Solvent Extraction Of Scandium Research Articles

Solvent extraction of scandium from leaching solution of red mud roasted with ammonium sulfate using D2EHPA/TBP

Red mud is an important secondary resource for scandium production. The red mud leaching solution containing scandium in this study was derived from environmentally friendly ammonium sulfate roasting and water leaching process. A synergistic extraction with a mixture of di(2-ethylhexyl) phosphate acid (D2EHPA) and tributyl phosphate (TBP) for recovery of scandium from red mud leaching solution is proposed. The effects of D2EHPA concentration, H2SO4 concentration, rare earth elements, dosage of TBP, phase ratio (A/O), contact time and H2O2 concentration on scandium extraction were investigated. The results show that more than 99% scandium is extracted under the optimal conditions while Fe, Al, Ti, Ca and rare earth elements (Ce, Y, La, Nd, Er, etc.) are hardly extracted. The stripping efficiency of Sc reaches above 92.37% under the optimal stripping conditions of 5 mol/L NaOH with an A/O of 1 at 90 °C for 30 min. The proposed technology could provide an effective method for extraction of scandium from red mud leaching solution.

Ternary extractant system consisting of PC-88A, TOPO, and Versatic 10 for recovery of scandium(III) from nickel laterite processing liquors

Solvent extraction of scandium(III) from an aqueous solution, which simulates a concentrated scandium solution generated from nickel/cobalt mixed-sulfide production process, was performed using a ternary mixed extractant system. Addition of tri-n-octylphosphine oxide and a long-chain alkyl carboxylic acid (Versatic 10) to an organophosphonic ester (PC-88A) drastically improved the separation factor of scandium over zirconium in comparison with that of a single extractant system. The optimum mixing ratio in the ternary extractant system was 10 mol% PC-88A, 60 mol% tri-n-octylphosphine oxide, and 30 mol% Versatic 10. The degree of scandium extraction was 90%, and the separation factors between scandium and other metals (i.e., Al, Fe, Ni, Cr, and Zr) were > 140 at pH 2 with the optimized ternary extractant system. The operating conditions for a countercurrent multistage extraction of scandium were investigated by McCabe–Thiele analysis. Ninety-nine percent recovery from 1800 mg dm−3 scandium was achieved by two- to three-stage countercurrent extraction at the flow ratio (A/O) = 1.01. The stripping efficiency of scandium reached >98% with 7 mol dm−3 H3PO4. Based on the results, a conceptual flowsheet for scandium recovery from waste solutions of laterite ore leachate is proposed.

Recovery of Scandium, Aluminum, Titanium, and Silicon from Iron-Depleted Bauxite Residue into Valuable Products: A Case Study

Bauxite residue is a high-iron waste of the alumina industry with significant contents of scandium, aluminum, and titanium. This study focuses on the recovery of Sc, Al, Ti, and Si from iron-depleted bauxite residue (IDBR) into valuable products. Iron depletion was carried out using reduction roasting followed by low-intensity magnetic separation to enrich bauxite residue in Al, Ti, and Sc and reduce an adverse effect of iron on scandium extraction. Hydrochloric high-pressure acid leaching, aluminum precipitation by saturation of the acid leachate, solvent extraction of scandium using di(2-ethylhexyl) phosphoric acid (HDEHP) and tributyl phosphate (TBP), alkaline leaching of the acid residue with subsequent silica precipitation were used to obtain appropriate selective concentrates. As a result, scandium concentrate of 94% Sc2O3, crude alumina of 93% Al2O3, titanium concentrate of 41.5% TiO2, and white carbon of 77% SiO2 were prepared and characterized. Based on the characterization of the treatment stages and the obtained valuable products, the prospect for the application of the suggested flowsheet was discussed.

