Separation of Zr and Hf from sulfuric acid solutions with amine-based extractants by solvent extraction

• Separation of Zr and Hf by extraction with amines was tested from sulfate medium.
• Zr was selectively extracted over Hf by amine-based extractants.
• Alamine 308 showed the highest separation factor of 12.4.
• Difference in extraction between amines and acidic extractants was discussed.
• Low concentration of Na2CO3 solution stripped most of Zr and Hf from the organic.

The extraction and separation behavior of Zr and Hf was investigated from sulfuric acid solutions by using amine-based extractants. In the sulfuric acid concentration range of 0.1–3 M, zirconium was selectively extracted over hafnium by using amines. Among the tested amines (Aliquat 336, Alamine 300, Alamine 308, Alamine 336, and TEHA), Alamine 308 led to the highest separation factor of 12.4 at 0.5 M H2SO4 solution. The extraction behavior of Zr and Hf in sulfate medium by amines was compared with that by acidic extractants in terms of solvent extraction reaction and complex formation. Quantitative stripping of both metals from the loaded Alamine 308 was achieved by using low concentration of Na2CO3 solution.