Solvent Extraction Of Vanadium Research Articles

A novel process to prepare high-purity vanadyl sulfate electrolyte from leach liquor of sodium-roasted vanadium slag

The leach liquor of sodium-roasted vanadium slag in vanadium industry is an alkaline solution containing vanadium, sodium, chromium, and other impurities, and preparing high-purity vanadyl sulfate electrolyte (used in vanadium redox flow battery) directly from this solution is challenging but cost-effective. A novel process consisting of selective reduction–precipitation of chromium and solvent extraction of vanadium was proposed and optimized in this study. Approximately 90% of Cr(VI) in the solution was reduced to Cr(III) and precipitated after adding sodium sulfite at a pH of 5.77 and 25 °C, while V(V) remained in this process and needed a further reduction to V(IV) prior to extraction. More than 99.9% of V(IV) remained in the solution was extracted by two-stage extraction using the “P507 + TBP + kerosene” extractant system at a pH of 2.00 and an organic-to-aqueous phase ratio of 1.5:1. Sodium entrained in the organic phase was washed off through three-stage scrubbing. A high-purity vanadyl sulfate solution of 2.1 mol L−1 was prepared by two-stage stripping using 5.5 mol L−1 sulfuric acid. According to the slope analysis and infrared spectra, the extraction of V(IV) by P507 follow the cation exchange mechanism. This study provides a feasible way to remove chromium and recover vanadium in the form of vanadyl sulfate from the industrial leach liquor of sodium-roasted vanadium slag.

Solvent Extraction of Vanadium from Sodium Carbonate–Sodium Bicarbonate Solution Using Aliquat-336

The solvent extraction of vanadium (V) from Na2CO3–NaHCO3 solution was attempted using Aliquat-336 (methyltrioctylammonium chloride) extractant dissolved in sulfonated kerosene as diluent with 2-octanol as phase modifier. The influence factors, such as Na2CO3 concentration, NaHCO3 concentration, temperature, extractant concentration and impurity P, on vanadium extraction were investigated. The results revealed that the single stage extraction efficiency of vanadium reached above 89% from 20 g/L Na2CO3 – 20 g/L NaHCO3 solution under the following conditions: extractant concentration of 15%, room temperature of 20–30 °C, 2-octanol of 6%, phase ratio (O/A) of 1:1, and oscillation time of 1 min. The addition of NaHCO3 into Na2CO3 solution could lower the pH value of the Na2CO3 solution, improve extraction efficiency of vanadium, and not introduce other impurities. The phosphate anion did not interact with the vanadate anion in the Na2CO3–NaHCO3 solution. The P in the Na2CO3–NaHCO3 solution had little influence on vanadium extraction.

Separation and recovery of vanadium and aluminum from oxalic acid leachate of shale by solvent extraction with Aliquat 336

The solvent extraction of vanadium has been widely studied in inorganic acid systems; but less in organic acid systems. In this study, the separation and recovery of vanadium and aluminum from oxalic acid leachate of shale by solvent extraction with Aliquat 336 was investigated. The results indicated that 99.06% of vanadium was extracted and only 7.95% of aluminum was co-extracted in a counter-current extraction comprising five stages under the optimal conditions; the separation factor (β) of vanadium and aluminum was 1221. 99.32% of vanadium stripped by 8 mol/L HCl in a counter-current stripping comprising four stages, and V2O5 with a purity of 98.4% was obtained by ammonium precipitation method from the stripped vanadium solution. The speciation and extraction mechanism of vanadium were revealed. Vanadium mainly existed as a complex anion, VO(C2O4)22−, and aluminum mainly existed in the forms of Al(C2O4)2− and Al(C2O4)33− in the oxalic acid leachate of shale. The extraction mechanism of vanadium by Aliquat 336 was an anionic exchange mechanism, and the structure of the extractable complex for vanadium could be determined as [(R4N)2·VO(C2O4)2]. A process flowsheet for the separation and recovery of vanadium and aluminum from the oxalic acid leachate of shale using solvent extraction was developed, which has the advantages of rapid extraction speed and without adjusting the initial pH of solution.