Solvent Extraction of Scandium and Yttrium Using Carboxylic Acid

Separation of scandium (Sc) from yttrium (Y) in aqueous chloride media by solvent extraction using Versatic acid 10 was investigated. Conventional slope analysis method revealed the extraction equilibrium formulation of the metals. Sc is more strongly extracted than Y by Versatic acid 10, and the separation factor of the metals is quite high at 1.93 × 104. Complete stripping of Sc from the loaded organic solution of Versatic acid 10 was achieved by 3M HCl solution. Then Versatic acid 10 was applied to solvent impregnated resin (SIR), separation of Sc was progressed via Langmuir adsorption model.

Solvent Extraction of Sc(III) by D2EHPA/TBP from the Leaching Solution of Vanadium Slag

The solvent extraction of scandium by the mixture of di-(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) has been investigated in the acidic leaching solution of vanadium slag. Thermodynamic analysis of the species distribution diagrams on the Sc-S-H2O system showed that scandium mainly exists as Sc3+ and Sc(SO4)+, and sulfur mainly exists as HSO4− in the actual leaching solution of vanadium slag (pH = −0.75). The extraction process was studied to optimize various parameters such as the extractant concentration, dosage of TBP, phase ratio, and stirring speed. The results indicated that 83.64% of scandium and less than 2% of co-extracted elements were extracted under optimal conditions. Then, over 95% of the co-extracted elements and less than 1.1% of scandium were scrubbed from the loaded organic phase by 4.0 mol/L of HCl. Finally, 87.20% of scandium was stripped with 2 mol/L of NaOH and 1 mol/L of NaCl at a stripping O/A of 1:1.

Solvent extraction of scandium from chlorination system with EHPAEH

The extraction of scandium from hydrochloric acid media with EHPAEH is investigated. Fe3+ in synthesized solution would reduce the purity of scandium, therefore, N235 is selected as extractant for separating Fe3+ and Sc3+. Experimental results indicated that separation factor βFe/Sc reached 5416.4 with the organic system consisting of 20 vol% trinoctylamine(N235), phase volume ratio(O/A) of 1:1, extraction stage of 3. Then mono(2-ethyl hexyl)-2-ethyl hexyl phosphonate(EHPAEH) is employed to extract Sc3+ from the leaching solution of Fe3+ free. With the organic phase containing 5 vol% EHPAEH, phase volume ratio O/A of 1:5, at pH 0.3, nearly 99% scandium is extracted. Finally, the scandium-loaded organic phase is stripped with 4.5N hydrochloric acid, under phase volume ratio of 1:1 at 65°C.

Extraction of scandium from scandium-rich material derived from bauxite ore residues

In our previous study, it has been proven that the content of scandium could be enriched to about 0.04wt% in a solid product after proper pretreatment of bauxite ore residue. The extraction of scandium from this scandium-rich material was investigated in the present study, with emphasis on both acid leaching of various components and solvent extraction of scandium from acidic leachate. It showed that more than 90% of Sc2O3 was leached out from this material with 6–8mol/L phosphoric acid at 120–140°C for 60–90min and liquid-solid ratio of 10–12mL/g. The presence of phosphoric acid promoted the leaching of scandium due to increased dissolution of perovskite, which converted to CaHPO4 and (TiO)3(PO4)2 and then TiO2 precipitates through TiO2+ hydrolysis precipitation. In the subsequent solvent extraction step, about 98% of Sc3+ was further extracted from the acidic leachate with 2% D2EHPA (P204) at pH1.8 and aqueous-organic ratio of 3:1. Compared with hydrochloric acid, sulfuric acid and nitric acid, phosphoric acid had much higher selectivity in separation of Sc from the other main constituents, as demonstrated by its large separation coefficient (β) between scandium and other elemental species (e.g., for iron, βSc/Fe=2703).

