Recovery of Pd(II) in chloride solutions by solvent extraction with new vinyl sulfide ploymer extractants

• Published in: Hydrometallurgy 2021-09, Vol.204, p.105716, Article 105716
• Main Authors: Shi, Wei, Hu, Ying, Li, Quan, Lan, Tianqi, Zhang, Xueyan, Cao, Jing
• Format: Article
• Language: English
• Subjects: Acid resistant; Pd(II) recovery; Solvent extraction; Vinyl sulfide polymer
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2021.105716

Unlike sulfur-containing extractants, extraction efficiency of extractants containing N atoms is often affected by the concentration of H+, but strong affinity of sulfur to Pd(II) may cause stripping process not smoothly. Since sulfur atom conjugated with CC decreases electron cloud density on S atom, a novel polymer extractant containing vinyl sulfide motifs (Poly-EDDYPF) was designed and prepared in this paper, the investigation of this acid resistant extractant shows that the polymer has high extraction efficiency of Pd(II) over 99% with nicely acid resistant. The loading experiment shows that the capacity of Pd(II) of Poly-EDDYPF is up to 268 mg/g. Nearly 95.6% Pd(II) in loaded organic phase could be easily stripped using acid thiourea solution (1 mol/L HCl + 0.1 mol/L thiourea) and the organic phrase could be reused at least 5 cycles without significant decrease of the extraction efficiency. The optimized conditions for the extraction process are given: [HCl] =1 mol/L, contact time = 20 min, amount of extractant =0.7 g/L, O/A ratio = 1/1. H+ concentration and Cl – concentration exhibit practically no effect on extraction efficiency. •We first used a polymer as the extractant in solvent extraction.•The polymer uses S as the active center to form a multidentate ligand chelating structure that can easily capture Pd(II).•The extractant has very good acid and salt resistance, with an extraction rate of 99% in 4 M HCl.•In extraction experiment, we found that the extraction efficiency is not changed in different concentration of Cl−.