Selective Recovery of Gold from Electronic Waste Using 3D-Printed Scavenger

Abstract

Around 10% of the worldwide annual production of gold is used for manufacturing of electronic devices. According to the European Commission, waste electric and electronic equipment is the fastest growing waste stream in the European Union. This has generated the need for an effective method to recover gold from electronic waste. Here, we report a simple, effective, and highly selective nylon-12-based three-dimensional (3D)-printed scavenger objects for gold recovery directly from an aqua regia extract of a printed circuit board waste. Using the easy to handle and reusable 3D-printed meshes or columns, gold can be selectively captured both in a batch and continuous flow processes by dipping the scavenger into the solution or passing the gold-containing solution through the column. The possibility to optimize the shape, size, and flow properties of scavenger objects with 3D printing enables the gold scavengers to match the requirements of any processing plants.

Selective Laser Sintering of Metal‐Organic Frameworks: Production of Highly Porous Filters by 3D Printing onto a Polymeric Matrix

“…Nylon‐12 provides an example of a functional printable polymer. It has been used to print selective filters for scavenging gold from acidic media . Another example of a hybrid material is a mixture of polypropylene and type‐I anion exchange resin as functional component …”

“…It has been used to print selective filters for scavenging gold from acidic media. [22] Another example of a hybrid material is a mixture of polypropylene and type-I anion exchange resin as functional component. [21] In the current work the same approach has been used to incorporate the MOF copper(II) benzene-1,3,5-tricarboxylate (HKUST-1) [23] into an SLS 3D-printed object.…”

Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions

“…Thes tudy was initiated by conducting Au dissolution experiments using our previously published procedure: [18] A small amount of fine Au powder was added to a16mm EtOH solution of 4-PSH, and the mixture was stirred for 23 hunder 10 bar of O 2 at 22 8 8C. This resulted in only 14 %o fd issolved Au ( [3][4][5][6], showing that the dissolution efficiency correlates directly with the 4-PSH concentration. Importantly,q uantitative dissolution of the Au sample was achieved either with an extended reaction time and al ow 4-PSH concentration or within 25 min using a4 -PSH concentration of 203 mm (Table 1, entries 2a nd 7).…”

Porous 3D Printed Scavenger Filters for Selective Recovery of Precious Metals from Electronic Waste

“…The chemical performance of the printed scavengers was evaluated by using a synthetic test solution containing 100 mg L −1 of Ni, Zn, Fe, and Cu and 50 mg L −1 of Al, Cr, Pb, and Sn along with 5 mg L −1 of Pd and Au and 1 mg L −1 of Pt in 5% aqua regia. The chosen composition mimics the metal ratio in an average sample of an aqua regia dissolved Printed Circuit Board (PCB) waste . Synthetic test solution was used due to the fact that the metal concentrations in true WEEE leachates vary considerably depending on the actual waste material.…”

“…From authentic PCB waste, silver can precipitate in presence of chloride, and hence it was not included in any of the test solutions. Similarly, gold can be removed completely and selectively by using the 3D printed nylon scavenger prior to 1 ‐PP filter (see below and Table S4, Supporting Information) . Hence, the synthetic test solution mimics the leachate after removal of Au and Ag.…”