Mining of the Deep Ocean

Flotation of rare earth minerals from silicate–hematite ore using tall oil fatty acid collector

Flotation behavior and electronic simulations of rare earth minerals in the presence of dolomite supernatant using sodium oleate collector

The role of sulfate-, alkali-, and halogen-rich fluids in mobilization and mineralization of rare earth elements: Insights from bulk fluid compositions in the Mianning–Dechang carbonatite-related REE belt, southwestern China

Recovery of rare earth elements minerals from iron oxide–silicate rich tailings – Part 2: Froth flotation separation

Comparison of the Daluxiang and Maoniuping carbonatitic REE deposits with Bayan Obo REE deposit, China

As the world's largest rare earth elements (REEs) deposit, the giant Bayan Obo deposit accounts for more than one third of the world's REEs resources. Fenitization is an alkali metasomatism that widely occurs around the carbonatite dykes at Bayan Obo and recent studies reveal huge quantities of REEs could be transferred from the alkaline magma to fenite (Sokół et al., 2022). However, the contribution of fenitization to REE mineralization at Bayan Obo remains unclear. Here, we present bulk rock chemical compositions, in-situ chemical and C-Sr isotopic investigations of calcite and apatite together with Th-Pb ages of monazite, aiming to provide new constraints on REE mineralization during fenitization.Carbonatite at Wu dyke is mainly composed of calcite, aegirine and barite associated with REE minerals dominated by bastnasite and parisite, which intruded into the surrounding wall rocks of quartz conglomerate. The associated fenites include the close Na-fenite and faraway K-fenite. Na-fenite contains calcite, riebeckite, aegirine and apatite with minor monazite and bastnasite in association with barite. K-fenite consists of K-feldspar and quartz with accessory riebeckite and albite. Both REE and SO3 contents decrease from the center to the wall rocks. REE are most enriched in the centered carbonatites (up to 7.39 wt%), and Na-fenites also display strong REE enrichment (9876-22492 ppm). Of note, high-grade Na-fenite is characterized by the highest LREE concentrations among fenites, whereas HREE is most enriched in medium-grade Na-fenite. The latter is dominantly controlled by apatite, which hosts abundant HREE (118-677 ppm). Calcite from fenites displays flat REE patterns with more depleted LREE (La/YbN=0.28-3.02) compared to that within carbonatite (La/YbN=1.66-6.52). Th-Pb ages of monazite from fenites cover a wide range from 420 Ma to 1.27 Ga, which suggests these fenites have also undergone the early Paleozoic hydrothermal alteration. In-situ Sr and C isotope analyses of calcite from carbonatite define a limited range (87Sr/86Sr=0.70344 to 0.70358 and δ13C=-4.36 to -5.1 ‰), which are consistent with a mantle origin . 87Sr/86Sr and δ13C values for calcite within Na-fenite show larger variations of 0.70358 to 0.70620 and -4.92 to -9.87 ‰, respectively. Negative shift in δ13C values suggest degassing through the fenitizing reaction of 18CO32-+2Na++3(Mg2+,Fe2+)+2Fe2++8SiO2+24H++0.5O2= Na2(Mg,Fe2+)3Fe3+2Si8O22(OH)2+18CO2+11H2O. More radiogenic Sr isotopic compositions of fenites result from both assimilation of wall rocks during fenitization and the redistribution of Sr isotopes among minerals during the Paleozoic hydrothermal alteration.Carbonatite-exsolved fenitizing fluids result in predominant REE enrichment within Na-fenite accompanying with light and heavy REE mineralization. LREE mineralization is dominated by monazite precipitation, and HREE enrichment is mostly controlled by apatite. Sulfate is an important ligand for REE transportation and mineralization during fenitization. Barite crystallization and simultaneous precipitation of LREE-bearing minerals lead to fenitizing fluids abundant in HREE, promoting the further formation of HREE-rich apatite.Reference:Sokół K., Finch A.A., Hutchison W., et al., 2022. Quantifying metasomatic high-feld-strength and rare-earth element transport from alkaline magmas. Geology, https://doi.org/10.1130/G49471.1.  

