1. Summary of commonly used extractants 1. Conventional solvents: butyl acetate, ethyl acetate, chloroform, toluene, etc. 2. Organic acid extractant: organic phosphoric acid, organic sulfonic acid, carboxylic acid, etc. 3. Neutral extractant: phosphorus-containing, oxygen-containing and sulfur-containing heavy-duty extractants, such as tributyl phosphate (TBP), methyl isobutyl ketone (MIBK), dioctyl sulfoxide (DOSO), etc. 4. Amine extractants: various organic amines and amine salts.
2. Key points of extracting agent selection: 1. Good selectivity: the extractant has a more extraordinary dissolving ability for one component but less for another, which shows a significant selectivity coefficient. 2. Large extraction capacity: The extractant per unit volume can extract many target substances, manifested by a significant partition coefficient. 3. The extractant's mutual solubility and the original solvent: it is incompatible with the solvent in the original solution, and the solubility of the solute is much more excellent than that of the original solvent. The extractant cannot react with the solvent of the real solution. 4. The extractant has a significant density difference with the original solvent, and it is easy to separate with the raw material liquid phase without emulsification and no third phase. The density of the extractant is preferably more significant than that of the original solvent. 5. The more significant the difference between the extractant's boiling point and the extractant, the better. 6. Strong chemical stability, acid and alkali resistance, oxidation and reduction resistance, heat resistance, and non-corrosion. 7. It is easy to back-extract or separate to facilitate the reuse of the extractant. 8. Good safety, non-toxic or low-toxic, non-flammable, non-volatile, and environmentally friendly. 9. Good economy, low cost and low loss.