Process mineralogy of rare earths from deeply weathered alkali-carbonatite deposits in Brazil

Antoniassi, Juliana Lívi; Uliana, Daniel; Contessotto, Renato; Kahn, Henrique; Ulsen, Carina

doi:10.1016/j.jmrt.2020.05.128

Cited by 12 publications

(5 citation statements)

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“…That is, SEM can be used to make qualitative descriptions of mineral alterations in terms of whether they result from chemical, physical, or even biological processes. Figure 3 also exemplifies the use of magnification levels on the identification of mineral phases and crystals within particles, as studied for the identification of rare earth elements (REEs) in carbonatite ore [8]. REEs are largely speciated as monazite ((REE)PO 4 ), and SEM images enable identification of the crystal structures, wherein larger colloform, acicular, and massive crystals, which are relatively large, are identifiable in lower magnification images, and the presence of submicrometer-sized crystals requires higher magnification to elucidate their associated porosity and crystal intergrowth [8].…”

Section: Basic Sem Operationmentioning

confidence: 99%

“…Figure 3 also exemplifies the use of magnification levels on the identification of mineral phases and crystals within particles, as studied for the identification of rare earth elements (REEs) in carbonatite ore [8]. REEs are largely speciated as monazite ((REE)PO 4 ), and SEM images enable identification of the crystal structures, wherein larger colloform, acicular, and massive crystals, which are relatively large, are identifiable in lower magnification images, and the presence of submicrometer-sized crystals requires higher magnification to elucidate their associated porosity and crystal intergrowth [8]. Such morphological and mineral assemblage information is critical in mineral processing to predict the behavior of the mineral upon comminution and hydrometallurgical processing.…”

Section: Basic Sem Operationmentioning

confidence: 99%

“…The qualitative analysis of minerals is usually conducted through conventional optical microscopy (OM), also known as light microscopy (LM), scanning electron microscopy (SEM), and infrared spectroscopy methods [6][7][8]. Mineral characteristics and mutual relationships are broadly analyzed by OM; however, due to resolution limitations, qualitative analyses of micro and nanoscale particles, including their structural characteristics and mineral morphology, are lacking [9,10].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mineral Characterization Using Scanning Electron Microscopy (SEM): A Review of the Fundamentals, Advancements, and Research Directions

Ali,

Zhang,

Santos

2023

Applied Sciences

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Scanning electron microscopy (SEM) is a powerful tool in the domains of materials science, mining, and geology owing to its enormous potential to provide unique insight into micro and nanoscale worlds. This comprehensive review discusses the background development of SEM, basic SEM operation, including specimen preparation and image processing, and the fundamental theoretical calculations underlying SEM operation. It provides a foundational understanding for engineers and scientists who have never had a chance to dig in depth into SEM, contributing to their understanding of the workings and development of this robust analytical technique. The present review covers how SEM serves as a crucial tool in mineral characterization, with specific discussion on the workings and research fronts of SEM-EDX, SEM-AM, SEM-MLA, and QEMSCAN. With automation gaining pace in the development of all spheres of technology, understanding the uncertainties in SEM measurements is very important. The constraints in mineral phase identification by EDS spectra and sample preparation are conferred. In the end, future research directions for SEM are analyzed with the possible incorporation of machine learning, deep learning, and artificial intelligence tools to automate the process of mineral identification, quantification, and efficient communication with researchers so that the robustness and objectivity of the analytical process can be improved and the analysis time and involved costs can be reduced. This review also discusses the idea of integrating robotics with SEM to make the equipment portable so that further mineral characterization insight can be gained not only on Earth but also on other terrestrial grounds.

