世界稀土产业格局变化与中国稀土产业面临的问题

稀土元素在永磁材料等新材料领域有着广泛的应用,被世界各主要国家列为战略资源.从资源、生产格局上看,近年来随着世界范围内稀土探矿热潮的出现以及中国稀土资源的大量开发,中国稀土资源优势地位正逐渐降低;美国等西方国家大力推动中国之外稀土矿山和冶炼分离项目的建设,全球稀土生产格局或将发生变化.从消费方面看,稀土消费可被归为永磁...     

风化壳离子吸附型稀土矿稀土浸出工业指标的意义

一直以来,风化壳型稀土矿床均以全相品位来圈定矿体,计算全相储量。而矿山实际生产长期以来是用浸出稀土品位及其总量为依据。在用浸出品位作为基本分析项目时,其分析成本仅有原全相分析的四分之一,且分析周期、普查周期亦大大缩短。同时选取合适的组合样求取浸出率可以求出全相储量,为国家提供稀土总量数据。总之,浸出工业指标比全相分析指标更能反映采选工艺的进步,保证充分利用资源,又能提供二种合理的储量。缩短资源评价周期。节约资源评价费用,是一种经济适用的工业指标,具有一定的参考价值。     

X射线荧光光谱法测定稀土精矿中的稀土元素分量

氟碳铈矿、独居石、磷钇矿和风化壳淋积型稀土矿四种稀土精矿样品采用化学法预分离富集,X射线荧光光谱法测定样品中稀土元素和伴生的铀、钍元素含量,选择以硼酸盐为主的混合熔剂高温熔融制样,消除矿物间存在的矿物结构影响,通过加大熔剂稀释比降低元素间的基体效应,人工标准样品绘制标准曲线,用数学校正方法校正元素间的谱线重叠效应。对淋积型稀土矿样品重复测定12次,方法检出限为0.9～42.1μg/g,待测组分的相对标准偏差(RSD)均小于10%,测定结果与电感耦合等离子体质谱法的测定值基本吻合。此方法应用于国家一级标准物质稀土标准样品定值工作,检出限和精密度能够满足分析要求,报出数据被采用率达到100%。     

典型稀土矿区周边土壤中稀土元素含量及赋存形态研究

研究不同类型稀土矿区周边土壤中稀土元素(REE)的含量与形态特征,可为矿区周边污染环境治理提供理论支持与科学建议。本文采用欧盟BCR顺序提取法、电感耦合等离子体质谱测定的方法,对内蒙古白云鄂博稀土尾矿区和江西赣南稀土矿区周边6个土壤样品中15种稀土元素进行了含量及形态分析测定。结果表明:矿区周边土壤中稀土元素总量约为264～15955μg/g,明显高于全国土壤背景值(186μg/g),白云鄂博尾矿区周边土壤富集轻稀土元素,稀土元素主要以残渣态富集,占总含量的64.0%～89.4%,生物有效性较低,对环境影响较小;赣南矿区周边土壤富集重稀土元素,稀土元素的主要存在形式是弱酸提取态和可还原态,占总含量的70%以上,易发生迁移转化及对周边环境造成污染。土壤中稀土元素的形态分布与pH值有显著相关性,随着土壤pH值的降低,稀土元素的弱酸提取态含量不断升高,残渣态含量不断降低。     

Geochemistry of Rare Earth Elements in the Ocean

This work briefly outlines modern ideas on geochemistry of rare earth elements (REE) in the ocean. Sources of REE and chemical properties of these elements, which govern their migration ability in natural processes, are considered. The REE behavior in the river water–seawater mixing zone is analyzed. The fractionation of dissolved and suspended REE in oceanic water in both aerobic and anaerobic conditions is also considered. It is shown that the variability of REE composition in pelagic sediments reflects the fractionation of these elements in the oceanic water as a consequence of material differentiation in the ocean. The REE distribution in terrigenous, authigenic, hydrothermal, and biogenic constituents of sediments, such as clay, bone debris, barite, phillipsite, Fe–Mn oxyhydroxides (ferromanganese nodules and micronodules), Fe–Ca hydroxo-phosphate, diatoms, and foraminifers, is considered.     

