Characterization and recycling potential of the discarded cathode ray tube monitors

Abundantly available discarded cathode ray tubes are a serious threat to the environment and loss to resource conservation and therefore requiring immediate recycling efforts. In this study, extensive characterization of all parts of the discarded cathode ray tube was carried out using X-ray diffraction, thermo-gravimetric, X-ray photoelectron spectroscopy, Scanning electron microscope, and Energy Dispersive Spectroscopy. The detailed mass balance and the overall potential (market value calculations) of discarded cathode tubes as an urban source, and the techno-economic calculations were carried to provide guidelines for the development of recycling technology. Recycling techniques of cathode-ray tubes were reviewed, and a concise flow sheet for overall recycling was prepared for evaluation and assessment of recycling potential. The thermal response and dissociation kinetics of the phosphor were investigated, and the activation energy in the temperature range (600-930 degrees C) for thermal processing of phosphor was determined as 105.4 kJ/ mol. Effective recycling of cathode ray tube phosphor can yield 4.5 g of Y, Eu and, La metal values per 500 kg of discarded units with a market value of 835 INR and an overall market value of 115,870 INR ($1567.34). The different fractions of cathode-ray tube glass were recycled using a combination of the pyrometallurgical and hydrometallurgical processes for metal recovery. Recycling of different fractions of hazardous discarded cathode ray tubes is necessary and is beneficial for a circular economy for recovery of phosphor, copper, glass and coating material, plastics, and steel.

Automated summary

In-depth characterization and recycling efforts for discarded cathode ray tubes can effectively recover metals and increase market value. The determination of activation energy for thermal processing of phosphors by thermo-gravimetric and X-ray photoelectron spectroscopy provides crucial information for phosphor recycling.