Development of an Integrated Process Flowsheet to Recover Valuable Metals from Waste Cathode Ray Tubes and Printed Circuit Boards

Electrical and electronic waste is considered a valuable stream of secondary metal resources because it contains metals such as copper, silver and gold. However, it is also classified as hazardous waste as it contains toxic heavy metals such as lead and cadmium. If electronic waste is not managed properly, the toxic metals may pose serious risks to the environment and human health, especially complex fractions such as printed circuit boards (PCBs) and cathode ray tubes (CRTs). The current study investigated a new process for the thermal treatment of CRTs and PCBs in an integrated flowsheet for metal recovery. Smelting tests were conducted to demonstrate that oxidative smelting of PCB concentrate and recycled CRT slag can produce a crude copper alloy with a grade of more than 95%. Another set of smelting tests was conducted to demonstrate that reductive smelting of CRT funnel glass and recycled PCB fume can produce a crude lead alloy with a grade of more than 95%. The investigations were undertaken in a pilot-scale top blown rotary converter (TBRC). The PCBs were smelted under mildly oxidising conditions at temperatures up to 1350 degrees C. The CRTs were smelted under mildly reducing conditions at temperatures up to 1250 degrees C. The study demonstrated that it is technically feasible to produce crude alloys of copper and lead from electronic waste, using an integrated process flowsheet.