Zinc separation from HFC leachate by solvent extraction using CYANEX302

Hot filter cake (HFC) which is the zinc plant cobalt purification residue contains 22.83% zinc, 0.65% cobalt, 5.97% manganese and some trace elements such as iron, copper, nickel and lead. After acid washing of the cake using 0.15 M H2SO4 in the optimum condition of: temperature: 60 °C, time: 60 minutes and S/L: 1/20 gr.mL-1, 1.5% zinc remained in the obtained solid. Afterward, leaching has been performed by sulfuric acid and the leachate containing Zn, Co and Mn was obtained with the concentration of 115,111 and 1150 ppm, respectively. Then, CYANEX302, as an extracting agent, was used to extract Zn selectively from Co and Mn. It was observed that CYANEX302 extracted 96 % zinc at pH 2.5; while, extraction of Co and Mn in this solution started after pH 2.5. Afterward, FT-IR was employed to propose the most probable chemical structure of zinc and CYANEX302. Besides, in accordance with the FT-IR spectra, solvent extraction reaction was also suggested.

Keywords:

Zinc (II) , Hot filter cake , CYANEX302 , Selective Extraction