Identification and recovery of rare metals in electric and electronic scrap : a review
Résumé
The production of electric and electronic appliances is increasing, and their economic life is short, while the development of new technologies makes them obsolete. The generated WEEE represents 14 kg/capita/year in the EU. The growth of WEEE is about three times higher than the growth of the average municipal waste. A large proportion of various pollutants that is found in municipal waste comes from WEEE. The electric and electronic scrap is a complex material, which contains not only precious metals such as gold, silver, but also rare and rare earth metals. Chromium, nickel are used as alloys in different components. Europium, yttrium are used in fluorescent powders for CRTs to give a brilliant red color. Europium has sometimes been substituted by terbium, in which case the color will be brilliantly white to green. Praseodymium and Neodymium can be added to CRTs to reduce glare from other light sources. Other rare metals such as Rubidium, Cesium, Strontium, Scandium, Iridium, Tellurium, Technetium, Osmium, Ruthenium, Gallium, Bismuth, Germanium, and Tantalum are identified in capacitors or collectors etc...The main objective of this investigation is to identify the rare metals and earth rare elements contained in the end of life of electric and electronic products (EOF-EEP), and to recover them in an economical way. In paper the characteristics of rare metals in the electric and electronic scraps and their recovery methods are reviewed.