Characterization of Wasted LEDs from Tubular Lamps Focused on Recycling Process by Hydrometallurgy
Lighting emitting diodes (LED) have impacted lighting products market. Its efficiency turned them the best choice for lighting. Consumption has increased and also the amount of waste. LED can be composed by some valuable and critical metals, such as silver, copper, yttrium and gallium. World demand for these metals in technological applications has attracted attention to urban mining, which also leads to circular economy. For this reason, LED recycling process can contribute as secondary source of critical metals. Also, recycling can benefit the decrease in the amount of waste generated. The recycling process is designed according to the characteristics of the material. For this reason, this work aims the characterization of waste LED from different brands in order to study a recycling route. SEM/EDS analyses were carried out to quantify the chemical distribution in the sample. FTIR analyses were carried out to identify composition of polymeric tubes, connectors, polymeric encapsulant of yellow phosphor and the structural polymer of LED chips. EDX and ICP-OES analyses were carried out to quantify the elements presented in the waste material. EDS analyses indicated silver on cathode and anode, yttrium on yellow phosphor, which was dispersed as particles in a polymeric matrix and presence of tin/lead electrical welding in a half of the lamp brands. Metals identified in LED chips from tubular lamps were specially Y (0.404%), Ga (0.070%), Ag (0.166%), Cu (50.455%), Pb (8.358%) and Sn (10.296%). Recovery of these metals may guarantee feasibility and reduce waste discharge.
KeywordsLight-emitting diodes WEEE Yttrium Gallium
We would like to thank University of Sao Paulo for support of this project, Counsel of Technological and Scientific Development (CNPq) for the financial support through doctorate grant and Sao Paulo Research Foundation and Capes (FAPESP—grant: 2019/09669-7) for financial support.
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