Extraction Of Niobium Research Articles

The effects of carboxylic acid addition on hydrofluoric acid autoclave leaching of a ferrocolumbite

The effects of adding carboxylic acid to the leaching media upon the extraction of niobium and tantalum from a ferrocolumbite are studied. Leaching tests were carried out with a pressure reactor in hydrofluoric and carboxylic acids media. Comparative experiments were performed modifying the following variables: temperature, hydrofluoric acid concentration, solid/liquid ratio and carboxylic acid type and concentration. The reagents and products have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDXS), X-ray fluorescence (XRF), X-ray diffraction (XRD), and surface area (BET) measurement. The results obtained show an increase in the niobium and tantalum dissolution when carboxylic acids such as oxalic and tartaric acids are added to the reaction media. The addition of tartaric acid also increases the iron and manganese recovery. The addition of oxalic acid decreases the extraction of manganese, while the extraction of iron is almost nonexistent under certain conditions due to the formation of an insoluble compound that remains in the residue. Results of the residue analysis by XRD show the formation of a new crystalline structure when oxalic acid is used. In experiments with other carboxylic acids such as formic and citric acids, no significant changes in the recovery are observed.

Liquid–liquid extraction of niobium and tantalum from aqueous sulphate/fluoride solutions by a tertiary amine

Niobium–tantalum ore containing euxenite, samarsakite and fergusonite was leached using sulphuric acid. Niobium and tantalum were extracted from the leach liquor with the tertiary amine, Alamine 336, using kerosene and xylene as diluents and n-decanol as a modifier. The effect of contact time, sulphate and fluoride concentrations in the aqueous phase, extractant concentration and aqueous to organic phase ratio were investigated. Both elements were extracted to different extents, with tantalum extraction slightly greater. The separation factor was greater for kerosene diluent. Selective stripping was performed using either 50 g/L potassium hydroxide or 25 g/L ammonium carbonate solutions for niobium and tantalum. Tantalum was stripped first and Ta(OH) 5 was precipitated during stripping. The separation of niobium from tantalum was achieved at this point. Niobium was then precipitated by adding ammonia.

Extraction of Niobium and Tantalum from Nitrate and Sulfate Media by Using MIBK

The niobium–tantalum ore material obtained from Ras Baroud locality in the central Eastern Desert of Egypt, consists mainly of two minerals namely: columbite and alvarolite. The extractive separation of niobium(V) and tantalum(V) from the acid media HF–HNO3 or HF–H2SO4 have been worked out using methyl isobutyl ketone (MIBK) as an extractant.

Extraction of Niobium and Tantalum from Nitrate and Sulfate Media by Using MIBK

The niobium-tantalum ore material obtained from Ras Baroud locality in the central Eastern Desert of Egypt, consists mainly of two minerals namely: columbite and alvarolite. The extractive separation of niobium(V) and tantalum(V) from the acid media HF-HNO3or HF-H2SO4 have been worked out using methyl isobutyl ketone (MIBK) as an extractant. The extraction system HF-H2SO4-MIBK proved to have the most promising separation effect with the highest purity of each niobium and tantalum oxides. The optimum loading conditions in HF-H2SO4-MIBK system were: O/A = 10/1.15 minutes contact time, 100% MIBK. while the feed solution assayed 4.3 N HF and 5.7 N H2SO4. Moreover, the stripping process was performed with 1.0 N HF and distilled water in subsequent steps.

Solvent extraction of niobium from alkali solution by methyltrioctylammonium chloride

For the purpose of developing an alkali leaching-solvent extraction directly from alkali solution process, the extraction of niobium from alkali solution by long-chain alkyl quternary ammonium salt (methyltrioctylammonium chloride R4NCl) in toluene was investigated. The experiments were carried out under conditions of 25 °C, Nb(V) concentration 0.01 mol/L, pH 10.7–13.8, R4NCI concentration 0.02–0.14 mol/L. It has been found that the distribution ratio of niobium increases with increasing R4NCl concentration and with decreasing KCl concentration, but it shows maximum value at pH value of about 12 and decreases below or above this pH value. Distribution ratio of niobium goes up to over 1 000 in appropriate conditions, and so it has been proved that R4NCl is an effective extractant for extraction of niobium from alkali solution.

