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Critical Metal Minerals
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Critical Metal Minerals

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Deposits".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 32662

Special Issue Editors

Prof. Dr. Pei Ni

E-Mail Website
Guest Editor
1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Institute of Geofluids, Nanjing University, Nanjing 210023, China
2. Joint Research Center for Circum-Pacific Strategic Mineral Resources, Nanjing 210000, China
Interests: hydrothermal ore deposits; mineral, fluid and melt inclusion; mineral resource prospecting and exploration; tectonics and metallogeny
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Mincheng Xu

E-Mail Website
Guest Editor
1. Joint Research Center for Circum-Pacific Strategic Mineral Resources, Nanjing 210000, China
2. Nanjing Center, China Geological Survey, Nanjing 210016, China
Interests: regional metallogenesis; mineral resources prospecting and exploration
Dr. Tiangang Wang

E-Mail Website
Guest Editor
1. Joint Research Center for Circum-Pacific Strategic Mineral Resources, Nanjing 210000, China
2. Nanjing Center, China Geological Survey, Nanjing 210016, China
Interests: hydrothermal ore deposits; ore-forming fluids; regional metallogenesis; mineral resources prospecting
Dr. Junyi Pan

E-Mail Website
Guest Editor
1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
2. Joint Research Center for Circum-Pacific Strategic Mineral Resources, Nanjing 210000, China
Interests: granite-related W-Sn deposits; porphyry-epithermal ore deposits; fluid and melt inclusion; LA-ICP-MS analytical techniques
Dr. Yitao Cai

E-Mail Website
Guest Editor
1. Joint Research Center for Circum-Pacific Strategic Mineral Resources, Nanjing 210000, China
2. Nanjing Center, China Geological Survey, Nanjing 210016, China
Interests: mineralogy; petrology, magmatic ore deposits; mineral resources evaluation

Special Issue Information

Dear Colleagues,

An increasingly wide range of mineral materials are used to enable the technologies that sustain our living standard in modern society. In particular, the “Critical Metals” or “Critical Minerals” have been regarded as crucial strategic resources for global high-technology applications. The critical metals generally consist of four major elemental groups: rare metals (e.g., Li, Be, Rb, Cs, W, Sn, Nb, Ta, Zr, Hf), REEs (e.g., La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y), rare disperse elements (e.g., Ga, Ge, Se, Cd, In, Te, Re, Tl) and other precious metals (e.g., PEG, Cr, Co). However, most of these elements are present at very low abundance in the earth’s upper crust and/or are difficult to efficiently extract and utilize. The rapidly growing demand for critical mineral resources worldwide requires new understandings of the characterization of metal-host minerals, the geochemistry and ore genesis of critical metal deposits, as well as exploration advances aiding in the discovery of new economic targets. In this regard, the present Special Issue is focused on relevant topics, including but not limited to (1) geochemical exploration, data handling and statistical analyses for critical minerals of economic and/or environmental importance; (2) mineralogy, geochemistry, geochronology, fluid evolution and isotopic constraints on critical mineral deposits; (3) experimental advances in critical metal behaviors during metallogenic processes; (4) geological controls of the global or regional distribution of critical mineral deposits; and (5) the resource assessment of critical minerals and developments in metal extraction and recovery.

Prof. Dr. Pei Ni
Prof. Mincheng Xu
Dr. Tiangang Wang
Dr. Junyi Pan
Dr. Yitao Cai
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • critical metals
  • geochemical exploration
  • statistical data analysis
  • mineral geochemistry
  • petrogenesis and ore genesis
  • resource assessment
  • mineral processing

Published Papers (15 papers)