应用电子探针分析技术研究某铌-稀土矿中铌和稀土元素的赋存状态

铌是一种战略金属,在现代钢铁技术中发挥着非常重要的作用。某铌-稀土矿矿石中的Nb_2O_5平均含量达0.0855%,稀土总量(REO)含量达1.03%,接近铌矿最低工业品位要求,并伴生有稀土矿,因此查明铌和稀土的赋存状态至关重要。由于铌矿物、稀土矿物具有颗粒细小且嵌布特征复杂的特点,在偏光显微镜下不容易发现,而且定名困难,很难达到研究目的,一直是地质分析测试的难点。为查明铌和稀土元素的存在形式以及铌、稀土元素的赋存矿物,本文应用电子探针背散射图像、能谱分析及电子探针波谱定量分析技术对某铌、稀土矿矿石进行分析,主要研究铌矿物和稀土矿物的种类、嵌布关系及化学成分等特征,更准确地分析铌和稀土元素的赋存状态。结果表明:(1)铌元素主要以铌铁矿、含铌金红石的形式存在,其中铌铁矿中Nb_2O_5的平均含量为78.26%,含铌金红石中Nb_2O_5的平均含量为5.26%。(2)稀土元素主要以独居石、氟碳钙铈矿和氟碳铈矿的形式存在,其中独居石中稀土总量(REO)的平均含量为64.84%,氟碳钙铈矿中稀土总量(REO)的平均含量为57.52%,氟碳铈矿中稀土总量(REO)的平均含量为70.61%。(3)铌矿物、稀土矿物分布分散,多包裹于钾长石、方解石及黑云母等脉石矿物中。本研究实现了常规岩矿鉴定手段难以完成的矿物识别和鉴定,查明该矿床矿石中主要的铌矿物和稀土矿物的种类及特征,为后续铌-稀土矿的综合利用提供了科学依据。     

Rare Earth Deposits of North America

Rare earth elements (REE) have been mined in North America since 1885, when placer monazite was produced in the southeast USA. Since the 1960s, however, most North American REE have come from a carbonatite deposit at Mountain Pass, California, and most of the world’s REE came from this source between 1965 and 1995. After 1998, Mountain Pass REE sales declined substantially due to competition from China and to environmental constraints. REE are presently not mined at Mountain Pass, and shipments were made from stockpiles in recent years. Chevron Mining, however, restarted extraction of selected REE at Mountain Pass in 2007. In 1987, Mountain Pass reserves were calculated at 29 Mt of ore with 8.9% rare earth oxide based on a 5% cut‐off grade. Current reserves are in excess of 20 Mt at similar grade. The ore mineral is bastnasite, and the ore has high light REE/heavy REE (LREE/HREE). The carbonatite is a moderately dipping, tabular 1.4‐Ga intrusive body associated with ultrapotassic alkaline plutons of similar age. The chemistry and ultrapotassic alkaline association of the Mountain Pass deposit suggest a different source than that of most other carbonatites. Elsewhere in the western USA, carbonatites have been proposed as possible REE sources. Large but low‐grade LREE resources are in carbonatite in Colorado and Wyoming. Carbonatite complexes in Canada contain only minor REE resources. Other types of hard‐rock REE deposits in the USA include small iron‐REE deposits in Missouri and New York, and vein deposits in Idaho. Phosphorite and fluorite deposits in the USA also contain minor REE resources. The most recently discovered REE deposit in North America is the Hoidas Lake vein deposit, Saskatchewan, a small but incompletely evaluated resource. Neogene North American placer monazite resources, both marine and continental, are small or in environmentally sensitive areas, and thus unlikely to be mined. Paleoplacer deposits also contain minor resources. Possible future uranium mining of Precambrian conglomerates in the Elliott Lake–Blind River district, Canada, could yield by‐product HREE and Y. REE deposits occur in peralkaline syenitic and granitic rocks in several places in North America. These deposits are typically enriched in HREE, Y, and Zr. Some also have associated Be, Nb, and Ta. The largest such deposits are at Thor Lake and Strange Lake in Canada. A eudialyte syenite deposit at Pajarito Mountain in New Mexico is also probably large, but of lower grade. Similar deposits occur at Kipawa Lake and Lackner Lake in Canada. Future uses of some REE commodities are expected to increase, and growth is likely for REE in new technologies. World reserves, however, are probably sufficient to meet international demand for most REE commodities well into the 21st century. Recent experience shows that Chinese producers are capable of large amounts of REE production, keeping prices low. Most refined REE prices are now at approximately 50% of the 1980s price levels, but there has been recent upward price movement for some REE compounds following Chinese restriction of exports. Because of its grade, size, and relatively simple metallurgy, the Mountain Pass deposit remains North America’s best source of LREE. The future of REE production at Mountain Pass is mostly dependent on REE price levels and on domestic REE marketing potential. The development of new REE deposits in North America is unlikely in the near future. Undeveloped deposits with the most potential are probably large, low‐grade deposits in peralkaline igneous rocks. Competition with established Chinese HREE and Y sources and a developing Australian deposit will be a factor.     

