Pb Recovery of Waste Cathode Ray Tube Funnel Glass by PbO Vapor Vacuum Reduction (PVVR) Process and the Feasibility of Luminescent Glass Production
Cathode ray tube (CRT) waste funnel glass as a past energy material is a hazardous waste that contains toxic lead oxide, presenting a great environmental challenge worldwide. There is a significant need for an effective treatment method to facilitate safe disposal of CRT. In this work, a novel and simple method to remove lead oxide and recycle metallic lead was developed by PbO vapor vacuum reduction (PVVR) process. Use of vacuum thermal process allows the successful removal of lead oxide from waste CRT funnel glass and recycling of PbO. To obtain metallic Pb and remove the volatile potassium and sodium elements, the PbO vapor vacuum reduction (PVVR) process was designed and implemented. The optimum reduction temperature and holding time for lead recovery were 1573 K and 120 minutes, respectively. Under this condition, more than 98 pct of lead can be removed from waste funnel glass and the Pb content in parent glass was successfully reduced to 0.38 pct. The metallic Pb microspheres with 99.36 pct purity were obtained and the Pb leaching concentration of residual glass was 1.67 mg/L as measured by the Toxicity Characteristic Leaching Procedure (TCLP) test. Additionally, the charcoal layers have a greater than 85 pct K adsorption effect and do not contaminate residual glass. Then, luminescent Tb3+ glass as an energy material using residual glass was greatly luminescence performance. Overall, this work presents a simple and effective process for the detoxification and utilization of waste CRT funnel glass as well as the recovery of Pb by vacuum metallurgy technology.