A review of reagents applied to rare-earth mineral flotation

Marion, Christopher; Li, Ronghao; Waters, Kristian E.

doi:10.1016/j.cis.2020.102142

Cited by 99 publications

(31 citation statements)

References 108 publications

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“…Since the inception of collection with hydroxamic acid ligands, extensive progress has been made in describing the interactions between the hydroxamic acid group ( Scheme 1 , with pKa values from Humbert et al., 1998 , Khalil et al., 2007 ) and metal ions in terms of chemisorption on REE mineral surfaces and weaker adsorption on gangue ( Anderson, 2015 ; Cao et al., 2019 ; Marion et al., 2020 ; Nagaraj, 2018 ; Pradip and Fuerstenau, 1983 , 1985 ; Xiong et al., 2020 ). Typically, chemisorption results in chelation, forming a five-membered ring through interactions between both hydroxamic oxygen atoms and a surface cation ( Nagaraj, 2018 ; Ren et al., 1997 ).…”

Section: Introductionmentioning

confidence: 99%

“…Aromatic hydroxamic ligands have shown recent promise for bastnäsite flotation ( Everly, 2017 ). Studies employing these collectors have optimized the conditions for flotation and describe the adsorption of some of these ligands onto the surface ( Cao et al., 2018 ; Jordens et al., 2014 , 2016 ; Li et al., 2018 ; Marion et al., 2020 ; Xia et al., 2014 ; Yang et al., 2017 ; Yu et al., 2020 ). Here, we provide mechanistic insight into the adsorption of one aromatic ligand, salicylhydroxamic acid ( N ,2-dihydroxybenzamide, SHA), through a series of investigations designed to relate structure to adsorption selectivity.…”

Section: Introductionmentioning

confidence: 99%

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A Molecular-Scale Approach to Rare-Earth Beneficiation: Thinking Small to Avoid Large Losses

et al. 2020

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Summary Separating rare-earth-element-rich minerals from unwanted gangue in mined ores relies on selective binding of collector molecules at the interface to facilitate froth flotation. Salicylhydroxamic acid (SHA) exhibits enhanced selectivity for bastnäsite over calcite in microflotation experiments. Through a multifaceted approach, leveraging density functional theory calculations, and advanced spectroscopic methods, we provide molecular-level mechanistic insight to this selectivity. The hydroxamic acid moiety introduces strong interactions at metal-atom surface sites and hinders subsurface-cation stabilization at vacancy-defect sites, in calcite especially. Resulting from hydrogen-bond-induced interactions, SHA lies flat on the bastnäsite surface and shows a tendency for multilayer formation at high coverages. In this conformation, SHA complexation with bastnäsite metal ions is stabilized, leading to advanced flotation performance. In contrast, SHA lies perpendicular to the calcite surface due to a difference in cationic spacing. We anticipate that these insights will motivate rational design and selection of future collector molecules for enhanced ore beneficiation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Molecular-Scale Approach to Rare-Earth Beneficiation: Thinking Small to Avoid Large Losses

et al. 2020

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“…It is an active reagent that reveals the properties of amides and oxime acids and is used for flotation of clay, copper oxide, cassiterite, etc. It can be adsorbed onto minerals by chemisorption between the metal ions on the mineral surface and the two O atoms in the molecule to form powerful five-membered ring chelation adsorption ( Marion et al, 2013 ). Many studies have attempted to use hydroxamate as a collector for the typical rare earth mineral, bastnaesite, and have proven that hydroxamate is more effective than fatty acid collectors.…”

Section: Introductionmentioning

confidence: 99%

Surface Mechanism of Fe3+ Ions on the Improvement of Fine Monazite Flotation With Octyl Hydroxamate as the Collector

Zheng¹,

Qian

Zou

et al. 2021

Front. Chem.

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Froth flotation of fine minerals has always been an important research direction in terms of theory and practice. In this paper, the effect and mechanism of Fe3+ on improving surface hydrophobicity and flotation of fine monazite using sodium octyl hydroxamate (SOH) as a collector were investigated through a series of laboratory tests and detection measurements including microflotation, fluorescence spectrum, zeta potential, and X-ray photoelectron spectroscopy (XPS). Flotation tests have shown that fine monazite particles (−26 + 15 μm) cannot be floated well with the SOH collector compared to the coarse fraction (−74 + 38 μm). However, adding a small amount of Fe3+ to the pulp before SOH can significantly improve the flotation of fine monazite. This is because the addition of Fe3+ promotes the adsorption of SOH and greatly improves the hydrophobicity of the monazite surface. This can result in the formation of a more uniform and dense hydrophobic adsorption layer, as shown by the fluorescence spectrum and zeta potential results. From the XPS results, Fe3+ reacts with surface O atoms on the surface of monazite to form a monazite–Osurf–Fe group that acts as a new additional active site for SOH adsorption. A schematic model was also proposed to explain the mechanism of Fe3+ for improving surface hydrophobicity and flotation of fine monazite using octyl hydroxamate as a collector. The innovative point of this study is using a simple reagent scheme to float fine mineral particles rather than traditional complex processes.

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“…Traditional organic collectors direct their hydrophobic chains to the solution, and the hydrophilic head is adsorbed to the active site on the mineral surface, making the mineral surface hydrophobic (Fuerstenau and Jia, 2004). Hydrophobic mineral particles can collide with bubbles and attach to them, lifting them onto the surface of the pulp (Marion et al, 2020). Therefore, much research has focused on the development of highly efficient collectors of various minerals.…”

Section: Introductionmentioning

confidence: 99%

Flotation of Smithsonite From Quartz Using Pyrophyllite Nanoparticles as the Natural Non-toxic Collector

2021

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The use of natural hydrophobic mineral nanoparticles as a collector in froth flotation has recently attracted the attention of researchers. In this article, the separation performance and mechanism of pyrophyllite nanoparticles (PNPs) on smithsonite and quartz flotation system were investigated using the method of flotation, zeta potential, contact angle, and scanning electron microscope (SEM)/energy disperse spectroscopy (EDS). The results of single mineral flotation showed that the difference in flotation recovery between smithsonite and quartz was large for NaOL, DDA, and PNP collectors in the acidic pH range, the largest of which was the PNP system. At pH 6, the optimal dosage of PNPs was 1,000 mg/L. Separation of mixed minerals of smithsonite and quartz using a PNP collector provides the optimum concentrate index (Zn grade 50.84% and Zn recovery 85.36%). According to the results of zeta potential measurement, PNPs and quartz were negatively charged, and the surface of smithsonite was positively charged at pH 6. This provided conditions for smithsonite to selectively adsorb PNPs due to different electrostatic forces. Selective adsorption of PNPs in the smithsonite/quartz flotation system was directly observed by SEM/EDS detection. Hydrophobic PNPs were adsorbed on the surface of hydrophilic smithsonite to make it hydrophobic, and the surface of quartz remained hydrophilic. This is the mechanism for separating smithsonite and quartz using PNPs.

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A review of reagents applied to rare-earth mineral flotation

Cited by 99 publications

References 108 publications

A Molecular-Scale Approach to Rare-Earth Beneficiation: Thinking Small to Avoid Large Losses

A Molecular-Scale Approach to Rare-Earth Beneficiation: Thinking Small to Avoid Large Losses

Surface Mechanism of Fe3+ Ions on the Improvement of Fine Monazite Flotation With Octyl Hydroxamate as the Collector

Flotation of Smithsonite From Quartz Using Pyrophyllite Nanoparticles as the Natural Non-toxic Collector

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