Separation of Ir(IV) and Rh(III) from strong hydrochloric acid solutions by solvent extraction with amines

Highly Effective Removal of Metal Cyanide Complexes and Recovery of Palladium Using Quaternary-Ammonium-Functionalized MOFs

“…Based on the principle of the minimum charge density, the charge density of Pd(CN) 4 2− is less than those of Co(CN) 6 3− and Fe(CN) 6 3− . Fewer water molecules are required to stabilize Pd(CN) 4 2− compared to multivalent anions in the aqueous solution [ 59 , 60 ]. Pd(CN) 4 2− possibly exhibited higher affinity for hydrophobic quaternary ammonium compared to Co(CN) 6 3− or Fe(CN) 6 3− .…”

Valuable Metals—Recovery Processes, Current Trends, and Recycling Strategies

“…Afterwards,t he Cu-PGM alloy is cast into anodes and subjected to electrolysis,w hereby PGMs accumulate in the sludge.A lternatively,t he alloy can be leached with sulfuric acid, with the PGMs remaining completely in the solid, undissolved residue.A fterwards the residue is treated analogously to primary raw materials,s tarting with aqua regia leaching. [189] Another approach deals with removing Ru from acetic acid solution using E. coli immobilized on filaments made of polyethylene imine/polysulfone composites.T hese filaments showed higher capacities for ion exchange than conventional resins,and have been applied to recover Ru from waste water originating from the production of acetic acid. Only the precipitation of (NH 4 ) 2 -[PtCl 6 ]isstill used to separate Pt.…”

“…Re-extraction with thiourea dissolved in water provides high separating factors of up to 82.5 for Ir. [189] Another approach deals with removing Ru from acetic acid solution using E. coli immobilized on filaments made of polyethylene imine/polysulfone composites.T hese filaments showed higher capacities for ion exchange than conventional resins,and have been applied to recover Ru from waste water originating from the production of acetic acid. [190] Osmium-based catalysts (Lemieux-Johnson reaction) can be recycled by reductive extraction.…”

Extraction and separation of iridium(IV) and rhodium(III) from hydrochloric acid media by a quaternary ammonium-based hydrophobic eutectic solvent

“…Recently, amine-based extractants inter alia tri-octylamine (TOA), tri-2-ethylhexyl amine (TEHA), tri-isooctyl amine (Alamine 308) and Aliquat 336 diluted in the molecular solvent were studied for the selective separation of Ir(IV) and Rh(IV) from acidic solutions. 10 The quaternary ammonium salts extract Ir(IV) from chloride solutions efficiently whereas the chloride complexes of Rh(III) have much lower distribution ratio values. Aliquat 336 was found to be a more effective extractant in terms of efficiency and selectivity but its high viscosity hinders handling.…”