Recycling Technologies for Extracting Gallium from Light-Emitting Diodes

Light-emitting diodes (LEDs) are made up of precious metals, e.g., gallium. These elements can be recovered and reused, reducing the need for new raw materials. Proper recycling prevents harmful substances in LEDs, such as lead and arsenic, from contaminating the environment. Recycling LEDs uses less energy compared to producing new ones, leading to lower carbon emissions. The valuable metal gallium faces the challenge of supply and demand due to the surge in its demand, the difficulty of separating it from minerals, and processing issues during extraction. In this review, we describe the methods for recycling gallium from LEDs by using different techniques such as pyrolysis (95% recovery), oxalic acid leaching (83.2% recovery), HCL acid leaching of coal fly ash (90–95% recovery), subcritical water treatment (80.5% recovery), supercritical ethanol (93.10% recovery), oxidation and subsequent leaching (91.4% recovery), and vacuum metallurgy separation (90% recovery). Based on our analysis, hydrometallurgy is the best approach for recovering gallium. It is reported that approximately 5% of the waste from LEDs is adequately recycled, whereas the total gallium potential wasted throughout production is over 93%. By recycling LEDs, we can minimize waste, conserve resources, and promote sustainable practices. Thus, recycling LEDs is essential for strengthening a circular economy.