In the disposal of electronic waste, cathode ray tube (CRT) funnel glass remains an urgent environmental problem because of its high lead content. This research developed mechanical activation as a pretreatment process, and it proved to be an effective method for extracting lead from CRT funnel glass. The effects of mechanical activation on the structural changes of CRT funnel glass were investigated using X-ray diffraction (XRD), particle size analysis, specific surface area (SSA), and a scanning electron microscope (SEM). Nitric acid leaching behaviors of the activated CRT funnel glass were studied by varying several parameters: leaching time, liquid-to-solid ratio, acid concentration, and heating temperature, as well as various conditions of activation. The lead recovery rate was observed to increase rapidly, particularly with increases in activation time and leaching temperature, but to vary relatively less under other experimental parameters. Under the optimal leaching conditions, the lead recovery rate for funnel glass activated for 2 hr at the rotational speed of 500 rpm (by ball mill) reached 92.5%, compared with 1.2% from the unactivated sample.
Implications: CRT funnel glass containing lead has become a serious environmental problem facing the whole world. In order to dispose of CRT funnel glass, some technologies have been developed. However, these technologies are associated with higher operation and maintenance costs. In this study, mechanical activation was introduced to change the physicochemical properties of CRT funnel glass, which can transform the glass into an easily dissolved one. Under atmospheric pressure leaching conditions, good recovery rate for lead can be achieved and the residue has wide uses. The process can be applied to treat other leaded glass or lead-containing wastes.