Ether derivatives – Efficient Fe(III) extractants from HCl solution

Abstract

In this research, N-decoxy-1-(pyridin-3-yl)ethanoimine, N-decoxy-1-(pyridin-3-yl)methanoimine and N'-(2-ethylhexyloxy)pyridine-4-carboximidamide were tested as novel extraction agents for the Fe(III) recovery. The solvent extraction of Fe(III) using the synthesised compounds has been investigated as a function of phase contact time, HCl, Cl− and Fe(III) concentrations, as well as the extractant structure and its concentration. The effect of different diluents (aliphatic and aromatic) with and without addition of decan-1-ol on extraction of iron(III) was also investigated. The discussion also included the mechanism of complexation. The speciation studies indicated that acidic conditions the extracted species was found to be (D-3EI)2·FeCl2, (D-3EI)2·HFeCl4, (D-3MI)2·FeCl2 and (Eh-4IA)3·FeCl2.Moreover, the laboratory-scale experiments indicated that N-decoxy-1-(pyridin-3-yl)ethanoimine was the most efficient in the Fe(III) extraction and it was proposed for the iron(III) removal from the leachate solution containing 190 g/L HCl, 36 g/L Fe(III) and others elements such as Cr, V, Ca, Mg, Al, Mn and Si.