CRUD FORMATION IN THE SOLVENT EXTRACTION SYSTEM Zr (IV), HNO₃-D2EHPA

Abstract

The limiting organic concentration (LOC) of zirconium (IV), which is the maximum possible concentration of the metal species in the organic phase without formation of crud as a third phase, was determined under different experimental conditions such as concentration of HNO₃ in the aqueous phase and concentration of a modifier (TBP or isodecanol) in the organic phase. Also, the effect of several diluents (orthoxylene, toluene, n-heptanes, n-dodecan, petroleum ether, chloroform, and kerosene) and the effect of aqueous solution aging on LOC have been investigated. The results showed that the formation of crud depends on the dipole moment of the organic phase, and that aging of the aqueous feed has a significant effect on the LOC of zirconium.

Keywords:

• crud formation
• D2EHPA
• extraction
• third-phase formation
• zirconium