Solvent Extraction of Scandium from the Waste Solution of TiO2 Production Process

Extraction and stripping properties of Sc3+ were investigated by using a mixed extractant of Versatic Acid 10 (VA10) and Tri-n-butyl phosphate (TBP). The effect of adding TBP to VA10 was considered by analyzing the binding state of VA10 and TBP by FT-IR. Solvent extraction of scandium from an aqueous solution of Sc3+–Ti4+–Zr4+, which simulated waste water from the titanium oxide manufacturing process, the Bayers process and others, was performed, and the separation factor of Sc3+ over Ti4+ and Zr4+ was investigated. To clarify the operating conditions of a countercurrent multistage process for Sc3+, McCabe–Thiele analysis was applied to the extraction isotherm and stripping isotherm of Sc3+. The extraction pH of Sc3+ was found to shift to higher pH, and Sc3+ was stripped at a lower concentration of H2SO4 by adding TBP to VA10. Addition of TBP to VA10 suppresses the extraction of Sc3+ and promotes the stripping of Sc3+. IR spectra of the organic phase suggested that the dimeric portion of VA10 formed hydrogen bonds with TBP. The extractions of Sc3+, Ti4+ and Zr4+ were 77, 3 and 8%, respectively. The separation factors of these metal ions were βSc/Ti = 100 and βSc/Zr = 38 at pH4.6 on extraction with VA10 + TBP from aqueous solutionof Sc3+–Ti4+–Zr4+. Stripping efficiency of 100, 8 and 22% could be achieved for Sc3+, Ti4+ and Zr4+, respectively by using 0.5 mol/dm3 H2SO4. From these results, it was possible to separate Sc3+from impurities such as Ti4+ and Zr4+ by countercurrent multistage extraction, and Sc3+ was recovered by one-stage stripping with 0.5 mol/dm3 H2SO4. Extraction of Sc3+from the dilute aqueous solution containing 500 mg/dm3 of Sc3+reached 99% at the flow ratio (A/O) = 1.01 in the two-stage countercurrent extraction, and Sc3+ in the organic phase was stripped to attain a six-fold concentration by applying one-stage stripping with flow ratio of (O/A) = 6.00.

Solvent extraction of scandium from lateritic nickel- cobalt ores using different organic reagents

Scandium is the most important and strategic metal that can be recovered as a by-product from lateritic nickel-cobalt ores. In this research, different extractants were investigated in order to extract scandium from a sulfate medium by a using a solvent extraction method. Generally, the organic extractants are classified as acidic, neutral and basic organophosphorus compounds. However, in solvent extraction of scandium, the acidic and neutral organophosphorus compounds are preferred due to their higher extraction efficiencies. Thus, the aim of the present study was to compare the scandium extraction efficiencies of some acidic and neutral organic reagents. For this reason, Ionquest 290 (Bis(2,4,4-trimethylpenthyl) phosphonic acid), DEHPA (Di(2-ethylhexyl) phosphoric acid), Cyanex 272 ((Bis(2,4,4-trimethylpentyl) phosphinic acid) which are acidic organophosphorus compounds, and Cyanex 923 (Trialkylphosphine oxide), which is a neutral organophosphorus compound, were used. The extraction capacities of these organics were studied with respect to the extractant concentration at same pH and phase ratio. As a result of the study, DEHPA was found to have higher scandium extraction efficiency with lower iron extraction at pH = 0.55 at a phase ratio of 10:1 = A:O.

Solvent Extraction of Scandium(III) by an Aqueous Biphasic System with a Nonfluorinated Functionalized Ionic Liquid

The use of ionic liquids (ILs) as solvents for extraction of metals is a promising development in separation science and technology; yet, the viscosities of ionic liquids (ILs) can be so high that long reaction times are required to reach the equilibrium state. An aqueous biphasic system (ABS) consisting of the nonfluorinated carboxyl-functionalized phosphonium IL [P444C1COOH]Cl and a 16 wt % NaCl solution is described. The IL-rich phase of the aqueous biphasic system has a very low viscosity, in comparison to the pure IL [P444C1COOH]Cl. This system has excellent extraction properties for scandium. Different extraction parameters were investigated, including contact time and metal loading. The influence of the pH on the solubility of the IL cation in the water-rich phase was determined via quantitative 1H NMR. The stripping of scandium with oxalic acid from the IL phase was also investigated. A plausible extraction mechanism is proposed where three IL cations are deprotonated to form zwitterionic compound...