Extraction of vanadium from direct acid leaching solution of clay vanadium ore using solvent extraction with N235

Solvent extraction of vanadium from a direct acid leaching solution, generated by the direct leaching of clay vanadium ore, was conducted using tertiary amine N235, and the effects of the main factors on the extraction of vanadium and iron were investigated. Through a three-stage countercurrent extraction under the following optimum conditions: N235 concentration of 10% (v/v), initial aqueous phase pH of 1.8–2.0, phase ratio (A/O) of 2.5, and extraction time of 5 min, vanadium extraction efficiency reached above 98% whereas iron and other impurities were barely extracted. In addition, the solution chemical behavior of the vanadium extraction with N235 was analyzed. After oxidation and neutralization, V(IV) was oxidized to V(V), and VO2+ was converted to various forms of anions. N235, acidified by H2SO4 to convert R3N to (R3NH)2SO4, was able to extract vanadium through anion-exchange reaction. When vanadium was in the specific form of [H2V10O28]4−, high extraction efficiency was obtained, and vanadium was extracted more easily. As the pH increased, the concentration of [H2V10O28]4− and the dissociation of HSO4− also increased, which improved extraction efficiency. Vanadium existed in form of [H2V10O28]4− within a wide pH range of 1–3.5, but dissociation of (R3NH)2SO4 occurred at pH > 2.0, which hampered the extraction. Moreover, Fe(III) was precipitated by hydrolysis at pH > 2.0, which prevented the two phases from separating and caused a coprecipitation loss of vanadium.

Effect of K2SO4 on solvent extraction of vanadium with D2EHPA/TBP

Effect of K2SO4 on solvent extraction of vanadium with D2EHPA/TBP

Study on the synergistic extraction of vanadium by mixtures of acidic organophosphorus extractants and primary amine N1923

Abstract In the present study, the solvent extraction of vanadium from chloride medium with acidic organophosphorus extractants, primary amine N1923, and their mixtures were investigated. The organophosphorus acids included di(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (HEHEHP), and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272). The extraction effects from chloride medium were studied in detail, illustrating that all the three mixtures of organophosphorus acids and N1923 have synergistic effects on vanadium. As a representative, extraction stoichiometries of vanadium with D2EHPA + N1923 were studied with the methods of slope and constant mole. The extraction capacity of temperature dependency was also investigated. Moreover, the separation of vanadium, nickel, and chromium with mixtures of D2EHPA + N1923 was studied.

Solvent extraction of vanadium(V) from sulfate solutions using LIX 63 and PC 88A

Extraction of V(V) by LIX 63 and PC 88A was investigated from sulfate solutions under initial pH 1.2–6. Equilibrium pH had a profound effect on the extraction of V(V) by the two extractants. The extraction of V(V) by PC 88A occurred by a cationic exchange, while that by LIX 63 changed as the equilibrium pH increased. The cationic exchange reaction of VO2+ by LIX 63 occurred at pH<2.5, while solvating reaction occurred in the equilibrium pH range of 2.5–5.4. The extraction reactions of V(V) by PC 88A and LIX 63 were identified by applying a slope method.

Solvent extraction of vanadium from a stone coal acidic leach solution using D2EHPA/TBP: Continuous testing

This paper reports on continuous testing of a process for the recovery of vanadium from a H2SO4-HF solution, generated from the leaching of stone coal, by solvent extraction using a D2EHPA/TBP mixture as the extractant. Three unit processes are included: fully continuous countercurrent solvent extraction and stripping; oxidation and precipitation; and calcination. The solvent-extraction circuit was operated for 96h. With six stages of countercurrent extraction, 97.7% vanadium, 98.3% molybdenum, and 97.9% titanium were extracted, while the sodium, potassium, fluorine, and nickel impurities were barely extracted. Scrubbing removed co-extracted and aqueous-entrained zinc, magnesium, silicon, and arsenic impurities. Most co-extracted impurities were scrubbed in two stages. Using five stages of stripping, more than 99.8% of the vanadium was stripped, yielding a vanadium concentration in the loaded strip solution of 34.1g/L. Co-extracted molybdenum(VI), titanium(IV), and iron(III) remaining in the stripped organic phase were removed by a saturated sodium carbonate solution and the regenerated organic was reused for vanadium extraction. Vanadium was selectively precipitated with 98.5% efficiency from the loaded strip solution by oxidation and precipitation with ammonium sulfate. A high-purity V2O5 (99.61%) product was successfully produced by this flowsheet.