Niobium extraction by TVEX-polymer resin containing tri-butylphosphate

The subject of the paper is niobium extraction by solid extractants (TVEX) on the basis of tri-butylphosphate from hydrochloric and sulfuric media. Comparison with niobium solvent extraction was carried out. Mechanism of Nb removal by tri-butylphosphate (TBP) liquid and introduced to TVEX matrix was established by means of 93Nb and 31P NMR spectroscopy. The data received allow to assume that niobium is extracted from 7 and 9 mol/l solutions niobium by both TBP and TVEX-TBP as [H 3O·( m−1)H 2O· nTBP] +[NbOCl 4] − anion complex, in which the metal is not bonded with TBP directly. At that time TVEX-TBP extracts Nb from 11 mol/l solution forming the complex [NbOCl 4·TBP] − in organic phase.

Solvent extraction of niobium(V) and tantalum(V) from fluorometallate acid solutions

The addition of Ti and Si to fluoride solutions containing no other mineral acids improves Nb and Ta extraction markedly. According to their effect on Nb extraction these fluorometallate and mineral acids can be arranged in the following order: H 2SiF 6 ≥ HCl > H 2TiOF 4 ≥ H 2SO 4 >> HF. Solvent extraction from fluorotitanium solution was used to show the possibility of producing pure Nb and Ta compounds.

Liquid—liquid extraction of niobium(V) in the presence of other metals with high molecular mass amines and ascorbic acid

A novel method is proposed for the solvent extraction of niobium(V). A 0.1 M solution of Aliquat 336S in xylene quantitatively extracts microgram quantities of niobium(V) from 0.01 M ascorbic acid at pH 3.5–6.5. Niobium from the organic phase is stripped with 0.5 M nitric acid and determined spectrophotometrically in the aqueous phase as its complex with TAR. The method permits separation of niobium not only from tantalum(V) but also from vanadium(IV), titanium(IV), zirconium(IV), thorium(IV), chromium(III), molybdenum(VI), uranium(VI), iron(III), etc. Niobium from stainless steel was determined with a precision of 0.42%.

Extraction and complex formation of niobium(V) with 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone

The extraction of niobium(V) from aqueous hydrochloric and sulphuric acid solutions with 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone (HY) dissolved in chloroform is described. Niobium(V) can be quantitatively extracted with HY in the form of two different complexes depending on the chloride ion concentration in the aqueous phase. At a low chloride concentration or without chloride in the aqueous phase niobium(V) is extracted with HY in the form of Nb(OH) 3Y 2 and at a high chloride concentration as a mixed Nb(OH) 3ClY complex. Niobium extraction with HY enables the separation of niobium(V) from zirconium(IV) and hafnium(IV). The formation of a mixed chloro-4-pyridone complex is also applicable for the spectrophotometric determination of niobium in the organic phase at the maximum absorption at 350 nm.

Synergic extraction study of niobium with 8-quinolinol, its 5-nitro analogue and heterocyclic nitrogen compounds

Equilibrium distribution coefficients have been determined for the extraction of niobium with 8-quinolinol and 5-nitro-8-quinolinol as a function of pH and reagent concentration at ambient temperature. Both the oxines form 1:3 simple chelates with Nb. Synergistic extraction was observed in the extraction of Nb on the addition of 5-nitro-8-quinolinol, as an adducting ligand in the presence of 8-quinolinol forming a di-adduct, NbQ 3 · (5-NO 2-8-HQ) 2. Synergy coefficients of the Nb adducts of the mixed ligands were evaluated. Synergistic enhancement was also observed with pyridine and its methyl derivatives with Nb-NO 2-8-quinolinate, forming mono-adducts. From the equilibrium data, the adduct formation constants of 1:1, chelate to adducting ligand, adducts were evaluated.