希薄水溶液中のScの溶媒抽出に関する研究

Versatic Acid 10（以下，VA10）にTri-n-butyl phosphate（以下，TBP）を添加した混合抽出剤を用いて，Sc3+の抽出および剥離特性を調べた．FT-IRによりVA10とTBPの結合形態を分析し，TBPの改質剤としての添加効果を考察した．酸化チタン製造工程の廃液を想定してSc3+–Ti4+–Zr4+水溶液からSc3+の溶媒抽出を行い，共存成分からのSc3+の分離を検討した．McCabe–Thiele解析によるSc3+の向流多段プロセスの操作条件の設定を行った．VA10にTBPを添加すると，Sc3+の抽出されるpHが高pH側にシフトし，低濃度のH2SO4にてSc3+を剥離することができた．VA10に添加したTBPはSc3+の抽出反応を抑制し，剥離反応を促進することがわかった．有機相のFT-IRスペクトルより，二量体として存在していたVA10の一部が改質剤のP=Oと水素結合を形成していることが示唆された．Sc3+–Ti4+–Zr4+混合水溶液からVA10+TBPを用いて溶媒抽出を行うと，pH 4.6のときSc3+, Ti4+およびZr4+の抽出率は77, 3, 8%，分離係数はβSc/Ti=100, βSc/Zr=38となった．0.5 mol/dm3 H2SO4を用いてSc3+, Ti4+およびZr4+をそれぞれ100, 8, 22%剥離することが可能であった．向流多段抽出によってSc3+とTi4+, Zr4+を分離し，Sc3+を回収することができる．流量比（A/O）=1.01での2段の向流抽出により，500 mg/dm3のSc3+を99%回収し，相比（O/A）=6.00の1段の剥離でSc3+を6倍濃縮して回収できることが明らかになった．

Solvent extraction of scandium(III), yttrium(III), lanthanum(III) and gadolinium(III) using Cyanex 302 in heptane from hydrochloric acid solutions

The extractions of the selected rare earths (Sc, Y, La and Gd) from hydrochloric acid solutions have been investigated using bis(2,4,4-trimethylpentyl)-mono thiophosphinic acid (Cyanex 302, HL) in heptane as an extractant. The results demonstrate that the extractions of rare earths occur via the following reaction: Sc( OH) 2++2[( HL) 2] ( O) ⇔[ Sc( OH) L 2·2( HL)] ( O) +2 H + Y 3++3[( HL) 2] ( O) ⇔[ Y( HL 2) 3] ( O) +3 H + La( OH) 2 ++3[( HL) 2] ( O) ⇔[ La( OH) 2 L·5( HL)] ( O) + H + Gd( OH) 2++3[( HL) 2] ( O) ⇔[ Gd( OH) L 2·4( HL)] ( O) +2 H + The pH 1/2 values and equilibrium constants of the extracted complexes have been deduced by taking into account the aqueous phase complexation of the metal ion with hydroxyl ligands and plausible complexes extracted into the organic phase. According to the pH 1/2 values, it is possible to realize mutual separation among Sc(III), Y(III), La(III) and Gd(III) with Cyanex 302 by controlling aqueous acidity.

