Extraction of scandium(III) from acidic solutions using organo-phosphoric acid reagents: A comparative study

Abstract

Comparative and synergistic solvent extraction of Sc(III) using two phosphoric acidic reagents such as di-(2-ethyhexyl) phosphoric acid and 2,4,4,tri-methyl,pentyl-phosphinic acid was investigated. Slope analysis method suggests a cation exchange reaction of Sc(III) with both extractants at a molar ratio of extractant: Sc(III) = 2.5:1 at equilibrium pH< 1.5. The plot of log D vs. log [Extractant] yield the slope (n) value as low as 1.2-1.3 and as high as n=7 at low and high extrcatant concentration level, respectively. Extraction isotherm study predicted the need of 2 stages at A: O=1:4 and A: O=1:3 using 0.1 M D 2 EHPA and 0.1 M Cyanex 272, respectively. Stripping of Sc (III) was carried out at varied NaOH concentration to ascertain the optimum stripping condition for effective enrichment of metal. The predicted stripping condition (2-stages with A: O=1:3 and 1:4 for D 2 EHPA and Cyanex 272, respectively) obtained from Mc-Cabe Thiele plot was further validated by 6-cycles CCS study. An actual leach solution of Mg-Sc alloy bearing 1.0 g/L of Sc (III), 2.5 g/L of Mg and 0.2 M HCl was subjected for selective separation of Sc at the optimum condition. The counter current simulation (CCS) study for both extraction and stripping of actual solution resulted quantitative separation of Sc with ~12 fold enrichment. The organic phase before and after loading of Sc (III) along with the diluents was characterized by FTIR to ascertain the phase transportation of Sc (III).

Selective Recovery of Europium and Yttrium Ions with Cyanex 272-Polyacrylonitrile Nanofibers

“…The results present a high homogeneity in the intensity for the different samples which indicate a homogeneous surface impregnation in the same sample and in the different modification batches. respectively [33,34]. The strong band at 2243 cm −1 correspond with the nitrile (-CN) of PAN nanofibers, observed in both samples as is expected [24].…”

“…CH-stretching (methyl, methylene) appears as a very strong band at 2950 cm −1 , especially on the PAN-272 spectra due to effect of the incorporation of the organic extractant. Then, C-H stretching bands of symmetric and asymmetric vibrations and the bending vibration were observed at 2904, 2867, and 1460 cm −1 respectively [33,34]. The strong band at 2243 cm −1 correspond with the nitrile (-CN) of PAN nanofibers, observed in both samples as is expected [24].…”

Selective scandium ion capture via coordination templating in a covalent organic framework

“…Isolating scandium in useful quantities from these ores is extremely costly-concentrations are as low as 10 −4 % 5 , and the energy required for the extraction and processing of scandium is estimated at ~97 GJ/kg, at least two orders of magnitude greater than for the lanthanides 6,7 . As a result, scandium is very expensive and used to a limited degree in industry, despite its demonstrated value in applications such as lighting and high-performance alloys [8][9][10] . The development of new methods and materials for the selective and e cient extraction of scandium is therefore of great interest.…”

Selective ion-exchange separation of scandium(III) over iron(III) by crystalline α-zirconium phosphate platelets under acidic conditions

“…Scandia-zirconia solid electrolytes can be used at lower temperatures than yttria-stabilised zirconia, because the former has a higher ionic conductivity, resulting in an increased operational stability of SOFCs [2]. Scandium in its metallic form has found applications in aluminium-scandium alloys that are used in aerospace, sports, transportation, and process industries [3][4][5]. These alloys are much stronger and lighter than other high-strength alloys, exhibit significant grain refinement, strengthen welds and are resistant to corrosion.…”