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16 pages, 8811 KiB  
Article
The Distribution Regularity and Flotation Study of Niobium-Bearing Minerals in Baiyun Obo
by Min Zhang, Fangfang Chen, Guoying Yan, Hongjing Li, Jing Li, Guan Peng and Hongdong Yu
Minerals 2023, 13(3), 387; https://doi.org/10.3390/min13030387 - 10 Mar 2023
Viewed by 1313
Abstract
The characteristics of Baiyun Obo niobium-bearing minerals are complex physicochemical properties that make the beneficiation of niobium minerals extremely difficult. In this paper, X-ray diffraction, X-ray fluorescence and mineral liberation analyzer (MLA) systems were used to study the niobium occurrence state and distribution [...] Read more.
The characteristics of Baiyun Obo niobium-bearing minerals are complex physicochemical properties that make the beneficiation of niobium minerals extremely difficult. In this paper, X-ray diffraction, X-ray fluorescence and mineral liberation analyzer (MLA) systems were used to study the niobium occurrence state and distribution of niobium-bearing minerals in the samples from Baiyun Obo. The results show that the chemical and mineral compositions of the sample are complex, with a Nb2O5 grading of 0.24%. There are many kinds of niobium minerals, including ilmenorutile, nioboaeschynite-Nd, baotite, latrappite, euxenite-Y, fergusonite and columbite-Mn, and the highest mass fraction of 0.55% is achieved with Nb in nioboaeschynite-Nd, followed by the mass fraction of ilmenorutile (0.33%). All of the niobium-containing minerals demonstrate a low degree of dissociation. Flotation experiments explored the optimal flotation conditions for HOBA (1-hydroxyoctyl-1,1-bisphosphonic acid) as a flotation collector for Baiyun Obo niobium minerals, which is able to increase the grade of Nb2O5 in the concentrate to 1.31%. The optimal use conditions of the reagent are pH 3.5–4.5, and the amount of the collector is 1000 g/t. By further optimizing the beneficiation process and reagent system, ilmenorutile and nioboaeschynite-Nd were significantly enriched in the concentrate, which suggested that HOBA can efficiently increase the grade of Nb2O5 in the concentrate. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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17 pages, 10573 KiB  
Article
Geochemical Characteristics of the Granodiorite Porphyry in Dongxiang W-Cu Deposit, SE China
by Yitao Cai, Pei Ni, Guoguang Wang and Hui Chen
Minerals 2023, 13(3), 380; https://doi.org/10.3390/min13030380 - 09 Mar 2023
Cited by 1 | Viewed by 1623
Abstract
The Dongxiang tungsten–copper deposit is a large W–Cu deposit located in the northeast of Jiangxi province in south China. Previous studies have mainly considered the geochemical and isotopic attributes of the ore deposit, but information is still lacking on the genesis and setting [...] Read more.
The Dongxiang tungsten–copper deposit is a large W–Cu deposit located in the northeast of Jiangxi province in south China. Previous studies have mainly considered the geochemical and isotopic attributes of the ore deposit, but information is still lacking on the genesis and setting of Dongxiang W–Cu mineralization-related intrusive rocks. This paper presents systematic elements and Sr–Nd–Hf isotopic data of the Dongxiang granodiorite porphyry. The Dongxiang granodiorite porphyry is intermediate–acidic in composition, with SiO2 contents of 60.00–75.16 wt.%, Al2O3 contents of 10.15–18.53 wt.%, an K2O contents of 2.95–4.28 wt.%. The REEs content ranges from 64.2 to 198.1 ppm, with LREE/HREE ratios of 7.67–17.47. It is characterized by adakitic geochemical affinities with high Sr/Y and (La/Yb)N ratios but low Y and Yb contents. A slight Eu anomaly, extreme depletion in Y and Yb, relatively low MgO content, and relatively high 207Pb/204Pb ratios together indicate that the Dongxiang granodiorite porphyry was likely derived from partial melting of the thickened lower continental crust. Based on zircon εHf(t) values (−11.8–−4.5), two-stage Hf model ages (1.33–1.94 Ga), and the regional geological setting, it can be inferred that Dongxiang granodiorite porphyry magma is mainly derived from Neoproterozoic juvenile crust with the involvement of Paleoproterozoic ancient crust. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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16 pages, 4133 KiB  
Article
Mineralogical and Geochemical Evidence of Paragenetic Unity of Igneous Silicate and Carbonatite Rocks of the Tomtor Massif in the North-East of the Siberian Platform
by Alexander Okrugin and Anatolii Zhuravlev
Minerals 2023, 13(2), 211; https://doi.org/10.3390/min13020211 - 31 Jan 2023
Viewed by 1204
Abstract
The Tomtor massif is a polychronous ring zonal complex of alkaline ultramafic and carbonatite rocks containing unique Nb and REE deposits. Mineralogical and geochemical studies of minerals from different types of silicate rocks and carbonatites of the Tomtor massif were performed. For excluding [...] Read more.