电感耦合等离子体发射光谱法测定包头稀土矿中的稀土总量

包头矿中的稀土总量根据提取稀土的工艺流程,含量范围为0.0x%~0.x%。对于高含量稀土总量（20%~80%）的测定,国家标准采用草酸盐重量法,但该方法分离干扰元素的步骤多,流程长。应用电感耦合等离子体发射光谱法不需复杂的分离步骤即可测定稀土元素,但由于受到精密度的限制,测定高含量稀土总量的波动范围较大,不易得到准确结果。本文针对包头稀土矿组成复杂、酸溶难于分解的情况,建立了应用碱熔处理样品,电感耦合等离子体发射光谱（ICP-AES）测定稀土总量的方法。用氢氧化钠、过氧化钠溶解样品,水提取熔融物,各种元素以离子或氢氧化物形式进入溶液,过滤除去铝、硅、磷等杂质元素及大量的钠盐,减小了基体元素及共存元素的干扰;以钪为内标校正仪器波动及基体效应的影响,无需基体匹配即可测定稀土总量。对于稀土总量在30%~50%的样品,相对标准偏差小于0.7%,对于稀土总量在2%的样品,相对标准偏差小于1.2%;各稀土元素回收率为98.0%~103.3%。本方法比国家标准方法简便,与文献中应用ICP-AES测定高含量稀土总量的方法相比精密度有很大改善,可快速准确地测定包头稀土矿中2%~50%的稀土总量。     

碱熔沉淀分离-电感耦合等离子体质谱法测定伴生重晶石稀土矿中的稀土元素

采用电感耦合等离子体质谱法(ICP-MS)测定伴生重晶石轻稀土矿中的稀土元素时,Ba以及轻稀土元素La、Ce、Pr、Nd、Sm等对中重稀土造成严重的质谱重叠干扰,因此在保证矿石完全消解的同时,若能选择合适的前处理方法实现目标元素与基体的有效分离,将有利于减少质谱干扰。本文采用过氧化钠-碳酸钠熔融分解伴生重晶石的稀土矿样品,熔融物用三乙醇胺溶液提取,将沉淀过滤去除硅、铁、锰、铝等大量基体元素,而稀土元素与钡、锶、钙等留存于沉淀中,沉淀经盐酸溶解后再用氨水进行二次沉淀,将稀土元素与伴生的高含量钡、锶、钙等元素分离,分离率超过96%,从而极大地降低了由钡的氧化物和氢氧化物对~(153)Eu等元素质量数的质谱干扰。轻稀土元素对中重稀土元素的干扰则通过测定高浓度的单元素标准溶液在m/z 138～175处的表观浓度来计算干扰校正系数,对干扰量进行扣除校正。该方法通过稀土矿石标准物质GBW07187、GBW07188验证,测定值与认定值的相对误差10%;应用于伴生重晶石稀土矿石实际样品分析,相对标准偏差(RSD,n=12)为0.5%～4.6%,证明了本方法可用于分析高钡矿石中的稀土元素。     

