Waste printed circuit boards (PCBs) contain a number of valuable constituents. It is of great significance to separate precious metals and non-metallic constituents from waste PCBs with appropriate methods for resource recycling and environment protection. A novel flowsheet for the recycling of waste PCBs using physical beneficiation methods was constructed. Waste PCBs were disassembled into substrates and slots firstly. The substrates were crushed to the size below 1mm through wet impact crushing and separated with a tapered column separation bed. The results indicated that products with integrated separation efficiency of 93.9% and metal recovery ratio of 93.7% were obtained by the primary separation with the water discharge of 5.5 m3/h, feed-rate of 250g/min and inclination angle of 35°. Waste PCBs slots components were crushed to the size of 0.5-5mm through impact crushing and separated with an active pulsing air classifier. The separation results showed that products with integration separation efficiency of 92.4% and metal recovery ratio of 96.2% were obtained with the airflow velocity of 2.90m/s and pulsing frequency of 2.33Hz. Precious metals could be obtained by further separation and purification of the metal components and the non-metal components could be used as refuse derived fuel. The flowsheet has great potential to be applied in the field of waste PCBs treatment and recycling.
Current Status on Leaching Precious Metals from Waste Printed Circuit Boards