The Tomtor massif is a polychronous ring zonal complex of alkaline ultramafic and carbonatite rocks containing unique Nb and REE deposits. Mineralogical and geochemical studies of minerals from different types of silicate rocks and carbonatites of the Tomtor massif were performed. For excluding traces of the interaction between silicate and carbonatite melts, we limited ourselves to the study of independent small secant bodies located in the immediate vicinity of the massif itself. The presence of through mineral series in various silicate igneous rocks and carbonatite ores of high-titanium chromium spinels, rare-metal, ore and other exotic phases with similar compositional trends was defined. Such studies will help reveal the mineralogical criteria for the genetic relationship between silicate melts and associated carbonatite derivatives, which can form rich rare elements mineralization. Also, such studies help to improve the petrochemical and mineralogical criteria for dividing potentially diamond-bearing magmatites (typical kimberlites) from non-diamond-bearing kimberlites, alpicrites and other non-diamond-bearing rocks convergent to kimberlites, which are formed under different physicochemical conditions. The existence of polychronous complex ore–magmatic ring complexes, such as the Tomtor massif, indicates the existence of large deep intraplate magma-generating chambers in the lithospheric mantle. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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14 pages, 2202 KiB  
Article
National-Scale Geochemical Baseline and Anomalies of Chromium in Papua New Guinea
by Yuhao Zhao, Conrad Kumul, Tiangang Wang, Nathan Mosusu, Zhongyou Yao, Yiping Zhu, Bimin Zhang and Xueqiu Wang
Minerals 2023, 13(2), 205; https://doi.org/10.3390/min13020205 - 31 Jan 2023
Cited by 4 | Viewed by 2567
Abstract
Papua New Guinea (PNG) is located at the convergence edge of the Pacific Plate and the Indo-Australian Plate, consisting of three units. There are three chromium mineralization types in PNG. Based on national-scale geochemical mapping in PNG during 2015–2018, 1399 samples of stream [...] Read more.
Papua New Guinea (PNG) is located at the convergence edge of the Pacific Plate and the Indo-Australian Plate, consisting of three units. There are three chromium mineralization types in PNG. Based on national-scale geochemical mapping in PNG during 2015–2018, 1399 samples of stream sediments were collected from Highland Region, Papua Peninsula, and New Guinea Islands. This paper preliminarily studied chromium’s geochemical background, spatial distribution characteristics, and geochemical anomalies. The chromium concentration ranged from 3 ppm to 74,600 ppm, with a median value of 145 ppm, which was higher than the upper crustal abundance of chromium and the chromium geochemical baseline of Europe, Australia, North America, and China. In terms of stream sediment samples in different tectonic units, as mafic–ultramafic magmatic rocks are widely developed, the median chromium values of the New Guinea Orogen, including the Papuan Fold Belt, the New Guinea Thrust Belt, the Finisterre Terrane, the Aure Fold Belt, the Eastern Fold Belt, and the Eastern Papuan Composite Terrane, were higher than the value of the Melanesian Arc. The ophiolitic complexes, such as the April ophiolite, the Marum ophiolite, and the Papua ultramafic belt, significantly correlated with the higher chromium concentration. Eleven chromium high anomalies with mineralization potential were delineated, including three laterite and podiform prospecting areas and eight placer prospecting areas. Based on the chromium–nickel integrated anomaly map, comprehensive exploration and exploitation of nickel and chromium can be carried out in 1 and 11 high anomaly areas related to lateritic mineralization. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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22 pages, 6968 KiB  
Article
Characteristics and Formation Conditions of Se-Bearing Metacinnabar in the Wanshan Mercury Ore Field, Eastern Guizhou
by Xiao Wang, Jiajun Liu, Emmanuel John M. Carranza, Degao Zhai, Qingqing Zhao, Guoming Weng and Bin Zhang
Minerals 2023, 13(2), 173; https://doi.org/10.3390/min13020173 - 25 Jan 2023
Viewed by 1413
Abstract
Cinnabar (α-HgS) is the most common sulfide of mercury while metacinnabar (β-HgS), a high-temperature homogeneous polymorph of the mercury sulfide, is relatively rare, and the α phase of cinnabar transforms to the β phase at 344 °C. Meanwhile, there is a complete isomorphic [...] Read more.
