Rare-Earth Elements Chapter O of Critical Mineral Resources of the United States—Economic and Environmental Geology and Prospects for Future Supply Professional Paper 1802–O U.S. Department of the Interior U.S. Geological Survey Periodic Table of Elements 1A 8A 1 2 hydrogen helium 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 lithium beryllium boron carbon nitrogen oxygen fluorine neon 6.94 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 13 14 15 16 17 18 sodium magnesium aluminum silicon phosphorus sulfur chlorine argon 22.99 24.31 3B 4B 5B 6B 7B 8B 11B 12B 26.98 28.09 30.97 32.06 35.45 39.95 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.39 69.72 72.64 74.92 78.96 79.90 83.79 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 85.47 87.62 88.91 91.22 92.91 95.96 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 cesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 132.9 137.3 178.5 180.9 183.9 186.2 190.2 192.2 195.1 197.0 200.5 204.4 207.2 209.0 (209) (210) (222) 87 88 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium flerovium livermorium (223) (226) (265) (268) (271) (270) (277) (276) (281) (280) (285) (284) (289) (288) (293) (294) (294) 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanide Series* lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 138.9 140.1 140.9 144.2 (145) 150.4 152.0 157.2 158.9 162.5 164.9 167.3 168.9 173.0 175.0 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Actinide Series** actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium (227) 232 231 238 (237) (244) (243) (247) (247) (251) (252) (257) (258) (259) (262) element names in blue are liquids at room temperature element names in red are gases at room temperature element names in black are solids at room temperature Modified from Los Alamos National Laboratory Chemistry Division; available at http://periodic.lanl.gov/images/periodictable.pdf. Cover. The Mountain Pass Mine, San Bernardino County, California, was the only active producer of rare-earth elements (REEs) in the United States in 2013. The orebody is a tabular carbonatite intrusion and is thought to be the largest REE resource in the United States. Photograph by Bradley S. Van Gosen, U.S. Geological Survey. Rare-Earth Elements By Bradley S. Van Gosen, Philip L. Verplanck, Robert R. Seal II, Keith R. Long, and Joseph Gambogi Chapter O of Critical Mineral Resources of the United States—Economic and Environmental Geology and Prospects for Future Supply Edited by Klaus J. Schulz, John H. DeYoung, Jr., Robert R. Seal II, and Dwight C. Bradley Professional Paper 1802–O U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior RYAN K. ZINKE, Secretary U.S. Geological Survey William H. Werkheiser, Acting Director U.S. Geological Survey, Reston, Virginia: 2017 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Van Gosen, B.S., Verplanck, P.L., Seal, R.R., II, Long, K.R., and Gambogi, Joseph, 2017, Rare-earth elements, chap. O of Schulz, K.J., DeYoung, J.H., Jr., Seal, R.R., II, and Bradley, D.C., eds., Critical mineral resources of the United States— Economic and environmental geology and prospects for future supply: U.S. Geological Survey Professional Paper 1802, p. O1– O31, https://doi.org/10.3133/pp1802O. ISSN 2330-7102 (online) iii Contents Abstract ........................................................................................................................................................O1 Introduction..................................................................................................................................................O2 Uses and Applications ......................................................................................................................O3 Availability of Supply .........................................................................................................................O4 Australia .....................................................................................................................................O4 China ...........................................................................................................................................O4 India.............................................................................................................................................O5 Malaysia .....................................................................................................................................O5 Russia..........................................................................................................................................O5 United States .............................................................................................................................O5 Conservation, Recycling, and Substitution ...........................................................................O5 Geology .........................................................................................................................................................O6 Geochemistry......................................................................................................................................O6 Rare-Earth-Element-Mineral Formation in Carbonatite Magmas ....................................O7 Rare-Earth-Element-Mineral Formation in Alkaline Magmas ...........................................O7 Rare-Earth-Element-Mineral Formation in Parental Magma Sources ............................O7 Rare-Earth-Element-Mineral Formation Through Hydrothermal Processes ..................O7 Aqueous Geochemistry of Rare-Earth Elements .................................................................O7 Mineralogy ..........................................................................................................................................O7 Deposit Types ...................................................................................................................................O10 Resources and Production ......................................................................................................................O17 Identified Resources .......................................................................................................................O17 Undiscovered Resources ...............................................................................................................O18 Exploration for New Deposits .................................................................................................................O18 Environmental Considerations ................................................................................................................O20 Sources and Fate in the Environment ..........................................................................................O21 Mine Waste Characteristics ..........................................................................................................O21 Human Health Concerns .................................................................................................................O22 Ecological Health Concerns ...........................................................................................................O22 Carbon Footprint...............................................................................................................................O22 Mine Closure.....................................................................................................................................O23 Problems and Future Research ..............................................................................................................O23 References Cited.......................................................................................................................................O24 iv Figures O1. Graph showing world mine production of rare-earth oxides, by country and year, from 1960 to 2012 ..............................................................................................................O4 O2. Graph showing radii of the trivalent ions of