Application of extractants

Release time:

2023-08-04

Source:

From the perspective of application, the conditions that extractants should have are: (1) a large extraction capacity, that is, a unit concentration of extractant has a greater extraction ability for the extracted substance; (2) Good selectivity, i.e. having a large separation coefficient for the separated related substances; (3) Good chemical stability, that is, the extractant is not easy to hydrolyze, not easy to decompose when heated, can withstand the action of acids, alkalis, salts, oxidants or reducing agents, has low corrosion to equipment, and has high radiation resistance; (4) The water solubility should be small while the oil solubility should be large, that is, the solubility in the water phase should be small, and the solubility in the diluent should be large, which is easy to layer with the water phase, does not generate a third phase, and does not cause emulsification; (5) Easy reverse extraction, which means that when changing the extraction conditions, the extracted substance can be easily transferred from the organic phase to the aqueous phase; (6) Safe operation, that is, the extractant is non-toxic, non irritating, non flammable (high flash point), and difficult to evaporate (high boiling point, low vapor pressure); (7) Easy to prepare, rich in raw material sources, and cheap in price, but there are quite few extractants that fully meet these conditions. When selecting extractants, one can only consider comprehensively, seize the main issues, and decide based on specific conditions.

Dozens of extractants have been applied, but only over ten have been widely used. TBP is widely used in uranium extraction, using amine extractants in the Amex process and DEHPA in the Dapex process. Trialkylamines are also widely used in the extraction of tungsten, molybdenum, and rhenium. Alkyl phosphoric acid is widely used for extracting rare earth elements such as nickel, cobalt, and indium. P507 can be effectively used for extraction, Co, Ga, In, etc. Naphthenic acid is a special extractant for yttrium. Amide extractants such as N503 and A101 have been applied in the separation of niobium and tantalum, extraction of thallium, and treatment of phenolic wastewater. Hydroxoxime extractants are widely used in the extraction of copper.

Key words:

Extracting scandium from laterite nickel ore using extraction method with low investment cost

Classification of extractants

Extracting scandium from laterite nickel ore using extraction method with low investment cost

Classification of extractants