Cinnabar (α-HgS) is the most common sulfide of mercury while metacinnabar (β-HgS), a high-temperature homogeneous polymorph of the mercury sulfide, is relatively rare, and the α phase of cinnabar transforms to the β phase at 344 °C. Meanwhile, there is a complete isomorphic series between HgS and HgSe, and the occurrence of Se-bearing metacinnabar is of great significance for the exploration of selenium resources. We studied through microscopic observation, electron-probe microanalysis, X-ray diffraction and field emission scanning electronic microscopy (FESEM) the Se-bearing metacinnabar of the Wanshan mercury ore field of southeastern Yangtze Block. These analyses, combined with physicochemical phase diagrams, constrained the textural and chemical evolution during the formation process of Se-bearing metacinnabar. Se-bearing metacinnabar was found in altered carbonatite, intergrown with cinnabar, sphalerite, pyrite, realgar and quartz. The Se-bearing metacinnabar contains 77.66–84.01 wt.% Hg, 0.18–1.17 wt.% Zn with extensive isomorphic substitution of Se and S (2.79–14.77 wt.% Se, 6.15–11.82 wt.% S). The presence of impurity elements (e.g., Zn and Se) is considered to be the key factor in expanding the stable range of Se-bearing metacinnabar. The cinnabar generated by the transformation of Se-bearing metacinnabar is characterized by inclusions of Hg-bearing sphalerite and pores, which indicate that this process was carried out through a coupled dissolution–reprecipitation (CDR) reaction. The formation temperature of Se-bearing metacinnabar is higher than that of cinnabar, and according to the phase relations between sulfides and selenides, we propose that logfS2(g) of ore-forming fluids is constrained within −15.663 to −13.141, and logfSe2 < logfS2–3.994 (150 °C). Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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22 pages, 4613 KiB  
Article
Geochronology of the Baishi W-Cu Deposit in Jiangxi Province and Its Geological Significance
by Li Li, Hai-Li Li, Guo-Guang Wang and Jian-Dong Sun
Minerals 2022, 12(11), 1387; https://doi.org/10.3390/min12111387 - 30 Oct 2022
Viewed by 1374
Abstract
The Baishi W-Cu deposit is located in the Nanling metallogenic belt, which is famous for its numerous W deposits and reserves. The formation age of this deposit remains unclear. In order to further infer the formation age of the deposit, this study conducted [...] Read more.
The Baishi W-Cu deposit is located in the Nanling metallogenic belt, which is famous for its numerous W deposits and reserves. The formation age of this deposit remains unclear. In order to further infer the formation age of the deposit, this study conducted detailed LA-ICP-MS U-Pb isotopic analyses of zircon and monazite selected from ore-related Baishi granite. The LA-ICP-MS zircon U-Pb weighted average ages of Baishi granite were determined to be 223 ± 2 Ma and 226 ± 1 Ma, and the LA-ICP-MS U-Pb weighted average ages of monazite were determined to be 224 ± 2 Ma and 223 ± 1 Ma. The BSE image of monazite was homogeneous, and the pattern of rare earth elements had an obvious negative Eu anomaly, indicating that monazite was of magmatic origin. Combining the ages of zircon and monazite, this study inferred that Baishi granite and the Baishi W-Cu deposit formed in the Triassic. The determination of the ore-forming event of the Baishi W-Cu deposit provides new data regarding the important Indosinian (Triassic) mineralization events in the Nanling metallogenic belt and suggests that geologists should strengthen the prospecting work of Indosinian tungsten deposits in the Nanling area. In terms of tectonic setting, it was inferred that the Triassic Baishi W-Cu deposit was formed in the extensional environment after intracontinental orogeny. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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20 pages, 4261 KiB  
Article
National-Scale Geochemical Baseline of 69 Elements in Laos Stream Sediments
by Wei Wang, Xueqiu Wang, Bimin Zhang, Qiang Wang, Dongsheng Liu, Zhixuan Han, Sounthone LAOLO, Phomsylalai SOUKSAN, Hanliang Liu, Jian Zhou, Xinbin Cheng and Lanshi Nie
Minerals 2022, 12(11), 1360; https://doi.org/10.3390/min12111360 - 26 Oct 2022
Cited by 2 | Viewed by 2033
Abstract
Geochemical baselines are crucial to explore mineral resources and monitor environmental changes. This study presents the first Laos geochemical baseline values of 69 elements. The National-scale Geochemical Mapping Project of Lao People’s Democratic Republic conducted comprehensive stream sediment sampling across Laos, yielding 2079 [...] Read more.
Geochemical baselines are crucial to explore mineral resources and monitor environmental changes. This study presents the first Laos geochemical baseline values of 69 elements. The National-scale Geochemical Mapping Project of Lao People’s Democratic Republic conducted comprehensive stream sediment sampling across Laos, yielding 2079 samples collected at 1 sample/100 km2, and 69 elements were analyzed. Based on the results of LGB value, R-mode factor analysis, and scatter plot analysis, this paper analyzes the relationship between the 69 elements and the geological background, mineralization, hypergene processes and human activities in the study area. The median values of element contents related to the average crustal values were: As, B, Br, Cs, Hf, Li, N, Pb, Sb, Zr, and SiO2, >1.3 times; Ba, Be, Cl, Co, Cr, Cu, F, Ga, Mn, Mo, Ni, S, Sc, Sr, Ti, Tl, V, Zn, Eu, Al2O3, Tot.Fe2O3, MgO, CaO, and Na2O, <0.7 times; and Ag, Au, Bi, Cd, Ge, Hg, I, In, Nb, P, Rb, Se, Sn, Ta, Th, U, W, Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and K2O, 0.7–1.3 times. R-mode factor analysis based on principal component analysis and varimax rotation showed that they fall into 12 factors related to bedrock, (rare earth, ferrum-group, and major Al2O3 and K2O elements; mineralization–Au, Sb, and As) and farming activities–N, Br, S, and C). This study provides basic geochemical data for many fields, including basic geology, mineral exploration, environmental protection and agricultural production in Laos. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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16 pages, 3042 KiB  
