Efficient diglycolamic acid extractant for separating and recycling Au(III)

• Published in: Minerals engineering 2020-05, Vol.150, p.106254, Article 106254
• Main Authors: Zhao, Zhigang, Chen, Peng, Yang, Fan, Liao, Qiuxia, Zhang, Yang, Zhao, Panpan, Guo, Wanghuan, Bai, Ruixi, Cai, Chunqing
• Format: Article
• Language: English
• Subjects: Diglycolamic acid extractant; Precious metals; Recyclability; Separation; Solvent extraction
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2020.106254

•D2EHDGAA was synthesized which had high extractability for metals.•D2EHDGAA exhibited high selectivity to Au from Pd, Pt, Rh, and Cu in a short time.•The extraction mechanism of Au and Pt were two and one extractants, respectively.•The Stripping of Au was completely with low concentration of thiourea.•The extraction could be recycled for 5 times with efficiency decreased less than 4%. The type of diglycolamic acid extractantN,N-di-2-ethylhexyldiglycolamic acid (D2EHDGAA) was examined for selective extraction and separation of Au(III) in acidic chloride solutions containing Pd(II), Pt(IV), Rh(III), and Cu(II). The separation factor βAu/Pt = 959.3 was observed in 7 M hydrochloric acid. The extraction of Au(III) was quick, and extraction equilibrium was reached in less than 5 min. The n-dodecane and kerosene diluents had a notable effect on the extraction of Au(III) with the D2EHDGAA, and the D2EHDGAA had excellent capacity in n-dodecane and kerosene. However, the selectivity coefficient of Au(III) and Pd(II) was better in n-dodecane (βAu/Pd = 1070) than in kerosene (βAu/Pd