A Typical e-waste—Cathode Ray Tube Glass: Alkaline Leaching in the Sulfur-Containing Medium

AbstractWith more and more cathode ray tube (CRT)-based sets reaching their end-of-life or being replaced, how to deal with the CRT glass has become a global concern due to its high lead level. There is a pressing and ongoing need to develop new recycling methods for CRT glass. In this work, the alkaline leaching of CRT funnel glass in the sulfur-containing medium (S and NaS) was probed. The effects of alkaline concentration, S/Pb molar ratio, temperature and leaching time were investigated. The results showed that the recovery rate of both Si and Pb increased with increasing alkaline concentration; however, it decreased again when the concentration was higher than the critical value 6M. The recovery rate of Pb in both media decreased with increasing S/Pb molar ratio. As a comparsion, the recovery rate of Si did not change significantly. The extraction of Si and Pb, especially Si, tightly depended on the temperature. They also increased with extending of time, however, they tended to decrease when the reaction time exceeded 8h. The optimal condition was determined as: alkaline concentration 6M, S/Pb molar ratio 1.0:1, temperature 180°C and leaching time 8h