The extraction of platinum from Pt(II) chloride solution by a quaternary ammonium compound

Abstract

The fundamental aspects of the extraction and stripping of platinum (11) from its chloride solution by Aliquat 336 diluted with toluene have been studied. The extraction and stripping was at 99.5 and 97.6% equilibrium within 30 s and 20 min respectively. The percentage extraction increased slightly with decreasing hydrochloric acid concentration. In 0.1 mol dm-3 hydrochloric acid, 1.0 volume percent Aliquat 336 in toluene could load 9.8 mmol dm-3 of platinum (11). The percentage stripping of platinum (11) from Pt(I1)-load organic solvent increased with increasing sodium bisulphite concentration. The enthalpy changes of extraction and of stripping were 12.8 and 114.9 kJ mol-' respectively. Both of the reactions were endothermic.

Liquid‐ and Solid‐based Separations Employing Ionic Liquids for the Recovery of Platinum Group Metals Typically Encountered in Catalytic Converters: A Review

“…Recovery of Pt is feasible via stripping with Na 2 HSO 3 at 50 °C and, according to the respective isotherm, four stages yield complete stripping of Pd from the organic phase. The effect of heat on increasing both the extraction and the stripping capacity verifies the conclusions reached by the respective isotherms; both processes are endothermic [128] …”

“…The two latter are also corrosive agents. Moreover, in a number of publications, solvents with potentially negative impacts on human health appear, namely, toluene, [128,134,146,168–171,174–176] nonane, [164] CH 2 Cl 2 , [146] and dodecane [129,132] …”

“…The effect of heat on increasing both the extraction and the stripping capacity verifies the conclusions reached by the respective isotherms; both processes are endothermic. [128] Later on, another extraction and stripping procedure for Pt IV employing Aliquat 336 was developed by a different research group. [129] Aliquat 336 in dodecane modified with 4 % dodecanol extracted > 80 % Pt from its aqueous model solution within 10 min.…”

“…Benzene additionally poses an environmental hazard, just as NH 4 SCN, [161] NH 4 OH, [161] and (NH 4 ) 2 S. [155] The two latter are also corrosive agents. Moreover, in a number of publications, solvents with potentially negative impacts on human health appear, namely, toluene, [128,134,146,[168][169][170][171][174][175][176] nonane, [164] CH 2 Cl 2 , [146] and dodecane. [129,132] Regarding the recovery of the PGMs that are extracted in the liquid or solid-based IL phase, either mineral acids (e. g., HNO 3 ), toxic organic compounds (e. g., thiourea), or their combinations (e. g., thiourea in HCl) are commonly employed.…”

Quaternary Ammonium and Phosphonium Ionic Liquids in Chemical and Environmental Engineering

“…Since then Aliquat ® 336 has been evaluated as extracting agent (in most cases dissolved in an appropriate organic solvent) for different metals from acidic aqueous solutions (e.g. Cd(II), Fe(III), Pt(II) and Hg(II) from hydrochloric acid solutions; El-Wakil et al, 1982;Hoh et al, 1985;de Mendonça Fábrega & Borges Mansur, 2007). Nayl (2010) presented a successful separation of Co(II) and Ni(II) from acidic sulfate solutions using Aliquat ® 336 dissolved in kerosene.…”