Leaching of fluorine and rare earths from bastnaesite calcined with aluminum hydroxide and the recovery of fluorine as cryolite

He, Jing; Li, Yong; Xue, Xiangxin; Ru, Hongqiang; Huang, Xiaowei; He, Yang

doi:10.1039/c6ra28106k

Cited by 13 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The upscaling of MXenes production requires the selective removal of MILD-induced Li 3 AlF 6 nanoparticles that persist after conventional washing. Inspired by the process used to leach Li and F from various minerals forming Li 3 AlF 6 (often named 𝛽cryolite), [48][49][50] we explored the use of sulfuric acid (H 2 SO 4 ) for the removal of pervasive Li 3 AlF 6 . We advocate the purification of Li 3 AlF 6 -containing Ti 3 C 2 T z MXene clay according to Reaction 6 and Figure 4.…”

Section: Selective Removal Of LI 3 Alf 6 From Etched Mxene Claymentioning

confidence: 99%

Upscaled Synthesis Protocol for Phase‐Pure, Colloidally Stable MXenes with Long Shelf Lives

Goossens,

Lambrinou,

Tunca

et al. 2023

Small Methods

View full text Add to dashboard Cite

MXenes are electrically conductive 2D transition metal carbides/nitrides obtained by the etching of nanolaminated MAX phase compounds, followed by exfoliation to single‐ or few‐layered nanosheets. The mainstream chemical etching processes have evolved from pure hydrofluoric acid (HF) etching into the innovative “minimally intensive layer delamination” (MILD) route. Despite their current popularity and remarkable application potential, the scalability of MILD‐produced MXenes remains unproven, excluding MXenes from industrial applications. This work proposes a “next‐generation MILD” (NGMILD) synthesis protocol for phase‐pure, colloidally stable MXenes that withstand long periods of dry storage. NGMILD incorporates the synergistic effects of a secondary salt, a richer lithium (Li) environment, and iterative alcohol‐based washing to achieve high‐purity MXenes, while improving etching efficiency, intercalation, and shelf life. Moreover, NGMILD comprises a sulfuric acid (H2SO4) post‐treatment for the selective removal of the Li3AlF6 impurity that commonly persists in MILD‐produced MXenes. This work demonstrates the upscaled NGMILD synthesis of (50 g) phase‐pure Ti3C2Tz MXene clays with high extraction yields (>22%) of supernatant dispersions. Finally, NGMILD‐produced MXene clays dry‐stored for six months under ambient conditions experience minimal degradation, while retaining excellent redispersibility. Overall, the NGMILD protocol is a leap forward toward the industrial production of MXenes and their subsequent market deployment.

show abstract

Section: Selective Removal Of LI 3 Alf 6 From Etched Mxene Claymentioning

confidence: 99%

Upscaled Synthesis Protocol for Phase‐Pure, Colloidally Stable MXenes with Long Shelf Lives

Goossens,

Lambrinou,

Tunca

et al. 2023

Small Methods

View full text Add to dashboard Cite

show abstract

“…The fact that B and Cr were immobilized under colder conditions but underwent aging at the highest temperatures enhanced the leachability of Cr in some samples, and the fluorine content effectively decreased under warmer conditions. Fluoride (the anion of fluorine) is listed as a common contaminant of water by the World Health Organization (WHO) because it can cause many human health problems [12]. In plants, F can be absorbed by plants under natural conditions, and it is bound to insoluble compounds such as CaF 2 [13].…”

Section: Introductionmentioning

confidence: 99%

Influence of Blending High-Calcium Additive on Environmental Safety of B, F, and Se: A Case Study from Thermodynamic Calculation

