Separation of GaCl₃ from AlCl₃ by Solid–Liquid Extraction and Stripping Using Anhydrous n-Dodecane and NaCl

Abstract

Separation of GaCl3 from other associating chloride compounds (e.g. AlCl3, SbCl3, and InCl3) is generally achieved by hydrometallurgical processes. In this study, we explore the separation of GaCl3 from these compounds on the basis of the exceptionally high solubility of GaCl3 in hydrocarbon solvents. We found that GaCl3 can be efficiently extracted by anhydrous n-dodecane from a solid mixture of GaCl3 and AlCl3; on the contrary, SbCl3 and InCl3 significantly reduce the extraction of GaCl3. On the basis of Lewis acidity theory and study of the Raman spectra, it is shown that formation of the ionic compound [SbCl2][GaCl4] is responsible for the reduced GaCl3 extraction. Formation of [InCl2][GaCl4] is also likely, but further study is needed to support the existence of this compound. Further making use of the strong Lewis acidity of GaCl3, GaCl3 can be efficiently stripped from the loaded n-dodecane phase by solid NaCl through formation of NaGaCl4. The extraction of GaCl3 by n-dodecane, in combination with its stripping by NaCl, is a solvometallurgical process that is essentially different from the hydrometallurgical processes for the separation of GaCl3 and AlCl3.

Mechanism of Ferric Chloride Facilitating Efficient Lithium Extraction from Magnesium-Rich Brine with Tri-n-butyl Phosphate

“…53 A weak and broad band at around 365 cm −1 seems observable, matching the band of [InCl 2 ] + at about 367 cm −1 . 53,54 The bands at 331 and 151 cm −1 in the spectrum of the Sn(IV)−TBP phase might be due to [SnCl 6 ] 2− (Figure 6b). The counter-cation for [SnCl 6 ] 2− is probably [SnCl 3 (TBP) x ] + since a similar compound, [SnCl 3 L] 2 [SnCl 6 ] (L = 1,4,7-trimethyl-1,4,7-triazacyclononane), was reported in the literature.…”

“…This band might be attributed to the solvated neutral species InCl 3 (TBP) x . Considering charge neutrality, [InCl 2 ] + may exist to neutralize [InCl 4 ] − because [InCl 2 ] + was previously found as a counter-cation for [GaCl 4 ] − . A weak and broad band at around 365 cm –1 seems observable, matching the band of [InCl 2 ] + at about 367 cm –1 . , …”

“…Considering charge neutrality, [InCl 2 ] + may exist to neutralize [InCl 4 ] − because [InCl 2 ] + was previously found as a counter-cation for [GaCl 4 ] − . A weak and broad band at around 365 cm –1 seems observable, matching the band of [InCl 2 ] + at about 367 cm –1 . , …”

Nonaqueous Solvent Extraction for Enhanced Metal Separations: Concept, Systems, and Mechanisms

“…The linearity of “salting-out” of HgX 2 is due to the covalent binding of HgX 2 , whereas many other salts are hydrated in aqueous solutions. The extraction of HgX 2 by the polyphenyl eutectic as covalent molecules is similar to the extraction of solid GaCl 3 as covalent dimers by aliphatic hydrocarbons, although the latter extraction must be performed under anhydrous conditions, because of the water sensitivity of GaCl 3 …”

Supported Liquid Membranes Based on Bifunctional Ionic Liquids for Selective Recovery of Gallium

“…Due to the high demand for gallium (Ga) resources used in optoelectronics, and particularly for semiconductors consisting of gallium compounded with nitrogen (GaN) or arsenic (GaAs), the utilization of gallium resources has received considerable interest [1,2]. Gallium is generally not found in its own ores, being normally extracted and recovered as a byproduct in bauxite processing and zinc processing [3]. Furthermore, growing demand for gallium makes it crucial to recover it from the inevitably increasing secondary resources, such as waste semiconductors [4].…”