Article
Genesis of the Beixiang Sb-Pb-Zn-Sn Deposit and Polymetallic Enrichment of the Danchi Sn-Polymetallic Ore Belt in Guangxi, SW China
by Jing Wu, Zhi Li, Minjie Zhu, Wenting Huang, Juan Liao, Jian Zhang and Huaying Liang
Minerals 2022, 12(11), 1349; https://doi.org/10.3390/min12111349 - 25 Oct 2022
Cited by 2 | Viewed by 1463
Abstract
Antimony deposits contain little Sn, whereas Sb and Pb are not the principally contained metal of granite-related Sn deposits. The Danchi Sn-metallogenic ore belt (DSOB) in southwestern China is characterized by Sn-Sb-Zn-Pb co-enrichment, yet the triggers are poorly constrained. The Beixiang deposit in [...] Read more.
Antimony deposits contain little Sn, whereas Sb and Pb are not the principally contained metal of granite-related Sn deposits. The Danchi Sn-metallogenic ore belt (DSOB) in southwestern China is characterized by Sn-Sb-Zn-Pb co-enrichment, yet the triggers are poorly constrained. The Beixiang deposit in the southern DSOB consists of stage I Sn-Zn and stage II Sb-Pb-Zn mineralization. Here, we analyzed the cassiterite U-Pb age, fluid inclusion H-O and sulfide Pb-S isotopes, and calcite trace elements of the Beixiang ores. By comparing with the Dachang and Mangchang Sn-polymetallic ore-fields within the DSOB, we constrained the timing of regional mineralization and revealed the processes causing the Sb-Pb co-enrichment. The cassiterite U-Pb dating yielded 90.6 ± 4.5 Ma (MSWD = 2.6), similar to the ages of the Dachang and Mangchang ore fields, indicating the Late Cretaceous mineralization event throughout the DSOB. The fluid inclusions from stage II ore have δ18OH2O (−2.8 to −7.8‰) and δDV-SMOW (−90.5 to −59.3‰), and the synchronous calcite features have low REE contents, upward-convex REE patterns, and weak Eu anomalies. These suggest that the ore fluids were derived from meteoric water and oil field brine, which dissolved S and Pb from local strata as recorded by sulfide sulfur (δ34SV-CDT = −6.2 to −4.0‰) and Pb isotopes. However, calcite from the stage I ore have higher REE contents and (La/Yb)N, with strong positive Eu anomalies, indicating that the Sn-rich ore fluids were released by greisenization of granite. Overall, we suggest that the combination of granitic magma- and oil field brine-derived fluids, rich in Sn-Zn and Sb-Pb-Zn, respectively, caused the co-enrichment of Sn-Sb-Pb-Zn in Beixiang and throughout the DSOB. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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20 pages, 3095 KiB  
Article
Association of Rare Earths in Different Phases of Marcellus and Haynesville Shale: Implications on Release and Recovery Strategies
by Shailee Bhattacharya, Vikas Agrawal and Shikha Sharma
Minerals 2022, 12(9), 1120; https://doi.org/10.3390/min12091120 - 02 Sep 2022
Viewed by 1786
Abstract
Hydrocarbon-rich shales have been a major natural gas source in the US over the last decade. These organic-rich shales can also potentially serve as a source of some rare earth elements (REYs). However, the mode of occurrence and the geochemical processes that led [...] Read more.
Hydrocarbon-rich shales have been a major natural gas source in the US over the last decade. These organic-rich shales can also potentially serve as a source of some rare earth elements (REYs). However, the mode of occurrence and the geochemical processes that led to REY enrichment in these shales are still poorly understood. In this study, we investigated the whole-rock REY content and associations of REYs in the different phases of Marcellus and Haynesville Shale samples. A traditional sequential extraction procedure was adopted to understand the association of REYs in (i) exchangeable, (ii) acid-soluble, (iii) pyritic, (iv) organic matter, and (v) silicate fractions. Extraction efficiency was assessed by comparing the mineralogy of the pre- and post-sequential extraction samples using XRD. Elemental ratios such as La/Lu, La/Sm, Gd/Lu, Y/Ho, and Ce and Eu anomalies were utilized to understand whole-rock-normalized REY distribution patterns. Further, the distribution pattern in each extracted phase was examined to account for the relative contribution of phases to REY enrichment. The economic potential of these samples was evaluated by calculating HREE/LREE ratios, outlook coefficients, and