Separation and recovery of gold from waste LED using ion exchange method

doi:10.1016/j.hydromet.2015.08.014

Hydrometallurgy

Volume 157, October 2015, Pages 194-198

https://doi.org/10.1016/j.hydromet.2015.08.014 Get rights and content

Highlights

•
Separation and recovery of gold from waste LED was investigated.
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Leaching of gold from LED terminal was achieved with aqua regia at 80 °C.
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Gold was separated from the solution by column adsorption with WA21J.
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Quantitative elution of gold was achieved with diluted thiourea solution.
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Elementary gold was obtained from the eluent with 100% purity.

Abstract

The separation and recovery of gold from waste LED using ion exchange method was investigated, employing commercial polyamine type anion exchanger, Diaion WA21J. Leaching of gold from LED terminal was successfully carried out with aqua regia at 80 °C. Separation of gold from the leaching solution was then carried out by column adsorption with WA21J. The selective adsorption of gold was achieved, while adsorption of the co-existing metals in the leaching solution was suppressed. Quantitative elution of gold from WA21J was achieved with diluted thiourea solution. Elementary gold was then obtained from the eluent by simultaneous precipitation and reduction of gold with sodium borohydride with 100% purity.

Graphical abstract

Introduction

Gold is currently used as a raw material in numerous industrial applications, due to its specific physical properties of electrochemical potential, and electro and thermal resistivity. The industrial demand of gold is expected to increase in the fields of pollution and emission control, chemical processing, and fuel cell applications (Corti et al., 2004, Corti et al., 2005). With the increasing demand, separation and recovery of gold from waste materials become an important issue from the view point of resource sustainability.

Generally, metals in waste materials are separated and recovered by solvent extraction and/or ion exchange in the hydrometallurgical process. There are several reports concerning the separation of gold by solvent extraction (Ohara et al., 1996, Narita et al., 2006, Pan and Gu, 2012) and by ion exchange (Iglesias et al., 1999, Matsubara et al., 2000, Sánchez et al., 2000, Gomes et al., 2001, Al-Merey et al., 2003, Hidalgo et al., 2006, Ertan and Gülfen, 2009, Erim et al., 2013). Comparing these separation methods, ion exchange has an advantage as an environmentally friendly process, since solvent extraction requires large amounts of organic solvent to dissolve both extractant and extracted metals, which leads to loss of the organic solvent (Kabay et al., 2003). The ion exchange method is also more effective for applying to the diluted metal solution leached from waste, rather than the solvent extraction method, since large amounts of organic solvent cause insufficient extractability of diluted metal ions (Saha et al., 2000). In the case of ion exchange for gold, anion exchange resins, based on amine group or quaternary ammonium salt group, are mainly used, since most gold exists as anionic species.

There are several reports concerning the separation and recovery of gold from waste materials. One of the waste materials applied for the separation and recovery of gold is printed circuit boards (PCBs). Adsorption process with Amberlite XAD-7HP, acrylic polymeric adsorbent, followed by leaching of the PCBs (Kim et al., 2011), adsorption process with bio-sorbent from persimmon residue (Fan et al., 2014), and electrochemical oxidation process for enrichment of gold (Fogarasi et al., 2014) have been reported. Adsorptive separation of gold from waste rinse water of the semiconductor manufacturing industry (Nguyen et al., 2010) and from wastewater of gold-plating (Soleimani and Kaghazchi, 2008) has also been reported. Chip-on-board LED (COB-LED) is also one of the attractive materials for the recovery of gold, since the COB-LED contains gold as wire. According to our literature survey, however, no hydrometallurgical separation and recovery process of gold from waste COB-LED was reported.

In the present work, the separation and recovery of gold from waste COB-LED was investigated using the ion exchange method. Commercial anion exchange resin, Diaion WA21J, having a polyamine group was used as an adsorbent. Leaching behavior of gold and co-existing components from LED terminal was first investigated by using aqua regia. Adsorption properties of gold and co-existing metals in the leaching solution were also investigated by both the batchwise and column adsorption systems. Precipitation and reduction of gold were then carried out by adding sodium borohydride to the eluent from the column operation. Recovery yield of the gold from the leaching solution was finally evaluated.

