Recycling of Gallium from End-of-Life Light Emitting Diodes

Abstract

Nowadays Light Emitting Diodes (LEDs) are widely utilized. They are applied as backlighting in Liquid Crystal Displays (LCD) and TV sets or as lighting equipments in homes, cars, instruments and street-lightning. End of life equipments are containing more and more LEDs. The recovery of valuable materials -such as Ga, Au, Cu etc. -from the LEDs is essential for the creating the circular economy. First task is the development of a proper recycling technology. Most of the researchers propose fully chemical or thermal-chemical pathway for the recycling of LEDs.In the meantime our approach based on the thorough investigation of the structure and composition of LEDs, and shown in this paper, is the combination of mechanical and chemical techniques in order to recover more valuable products, as well as to facilitate the mass transfer. Our laboratory scale experiments are introduced, the final aim of which is Ga recovery in accordance with our above approach. It was experimentally proved that the LED chips contain Ga and can be recovered by mechanical processes along with copper-product. Ga is presented on the surface of the chips in GaN form. Mechano-chemical activation in high energy density stirred medium mill and the following acidic leaching resulted in the enrichment of 99.52% of gallium in the pregnant solution.

The comminution of PCB and LED in order to improve metal recovery

“…The technology could be utilised to recover Ga and In from the examined LED waste [37]. In [39] the possibility of the recovery of Ga from end-of -life LEDs was investigated at labour scale combining the mechanical pre-treatment with the following chemical-thermal techniques. By the mechanical preparation, after physical liberation the conductive parts (Cu) were successfully removed.…”

A Review on Recycling of End-of-Life Light-Emitting Diodes for Metal Recovery

“…[1][2][3] The growth of LEDs is caused by their low energy consumption (10 W/800 lumens), low heat emissions, long life, diversity of colors, and mercury absence. [4][5][6] The application of LEDs worldwide is promoted by actions such as marketing, replacement campaigns, and legislation. 1,7,8 LEDs are extensively used in displays, screens, backlights for liquid crystal displays, televisions, cellular phones, signage, lightings in homes, cars, and instrument panels.…”

The Potential and Limitations of Critical Raw Material Recycling: The Case of LED Lamps

“…Only a few studies have investigated the recycling and material recovery of LED lighting. While some focused on technological development [11][12][13], others assessed the environmental impacts of LED lamps and their EoL phase [14] or discussed the economic potential of material recovery [9,15,16]. Studies analyzing the economic viability of LED lighting and other WEEE streams often focused on the absolute raw material amounts in the EoL products combined with their prices to derive recommendations for actions [16][17][18], or they focused on a cost-benefit analysis [19,20].…”