ICP-AES Determination of Gold, Platinum and Palladium in Copper Concentrates by Adsorption on Denatured Lignin

Denatured lignin was prepared by the reaction of lignin with thio-glycolic acid and acetic anhydride. Structure of the denatured lignin and its adsorptivity toward Au, Pt and Pd ions in copper concentrates were studied in detail. It was found that the denatured lignin behaved to adsorb Au, Pt and Pd ions strongly and adsorption equilibrium was achieved by stirring with the lignin for 80 min. Values of adsorbility of Au, Pt and Pd ions at equilibrium were 50, 50, 25 μg·g-1. The 3 ions adsorbed on the surface of the lignin were completed desorbed by extracting with HCl (1+99) solution, in which their contents were determined by ICP-AES. Values of detection limit (3S/N) of Au, Pt and Pd ions found were 0.041, 0.16, 0.16 mg·L-1 respectively.