The solvent extraction and stripping process using Alamine 336 with a case study of uranium

Area of Science:

• Hydrometallurgy
• Nuclear Chemistry
• Separation Science

Background:

• Uranium (VI) recovery from acidic sulfate solutions is crucial for nuclear fuel reprocessing.
• Solvent extraction is a key technology for separating and purifying uranium.
• Alamine 336 in kerosene offers potential for efficient uranium extraction.

Purpose of the Study:

• To comprehensively study the solvent extraction of uranium (VI) from acidic sulfate solutions using Alamine 336.
• To investigate the influence of various parameters on uranium extraction efficiency.
• To optimize the stripping process for uranium recovery and assess purification selectivity.

Main Methods:

• Solvent extraction experiments were conducted using varying concentrations of sulfuric acid, Alamine 336, and uranium (VI).
• Parameters like contact time, organic/aqueous phase ratio, and temperature were systematically varied.
• Stripping efficiency was evaluated using different salt and acid solutions, including ammonium carbonate.

Main Results:

• An extraction efficiency of 99.72% was achieved under optimal conditions (0.15 mol L⁻¹ H₂SO₄, 0.05 mol L⁻¹ Alamine 336, 25°C, 1:1 O/A ratio).
• The extraction process was found to be rapid, exothermic, and spontaneous, with a Log Kex of 5.92.
• Stripping with 0.5 mol L⁻¹ (NH₄)₂CO₃ yielded 99.87% uranium recovery in a single step, indicating high selectivity.

Conclusions:

• Solvent extraction with Alamine 336 is a highly effective method for uranium (VI) recovery from acidic sulfate leach liquors.
• Sulfuric acid concentration significantly impacts uranium extraction efficiency.
• The process demonstrates excellent selectivity for uranium purification and efficient recovery of the loaded organic phase.