Studies on the liquid–liquid extraction of mercury(II) from acidic chloride solutions using Cyanex 923

The extraction of mercury(II) from dilute hydrochloric acid solutions has been investigated using Cyanex 923 (=TRPO) as an extractant. The extraction data have been analysed by both graphical and theoretical methods taking into account aqueous phase speciation and all plausible complexes extracted into the organic phase. The results demonstrate that mercury(II) is extracted into xylene as HgCl 2·3TRPO. IR spectral studies of the extracted complex were used to further clarify the nature of the extracted complex. The loading capacity of the solvent was determined. The effect of the diluent on the extraction process of mercury has been studied and correlated with dielectric constants. The developed extraction procedure has been explored for the recovery of mercury from the brine–sludge of Chlor-Alkali industry.