Mineralogical analysis of waste LEDs and the recovery process of valuable components

LED lights are widely used in household appliances, automotive lighting, decorative materials, and other fields due to their high energy efficiency. At the same time, LED waste is also growing rapidly. LED lamps contain some valuable elements, such as Ga and In, as well as some toxic and hazardous substances. Properly processing and recycling of LED lamps are significant for resources recovery and ecological protection. The particle size distribution, morphology, and elemental composition of the separated products of the LED light strip were analyzed. The results show that with the extension of the crushing time, the contents of Fe, Cu and C increased, while the contents of Si did not change significantly in the lamp bead powder. The contents of Cu, C and Si in magnetic materials decreased, more than 98% of the Fe entered the magnetic product following magnetic separation. Taking into considering the peeling off of the lamp bead powder and the distribution of elements in it, the optimal crushing time appears to be 9 s. The Ga-containing particles in − 0.074 mm were fully dissociated. The relative content of Ga and In in this particle size range reached 22.30% and 16.46%, respectively. In the thermogravimetric analysis of the LED lamp, the pyrolysis temperature was 400 °C, and the largest weightlessness peak was found to appear at 462 °C. The Mineralogy analysis provides a basic data for the recycling of waste LEDs, and a recycling process for waste LED is developed.