A Detailed Assessment of Global Rare Earth Element Resources: Opportunities and Challenges
A Detailed Assessment of Global Rare Earth Element Resources: Opportunities and Challenges
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DOI：
10.2113/econgeo.110.8.1925
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发表时间：
2015-12
期刊：
影响因子：
5.8
通讯作者：
Zhehan Weng;S. Jowitt;G. Mudd;N. Haque
中科院分区：
文献类型：
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作者：
Zhehan Weng;S. Jowitt;G. Mudd;N. Haque
稀土元素是基础设施、技术和现代生活方式不可缺少的元素，这导致了对这些元素的需求不断增加。目前全球稀土氧化物(REO)市场由中国产量主导，中国产量在2006年达到峰值，达到13.3万吨/年，约占全球产量的97.1%，这引发了人们对稀土资源长期供应的担忧。虽然稀土元素由17种单独的元素(15种稀土元素外加Sc和Y)组成，赋存于多种类型的矿化中，但与铜和铁等金属相比，全球稀土开采部门的规模相对较小，限制了我们对稀土矿产资源和矿化系统的了解，因为铜和铁等金属的产量要大得多。为了定量分析稀土矿床的矿物学、浓度和地质类型，我们根据最新的可用数据(2013-2014)编制了全球稀土矿产资源数据集。这一汇编产生的全球稀土氧化物加氧化钇(TREO+Y)最低总资源量为619.5公吨，分布在267个矿床中。有品位和吨位数据的矿床(我们数据库中的267个矿床中的260个)包含约88,483公吨的矿产资源，平均浓度为0.63%TREO+Y，拥有553.7公吨TREO+Y。在我们数据库中的267个矿床中，约有160个具有使用法定采矿法规(如JORC、NI43-101、SAMREC)报告的矿产资源，其余107个项目具有CRIRSCO不符合规定的矿产资源，这些项目基于行业文献和同行评审的科学文章中提供的信息。全球约51.4%的REO资源赋存于碳酸盐岩矿床中，其中氟碳榴石、独居石和辉石是三种最重要的稀土矿物，占我们数据库中总资源量的90%。就个别国家的稀土资源量而言，中国是目前已知的TREO+Y资源量(268.1公吨)的主要来源，占我们数据库中全球REO资源量的43%，澳大利亚、俄罗斯、加拿大和巴西的TREO+Y资源量分别为64.5百万吨、62.3公吨、48.3公吨和47.1公吨。约84.3公吨TREO+Y赋存于尾矿中(主要是白云鄂博的尾矿，但帕拉博拉、Steenkampskraal和Mary Kathen的资源较少)，12.4公吨TREO+Y赋存于重矿物砂矿项目中的独居石中，这表明了从传统硬岩采矿以外的资源中生产REO的潜力。全球稀土资源以轻稀土为主，轻稀土(LREO；La-Gd)与重稀土(Tb-Lu和Y)的平均比例为13：1。这些稀土矿床平均含有81ppm的Th和127ppm的U，表明与稀土提取和精炼相关的放射性废物可能令人担忧。对2012年11万吨TREO+Y的全球产量数据进行建模，并假设稀土需求年增长率为5%，表明已知的稀土资源可以维持生产到2100年，地质稀缺不是迫在眉睫的问题。这表明，环境、经济和社会因素等其他问题将强烈影响稀土资源的开发。
Rare earth elements (REE) are indispensable to infrastructure, technology, and modern lifestyles, which has led to an increasing demand for these elements. The current global rare earth oxides (REO) market is dominated by Chinese production, which peaked in 2006 at 133,000 tonnes REO per year, accounting for some 97.1% of global production, causing concern about the long-term supply of REE resources. Although the REE consist of 17 individual elements (15 lanthanides plus scandium and yttrium) that are hosted by numerous types of mineralization, the relatively modest scale of the global REE mining sector has limited our knowledge of REE mineral resources and mineralizing systems compared to metals such as copper and iron, which are produced in much larger quantities. In order to quantitatively analyze the mineralogy, concentrations, and geologic types of REE deposits, we compiled a global dataset of REE mineral resources based on the most recently available data (2013–2014). This compilation yields minimum global contained total rare earth oxides plus yttrium oxide (TREO + Y) resources of 619.5 Mt split between 267 deposits. Deposits with available grade and tonnage data (260 of the 267 deposits in our database) contain some 88,483 Mt of mineral resources at an average concentration of 0.63% TREO + Y, hosting 553.7 Mt TREO + Y. Of the 267 total deposits in our database, some 160 have mineral resources reported using statutory mining codes (e.g., JORC, NI43-101, SAMREC), with the remaining 107 projects having CRIRSCO-noncompliant mineral resources that are based on information available in the industry literature and peer-reviewed scientific articles. Approximately 51.4% of global REO resources are hosted by carbonatite deposits, and bastnasite, monazite, and xenotime are the three most significant REE minerals, accounting for >90% of the total resources within our database. In terms of REE resources by individual country, China dominates currently known TREO + Y resources (268.1 Mt), accounting for 43% of the global REO resources within our database, with Australia, Russia, Canada, and Brazil having 64.5, 62.3, 48.3, and 47.1 Mt of contained TREO + Y resources, respectively. Some 84.3 Mt TREO + Y is hosted within tailings (dominated by tailings from Bayan Obo but with smaller resources at Palabora, Steenkampskraal, and Mary Kathleen) and 12.4 Mt TREO + Y is hosted by monazite within heavy mineral sands projects, illustrating the potential for REO production from resources other than traditional hard-rock mining. Global REE resources are dominated by the light REE, having an average light REO (LREO; La-Gd) to heavy REO (Tb-Lu and Y) ratio of 13:1. These REE deposits contain an average of 81 ppm Th and 127 ppm U, indicating that radioactive waste associated with REE extraction and refining could be a concern. Modeling the 2012 global production figures of 110 kt TREO + Y combined with an assumed 5% annual growth in REE demand indicates that known REE resources could sustain production until 2100 and that geologic scarcity is not an immediate problem. This suggests that other issues such as environmental, economic, and social factors will strongly influence the development of REE resources.