Detoxification of GaAs Bearing Waste LED and Recovery of Metal Values Through Understanding the Thermodynamics and Chemistry: A Perspective

摘要

Light-emitting diodes (LEDs) are energy-efficient and mercury-free, conventionally it is considered environment-friendly, which is not true depending upon kind of LED material constituents. Those LEDs provides yellow, red light and used for infrared light resources are mainly made from Ga, As and P. End of life LED bearing waste is an environmental challenge considering hazardous As content. Also, Ga is a vital metal for the electronics industry, is classified as significant from the industrial application and critical from a supply chain scarcity perspective. The Republic of Korea depends upon import of Ga, under the national policy of securing a stable supply, much attention has been paid to the notion of "urban mining". Hence, Ga values recovery and detoxification of As from EOL LED can address two different issues. Through high-temperature sublimation followed As recovery by condensation for safe disposal or reuse purpose could be a potential technique. For the purpose, reactor design and thermal parameters are two important aspects needed to be addressed. Hence, in our current study focusses on understanding of thermochemistry and thermodynamics of GaAs bearing LED. It can provide potential information for the recovery of metal values and detoxification of hazardous substances from the LED.