Carbonatite-Related REE Deposits: An Overview

Abstract

The rare earth elements (REEs) have unique and diverse properties that make them function as an “industrial vitamin” and thus, many countries consider them as strategically important resources. China, responsible for more than 60% of the world’s REE production, is one of the REE-rich countries in the world. Most REE (especially light rare earth elements (LREE)) deposits are closely related to carbonatite in China. Such a type of deposit may also contain appreciable amounts of industrially critical metals, such as Nb, Th and Sc. According to the genesis, the carbonatite-related REE deposits can be divided into three types: primary magmatic type, hydrothermal type and carbonatite weathering-crust type. This paper provides an overview of the carbonatite-related endogenetic REE deposits, i.e., primary magmatic type and hydrothermal type. The carbonatite-related endogenetic REE deposits are mainly distributed in continental margin depression or rift belts, e.g., Bayan Obo REE-Nb-Fe deposit, and orogenic belts on the margin of craton such as the Miaoya Nb-REE deposit. The genesis of carbonatite-related endogenetic REE deposits is still debated. It is generally believed that the carbonatite magma is originated from the low-degree partial melting of the mantle. During the evolution process, the carbonatite rocks or dykes rich in REE were formed through the immiscibility of carbonate-silicate magma and fractional crystallization of carbonate minerals from carbonatite magma. The ore-forming elements are mainly sourced from primitive mantle, with possible contribution of crustal materials that carry a large amount of REE. In the magmatic-hydrothermal system, REEs migrate in the form of complexes, and precipitate corresponding to changes of temperature, pressure, pH and composition of the fluids. A simple magmatic evolution process cannot ensure massive enrichment of REE to economic values. Fractional crystallization of carbonate minerals and immiscibility of melts and hydrothermal fluids in the hydrothermal evolution stage play an important role in upgrading the REE mineralization. Future work of experimental petrology will be fundamental to understand the partitioning behaviors of REE in magmatic-hydrothermal system through simulation of the metallogenic geological environment. Applying “comparative metallogeny” methods to investigate both REE fertile and barren carbonatites will enhance the understanding of factors controlling the fertility.

Lanthanides as impurities in the Bayer production cycle of the aluminum hydroxide from Sierra Leone bauxite

“…The most important lanthanide resources are found in four groups of minerals with high lanthanide content, exploitable in various geographical areas: carbonate ores, phosphate ores, silicate ores, oxide ores and materials. In these resources, the lanthanides are most often in the form of the following natural mineral phases [3]: a) Carbonate minerals: Bastnaesite (Ce,La)(CO3)F; Parisite Ca(Ce,La)2(CO3)3F2; Synchysite Ca(Ce,La)(CO 3 ) 2 F and Cebaite Ba 3 Ce 2 (CO 3 ) 5 F 2 containing lanthanides [6][7][8]; and Breunerite (Mg,Fe,Sc)CO3 or Dolomite (Ca,Mg,Sc)CO3 (accompanying the silicate albite mineral phase) containing scandium [9]; Yttrium bonded to 25 carbonates compounds. b) Phosphate minerals: Lanthanides in calcium substituted in phosphates as fluoride, chloride or hydroxide) Ca5(PO4)3(F,Cl,OH): Polymetalic monazite; (Ce,La,Nd,Th)PO4: Aluminum phosphates florencite CeAl3(PO4)2(OH)6 containing lanthanides [10][11][12] and Scandium phosphate anhydrous and hydrous species, such as Pretulite (ScPO4) and Kolbeckite (ScPO4 2H2O) [13]; Yttrium phosphate minerals -Xenotime (YPO4) and also, other 9 phosphates, vanadates and arsenates [14]; c) Silicate minerals: Kainosite Ca2(Y,Ce)2Si4O12CO3H2O; Ritholite (Ce,Ca)5(SiO4,PO4)3(OH,F); Gadolinite (Ce,La,Nd,Y)2Fe 2+ Be2Si2O10; Allanite (Ce,Ca,Y)2(Al,Fe 3+ )3(SiO4)3OH, containing lanthanides and yttrium [15][16][17][18]; Scandium as an essential element in the following silicate minerals mono silicate Cascandite Ca(Sc,Fe 2+ )Si3O8(OH)), Cyclosilicate bazzite Be3(Sc,Al)2Si6O18, Disilicate thortveitite (Sc,Y)2Si2 O7), and Orthosilicate eringaite Ca3Sc2 (SiO4)3 [19].…”

“…The search for new natural resources of critical metals has encouraged research works about identifying some new available raw materials supply and new strategies for intensive valorization. The recent published reviews are available on such subjects as occurrence, exploration and analysis of the critical lanthanides minerals [4][5][6][22][23][24][25][26][27][28][29][30][31], as well as the new strategies to bring all these resources in the circular economy [32][33][34][35]. Also, valuable reviews cover different subjects concerning the mobilization of huge deposits residual materials from other large-scale industries, like red mud and other poly-metallic resources [36][37][38][39][40][41][42][43][44][45][46][47], phosphate materials and phospho-gypsum [10-12, 18, 27, 48-51] and the coal and coal ashes [52][53][54][55][56].…”

An integrated ASTER-based approach for mapping carbonatite and iron oxide-apatite deposits

“…Carbonatites and alkaline-carbonatite complexes are the primary sources for several strategic metals such as rare earth elements (REE) and niobium (Nb), which are vital in the development of emerging industries and green technologies (e.g., Mariano 1989;Chakhmouradian et al 2015;Verplanck et al 2016;Wang et al 2020). They also host considerable apatite deposits that are often related to magmatic and/or weathering processes (e.g., Willet et al 1989;Toledo et al 2004;Zaitsev et al 2015;Ouabid et al 2021).…”

Removal of Fluorine from RECl3 in Solution by Adsorption, Ion Exchange and Precipitation

“…Rare earth is indispensable strategic material for the development of new technology due to its unique magnetic, optical and electrical properties [1]. In the rare earth industry, mixed rare earth minerals, bastnaesite, monazite, ion-absorbed rare earth ore and xenotime are generally used as feedstock to produce rare earth products [2]. The mixed rare earth mines in Bayan Obo are some of the most critical rare earth mines in China and in the world because of their large reserves and output [3].…”