Niobium in the Environment and a New Method for its Trace Analysis Using Molecular or Atomic Absorption Spectrometry

Abstract The status of niobium in the environment is briefly reviewed and a new method suitable for the trace analysis of the metal in ores, alloys, plant tissues, animal tissues, and natural waters is presented. The method is based on the selective extraction of niobium as its complex with N-p-methoxyphenyl-2-furylacrylohydroxamic acid (MFHA) in organic solvents. For molecular absorption spectrophotometric analysis chloroform is used in extraction and a ternary complex is formed in the extract by adding 4-(2-pyridylazo) resorcinol (PAR). The ternary complex has an absorbance maximum at 550nm (e=3.6 × 104 1 mole−1 cm−1). Solvent extraction from the aqueous phase to lower volumes of organic phase enables up to 20-fold enrichment of niobium(V) and the method is capable of determining niobium levels down to 10−4 ppm (0.1 ppb). For the atomic absorption spectrometric determination, methyl isobutyl ketone is used as extracting solvent and a sensitivity of 0.3 ppm, which is over 3 times higher than attained so ...

Extractive spectrophotometric determination of niobium(V) with promazine hydrochloride

The extraction of niobium(V)-thiocyanate complex with promazine from hydrochloric acid has been studied. The complex, dissolved in trichloroethylene, has a maximum absorbance at 400 nm and a molar absorptivity of 2.52 × 10 4 mol −1 cm −1 liter. Niobium(V) was determined spectrophotometrically in the organic phase. Beer's law is obeyed in the niobium concentration range 0.2–3.2 μg/ml.

EXTRACTION AND SEPARATION OF NIOBIUM(V( WITH 3-HYDR0XY-2-METHYL-1-PHENYL-4-PYRID0NE

ABSTRACT Niobium(V) in hydrochloric and sulphuric acid media in the presence of an excess of chloride or thiocyanate ions reacts with 3-hydroxy-2-methyl-l-phenyl-4-pyridone (HX) to give complexes which are ex-tractable into chloroform. The experimental conditions for the quantitative extraction of niobium and its subsequent spectrophotometry determination in the organic phase are described. The mechanism of extraction is based on the formation of a mixed Nb(OH)3ClX or Nb(OH)3(NCS)X complex. The extraction with HX permits to separate niobium(V) from zircomum(IV) and hafnium(IV).

Extraction and spectrophotometric determination of niobium by tetraphenylarsonium and phosphonium chloride from a hydrochloric acid solution

The extraction of niobium(V) in the form of a chloro complex has been studied. Radiometrical and spectrophotometrical studies show that niobium(V) is extracted practically completely from a solution containing more than 9 mol dm −3 chloride in the range of 2–5 M hydrogen ion concentration by chloroform solutions of tetraphenylarsonium (TPA) and tetraphenylphosphonium (TPP) chloride and that niobium is not extracted at chloride concentrations less than 6 mol dm −3. The mechanism of extraction is based on the formation of the ion-associated compounds that form between the onium cation and the oxotetra-chloroniobate(V) anion. The extracted complexes in chloroform have a maximum absorbance at 282 nm (TPA) and 285 nm (TPP); they obey Beer's law in the range of 1–10 μg Nb ml −1, and are stable for at least 24 hr. The molar absorptivity of the method is 1.33 × 10 4 dm 3 mol −1cm −1. The composition of the extracted species [(C 6H 5) 4 X] [NbOCl 4] where X = As or P was determined spectrophotometrically, radiometrically, and by characterization of the crystalline compounds isolated.

Extraction-spectrophotometric and radiometric investigation of the ternary ion-association complex of niobium(V) with pyrocatechol and triphenyl-tetrazolium chloride

The optimum conditions for extraction of niobium(V) as a ternary ion-association complex with pyrocatechol and triphenyltetrazolium chloride(TTC) have been determined. The investigation of the composition has shown that the ratio Nb:proocatechol:TTC is 1:2:1 Kex, KD and β have been determined radiometrically, using the chemical model. The influence of foreign ions on the extraction of the ion-association complex has been studied. A method for artifical mixture and steel containing niobium has been used.

