Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE) Using a pH-Responsive Fluorine-Based Surfactant

Abstract

Abstract:A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE) using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr) were examined. By changing pH from a neutral or alkaline solution (pH ≥ 6.5) to that of an acidic solution (pH < 4.0), gallium, zirconium, palladium, silver, platinum, and rare earth elements were extracted at >90% efficiency into a sedimented Zonyl FSA ® (CF3(CF2)n(CH2)2S(CH2)2COOH, n = 6-8) liquid phase. Moreover, all rare earth elements were obtained with superior extraction and stripping percentages. In the recycling of rare earth elements, the sedimented phase was maintained using a filter along with a mixed solution of THF and 1 M sodium hydroxide aqueous solution. The Zonyl FSA ® was filtrated and the rare earth elements were recovered on the filter as a hydroxide. Furthermore, the filtrated Zonyl FSA was reusable by conditioning the subject pH. OPEN ACCESSMetals 2015, 5 1544

Hydrometallurgical Methods of Indium Recovery From Obsolete LCD and Led Panels

“…The HoLLE method was studied for the separation and recycling of indium and other rare metals [26,27]. Kato et al [26] investigated the recovery of indium from LCD screens of mobile phones.…”

“…Saito et al [27] investigated the application of the HoLLE method for the separation of 62 elements from HNO 3 , HCl, HF H 2 SO 4 or KOH solutions of various concentrations. 1,10-phenantroline was applied as chelating compound.…”

Powerful Concentration of Rhodium in Plating Wastewater Using Homogeneous Liquid–Liquid Extraction (HoLLE) and Study for Scale-up

“…Perfluoro compounds, such as Zonyl FSA, can be removed with back-extraction by adding solvent (Takagai & Igarashi, 2003), recovery using a chemically modified polymer gel (Butsugan & Igarashi, 2009), removal by solid-phase extraction (Japanese Standard Association, 2011), and reuse on the basis of the mixed solution (Saito, Ohno, Igarashi, Kato, & Yamaguchi, 2015). For example, rhodium leads to the formation of hydroxide, Zonyl FSA is recovered by a chemically modified polymer gel (Butsugan & Igarashi, 2009), and PAN remains in residual liquid after the Zonyl FSA of the sedimented liquid phase is dissolved in water at a higher pH value than its acid dissociation constant (pKa = 6.5) (Sudo & Igarashi, 1996).…”

“…In HoLLE, the target solute is concentrated into a small secondary phase through the effect of some stimulation such as pH, or light. HoLLE has been widely used to extract target solutes such as indium (In) (Kato, Igarashi, Ishiwatari, Furukawa, & Yamaguchi, 2013), cobalt (Co) (Kato, Igarashi, Saito, Ando, & Asano, 2014), rare earth elements (Saito, Ohno, Igarashi, Kato, & Yamaguchi, 2015), and Pd (Kato, Igarashi, Ohno, Saito, & Ando, 2016), although the target solute is not limited to metals. Additionally, HoLLE can be applied to organic compounds (Takagai & Igarashi, 2002) and biological materials (Sudo & Igarashi, 1996).…”

REE Geochemistry of Euphrates River, Turkey

“…0.5 g of each sediment sample was leached with 90 mL HCl-HNO 3 -HF at 95 ∘ C for 1 hour, diluted to 150 mL, and then analyzed by ICP-OES. The extraction method used by Saito et al [42] was used to obtain the maximum REE concentration at 9.95 mL 0.01-1 m nitric acid aqueous solution (pH < 4). Standard DS5 was used for the sediment analyses.…”