Research Article| July 01, 2015 Evaluating rare earth element (REE) mineralization mechanisms in Proterozoic gneiss, Music Valley, California S. Tyson McKinney; S. Tyson McKinney Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA Search for other works by this author on: GSW Google Scholar John M. Cottle; John M. Cottle † Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA †cottle@geol.ucsb.edu Search for other works by this author on: GSW Google Scholar Graham W. Lederer Graham W. Lederer Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA Search for other works by this author on: GSW Google Scholar Author and Article Information S. Tyson McKinney Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA John M. Cottle † Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA Graham W. Lederer Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA †cottle@geol.ucsb.edu Publisher: Geological Society of America Received: 16 Jul 2014 Revision Received: 15 Dec 2014 Accepted: 09 Feb 2015 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2015 Geological Society of America GSA Bulletin (2015) 127 (7-8): 1135–1152. https://doi.org/10.1130/B31165.1 Article history Received: 16 Jul 2014 Revision Received: 15 Dec 2014 Accepted: 09 Feb 2015 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation S. Tyson McKinney, John M. Cottle, Graham W. Lederer; Evaluating rare earth element (REE) mineralization mechanisms in Proterozoic gneiss, Music Valley, California. GSA Bulletin 2015;; 127 (7-8): 1135–1152. doi: https://doi.org/10.1130/B31165.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Monazite ([LREE]PO4, where LREE stands for light rare earth element) and xenotime (Y[HREE]PO4, where HREE stands for heavy rare earth element) occur in ore-grade concentrations within the Pinto Gneiss in the Music Valley region of southern California. However, both the age and petrogenesis of this potentially economically significant rare earth element (REE) deposit remain uncertain. New petrologic and geochronologic data enable assessment of the textural and temporal relationships between REE-bearing minerals and the host rock and development of a petrogenetic model for REE mineralization. Ore-forming monazite and xenotime are typically restricted to biotite folia within the host Pinto Gneiss, with greatest modal abundances occurring within a few meters of contacts between the host gneiss and a metadiorite intrusive unit, the latter of which is crosscut by pegmatite veins generated by partial melting of the Pinto Gneiss. Ore-forming monazite and xenotime preserve complex internal elemental zonation defining two distinct textures: (1) oscillatory zoning interpreted to represent primary crystallization, overprinted by (2) irregular embayed textures inferred to be the result of fluid-mediated dissolution re-precipitation reactions. The altered domains in monazite consist of primary monazite replaced by secondary monazite along with xenotime and uranothorite [(U,Th)SiO4] inclusions. Similarly, primary xenotime is replaced by secondary xenotime with monazite and uranothorite inclusions. Localized breakdown of monazite, anorthite, and biotite to apatite and allanite provides further evidence for postmineralization metasomatism of the ore bodies. In situ monazite and xenotime U-Pb geochronology constrains the timing of primary REE mineralization to ca. 1.71 Ga, consistent with zircon dates obtained from the Pinto Gneiss. Based on the similarity in ages of monazite, xenotime, and zircon in the Pinto Gneiss, along with relict "igneous" zoning in the ore-bearing phosphate minerals, REE mineralization is inferred to have occurred during crystallization of the igneous protolith to the Pinto Gneiss. Metadiorite emplacement at ca. 1.4 Ga and pegmatite genesis at ca. 165 Ma both postdate the main phase of REE mineralization but likely played a role in fluid-assisted alteration, breakdown, and partial resetting of monazite and xenotime U-Pb systematics in the Pinto Gneiss. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Due to the advantage in deactivating fluorine and enhancing the decomposition of rare earth (RE) minerals, MgO was applied to the magnetizing roasting of Bayan Obo tailings in this work. The effects of MgO dosages, roasting temperature, and holding time on the decomposition rate of RE minerals were experimentally studied. With a MgO dosage of 10 wt.%, the decomposition rate of RE minerals reached 98.09% at 750 °C. The phase composition of roasted samples was characterized by XRD and SEM-EDS. The incomplete decomposition rate was investigated with the observation of leaching residual by SEM-EDS. The decomposition kinetics of the RE minerals with the addition of MgO was analyzed with the Ginstling-Brundshtein model, where the reaction rate was controlled by chemical reaction.

Two discrete stages of fenitization in the Lizhuang REE deposit, SW China: Implications for REE mineralization

The Lala Fe-Cu-(Mo, REE) deposit in the northern Kangdian IOCG metallogenic province, SW China, has a paragenetic sequence that includes pre-ore Na-alteration (Stage I), Fe-(P) mineralization (Stage II), and sulfide mineralization (Stage III). Rare earth element (REE) minerals, which are chiefly monazite, parasite, and bastnäsite with minor xenotime, are associated with sulfide mineralization. These REE minerals, together with biotite, muscovite, and calcite, are accompanied with K-Ca-carbonate alteration of Stage III. Where magnetite and apatite of Stage II are overprinted by minerals of Stage III, the apatite grains are commonly embayed or eroded and contain abundant rounded to subrounded and needle-like inclusions of monazite and minor bastnäsite, calcite, and sulfide minerals. These monazite-bearing apatite grains are texturally similar to metasomatized apatite in the laboratory, and can be attributed to the formation from Stage II apatite via a dissolution-precipitation process during fluid infiltration. The monazite-bearing apatite has REE contents and La/Sm ratios much lower than the original Stage II apatite, suggesting that REEs were leached and mobilized from this Stage II apatite, and that these processes were responsible for the formation of monazite inclusions within the apatite hosts. The monazite inclusions have compositions similar to those of Stage III monazite, suggesting that REEs in Stage II apatite were mobilized by Stage III fluids, consistent with occurrences of sulfide and calcite inclusions within the apatite. Mass balance analysis using bulk compositional data for host rocks that underwent K-Ca-carbonate alteration indicates that REEs of the hosting rocks were also mobilized, and that up to 70 percent of the light REEs were leached out during alteration. Therefore, REE mobilization recorded in apatite grains and country rocks support a model in which the country rocks were important sources for REEs in the Lala deposit. Compositions of amphibole and biotite, together with previously acquired fluid inclusion data, demonstrate that Stage III fluids are dominated by Na⁺ and Cl⁻ but had higher K, CO₂ (or HCO₃⁻ and CO₃²⁻), and HF/HCl fugacity and lower salinity (NaCl) than Stage II fluids. Elevated K and CO₂ in Stage III fluids, or associated K-carbonate alteration, is proposed to be important for extensive REE mobilization on country rocks. The REEs leached from country rocks are inferred to have been transported as chloride complexes prior to being deposited as REE minerals. Deposition of REE minerals from Stage III fluids was likely triggered by mixing with external, relatively low temperature, F-rich, and high-pH fluids and/or by local interaction with carbonate host rocks. We suggest that the common association of REEs with Cu ores in many IOCG deposits is related to the unique nature of the Cu mineralizing fluids.

