Extraction of scandium from aqueous sulfate solutions by bis(3,5,5-trimethylhexyl)ammonium sulfate

Cattrall, RW; Slater, S.J.E.

doi:10.1021/ic50085a032

Cited by 11 publications

(4 citation statements)

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“…During the extraction, metal separation is achieved on the basis of the difference in affinity of the metal ions for the selected extractant. The extractants can be divided into three main classes: (1) cation exchangers or acidic extractants (e.g., alkyl phosphorus acids or carboxylic acids), , (2) solvating extractants or neutral extractants (e.g., ketones or organophosphorus esters), , and (3) anion exchangers or basic extractants (e.g., protonated amines or quaternary ammonium salts). − …”

Section: Introductionmentioning

confidence: 99%

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

et al. 2019

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The metal extraction mechanism of basic extractants is typically described as an anion exchange process, but this mechanism does not correctly explain all observations. This paper introduces a novel model for the extraction of metals by basic extractants from chloride media supported by experimental data on methyltrioctylammonium chloride and Aliquat 336 chloride systems. This model relies on the hypothesis that the metal species least stabilized in the aqueous phase by hydration (i.e., the metal species with the lowest charge density) is extracted more efficiently than the more water stabilized species (i.e., species with higher charge densities). Once it is transferred to the organic phase, the extracted species can undergo further Lewis acid−base adduct formation reactions with the chloride anions available in the organic phase to form negatively charged chloro complexes, which than associate with the organic cations. Salting-out agents influence the extraction, most likely by decreasing the concentration of free water molecules, which destabilizes the metal complex in the aqueous phase. The evidence provided includes (1) the link between extraction and transition-metal speciation, (2) the trend in extraction efficiency as a function of the concentration of different salting-out agents, and (3) the behavior of HCl in the extraction system. The proposed extraction model better explains the experimental observations in comparison to the anion exchange model and allows the prediction of optimal conditions for metal extractions and separations a priori, by selecting the most suitable salting-out agent and its concentration.

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Section: Introductionmentioning

confidence: 99%

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

et al. 2019

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“…The extraction of Sc from acidic sulfate solutions by bis(3,5,5-trimethylhexyl) (NH₄)₂SO₄ was found to have stoichiometry of (R 2 NH 2 ) 4 ScOH(SO 4 ) 3 , where R is 3,5,5-trimethylhexyl [ 28 ].…”

Section: Separation and Purification Of Rare Earth Elements Using Sxmentioning

confidence: 99%

“…The complications of scandium recovery flow-charts depend on the various types and number of contaminants [ 27 ]. The separation and recovery of metals such scandium from other metallic impurities using an appropriate technology resulting in zero waste would solve a number of environmental problems [ 28 ]. Producing pure scandium metal from low-grade ores, secondary mud, or bauxite residue with overall scandium content around 100 mg/kg is a challenging task [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

Scandium Recovery Methods from Mining, Metallurgical Extractive Industries, and Industrial Wastes

et al. 2022

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The recovery of scandium (Sc) from wastes and various resources using solvent extraction (SX) was discussed in detail. Moreover, the metallurgical extractive procedures for Sc recovery were presented. Acidic and neutral organophosphorus (OPCs) extractants are the most extensively used in industrial activities, considering that they provide the highest extraction efficiency of any of the valuable components. Due to the chemical and physical similarities of the rare earth metals, the separation and purification processes of Sc are difficult tasks. Sc has also been extracted from acidic solutions using carboxylic acids, amines, and acidic β-diketone, among other solvents and chemicals. For improving the extraction efficiencies, the development of mixed extractants or synergistic systems for the SX of Sc has been carried out in recent years. Different operational parameters play an important role in the extraction process, such as the type of the aqueous phase and its acidity, the aqueous (A) to organic (O) and solid (S) to liquid (L) phase ratios, as well as the type of the diluents. Sc recovery is now implemented in industrial production using a combination of hydrometallurgical and pyrometallurgical techniques, such as ore pre-treatment, leaching, SX, precipitation, and calcination. The hydrometallurgical methods (acid leaching and SX) were effective for Sc recovery. Furthermore, the OPCs bis(2-ethylhexyl) phosphoric acid (D2EHPA/P204) and tributyl phosphate (TBP) showed interesting potential taking into consideration some co-extracted metals such as Fe(III) and Ti(IV).

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“…The scandium extraction from acidic sulphate solutions by a secondary amine bis(3,5,5‐trimethylhexyl) ammonium sulphate was found to have stoichiometry of (R 2 NH 2 ) 4 ScOH(SO 4 ) 3 , where R is 3,5,5‐trimethylhexyl 38. Ma and Li37 reported that the Sc(III) was extracted as Sc(OH) 2+ to the organic phase for the extraction by primary amine N1923 from thiocyanate and nitrate–thiocyanate solutions.…”

Section: Separation and Purification Of Scandium Using Solvent Extracmentioning

confidence: 99%

Separation and purification of scandium by solvent extraction and related technologies: a review

Wang

Cheng

2011

J of Chemical Tech & Biotech

181

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The technologies of solvent extraction, ion exchange, and liquid membrane for the separation and purification of scandium are reviewed. Acidic and neutral organo-phosphorus extractants are most widely used in practice, with high extraction efficiencies. Their disadvantages originate from the high stripping acidity required for the former and the poor selectivity for the latter. Carboxylic acids, amines, and acidic β-diketone have also been widely used to extract scandium from solutions with low acidities. Mixed extractants or synergistic systems for the solvent extraction of scandium have been developed. Extraction efficiencies are influenced by extraction conditions such as aqueous matrixes and acidities, types of diluents and A/O ratios. Scandium(III) extractions are interfered with by commonly associated elements such as iron(III), zirconium(IV), titanium(IV), thorium(IV), yttrium(III) and lanthanides(III). The advantages and disadvantages of applications of ion exchange and liquid membrane technologies for scandium recovery are reviewed and compared with solvent extraction.

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Extraction of scandium from aqueous sulfate solutions by bis(3,5,5-trimethylhexyl)ammonium sulfate

Cited by 11 publications

References 0 publications

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

Scandium Recovery Methods from Mining, Metallurgical Extractive Industries, and Industrial Wastes

Separation and purification of scandium by solvent extraction and related technologies: a review

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