赣南稀土精矿粉配制的稀土溶液反射波谱特征研究

赣南离子吸附型稀土矿是我国重要的稀土资源,本文运用美国ASD FieldSpec-3便携式地物波谱仪,对赣南寻乌稀土矿区稀土精矿粉配置的25个稀土溶液样品进行波谱测试,获取了不同稀土含量的波谱特征,结果表明溶解在水体中的稀土元素在可见光-近红外574 nm、790 nm、736 nm、520 nm、861 nm、443 nm等波段具有多个明显的稀土特征吸收谷及若干次级的稀土特征吸收谷;通过与15种稀土单元素波谱特征对比分析,可见这些吸收特征主要由一种或几种稀土单元素引起;随着稀土浓度的降低,这些吸收特征逐渐减弱甚至消失。这一研究进一步加深了对我国赣南稀土溶液波谱特征的认识,同时为赣南稀土元素的高光谱遥感研究奠定了理论基础。     

四川稀土矿尾砂的稀土元素和微量元素地球化学特征及开发利用意义

四川是我国轻稀土的重要产地,稀土开采至今已有二十多年的历史,积存了大量尾砂。尾砂中仍然有丰富的稀土资源,但这部分资源究竟有多大的量、能不能再次回收,如何回收,则是当务之急。为查明稀土尾砂中各类元素的分布特征,本文对A、B、C、D四个稀土矿山的尾砂开展了稀土元素和微量元素地球化学特征的初步研究。结果表明:尾砂中稀土元素配分特征继承了原矿石,稀土氧化物含量普遍偏高(0.78%~2.12%),均超过了现行工业指标的边界品位(0.5%~1.0%),且老尾砂的稀土含量高于新尾砂;除了富集稀土元素之外,B尾砂中Sr含量超过10%,C矿区尾砂中Sr含量为2.7%,A矿区尾砂中Ba含量可达1.8%。同时,不同矿区的尾砂中Mo、Bi、Pb、Ag等有用元素发生了不同程度地富集(值得综合回收利用),尤其是Mo达到了边界品位(磁选后的尾砂Mo含量达到2.275%)。本文提出,今后不仅要加强保护四川稀土尾砂,而且需对富集的有用元素采取恰当的方式加以综合回收。     

稀土资源储备刻不容缓

本文基于全球稀土资源供需形势和我国储量减少的趋势分析了我国开展稀土资源储备的紧迫性.从储备规避“世贸规则”进行间接控制出口、增强在国际稀土市场的话语权以及降低国家外汇储备风险三个方面阐明了我国开展稀土资源储备的必要性.通过借鉴美国和日本在稀土矿产地和矿产品储备方面的成功经验,结合我国稀土资源储备现状,初步构建了适合我国...     

四川稀土精矿的稀土元素和微量元素地球化学特征及开发利用意义

四川省是我国轻稀土的重要产地,开采近二十年来生产了大量稀土精矿,精矿的稀土品位及其他有用元素组成对矿山资源评价及企业生存至关重要。本文对A、B、C三个稀土矿区稀土精矿的稀土元素和微量元素组成特征进行了研究。结果表明:不同矿区、不同选矿方法、不同企业生产的精矿,其稀土元素和微量元素含量存在显著差异;A矿区浮选精矿的稀土含量最低(ΣREEs=41.57%),而C矿区精矿的稀土含量最高(ΣREEs=55.83%);A矿区磁选精矿的稀土含量(ΣREEs=49.96%)高于浮选精矿(ΣREEs=41.57%);B矿区甲公司(ΣREEs=48.35%)精矿产品的稀土含量高于乙公司精矿产品(ΣREEs=42.92%)。精矿的稀土元素配分特征继承了原矿石的同时普遍亏损Tb和Yb,推测是选矿过程导致了元素的亏损。精矿中除了富集稀土元素,Mo、Bi、Pb、Ga、Th、U、W等有用元素也发生了不同程度的富集,综合利用价值高,尤其是Mo(0.56%)和Ga(0.036%)的含量已达到现行边界品位。本文提出,今后在提高精矿稀土品位的同时,需对富集的元素采取恰当的方式加以综合回收。     