Sutopo,

Desfitri,

Hayakawa

et al. 2024

Environments

View full text Add to dashboard Cite

Coal remains an important fuel for use in thermal power plants. However, coal-burning power plants produce large amounts of CFA, which contains TEs such as B, F, and Se, which are leached upon contact with water and act as potential polluters of aquifer systems and soil. To study the transformation of TEs, a thermodynamic calculation (FactSage 7.2) was used. Paper sludge ash was used as a calcium compound additive. The influence of blending a high-calcium additive on the environmental safety of TEs was investigated based on the effect of the mass addition ratio of PS ash. This study’s results confirmed that the leaching processes of TEs, namely (CaO)2(Al2O3), CaF2, Ca10(PO4)F2, and CaSeO4(H2O)2, were caused by the formation of B, F, and Se compounds during the leaching process. Thus, it is clear that calcium has the greatest influence on the transformation of TEs due to their reaction, which, in turn, minimizes the effects of the TEs’ release into the environment. The concentrations of TEs from the sample and addition of PS ash decreased slightly, indicating that the inhibition of TEs was enabled through the addition of PS ash. Although the PS ash YB had the highest calcium content, the PS ash YC gave the best results during the B and Se inhibition processes. The experimental observation was also evaluated for comparison. For the analysis of TEs’ leaching ratios using the thermodynamic calculation and experiment, the experimental results were lower than those initially predicted. These results will help us to choose the best available control technology to minimize the effects of TEs released into the environment.

show abstract

“…Currently, the main treatment processes for bastnaesite include oxidation roasting-acid leaching and sodium hydroxide decomposition-hydrochloric acid leaching [8][9][10][11][12][13]. Hydrometallurgical processes for bastnaesite are still plagued by the element fluorine [14][15][16], especially in the acid-leaching step [17][18][19]. When using inorganic acid to leach bastnaesite or its decomposition products, high leaching acidity will easily lead to the escape of hydrogen fluoride, and low leaching acidity will lead to a low recovery of rare earth.…”

Section: Introductionmentioning

confidence: 99%

A Novel Dissolution and Synchronous Extraction of Rare Earth Elements from Bastnaesite by a Functionalized Ionic Liquid [Hbet][Tf2N]

et al. 2022

View full text Add to dashboard Cite

Rare earth elements (REEs) are widely used in high-tech industries and are important basic raw materials. Bastnaesite is one of the most important minerals used in the rare earth extraction industry, and the efficient development of it is the key guarantee for the safe supply of rare earth raw materials. In this study, a novel method for dissolving bastnaesite using a carboxyl-functionalized ionic liquid ([Hbet][Tf2N]) is proposed. This innovative method provides a collaborative model with the dissolution and synchronous extraction of rare earth elements during the heating and cooling of the [Hbet][Tf2N]–H2O system. In the heating process, rare earth elements can be dissolved in a weakly acidic environment of ionic liquid without the trouble of HF escaping, and the leaching efficiencies of rare earth elements are above 95%. During the cooling of the leaching system, the rare earth ions in the dissolved state are extracted into the ionic liquid phase due to the two-phase stratification of [Hbet][Tf2N] and aqueous solution. It has been proved that rare earth ions recovery and ionic liquid regeneration can be achieved by back extraction using oxalic acid for the REEs-loaded ionic liquid.

show abstract

Leaching of fluorine and rare earths from bastnaesite calcined with aluminum hydroxide and the recovery of fluorine as cryolite

Abstract: Bastnaesite is decomposed with aluminium hydroxide to avoid fluorine loss and contamination, to recover fluorine as cryolite.

Cited by 13 publications

References 19 publications

Upscaled Synthesis Protocol for Phase‐Pure, Colloidally Stable MXenes with Long Shelf Lives

Upscaled Synthesis Protocol for Phase‐Pure, Colloidally Stable MXenes with Long Shelf Lives

Influence of Blending High-Calcium Additive on Environmental Safety of B, F, and Se: A Case Study from Thermodynamic Calculation

A Novel Dissolution and Synchronous Extraction of Rare Earth Elements from Bastnaesite by a Functionalized Ionic Liquid [Hbet][Tf2N]

Contact Info

Product

Resources

About