Measurement and modeling for vanadium extraction from the (NaVO3 + H2SO4 + H2O) system by primary amine N1923

In this work, the solvent extraction of vanadium by using the primary amine N1923 as extractant was studied. Within different vanadium concentration ranges, the extraction reactions were determined using the slope method at T=298.15K based on the vanadium phase diagram. The slopes (the stoichiometric ratio) were determined as 5/3, 1 and 11/3 for (RNH2)5/3H3VO4,(RNH2)H3V3O9 and (RNH2)11/3H6V10O28, respectively. The thermodynamic model was established through regression of the experimental results with the Pitzer equation for both aqueous and organic phases by the General Algebraic Modelling System (GAMS). Three different sets of parameters and chemical equilibrium constants K were determined, which corresponded to the three extraction reactions. The orders of the lnK values are V10>V3>V1 (organic V species), and the distribution coefficients (DV) are DV1>DV3>DV10. The new model was applied to predict the regularities of extraction yield along with different initial conditions, and the results agree well with the experimental values.

Solvent Extraction of Vanadium (V) from Phosphate Solutions with Trioctylmethylammonium Chloride (TOMAC)

Solvent Extraction of Vanadium (V) from Phosphate Solutions with Trioctylmethylammonium Chloride (TOMAC)

Solvent extraction of vanadium from sulfuric acid solution

The behaviour of vanadium(V) extracted from sulfuric acid solution was investigated using Cyanex 923 as an extractant. The effects of the concentration of Cyanex 923 and the pH of the solution were studied. The extraction of vanadium(V) increases with the increase of Cyanex 923 concentration and shaking time. Cyanex 923 can extract vanadium(V) from sulfuric acid solution at low pH conditions, and the best pH conditions for extraction of vanadium(V) are at pH 1.0–2.0. The species extracted into the organic phase is VO2HSO4 with one molecule of Cyanex 923. Equilibrium studies were used to assess the extraction efficiency of vanadium(V) recovery from the sulfuric acid solution.

Solvent extraction of Vanadium (IV) with di(2-ethylhexyl) phosphoric acid and tributyl phosphate

Vanadium pregnant solution recovered from the Syrian Petroleum coke by means of salt roasting was acidified by dilute sulfuric acid. Solvent extraction of tetravalent vanadium with a mixture of di(2-ethylhexyl) phosphoric acid (DEHPA) and Tributylphosphate (TBP) was carried out. Kinetic effects are involved in competitive extraction of other metals such as iron and aluminum.

Solvent Extraction of Vanadium from Nigerian Bitumen Using Tri-Butylphosphate

Solvent Extraction of Vanadium from Nigerian Bitumen Using Tri-Butylphosphate

Simultaneous determination of trace uranium and vanadium in biological samples by radiochemical neutron activation analysis

A radiochemical neutron activation analysis (RNAA) for simultaneous determination of uranium and vanadium in a single sample at trace levels is described. The method is based on post-irradiation wet-ashing and solvent extraction of vanadium with N-benzoyl-N-phenyl-hydroxylamine reagent. From the remaining aqueous phase, uranium is extracted into a toluene solution of tri-n-butyl phosphate. The chemical yields are determined spectrophotometrically for vanadium and by gamma-counting of the added natural uranium carrier for uranium. The method was evaluated by the analysis of reference materials and the results showed a good agreement with the certified values. The method was applied to the determination of vanadium and uranium in five military total diet samples in Slovenia.

Determination of vanadium in biological and environmental samples by RNAA with emphasis on quality control

In the present work an improvement of radiochemical neutron activation analysis for determination of nanogram levels of vanadium is described. The method is based on post-irradiation wet ashing and solvent extraction of vanadium with N-benzoyl-N-phenyl-hydroxylamine (BPHA) forming a violet chelate complex in strongly acidic medium. For quality assurance purposes a procedure for determination of the overall chemical yield using spectrophotometry of the V-BPHA complex is described, and possible interferences are evaluated. The procedure was applied to the determination of vanadium in reference materials and selected food samples from Slovenia.

