Process for synergistic extraction of Hf(IV) over Zr(IV) from thiocyanic acid solution with TOPO and N1923

Liquid-liquid extraction of zirconium(IV) from sulphuric acid medium using a binary mixture of tri-n-octylamine and Cyanex923 in kerosene

“…After five minutes, the phases were settled, and then they were disengaged. The concentration of Zr(IV) in the aqueous phase before and after extraction was determined using the Arsenazo (III) method [18] using a PerkinElmer UV-visible spectrophotometer. The ratio of the equilibrium concentration of Zr(IV) inorganic phase and that in the aqueous phase was taken in the calculation of the distribution coefficient (D).…”

“…Spectrophotometrically, the absorbance of the metal was measured [18] before and after extraction, from which the distribution ratio was calculated as follows:…”

“…For a successful solvent extraction system, there are two vital aspects, that is, the selection of extractants and diluents [18]. The influence of diluents on the distribution of metal is correlated with the physicochemical properties of an organic solvent such as dipole moment, dielectric constant, solubility parameter, etc.…”

“…The influence of diluents on the distribution of metal is correlated with the physicochemical properties of an organic solvent such as dipole moment, dielectric constant, solubility parameter, etc. [18]. Using a binary mixture of 0.007 M Cyanex923 and 0.060 M TOA, the extraction of Zr(IV) has been studied in various organic diluents such as kerosene, benzene, diethyl ether, xylene, carbon tetrachloride, and chloroform.…”

“…Wu et al proposed a pathway for synergistic extraction of Hf over Zr using a binary mixture extractant, i.e., TOPO and N1923 from thiocyanic acid. The efficiency of their process was found to be 86.3% [18]. Solvent extraction behavior of trace level tantalum and niobium by using trioctylamine from sulphuric acid and hydrofluoric acid media that have greater affinities towards niobium and tantalum with TOA was studied by Das et al [19].…”