Carbonatite hosts the most important rare earth resources in the world, but the precise timing, ore-forming history, and mechanism of rare earth mineralization in carbonatite systems are still in debate. Here, we report a rare corona texture of monazite-allanite-fluorapatite from the Huangjiagou carbonatite in the Lesser Qinling of central China, and demonstrate that the U-Th-Pb dating, trace elements, and Sr-Nd isotopes of these minerals in the corona are useful tools to unravel multiple-stage events for rare earth element (REE) mineralization and mobilization. The first mineralization event took place at ca. 219 Ma as revealed by the monazite U-Pb age, the same as regional carbonatite forming ages, but the Th-Pb age has been disturbed, which shows a negative correlation with Th contents. The second mineralization event occurred at ca. 128 Ma, as revealed by in situ U-Pb dating of allanite, coeval with the intrusions of neighboring I-type granite. The initial Sr-Nd isotope ratios of allanite show a downtrend from the center to the rim of monazite-allanite-apatite coronas to approach the ratios of neighboring granite, indicating an increasing effect by the metasomatism of magmatic-hydrothermal fluids during the growth of these REE-mineral coronas. Therefore, a two-episode REE mineralization was recognized with the replacement of ca. 219 Ma monazite by ca. 128 Ma allanite-apatite coronas on the function of magmatic-hydrothermal fluid metasomatism, and this process accompanies the disturbance of Th/Pb geochronology in monazite. Allanite as the product of monazite dissolution can represent the later-stage REE mineralization tracing the REE reworking processes under the hydrothermal conditions in carbonatite systems. Our study highlights the implication of monazite-allanite-fluorapatite coronas on the REE remobilization and mineralization in carbonatite systems.

Carbonatite has enormous potential for rare earth element resources, typically enriched in light rare earth elements, and has attracted increasing attention from geologists and economists. However, there are a small number of documented instances of carbonatite-related heavy rare earth elements enrichment. The Jialu carbonatites in the Qinling orogenic belt (central China) are characterized by the enrichment of heavy rare earth elements compared with typical global carbonatites. The carbonatites are dominantly comprised of calcite, quartz, sulfate, K-feldspar, minor sulfides, and rare earth minerals such as monazite, bastnäsite, parisite, and xenotime, with two mineralization stages including the early quartz-K-feldspar-calcite stage (Stage I) and the late sulfide-rare earth mineral-calcite stage (Stage II). The rare earth element contents of Stage I calcite are higher than those of the Stage II, especially heavy rare earth elements. Calcite from the different mineralization stages exhibits variable chondrite-normalized REE patterns, with the heavy rare earth elements and rare earth element abundances (134–1023 ppm) decreasing from the early to the late stage owing to the crystallization of xenotime. The δ13C (−5.39‰ to −6.68‰) and slightly higher δ18O (10.77‰ to 12.60‰) values for calcite from the Jialu carbonatites generally deviate from the values observed in the primary carbonatite field, which may be a result of Rayleigh-type fractionation. LA–ICP–MS U–Pb dating shows the lower-intercept ages of 243.8 ± 5 and 237.6 ± 1.3 Ma for the monazite and xenotime, respectively, with the weighted average 206Pb/238U ages of 240.9 ± 6 and 239.2 ± 1.3 Ma. These results indicate that the Jialu deposit was concurrent with Triassic carbonatite magmatism and rare earth element mineralization observed on the southern margin of the North China Craton. This implies that this region may have great rare earth element mineralization potential.

A critical review on tackling complex rare earth supply security problem

Recurrent rare earth element mineralization in the northwestern Okcheon Metamorphic Belt, Korea: SHRIMP U–Th–Pb geochronology, Nd isotope geochemistry, and tectonic implications

Recovery of rare earth elements minerals from iron oxide–silicate rich tailings – Part 1: Magnetic separation