关键词: 微波, 废旧印刷电路板, 电解氯, 强化浸出

Abstract: Aiming at the problems of long leaching time and low leaching rate of metal from waste printed circuit boards ( WPCBs),due to advantages of microwave heating,such as high penetrability,selective heating,small thermal inertia and nonionization,microwave-enhanced chlorine was utilized to leach metals from WPCBs combining microwave and electrochemistry. The results showed that:under the conditions of microwave power of 500 W and electrolysis leahing time of 100 min,the mass loss rate of WPCBs samples was 63. 49%,and the leaching rate of Cu was 83. 50% when plastic foam was used as the carrier medium. The increases of microwave power and electrolysis time were beneficial to the improvement of the leaching rate of Cu. Calorimetry,heating method,dielectric constant and other testing methods were used to reveal the microwave heating mechanism of pure metal powder and WPCBs materials,and microwave-enhanced leaching mechanism. The test results show that the metal of WPCBs being heated in the microwave field consumed the magnetic field. The metal in the WPCBs after absorbing the microwave energy and its temperature is higher than the temperature of the solution. The metal surface has a high energy and high temperature,and easy to react with the dissolved leaching agent and Cl2 which dissolved in solution. The temperature between metal surface and the solution are difference,therefore,the formation of thermal perturbation of the solution to promote the migration of leaching reagents in the solution occured to promote the reaction,and ultimately to enhanced leaching and improve leaching rate of metal in a shorter time and lower acid concentration. The results of the study provide a new microwave electrochemical leaching recovery pathway for WPCBs metal resource recovery.

Key words: microwave,waste printed circuit boards,electrolytic chloride,enhancing leaching