Research on extraction of Cr(III) by D2EHPA/n‐octanol/sulphonated kerosene

Abstract

Chromium is an important industrial raw material. As far as China is concerned, chromium is in great demand, which is dependent on imports and large emissions. So recovery of chromium has important economic and environmental protection value. The extraction and back extraction of Cr(III) from solution by the extractant diisooctyl phosphate (di‐2‐ethylhexylphosphoric acid [D2EHPA]) with n‐octanol as assistant and sulphonated kerosene as diluent was studied. The effects of saponification rate, phase ratio, temperature, condensation of extract, aging of extractant, and pH of aqueous phase on extraction equilibrium were discussed, and the formulation of extractant was optimized. The coordination number of the extraction reaction under specific conditions was discussed by the saturation capacity method. The extraction reaction kinetics were mathematically characterized by binary linear regression. The advantages and disadvantages of back extraction with H2SO4 or NaOH were compared. At last, a process to realize the recycling of extractant was obtained.

Study on the adsorption–desorption behaviours of La3+, Sm3+, and Y3+ by HEHEHP extraction resin in chloride medium

“…In general, solvent extraction and the extraction resin method are widely used in the preparation of ultra-high purity RE, and mainly 2-ethylhexylphosphonic acid mono-2-ethyl hexyl ester (HEHEHP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) are used. [9][10][11][12][13] However, solvent extraction is suitable for industrial large-scale production, and the purity of individual RE elements can reach 99.999%, while the purity of other RE elements is generally below 99.99%, which is difficult to meet the demand for RE high-performance materials. Compared with solvent extraction, the main advantage of the extraction resin method is that the extractant can be minimized and stoichiometrically optimized for trace level separations.…”