Liquid-liquid distribution of niobium in malonate solutions with liquid anien exchangers

Abstract Niobium was quantitatively extracted at pri 3-4.5 with 0.08 M Amoerlite LA-2 in xylene from 0.02 M malonic acid. It was stripped from the organic phase with 0.25 M potassium carbonate solution and was determined spectrophotometrically with TAR at 540 nm. Apart from Amberlite LA-2, Primene JM-T quantitatively extracted niobium and xylene were the only satisfactory dilutents. Wiobium was separated from various elements which formed weak complexes with malonic acid by stripping these elements before extraction of niobium. By the process of selective stripping it was separated from elements forming strong complexes. The method was used for the determination of niobium from stainless steel.

Extraction of niobium, tantalum and titanium from columbite

AIChE JournalVolume 28, Issue 3 p. 522-524 R & D Note Extraction of niobium, tantalum and titanium from columbite Nobuaki Sato, Nobuaki Sato Research Institute of Mineral Dressing and Metallurgy, Tohoku University Sendal, JapanSearch for more papers by this authorAkiichi Kigoshi, Akiichi Kigoshi Research Institute of Mineral Dressing and Metallurgy, Tohoku University Sendal, JapanSearch for more papers by this author Nobuaki Sato, Nobuaki Sato Research Institute of Mineral Dressing and Metallurgy, Tohoku University Sendal, JapanSearch for more papers by this authorAkiichi Kigoshi, Akiichi Kigoshi Research Institute of Mineral Dressing and Metallurgy, Tohoku University Sendal, JapanSearch for more papers by this author First published: May 1982 https://doi.org/10.1002/aic.690280326Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume28, Issue3May 1982Pages 522-524 RelatedInformation

Extraction of niobium and tantalum from hydrofluoric acid solutions with diantipyrylmethans

The extraction of niobium, tantalum and some other elements by diantipyrylmethane (DAM) and hexyldiantipyrylmethane from hydrofluoric acid has been investigated in detail. The formation of DAM H 2·2 MeF 6 and DAM H 2·MeF 7 complexes is expected. The effect of HCl, HNO 3, H 2SO 4, NH 4F, NaF, KF was also studied. The association constants of the fluorotantalates are calculated from the extraction experiments. A method for separation of niobium and tantalum is also described.

Niobium(V) extraction by butyl lauryl phosphoric acid-dodecane from nitric acid

Extraction of niobium by tributyl phosphate (TBP) in the Purex process is inefficient; and in spite of this, niobium is found in solvent streams. Alternate mechanisms for niobium transfer into the solvent were sought. Butyl lauryl phosphoric acid (HBLP), a model compound of secondary degradation products of the solvent used in the process, was found to enhance niobium extraction above a threshold concentration of 5 × 10 −4 M. A study of the niobium distribution coefficient dependences in the system HNO 3-HBLP-dodecane on the HBLP, hydrogen ion and nitrate ion concentration suggests an extraction mechanism involving neutralization of an hydroxyl group bound to the niobium and no incorporation of nitrate into the extracted species. These results are supported by chemical analysis of the extracted species which show an empirical formula corresponding to Nb(OH) 4BLP. Silica and zirconium monobutyl phosphate, under certain conditions, disperse adsorbed niobium in the solvent phase in the form of emulsions or suspensions. Centrifugation of these give no net enhancement of niobium transfer.

The mechanism of extraction of niobium(V) from hydrochloric acid by bis(3,5,5-trimethylhexyl) ammonium chloride dissolved in chloroform, carbon tetrachloride and benzene

Equilibrium studies of niobium(V) transfer between 10.8 M hydrochloric acid, and bis(3,5,5-trimethylhexyl) ammonium chloride solutions in chloroform, carbon tetrachloride and benzene, have been combined with kinetic and osmometric data to elucidate the mechanisms for extraction. From previous studies [1–3], metal transfer occurs via an interfacial complex, pictured as (BTHA·HCl)(NbCl 5). In this work it is suggested that further reaction then occurs with this species at the interface in carbon tetrachloride and benzene systems, and in the bulk organic phase in the chloroform system. The overall aggregation in the organic phases changes little on metal extraction, in keeping with the proposed mechanism for each system.