by comparing their REY levels with those of coal fly ash deposits. Our results indicate that whole-rock REY content in the analyzed shale samples ranged from 295 to 342 ppm, with Haynesville Shale having a higher concentration than the Marcellus Shale sample. All samples exhibited an MREE–HREE-enriched pattern, indicating that the REY content is primarily contributed by carbonate and siliciclastic inputs. However, the average total REY extraction efficiency was only approximately 20% from the Haynesville samples and 9% from the Marcellus sample. We postulate that the poor REY yield is due to a high amount of refractory aluminosilicate/clay fraction in these samples. We demonstrate that traditional sequential extraction procedures may not be effective for extracting REYs from high organic–high aluminosilicate shale. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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11 pages, 2849 KiB  
Article
Amgaite, Tl3+2Te6+O6, a New Mineral from the Khokhoyskoe Gold Deposit, Eastern Siberia, Russia
by Anatoly V. Kasatkin, Galina S. Anisimova, Fabrizio Nestola, Jakub Plášil, Jiří Sejkora, Radek Škoda, Evgeniy P. Sokolov, Larisa A. Kondratieva and Veronika N. Kardashevskaia
Minerals 2022, 12(9), 1064; https://doi.org/10.3390/min12091064 - 24 Aug 2022
Cited by 2 | Viewed by 2949
Abstract
The new mineral amgaite was discovered at the Khokhoyskoe gold deposit, 120 km W of Aldan town, Aldanskiy District, Sakha Republic (Yakutia), Eastern Siberia, Russia. Amgaite forms fine-grained colloform aggregates up to 0.05 mm across, and is often intimately intergrown with avicennite, unidentified [...] Read more.
The new mineral amgaite was discovered at the Khokhoyskoe gold deposit, 120 km W of Aldan town, Aldanskiy District, Sakha Republic (Yakutia), Eastern Siberia, Russia. Amgaite forms fine-grained colloform aggregates up to 0.05 mm across, and is often intimately intergrown with avicennite, unidentified carbonates and antimonates of Tl. Other associated minerals include gold, silver, acanthite, arsenopyrite, pyrite, berthierite, chalcocite, weissbergite, chlorargyrite, calcite, quartz, goethite etc. Amgaite is dark reddish brown to black. It has submetallic luster, black streak, brittle tenacity and conchoidal fracture. Its density calculated from the empirical formula and powder XRD data is 8.358 g/cm3. Its Mohs’ hardness is ca. 1.5–2. Optically, amgaite is uniaxial. In reflected light, it is gray with a bluish shade, very weakly anisotropic with rare brownish red internal reflections. Reflectance values for the four COM wavelengths [Rmin, Rmax (%)(λ in nm)] are: 13.5, 14.2 (470); 12.7, 13.2 (546); 12.3, 12.7 (589); and 11.7, 12.3 (650). The Raman spectrum shows bands of Te–O and Tl–O bonds and confirms the absence in amgaite of H2O, OH–, CO32– groups and B–O bonds. The chemical composition is (electron microprobe, wt.%): MgO 0.43, CaO 1.62, Fe2O3 0.36, Tl2O3 66.27, Sb2O5 3.48, TeO3 27.31, total 99.47. The empirical formula based on 6 O apfu is Tl3+1.74Ca0.17Mg0.06Fe3+0.03Te6+0.93Sb5+0.13O6. Amgaite is trigonal, space group P321; unit-cell parameters are as follows: a = 9.0600(9), c = 4.9913(11) Å, V = 354.82(8) Å3, Z = 3. The strongest lines of the powder X-ray diffraction pattern [dobs, Å (I, %) (hkl)] are as follows: 3.352 (100) (111), 3.063 (15) (201), 2.619 (49) (300), 2.065 (18) (221), 1.804 (28) (302), 1.697 (8) (321), 1.625 (9) (411). The crystal structure of amgaite is the same as of synthetic Tl3+2Te6+O6. The new mineral is named after the Amga River, the basin of which hosts the type locality, Khokhoyskoe occurrence. The type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, with the registration number 5773/1. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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15 pages, 2422 KiB  
Article
Selective Comminution Applied to Mineral Processing of a Tantalum Ore: A Technical, Economic Analysis
by Lorena Guldris Leon and Magnus Bengtsson
Minerals 2022, 12(8), 1057; https://doi.org/10.3390/min12081057 - 21 Aug 2022
Cited by 2 | Viewed by 2071
Abstract
There is an increasing demand to simulate and optimize the performance and profit of comminution circuits, especially in low-grade ore processing, as is the case with critical metals minerals. Recent research has shown that the optimization result is greatly influenced by quality aspects [...] Read more.
There is an increasing demand to simulate and optimize the performance and profit of comminution circuits, especially in low-grade ore processing, as is the case with critical metals minerals. Recent research has shown that the optimization result is greatly influenced by quality aspects of the products, such as cost, profit, and capacity. This paper presents a novel approach to performing a multi-objective technical and economic analysis of tantalum ore processing to increase the production of critical metals minerals. The article starts with mineral composition analysis to highlight the potential of strategies for balancing the process layout for maximized production. The introduction of a combined technical and economic analysis presents the possibility of improving the profit by rearranging the mass flow given the rock’s mineral composition. Results show that selective comminution can improve process capacity by 23% and decrease production cost by 10% for the presented case. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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16 pages, 1694 KiB  
