Extraction of heavy metal (Ba, Sr) and high silica glass powder synthesis from waste CRT panel glasses by phase separation.

In this study, a novel process for the extraction of heavy metal Ba and Sr from waste CRT panel glass and synchronous preparation of high silica glass powder was developed by glass phase separation. CRT panel glass was first remelted with BO under air atmosphere to produce alkali borosilicate glass. During the phase separation process, the glass separated into two interconnected phases which were BO-rich phase and SiO-rich phase. Most of BaO, SrO and other metal oxides including NaO, KO, AlO and CaO were mainly concentrated in the BO-rich phase. The interconnected BO-rich phase can be completely leached out by 5mol/L HNO at 90 ℃. The remaining SiO-rich phase was porous glasses consisting almost entirely of silica. The maximum Ba and Sr removal rates were 98.84% and 99.38% and high silica glass powder (SiO purity > 90 wt%) was obtained by setting the temperature, BO added amount and holding time at 1000-1100 ℃, 20-30% and 30 min, respectively. Thus this study developed an potential economical process for detoxification and reclamation of waste heavy metal glasses.