Rare Earth Magnets: Conservation of Energy and the Environment

Rare earth sintered magnets (Nd magnet) have been used in many applications such as computer and industrial equipment, automobile manufacturing and many others. They are highly efficient and reduce energy consumption because of their superior magnetic properties. The element dysprosium (Dy) contained in the Nd magnet is important and indispensable. It improves the stability of the Nd magnet by enhancing the coercive force of its magnetic properties at high temperature. Dy is not so abundant. The rapid growth of the Nd magnet may result in Dy shortage. Exploration for new deposits of Dy is desired.     

欧洲稀土矿产资源形势

在欧洲,已知的稀土元素潜力大概有700万吨REO。格陵兰的Kvanefjeld矿床是世界大型REE矿床之一,瑞典Norra K?rr和格陵兰Kringlerne这两个矿床在全球占有重要地位,因为它们具有较高的重/轻稀土元素比值。根据欧洲和格林兰岛主要稀土矿化类型的地质条件和成分特征可以看到,格林兰岛和北欧国家的原生矿床以及法国西北部、希腊和巴尔干半岛西部的次生矿床勘查潜力最大,预期收益最高。     

Extraction of Rare Earth from K-rich Syenite Tailings

The application of K-rich nephline syenite ores would produce some tailings, which will cause many disadvantages such as more land occupation. In this research, an process was obtained to extract rare earth from the K-rich nephline syenite tailings of Gejiu, Yunnan province, China. This tailings mainly composed of K-feldspar, biotite, magnetite, andradite, nepheline and 0.1% rare earth. The chemical compositions are shown in Table 1.     

DBC-偶氮氯膦光度法测定地质样品中 15种稀土元素的研究

建立了DBC-偶氮氮膦-稀土元素显色体系,该体系的灵敏度高,摩尔吸光系数为(1.3×104～1.2×105)L@mol-1@cm-1,体系稳定,重现性好,并将偏最小二秉计算法用于数据处理中,较准确地预测出地质样品中15种稀土元素各自的含量,其标准偏差(S)为3.3×104～9.1 × 103,相对标准偏差为0.81%～5.0%;其相对误差一般都小于15%,结果满足微量稀土元素分析的要求.     

Rare and Rare Earth Elements in Lateritized Bauxites of the Chadobets Uplift (Siberian Platform)

Doklady Earth Sciences - The mineral and chemical composition of bauxites from the Chadobets uplift of the Siberian Platform is the total product of laterites on aluminosilicate rocks (source of...     

基于PCA-SVM算法对稀土元素与稀土判别指标耦合数据集的铀矿床分类

不同类型铀矿床的沥青铀矿/晶质铀矿具有不同的稀土元素组成,其组成可作为判别铀矿床类型的重要指标。采用基于Python语言的主成分分析（principal component analysis,PCA）与支持向量机（support vector machines,SVM）结合的分类模型,对收集到的全球已知6种类型铀矿床的216组沥青铀矿/晶质铀矿稀土元素数据进行研究。以216组数据为训练集,通过数据清洗、特征缩放、PCA特征提取、网格搜索和交叉验证参数寻优构建SVM分类模型,对24组同变质型胡家峪晶质铀矿进行智能识别。研究结果显示：仅使用稀土元素的14维训练集最优模型判定胡家峪晶质铀矿类型的测试准确率为0.4%;由稀土元素、稀土总量、轻重稀土比、铕异常组成的17维训练集最优模型的测试准确率为75.0%,较14维训练集提高74.6%,模型泛化能力强;而通过传统稀土元素配分曲线、w（ΣREE）-（LREE/HREE）_N图解不能有效判定胡家峪晶质铀矿类型。本次研究表明,PCA-SVM算法对增有传统稀土判别指标数据集进行挖掘可有效厘定铀氧化物成因类型,效果明显优于单纯的稀土元素数据集以及传统的稀土配分曲线、w（ΣREE）-（LREE/HREE）_N图解。     

Rare Earth Element Enrichments in the Elk Creek Carbonatite

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