Vanadium Oxide Complexes in Room-Temperature Chloroaluminate Molten Salts

and, R. C. Bell; Castleman, A. W.; Thorn, David L.

doi:10.1021/ic990693o

Cited by 27 publications

(19 citation statements)

References 74 publications

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“…The new band observed at 954 and 917 cm -1 in the aqueous and floated complexes, respectively, is due to ν(VO) vibration. 24 The existence of this band is similar to that reported for VO 2+ complexes having a square pyramidal structure. 25 …”

Section: Stoichiometry and Stabilitysupporting

confidence: 83%

Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

2005

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1-(2-Hydroxy-4-methoxybenzophenone)-4-phenylthiosemicarbazone (HMBPT) was investigated as a new reagent for the flotation of vanadium(IV). At pH ∼1.5, vanadium(IV) forms a 1:1 pale-violet complex with HMBPT in aqueous solution. An intense clear violet layer was formed after flotation, by adding an oleic acid (HOL) surfactant. The composition of the float was 1:1 [V(IV)]: [HMBPT]. A highly selective and sensitive spectrophotometric procedure was proposed for the determination of microamounts of V(IV) as its floated complex. The molar absorptivities of the V(IV)-HMBPT and V(IV)-HMBPT-HOL systems were 0.4 × 10 4 and 0.12 × 10 5 L mol -1 cm -1 at 560 nm, respectively. The formation constants of the species formed in the presence and absence of HOL were 4.6 × 10 7 and 8.7 × 10 5 L mol -1 , respectively. Beer's law was obeyed up to 1 × 10 -4 mol L -1 in the aqueous layer as well as in the oleic acid layer. The HMBPT-V(IV) complexes formed in the aqueous solution and scum layer were characterized by elemental analysis, infrared and UV spectrophotometric studies. The mode of chelation between V(IV) and HMBPT is proposed to be due to a reaction between the protonated bidentate HMBPT ligand and V(IV) through the S=C and N=C groups. Interferences from various foreign ions were avoided by adding excess HMBPT and/or Na2S2O3 as a masking agent. The proposed flotation 1 method was successfully applied to the analysis of V(IV) in synthetic mixtures, wastes of power stations, simulated samples and in real ores. The separation mechanism is discussed.

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Section: Stoichiometry and Stabilitysupporting

confidence: 83%

Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

2005

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“…First dissolutions of metal oxides were reported in chloroaluminate ILs, formed by the mixing of an organic salt and AlCl 3 . [12,[26][27][28] These ILs are suitable to provide strong interactions to metal atoms, hence supporting the dissolution of the oxides. However, the hygroscopic AlCl 3 causes the ILs' decomposition in the presence of air and moisture.…”

Section: Introductionmentioning

confidence: 99%

Speciation of Copper(II)‐Betaine Complexes as Starting Point for Electrochemical Copper Deposition from Ionic Liquids

2020

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The application of ionic liquids for the dissolution of metal oxides is a promising field for the development of more energy‐ and resource‐efficient metallurgical processes. Using such solutions for the production of valuable chemicals or electrochemical metal deposition requires a detailed understanding of the chemical system and the factors influencing it. In the present work, several compounds are reported that crystallize after the dissolution of copper(II) oxide in the ionic liquid [Hbet][NTf2]. Dependent on the initial amount of chloride, the reaction temperature and the purity of the reagent, copper crystallizes in complexes with varying coordination geometries and ligands. Subsequently, the influence of these different complex species on electrochemical properties is shown. For the first time, copper is deposited from the ionic liquid [Hbet][NTf2], giving promising opportunities for more resource‐efficient copper plating. The copper coatings were analyzed by SEM and EDX measurements. Furthermore, a mechanism for the decomposition of [Hbet][NTf2] in the presence of chloride is suggested and supported by experimental evidence.

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“…Nevertheless, some examples of ionic liquids that were able to dissolve metal oxides have been reported (Abbott et al, 2011b;Tian et al, 2010). Dai et al and later Bell et al reported the solubility of uranium(VI) oxide and vanadium (V) oxide, respectively, in imidazolium chlororoaluminate ionic liquids (Bell et al, 1999;Dai et al, 1997). Unfortunately, chloroaluminate ionic liquids are not suitable for ionometallurgical processing of metal oxides, since these ionic liquids are extremely sensitive to moisture.…”

Section: Introductionmentioning

confidence: 99%

Dissolution of metal oxides in an acid-saturated ionic liquid solution and investigation of the back-extraction behaviour to the aqueous phase

et al. 2014

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The dissolution of metal oxides in an acid-saturated ionic liquid, followed by selective stripping of the dissolved metal ions to an aqueous phase is proposed as a new ionometallurgical approach for the processing of metals in ionic liquids. The hydrophobic ionic liquid trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) saturated with a concentrated aqueous hydrochloric acid solution was used to dissolve CaO, NiO, MnO, CoO, CuO, ZnO and Fe 2 O 3. It was found that nickel(II) and calcium(II) could be separated from all other transition metals present in the ionic liquid phase by stripping at high chloride concentrations. By scrubbing the ionic liquid solutions phase with water, manganese(II) and cobalt(II) could be stripped together with a fraction of iron(III) and copper(II), leaving zinc(II) and the remainder of copper(II) and iron(III) in the ionic liquid phase. These metal ions could be removed from the ionic liquid using ammonia. Copper(II) and zinc(II) formed ammine complexes and were back-extracted, while iron(III) precipitated as iron(III) hydroxide. After removal of all the metals present in the ionic liquid phase, the ionic liquid was prepared for reuse. Unfortunately, the mutual separations nickel-calcium, cobaltmanganese, or zinc-copper could not be achieved. This system would be useful when nickel is the metal of interest, since separation of nickel from all other transition metals present in the solution is achieved by one stripping step.

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Vanadium Oxide Complexes in Room-Temperature Chloroaluminate Molten Salts

Cited by 27 publications

References 74 publications

Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

Separation via Flotation, Spectrophotometric Speciation, and Determination of Vanadium(IV) in Wastes of Power Stations

Speciation of Copper(II)‐Betaine Complexes as Starting Point for Electrochemical Copper Deposition from Ionic Liquids

Dissolution of metal oxides in an acid-saturated ionic liquid solution and investigation of the back-extraction behaviour to the aqueous phase

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