An overview of rare-earth recovery by ion-exchange leaching from ion-adsorption clays of various origins

Abstract Continuous development of advanced technologies has created increasing demand for rare-earth elements (REE), with global emphasis on identifying new alternate sources to ensure adequate supply. Ore deposits containing physically adsorbed lanthanides are substantially lower grade than other REE deposit types; however, the low mining and processing costs make them economically attractive as sources of REE. To evaluate the commercial potential for the recovery of REEs from ion-adsorption deposits in a systematic manner, a standardized procedure for REE leaching was developed previously. Using this procudure it was found that, regardless of variations in ore origin and REE content, all REE consistently reached peak extraction levels under ambient conditions with fast kinetics. Various techniques to improve the REE extraction through process variations were also investigated: it was found that decreasing the L:S ratio, re-using leachate on fresh ores and counter-current leaching were all capable of increasing REE concentrations in the resultant leachate, albeit at the expense of REE extraction levels. In addition, the water content trapped in the leached material was found to contain significant amounts of REE and residual lixiviant requiring thorough washing of the solid residue.

[1]  G. Adachi,et al.  Research trends in rare earths: A preliminary analysis , 2010 .

[2]  Stephen B. Castor,et al.  Rare Earth Deposits of North America , 2008 .

[3]  D. Sverjensky,et al.  Speciation of adsorbed yttrium and rare earth elements on oxide surfaces , 2008 .

[4]  M. Bradbury,et al.  Sorption of Eu on Na- and Ca-montmorillonites: Experimental investigations and modelling with cation exchange and surface complexation , 2002 .

[5]  Koichiro Watanabe,et al.  Geochemical and mineralogical characteristics of ion-adsorption type REE mineralization in Phuket, Thailand , 2011, Mineralium Deposita.

[6]  Y. Kanazawa,et al.  Rare earth minerals and resources in the world , 2006 .

[7]  G. Mudd,et al.  A Detailed Assessment of Global Rare Earth Element Resources: Opportunities and Challenges , 2015 .

[8]  S. Cotton.  Lanthanide and Actinide Chemistry , 1991 .

[9]  S. Ishihara,et al.  REE Abundance and REE Minerals in Granitic Rocks in the Nanling Range, Jiangxi Province, Southern China, and Generation of the REE‐rich Weathered Crust Deposits , 2008 .

[10]  Huan Li,et al.  Role of minerals properties on leaching process of weathered crust elution-deposited rare earth ore , 2015 .

[11]  J. Nieuwenhuize,et al.  Comparison of microwave and conventional extraction techniques for the determination of metals in soil, sediment and sludge samples by atomic spectrometry , 1991 .

[12]  R. Chi,et al.  Novel solution injection technology for in-situ leaching of weathered crust elution-deposited rare earth ores , 2016 .

[13]  Z. Bao,et al.  Geochemistry of mineralization with exchangeable REY in the weathering crusts of granitic rocks in South China , 2008 .

[14]  J. Wübbeke.  Rare earth elements in China: Policies and narratives of reinventing an industry , 2013 .

[15]  X. Yang,et al.  China's ion-adsorption rare earth resources, mining consequences and preservation , 2013 .

[16]  S. Taylor,et al.  The continental crust: Its composition and evolution , 1985 .

[17]  Atsuyuki Ohta,et al.  REE(III) adsorption onto Mn dioxide (δ-MnO2) and Fe oxyhydroxide: Ce(III) oxidation by δ-MnO2 , 2001 .

[18]  A. Townshend.  Standard potentials in aqueous solutions , 1987 .

[19]  A. Bard,et al.  Standard Potentials in Aqueous Solution , 1985 .

[20]  G. Moldoveanu,et al.  Recovery of rare earth elements adsorbed on clay minerals: II. Leaching with ammonium sulfate , 2013 .

[21]  S. Massari,et al.  Rare earth elements as critical raw materials: Focus on international markets and future strategies , 2013 .

[22]  Huan Li,et al.  Recovery of rare earths from weathered crust elution-deposited rare earth ore without ammonia-nitrogen pollution: I. leaching with magnesium sulfate , 2015 .

[23]  R. Chi,et al.  Weathered crust elution-deposited rare earth ores , 2008 .

[24]  C. Hurst.  China's Rare Earth Elements Industry: What Can the West Learn? , 2010 .

[25]  Yalin Lei,et al.  Production forecast of China׳s rare earths based on the Generalized Weng model and policy recommendations , 2015 .

[26]  Zhigao Xu,et al.  The basic research on the weathered crust elution-deposited rare earth ores , 2012 .

[27]  A. Bauer,et al.  Sorption of lanthanides on smectite and kaolinite , 2002 .

[28]  吴元欣,et al.  Existing State and Partitioning of Rare Earth on Weathered Ores , 2005 .

[29]  Vladimiros G. Papangelakis,et al.  Recovery of rare earth elements adsorbed on clay minerals: I. Desorption mechanism , 2012 .

[30]  B. Velde,et al.  The Origin of Clay Minerals in Soils and Weathered Rocks , 2008 .

[31]  S. Ishihara,et al.  REE Mineralization of Weathered Crust and Clay Sediment on Granitic Rocks in the Sanyo Belt, SW Japan and the Southern Jiangxi Province, China , 2008 .

[32]  N. Krishnamurthy,et al.  Extractive metallurgy of rare earths , 1992 .

[33]  Xianping Luo,et al.  Enhanced Leachability of a Lean Weathered Crust Elution-Deposited Rare-Earth Ore: Effects of Sesbania Gum Filter-Aid Reagent , 2013, Metallurgical and Materials Transactions B.

[34]  黄莉,et al.  Role of minerals properties on leaching process of weathered crust elution-deposited rare earth ore , 2015 .