳的成矿前景,以区内狮子山地区为研究对象,部署多道伽马能谱测量、土壤剖面测量和浅钻工程,在摩所营花岗岩风化壳中圈定1处离子吸附型稀土矿点。对地、物、化剖面及含矿量的放射性响应进行分析,发现Th与K含量对稀土稀有矿化具有较高的指示意义,当6.2537×10^(-6),w(K)>4.2%时,就可能出现矿化好、具有工业规模的离子吸附型稀土矿。从放射性异常对表生风化的响应特征分析,钍异常晕对花岗岩岩体具有较好的指示作用,钾异常晕能较好地圈定花岗岩风化壳的范围。

湖南省幕阜山岩体外接触带稀有金属成矿规律分析

本文主要研究了幕阜山岩体南缘的仁里-传梓源矿区及周边地区区域地质背景,对区内花岗伟晶岩铌钽矿及铜铅锌矿的成矿地质条件、矿化特征、成矿规律等进行了综合评价,为对今后幕阜山岩体稀有金属资源的持续勘查提供找矿方向。