Recovery by solvent extraction of vanadium from spent catalysts leaching solutions using Primene 81R

Recovery of vanadium contained in solutions coming from spent catalysts leaching process by means of solvent extraction techniques using primary amine Primene 81R, has been studied in this work, resulting in an industrial multistage process for the treatment of these effluents. Results obtained allows to propose an extraction mechanism for vanadium(V) with this amine in acidic media, verifying the great influence of pH on the process and fix adequate ranges for variables: O/A ratio, organic phase composition, pH, stirring speed and phase separation speed. These values were simulated in industrial conditions. Vanadium is finally recovered by means of precipitation as ammonium metavanadate and later calcination to obtain vanadium pentoxide of commercial grade.

Solvent Extraction of Vanadium with α‐Benzoin Oxime

AbstractThe solvent extraction of vanadium by a chloroform solution of α‐benzoin oxime was investigated. The most favorable condition for the extraction has been found in the pH rang of 1.8 to 3.0 in sulfate or chloride buffer solutions, but with better extraction efficiency when sulfate was used. A solution of 2×10−2 M α‐benzoin oxime in chloroform was used, and 1×10−4 to 2×10−2 M vanadium(V) was extracted favorably in about 89% yield by a single extraction, and in about 97% yield by a double extraction. The effects of shaking time, concentration of α‐benzoin oxime, and diverse ions have also been investigated. Vanadium(V) can be readily extracted without interference in the presence of copper(II), aluminum(III), iron(III), silver(I), zirconium(IV), and chromium(III).

Separation and purification of vanadium and molybdenum by solvent extraction followed by reductive stripping.

The solvent extraction of vanadium and molybdenum by tri-n-octylmethylammonium chloride (TOMAC) from neutral solutions was studied and it was found that vanadium was extracted preferentially by an anion exchange mechanism. The pentavalent vanadyl anion in the organic solution was found to be reduced to the form of tetra- or trivalent cations by contact with an aqueous solution containing a reduction agent such as L-ascorbic acid. This enables the vanadium to be stripped selectively by chemical reduction, with the molybdenum remaining in the organic phase

Solvent Extraction of Vanadium(V) as a Ternary Complex with N‐Hydroxy‐N‐p‐Chlorophenyl‐N′‐(2‐Methyl‐5‐Chloro)‐Phenyl‐p‐Toluamidine Hydrochloride and p‐Chlorophenol

AbstractN‐Hydroxy‐N‐p‐chlorophenyl‐N′‐(2‐methyl‐5‐chloro)‐phenyl‐p‐toluamidine hydrochloride (HCPMCPTH) reacts with vanadium(V) to form a 1:2 (metal:reagent) blue‐violet complex which can be quantitatively extracted into chloroform from acetic acid solutions. The deep blue adduct having 1:2:1 (V:HCPMCPTH:PCP) stoichiometry gets quantitatively extracted into chloroform from 0–2.5 M acetic acid media. The formation of the ternary complex has been made the basis for the development of a simple, rapid, sensitive and selective extractive‐photometric method for the determination of microamounts of vanadium(V). The method has been applied to the determination of vanadium in steels.

Determination of vanadium in petroleum crudes and fuel oils by gas chromatography

A method is described for determining levels of vanadium as low as 0.1 μg g -1 in petroleum oils by gas chromatography with flame-ionization detection. The method involves decomposition of the oils, derivatization and solvent extraction of vanadium as the chelate, [2,2,2',2'-tetramethyl-5,5'-(ethane-1,2-diyldiimino)bis(hex-4-en-3-onato)-(2-)] oxovanadium(IV), followed by gas chromatography on a non-polar (SE-30) column. The procedure is applied to a variety of samples, including standard reference and fuel oils used in an interlaboratory study. The results are compared with those of emission spectrography and two standard methods. The new procedure can be extended to the selective, simultaneous detection of copper, nickel and vanadium in such samples.