Article
Evaluation of Refractory Metal Concentrations in Nano-Particulate Pressed-Powder Pellets Using LA-ICP-MS
by Lorena Guldris Leon, Johanne Lebrun Thauront, K. Johan Hogmalm, Erik Hulthén and Johan Malmqvist
Minerals 2022, 12(7), 869; https://doi.org/10.3390/min12070869 - 09 Jul 2022
Cited by 1 | Viewed by 1351
Abstract
Whole-rock geochemical analysis is a standard method to measure the chemical composition of ores. Analysis of refractory ore metals such as Ta and W typically requires fused bead and acid digestion followed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled [...] Read more.
Whole-rock geochemical analysis is a standard method to measure the chemical composition of ores. Analysis of refractory ore metals such as Ta and W typically requires fused bead and acid digestion followed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled mass spectrometry (ICP-MS). Since these techniques are time-consuming and expensive, there is a demand for methods that can quantitatively measure low elemental concentration of refractory ore metals using a less expensive and simple approach. This paper evaluates preparation and analytical procedures developed to obtain whole-rock element concentrations of ore samples and mineral concentrates. It shows that the production of nano-particulate pressed-powder pellets followed by LA-ICP-MS analysis of W and Ta ores can be used to determine, within the error margin, the concentrations of the refractory metals W, Ta, Nb, and Sn compared to a reference values obtained by solution analysis. The results have implications for developing a commercially viable method for analysis of refractory elements to benefit mineral processing given the simplicity and resource-efficiency of the combined pressed pellet production and laser ablation analytical methodology. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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13 pages, 3914 KiB  
Article
Mineralogical Characteristic and Beneficiation Evaluation of a Ta-Nb-Li-Rb Deposit
by Zihu Lv, Hongwei Cheng, Min Wei, Dengkui Zhao, Dongyin Wu and Changmiao Liu
Minerals 2022, 12(4), 457; https://doi.org/10.3390/min12040457 - 08 Apr 2022
Cited by 2 | Viewed by 1941
Abstract
In order to rationally develop and utilize a Ta–Nb–Li–Rb rare metal deposit in Jiangxi Province, the mineralogical characteristics of the ore, such as chemical composition, mineral composition, modes of occurrence of major elements, and dissemination characteristics of major minerals, were investigated in detail [...] Read more.
In order to rationally develop and utilize a Ta–Nb–Li–Rb rare metal deposit in Jiangxi Province, the mineralogical characteristics of the ore, such as chemical composition, mineral composition, modes of occurrence of major elements, and dissemination characteristics of major minerals, were investigated in detail based on optical microscopy analysis, chemical analysis, X-ray diffraction analysis, artificial panning, mineral liberation analysis, and electron probe microanalysis. The results reveal that the main useful elements in the ore are tantalum, niobium, lithium, and rubidium. Niobium and tantalum are mainly found in the mineral form of columbite. Columbite has particle sizes ranging from 0.5 mm to 0.012 mm, with the most common sizes being 0.3 to 0.044 mm. Intergranular dispersion accounts for 73.92% of the embedding in columbite, whereas inclusions account for 26.08%. Lithium is found mostly in zinnwaldite, while rubidium is found primarily in feldspar and zinnwaldite, both in a homogenous distribution. The beneficiation evaluation of this ore was conducted based on the mineralogical characteristic, and it indicates that the tantalum-niobium–lithium–rubidium rare metal resources, as well as the feldspar and quartz non-metallic resources in the ore, can be effectively and comprehensively recovered using gravity, magnetic, and flotation separation methods. A staged grinding and separating process was adopted which could produce tantalum–niobium mineral concentrates (18.34% Ta2O5 at a recovery of 47.65% and 41.33% Nb2O5 at a recovery of 69.96%), zinnwaldite concentrate (2.41% Li2O and 0.80% Rb2O at a recovery of 81.82%) and other concentrates such as cassiterite, topaz, galena, sphalerite, and feldspar. This study provides suggestions for the rational development and utilization of the deposit and provides a reasonable level of recovery prediction. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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Review