Section snippets

Reagents

Commercial ion exchange resin, WA21J, was kindly supplied by Nippon Rensui Co., Ltd. (Tokyo, Japan). Gold(III) chloride was supplied by Alfa Aesar, and all other inorganic reagents were supplied by Wako Pure Chemical Industries, Ltd. (Osaka, Japan), as analytical-grade reagents.

Leaching of waste LED

Actual waste COB-LED samples (Panasonic) were used in the present work. The waste LED terminal was first taken off from the lamp. The LED terminal (0.5 g) was then treated with aqua regia ([aqua regia] = 12.0 mol/L, ORP = 972

Leaching of metals from waste LED

Leaching of the waste LED terminal was firstly investigated. Our preliminary experiments revealed that a solid/liquid ratio of 0.2 g/mL is suitable for the leaching of gold. Table 1 shows the compositions leached from the waste LED. Precise concentration of silver could not be determined, because aliquots of silver were precipitated by formation of silver chloride after dilution of the leaching solution for ICP-AES measurement. 2.17 mg/g of gold was leached from the waste LED. In addition, no

Conclusions

Separation and recovery of gold from waste LED was investigated using ion exchange method with polyamine type anion exchange resin. The important features of the system are summarized as follows:

(1)
Leaching of gold could be successfully achieved with aqua regia at 80 °C for 24 h, and 2.17 mg/g of gold was leached together with co-existing metals namely iron, calcium, silver, manganese, and zinc.
(2)
Adsorption of gold with WA21J was decreased with increase in the concentration of aqua regia, due to

References (22)

C.W. Corti et al.
Commercial aspects of gold catalysis
Appl. Catal. A Gen.
(2005)
H. Narita et al.
Extraction of gold(III) in hydrochloric acid solution using monoamide compounds
Hydrometallurgy
(2006)
M. Iglesias et al.
Recovery of palladium(II) and gold(III) from diluted liquors using the resin duolite GT-73
Anal. Chim. Acta
(1999)
C.P. Gomes et al.
Gold recovery with ion exchange used resins
Sep. Purif. Technol.
(2001)
R. Al-Merey et al.
Selective separation of gold from iron ore samples using ion exchange resin
Microchem. J.
(2003)
Ü.C. Erim et al.
Separation of gold(III) ions by 1,8-diaminonaphthalene-formaldehyde chelating polymer
Hydrometallurgy
(2013)
N. Kabay et al.
Removal of Cr(VI) by solvent impregnated resins (SIRs) containing aliquat 336
React. Funct. Polym.
(2003)
E.Y. Kim et al.
Selective recovery of gold from waste mobile phone PCBs by hydrometallurgical process
J. Hazard. Mater.
(2011)
R. Fan et al.
Selective adsorption and recovery of Au(III) from three kinds of acidic systems by persimmon residual based bio-sorbent: a method for gold recycling from e-wastes
Bioresour. Technol.
(2014)
S. Fogarasi et al.
Copper recovery and gold enrichment from waste printed circuit boards by mediated electrochemical oxidation
J. Hazard. Mater.
(2014)

M. Soleimani et al.

Adsorption of gold ions from industrial wastewater using activated carbon derived from hard shell of apricot stones — an agricultural waste

Bioresour. Technol.

(2008)

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Separation and recovery of gold from waste LED using ion exchange method

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Reagents

Leaching of waste LED

Leaching of metals from waste LED

Conclusions

Appl. Catal. A Gen.

Hydrometallurgy

Anal. Chim. Acta

Sep. Purif. Technol.

Microchem. J.

Hydrometallurgy

React. Funct. Polym.

J. Hazard. Mater.

Bioresour. Technol.

J. Hazard. Mater.

Bioresour. Technol.