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Section: Basic Sem Operationmentioning

confidence: 99%

Section: Basic Sem Operationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mineral Characterization Using Scanning Electron Microscopy (SEM): A Review of the Fundamentals, Advancements, and Research Directions

Ali,

Zhang,

Santos

2023

Applied Sciences

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“…In recent decades, attention to rare-earth mineral resources has increased worldwide [1,2]. The growing demand for green technologies has led to the large-scale application of rare-earth elements in advanced electronic products and increased the demand for rare-earth elements in the world's major economies, including the United States, the European Union, the United Kingdom, and Japan [3,4], with an estimated annual growth rate of 3.7% to 8.6% [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Bayan Obo tailing pond, one of the world's largest rare-earth tailing ponds [8], contains tailings generated since the 1960s, at the rate of 386,000 tpa [9][10][11][12]. Currently, the tailing pond covers approximately 12 km 2 and stores approximately 200 million tons of tailings [13][14][15][16][17]. Tailings contain a large amount of iron, rare-earth elements, fluorine, Niobium, and other elements, which are a valuable secondary resource [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

The Process Mineralogical Characterization of Bayan Obo Rare-Earth Tailings and Density Functional Theory Study of the Occurrence State of Sc

Shao,

Du,

Deng

et al. 2023

Minerals

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As Bayan Obo rare-earth tailings, which are generated after the production of mineral products with the raw ore from different mining areas, are considered secondary resources rich in valuable elements such as F, Fe, REE, and Nb, an effective method is urgently needed to recover such valuable elements for resource recycling and environmental conservation. A mineralogical analysis can enable process diagnosis, design, and optimization and is the key to comprehensively utilizing valuable elements. Hence, detailed mineralogical characterization is necessary as a starting point to develop a feasible processing flowsheet. In this study, various detection methods, namely inductively coupled plasma-optical emission spectrometry (ICP), X-ray Fluorescence Spectrometer (XRF), X-ray powder diffractometer (XRD), scanning electron microscopy system with an energy dispersive spectrometer (SEM-EDS), mineral liberation analysis (MLA), and electron probe microanalysis (EPMA), were applied to conduct detailed mineralogical characterization of Bayan Obo rare-earth tailings, and the occurrence state of Sc in the main Sc-bearing minerals was studied using density functional theory (DFT). The results showed that Fe mainly occurs in hematite, riebeckite, ankerite, siderite, and pyrite, with contents of 50.15 wt%, 27.94 wt%, 8.34 wt%, 4.92 wt%, and 5.59 wt%, respectively. Nearly all F occurs in 26.8 wt% fluorite. The main rare-earth minerals are bastnasite, apatite, and monazite (La), with contents of 5.0%, 5.0%, and 1.6% in Bayan Obo rare-earth tailings, respectively. Notably, 48.47%, 21.70%, 10.34%, and 10.28% of niobium element occurs in nioboaeschynite, pyrochlore, dingdaohengite, and ilmenorutile, respectively. Scandium was detected in five minerals, namely aegirine, riebeckite, monazite, ilmenorutile, and niobite, with average contents of 0.04 wt%, 0.22 wt%, 0.06 wt%, 0.06 wt%, and 1.58 wt%, respectively. According to the DFT analysis, the state of Sc in aegirine is different from that in riebeckite. Scandium in aegirine mainly substitutes Fe or enters the interstitial lattice site, while Sc in riebeckite tends to replace Fe. Based on these results, a process for recovering valuable elements from tailings is proposed.

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Physicochemical characterization of monazite sand and its associated bacterial species from the beaches of southeastern Brazil

Orlando

Galvão

Passamai

et al. 2021

Environ Sci Pollut Res

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Process mineralogy of rare earths from deeply weathered alkali-carbonatite deposits in Brazil

Cited by 12 publications

References 12 publications

Mineral Characterization Using Scanning Electron Microscopy (SEM): A Review of the Fundamentals, Advancements, and Research Directions

Mineral Characterization Using Scanning Electron Microscopy (SEM): A Review of the Fundamentals, Advancements, and Research Directions

The Process Mineralogical Characterization of Bayan Obo Rare-Earth Tailings and Density Functional Theory Study of the Occurrence State of Sc

Physicochemical characterization of monazite sand and its associated bacterial species from the beaches of southeastern Brazil

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