Coalescence Extraction System for Rapid Efficient and Selective Separation of Zirconium and Hafnium

Abstract

The coalescence extraction system was developed for rapid, efficient, and selective separation of zirconium and hafnium from an aqueous solution containing alkali, alkaline earth, and transition metal ions. Extraction was based on the coalescence properties of glutaronitrile in combination with the aqueous solution at elevated temperature from a homogeneous solution. In the next step, a significant temperature reduction (temperature-induced phase separation) was used to enter the spinodal to form the two phase’s regions. The particle-size distribution at coalescence temperature was measured by a laser particle-size analyzer. Metal separation could be completed in a single operation lasting only 2 min with the extraction efficiency of more than 90%. The extractability in the coalescence extraction was comparable to that of traditional methods and was feasible for rapid separation of zirconium and hafnium. The mechanism of extraction was proposed depending on the hydrolysis and polymerization of these ions and the temperature of extraction.

Homogeneous liquid–liquid extraction of neodymium(iii) by choline hexafluoroacetylacetonate in the ionic liquid choline bis(trifluoromethylsulfonyl)imide

“…[28][29][30][31][32][33][34][35][36] Examples of hydrometallurgical applications, however, are scarce and make use of molecular solvents only. [37][38][39][40][41] To the best of our knowledge, HLLE has not yet been applied to hydrometallurgical applications with ionic liquids, besides the previous work by our group. 19,20 In this paper, the potential of the ionic liquid choline bis-(trifluoromethylsulfonyl)imide, [Chol][Tf 2 N], for use in HLLE of neodymium(III) is described (Fig.…”

Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System

“…Viscosity is decreased and mass transfer and kinetics are accelerated in this way. This type of extraction is called homogeneous liquid–liquid extraction (HLLE), coalescence extraction or phase-transition extraction and has been used mainly for the extraction of natural products [ 34 – 36 ], although some examples of HLLE for metal extraction are also known [ 34 , 37 , 38 ]. To the best of our knowledge, the only example of HLLE for metals with ionic liquids has been reported by Vaezzadeh et al [ 39 ].…”

Homogeneous Liquid–Liquid Extraction of Metal Ions with a Functionalized Ionic Liquid

“…Upon cooling, phase separation occurs with transfer of the metal complex to the IL phase. This separation technique is called homogeneous liquid–liquid extraction , coalescence extraction , or phase-transition extraction, and it is typically used for the extraction of natural products. − The scarce examples of separation of metal ions via homogeneous liquid–liquid extraction make use of nitriles (adiponitrile, glutaronitrile, succinonitrile, malononitrile), or propylene carbonate as organic phase. ,− …”