Solvent Extraction Of Scandium Research Articles

Solvent extraction of scandium from malonic acid with high molecular-weight amines

Scandium is quantitatively extracted with 4% Amberlite LA-1 or Amberlite LA-2 in xylene at pH 2.5–5.5 from 0.1 M malonic acid. Scandium is stripped from the organic phase with 0.5 M hydrochloric acid and determined spectrophotometrically at 525 nm, as its complex with Alizarin Red S. Primene JM-T, tri-iso-octylamine, tributylamine and tribenzylamine have also been studied as extractants, but found to be unsatisfactory for various reasons. Xylene, toluene, benzene, chloroform, carbon tetrachloride, hexane, cyclohexane and kerosene have been studied as diluents. Xylene is found to be the most efficient. Scandium can be separated from most metals by selective extraction, and from gallium, thallium(III), bismuth, antimony(III), chromium(III), copper(II), iron(III), uranium(VI), cerium, zirconium, indium, thorium and titanium by selective stripping, in some cases combined with use of suitable complexing media to retain the other metals in the organic phase.

Effects of a party inserted absorbing rod on a neutron flux density distribution

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 HNO3–HClO4, 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–H2SO4 treatment and the rare-earth minerals (monazite/xenotime) were digested by H2SO4–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 Na2O2, dissolution in HCl followed by NH3 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, yttrium and lanthanum by the monoalkyl orthophosphoric acids

The extraction of scandium(III), yttrium(III) and lanthanum(III) into an amyl alcohol solution containing the mono(n-alkyl) orthophosphoric acid, H 2RPO 4, from an aqueous HNO 3 solution was investigated. The variation of the distribution of these elements with the concentration of both HNO 3 and H 2RPO 4 indicated that the complexes, tentatively identified as Sc(HRPO 4) 3, HY(HRPO 4) 4, and HLa(HRPO 4) 4, were extracted. The mono(n-alkyl) orthophosphoric acids were synthesized by first preparing the alkyl dichloro phosphate from the normal alcohol and phosphorus (V) oxychloride. This was hydrolysed to the corresponding H 2RPO 4.