Determination of scandium in geological materials, rare earth minerals and niobate/tantalate-type of samples by inductively coupled plasma atomic emission spectrometry after solvent extraction/acid hydrolysis separation

Solvent extraction of scandium from 1.5 M HCl medium using di(2-ethyl hexyl) phosphoric acid in hexane or benzene selectively separates Sc from the accompanying elements in rare-earth minerals (like monazite, xenotime, gadolinite) and also in geological materials. Acid hydrolysis separation of Nb/Ta-type samples separates Sc from the major matrix elements and the remaining elements do not influence the Sc signal in inductively coupled plasma atomic emission spectrometry or flame atomic absorption spectrometry. To avoid the matrix effect due to sodium that accompanies the analyte using the reported backstripping of Sc from the organic extract by 2 M NaOH, the organic extract was evaporated off leaving the Sc in the residue which in turn was treated with a mixture of HNO 3–HClO 4, dissolved in HCl (10%, v/v) and made up to a known volume before aspiration in the plasma for estimation. The silica-rich geological materials were dissolved by HF–HCl–H 2SO 4 treatment and the rare-earth minerals (monazite/xenotime) were digested by H 2SO 4–HCl followed by dissolution in 1.5 M HCl before applying the solvent extraction procedure. In Nb/Ta-type of samples, Sc was separated from Nb and Ta by acid hydrolysis, involving fusion with Na 2O 2, dissolution in HCl followed by NH 3 precipitation and hydrolysis in HCl. The oxychloride precipitates of Nb and Ta are filtered off and the filtrates assayed for Sc. The proposed methods have been applied to some international geological reference standards (SY-2, SY-3, MRG-1, Mica-Fe, G-2, GH and ASK-2), rare-earth minerals like monazite, xenotime and gadolinite and also to some Nb/Ta-type samples including reference standards IGS-33 and IGS-34, and the results are compared. Both methods are simple, rapid and accurate, showing a relative standard deviation of less than 1% at the 55 μg g −1 level and 9.0% (at the 1.0 μg g −1).

Solvent extraction of Scandium(III) by Cyanex 923 and Cyanex 925

The extraction equilibria of Sc(III), Zr(IV), Ti(IV), Th(IV), Fe(III) and Lu(III) from sulphuric or hydrochloric acid media by Cyanex 923 (mixture of straight chain alkylated phosphine oxides) and Cyanex 925 (mixture of branched chain alkylated phosphine oxides) were studied at various aqueous acidities. The extractant Cyanex 923 demonstrated better scandium loading and selectivity for Ti(IV), Fe(III) and Lu(III) than Cyanex 925. The effects of extractant concentration on the extractions of sulphuric acid and Sc(III) by Cyanex 923 were examined. The stoichiometries of the extraction reactions were postulated based on slope analysis. The experimental results indicate that Cyanex 923 can be employed to recover scandium directly from the hydrolytic mother solution arising from TiO 2 production via the sulphate process. The parameters studied were scandium loading capacity, phase ratio, concentrations of Ti(IV) scrubbing and Sc(III) stripping agents. A new solvent extraction technology of scandium recovery was developed. The purity of the final Sc(III) product is above 95% with a yield>94%.

Solvent Extraction of Seven Trivalent Metal Ions in Aqueous Perchlorate Solutions with Trioctylphosphine Oxide in Hexane and Rapid Extraction of Chromium(III)

Solvent extraction of scandium(III), yttrium(III), lanthanum(III), europium(III), gallium(III), indium(III), and chromium(III) in weakly acidified 1 mol dm−3 NaCIO4 solutions with trioctylphosphine oxide (TOPO) in hexane was studied. The extraction equilibrium was established by the two phase agitation for within 3 min and the extracted species except chromium(III) were found to be M(TOPO)43+(CIO4−)3. The extraction of chromium(III) was also achieved by the two phase agitation for only a short time but, from the dependence of the extraction on the TOPO concentration, the extracted species was assumed to be Cr(TOPO)63+(C104−)3. Since the inert Cr(H2O)63+ was so rapidly extracted and the solvation number was higher than that of the other metal ions, the TOPO molecules were assumed to combine with the hydrating water molecules by hydrogen bonds which can be formed in a short time even when the metal ion was inert. The chromium(III) was also extracted rapidly from 1 mol dm−3 NaSCN, NaNO3, NaBr, and NaCl solutions with TOPO in hexane and the extraction was better from NaSCN solution than from NaC104 solution but it was not effective from the solutions of other salts.

