Extractions of zinc from ammoniacal solutions by Hostarex DK16.

The reagent, manufactured by Hoechst, has an empirical formula of C16H22O2, a molecular weight of 246 and includes a beta-diketone group. It was diluted to 10 vol% with kerosene. Aqueous solutions of 0.005-0.05 M zinc sulphate and 0.5 M ammonium sulphate were used. Zinc extraction efficiency was found to increase with pH to a maximum at 7.5. The decrease at higher pH was attributed to the formation of a non-extractable zinc ammine complex. Extraction was exothermic, decreasing as temperature rose, while stripping was endothermic. Efficiency of stripping also increased with sulphuric acid concentration up to 0.08 M, beyond which there was no further improvement. Hostarex DK16 was seen to have better loading capacity than DEHPA and LIX 34, but its extraction efficiency was low compared with LIX 34.
The reagent, manufactured by Hoechst, has an empirical formula of C16H22O2, a molecular weight of 246 and includes a beta-diketone group. It was diluted to 10 vol% with kerosene. Aqueous solutions of 0.005-0.05 M zinc sulphate and 0.5 M ammonium sulphate were used. Zinc extraction efficiency was found to increase with pH to a maximum at 7.5. The decrease at higher pH was attributed to the formation of a non-extractable zinc ammine complex. Extraction was exothermic, decreasing as temperature rose, while stripping was endothermic. Efficiency of stripping also increased with sulphuric acid concentration up to 0.08 M, beyond which there was no further improvement. Hostarex DK16 was seen to have better loading capacity than DEHPA and LIX 34, but its extraction efficiency was low compared with LIX 34.