ECOLOGICAL AND EFFICIENT METHOD FOR THE RECOVERY OF NONFERROUS METALS FROM INDUSTRIAL WASTES BY PROCESSING IN MICROWAVE FIELD

The present paper presents an innovative ecological and efficient method to recover the useful metals from various types of industrial wastes by processing in a microwave field. Compared to the classical methods, microwave melting presents a series of major advantages, such as: i. simultaneous evolution of the heating gradient in the entire volume of material; ii. much higher heating rates that shorten the melting time by 70-85%, thus leading to energy savings and higher processing capacities; iii. superior quality of the obtained materials by reducing the melt impurification through oxidation; iv. remarkable versatility, as wastes with a wide range of shapes, chemical compositions and structures can be processed in the same installation; v. the possibility to neutralize the gaseous emissions also in microwave field. In the present work two types of wastes from the obtaining of aluminum-silicon and respectively antifriction antimony-tin-lead alloys, were melted in a microwave furnace. The values of the metal recovery efficiencies were of approximately 90%. Also, the treatment of the gaseous emissions in microwave field lead to the reduction of the hazardous substances' contents to values under the legal limits.