CYANEX^® Extractants

CYANEX extractants are phosphorus-based products that act in two different ways:

• Chelating Extractants

• Solvating Extractants

Chelating Extractants
CYANEX 272 solvent extraction reagent was developed specifically for the separation of cobalt from nickel by solvent extraction.

• It is extimated that 40% of the cobalt in the western hemisphere is produced using CYANEX 272 solvent extraction reagent, at plants Europe, South America , Canada , Africa, China and Australia.
  

• CYANEX 272 solvent extraction reagent can also be used to separate the rare earth elements from one another. The acid concentration required for metal stripping is lower than when phosphoric acid or phosphonic acid are used as extractants.

CYANEX 301 solvent extraction reagent is an analogue of CYANEX 272 solvent extraction reagent.

• Thiophosphinic acid CYANEX 301 solvent extraction reagent exhibits interesting extraction characteristics for the recovery of cobalt and nickel. A potential advantage of the dithiophosphinic acid CYANEX 301 over CYANEX 272 is its ability to extract both cobalt and nickel under very acidic conditions avoiding therefore the need for pH adjustment of the acidic leach liquors.

Solvating Extractants
CYANEX 921 and 923 solvent extraction reagents have potential in a wide range of applications. Specific applications are the recovery of organic solutes and/or inorganic mineral acids from waste effluents, and metal extraction processes.

Unlike its phosphine oxide analogues, CYANEX 471X solvent extraction reagent is a soft Lewis base. Under the HSAB principle, it will only complex readily with metals that exhibit the characteristics of soft Lewis acids. Specific characteristics of these so-called soft Lewis acids are their large ionic radius, their low oxidation state and their ease to be polarized. Examples of metals falling upon those criteria are Pd(II), Pt(II), Ag(I), Cd(II), Hg(I), Hg(II) and Au(III).