Jump to: Research

32 pages, 3921 KiB  
Review
A Review of Fatty Acid Collectors: Implications for Spodumene Flotation
by Brian Kawenski Cook and Charlotte E. Gibson
Minerals 2023, 13(2), 212; https://doi.org/10.3390/min13020212 - 31 Jan 2023
Cited by 6 | Viewed by 4789
Abstract
Increasing demand for lithium-ion batteries has led to the development of several new lithium mineral projects around the globe. Some major mineral processing challenges these projects face are similarities in gangue and value mineral behaviour and poor selectivity in froth flotation. Unsaturated anionic [...] Read more.
Increasing demand for lithium-ion batteries has led to the development of several new lithium mineral projects around the globe. Some major mineral processing challenges these projects face are similarities in gangue and value mineral behaviour and poor selectivity in froth flotation. Unsaturated anionic fatty acids are the primary spodumene flotation collectors, known to be strong collectors with poor solubility and selectivity. Fundamental flotation research consensus is that spodumene flotation is driven by a fatty acid–anion complex adsorbed at cationic aluminum sites. However, many small-scale studies result in poor recoveries, prompting several researchers to investigate cationic activators or mixed anionic/cationic collectors to improve flotation performance. Testwork with real spodumene ore is rare in recent literature, but older publications from several deposits prove that fatty acids can successfully concentrate spodumene. The process generally includes alkaline scrubbing, high-density fatty acid conditioning, and flotation at pH 7.5–8.5 with 500–750 g/t fatty acid collector. The collector speciation behaviour is notably sensitive to pulp conditions around this pH; possibly resulting in unstable flotation circuits and inconsistent results. This paper reviews fatty acid collector properties and the available industrial and fundamental spodumene flotation research. We aim to provide new insight for understanding particle-collector interactions in spodumene flotation and help bridge the gap between fundamental and industrial processes which will be needed to de-risk projects in the growing lithium mineral industry. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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17 pages, 5040 KiB  
Review
Advances on Exploration Indicators of Mineral VNIR-SWIR Spectroscopy and Chemistry: A Review
by Yan Zhou, Tiangang Wang, Feipeng Fan, Shizhong Chen, Weimin Guo, Guangfu Xing, Jiandong Sun and Fan Xiao
Minerals 2022, 12(8), 958; https://doi.org/10.3390/min12080958 - 28 Jul 2022
Cited by 4 | Viewed by 3007
Abstract
Establishing exploration vectors to infer the properties of ore-forming fluids, locate blind ore bodies with the aid of visible to near-infrared (VNIR) and short-wave infrared (SWIR) spectroscopy, and infer the chemistry of minerals, is a new research interest for economic geology. Common alterations [...] Read more.
Establishing exploration vectors to infer the properties of ore-forming fluids, locate blind ore bodies with the aid of visible to near-infrared (VNIR) and short-wave infrared (SWIR) spectroscopy, and infer the chemistry of minerals, is a new research interest for economic geology. Common alterations and clay minerals, including sericite, chlorite, epidote, alunite, kaolinite, tourmaline, etc., are ideal objects for the study of exploration indicators due to their sensitivity to variations in the nature of hydrothermal fluid. The diagnostic spectral feature and chemistry vary spatially and systematically with physicochemical change. VNIR spectroscopy can characterize the REE-bearing clay minerals directly. Obtaining spectral or chemical parameters with the aid of VNIR-SWIR spectroscopy, electron probe micro-analyzer (EPMA) or laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) can help to establish exploration vectors. This paper systematically summarizes recent advances in mineral exploration indicators (MEIs) of VNIR-SWIR spectroscopy and chemistry, and compares them in different regions or deposits. We found that some MEI spatial variation trends are random, even the same type of deposit can show an opposite trend. The controlling factors that limit the application of the established MEIs are vague. Conducting further research on petrology and mineralogy with the aids of observation under microscopy, X-ray diffraction (XRD), TESCAN Integrated Mineral Analyzer (TIMA), and EPMA are suggested to discover alteration mineral assemblage, alteration stages, and behaviors of “the pathfinder elements” related to mineralization. Based on the above research, the physicochemical properties of ore-forming fluids and their control over MEIs can be inferred. Refining the theoretical basis is critical to understanding and popularization of spectral and chemical MEIs. Full article
(This article belongs to the Special Issue Critical Metal Minerals)
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