Solvent Extraction of Scandium(III) with Hexafluoroacetylacetone into Chloroform in the Absence and Presence of Tetrabutylammonium Ions or Trioctylphosphine Oxide

Abstract The anionic chelate of scandium(III) with hexafluoroacetylacetone (Hhfa) was extracted into chloroform in the presence of the tetrabutylammonium ion (tba+), though such an anionic chelate was not extracted when the chelating extractant was 2-thenoyltrifluoroacetone (Htta). The extraction was also studied in the same systems in the presence of trioctylphosphine oxide (TOPO); the extraction of the anionic complex, Sc(hfa)4−tba+, was compared with that of the adducts with TOPO, Sc(hfa)3(TOPO)n.

Enhancement Effect of 3,5-Dichlorophenol on the Solvent Extraction of Scandium(III) with Acetylacetone

Enhancement Effect of 3,5-Dichlorophenol on the Solvent Extraction of Scandium(III) with Acetylacetone

Solvent Extraction of Scandium(III), Yttrium(III) and Some Lanthanoid(III) Ions with N-Alkylcarbonyl Substituted N-Phenylhydroxylamines

The extraction behavior of scandium(III), yttrium(III) and certain lanthanoid(III) ions, namely praseodymium, europium and ytterbium, from aqueous solutions into carbon tetrachloride solutions containing various N-alkylcarbonyl-N-phenylhydroxylamines(R-PHAs) has been studied at 298 К and the ionic strength, 0.1(NaN03) The chelating extractante studied were N-octanoyl-N-phenylhydroxylamine (C8-PHA), N-(2-propylpentanoyl)-N-phenylhydroxylamine(PP-PHA) and N-(2-hexyldecanoyl)-N-phenylhydroxylamine(HD-PHA). The metal ions studied were all extracted with all the R-PHAs as self-adducts of the form ML3(HL)2, where L and HL represent the ligand anion and neutral ligand, respectively The extraction constants and separation factors for the extraction systems were evaluated. HD-PHA and PP-PHA were excellent extractants for the separation of yttrium from heavy lanthanoids.

Extraction of scandium with tetraphenyl imidodiphosphate and its sulfur analogues, and the radiation stability of the reagent

Solvent extraction of scandium from perchloric or hydrochloric acid aqueous systems into benzene solutions of tetraphenyl imidodiphosphate, (PhO)2P(O)NHP(O)(PhO)2 (HA), and its sulfur analogues containing the P(O)NHP(S) or P(S)NHP(S) groups was studied. Behaving as weak acids in the aqueous phase, the reagents form complex extractable compounds ScA3 with scandium. The extraction constants were measured and found lower for the sulfur analogues than for the oxygen reagent. The configuration changes induced in the reagent by gamma irradiation from a 60Co source were studied by examining the extraction of scandium with it and by 31P NMR measurements. Whereas the changes in the solid reagent are not very marked and appear only at doses in excess of 800 kGy, the reagent dissolved in benzene exhibits configuration changes even on the application of doses at the 10 kGy level. This fact is related to the presence of benzene and dissolved oxygen in the system.

Solvent extraction of scandium(III)

Separation of scandium(III) from iron(III), molybdenum(VI), vanadium(V), chromium(VI), titanium(IV), bismuth(III), zirconium(IV), lanthanum(III), and thorium(IV) is achieved by solvent extraction with mesityl oxide from sodium sallcylate solution (0.1 M) adjusted to pH 4. Scandium from the organic phase is stripped with water and determined photometrically as its arsenazo complex at 570 nm. The extracted species is trisolvated, i.e., Sc(HOC/sub 6/H/sub 4/COO)/sub 3/3Me0. 1 figure, 1 table.