Etude de faisabilité d’un processus de biolixiviation pour le recyclage des métaux et terres rares contenus dans les téléphones portables.

The electronics industry is one of the most successful in the world (Veit & Bernardes, 2015). Computers, mobile phones, television screens, touch pads are now part of the daily lives of many people of this planet. The advent of more and more sophisticated products, innovations and continuous updates contribute to constant lifespan reduction of existing devices (Li, 2015). For a computer, for example, it went from 4.5 years in 1992 to 2 years for the year 2005 (Veit & Bernardes, 2015). Currently, sales of electronic devices is strengthened by the implementation of attractive marketing strategies, the development of new markets in emerging countries, as well as the accessibility to an enlarged audience (Hadi et al., 2014). However, the end-of-life of these devices is rarely planned, causing the accumulation of millions of tons of waste on a global scale (Veit & Bernardes, 2015, Zhang & Xu, 2016, Mmereki et al., 2016). A small proportion only of electronic waste is currently recycled (Mmereki et al., 2016), whereas these contain significant amounts of metals, precious metals and rare earth elements (Zhang, Xu, 2016). Although it is the responsibility of producers to dispose of their electronic waste and despite the illegality of the shipment abroad, many African and Asian countries suffer from illegitimate importations (Amankwah-Amoah, 2016). These e-waste are discarded in open dumps, causing the contamination of soil, water and air, affecting the health and the quality of life of local populations (Veit & Bernardes, 2015, Amankwah-Amoah, 2016) Main forms of recycling used for the treatment of e-waste are the pyrometallurgy and hydrometallurgy. The heterogeneity of the raw material, the energy consumption and the generation of secondary pollution sources are the main reasons why these methods are not giving satisfaction to date (Priya & Hait, 2017). In this project, an innovative method dedicated to the recycling of the elements composing mobile phones is evaluated. This method is based on the bioleaching potential of complex bacterial communities. Leaching of compounds was evaluated first on pure metals, then on samples issued from fragmented mobile devices. As a result, this study confirmed the feasibility of metal leaching of e-waste mediated by complex bacterial communities. These latter showed high tolerance potential towards toxic compounds and high intrinsic capabilities in the leaching of metals and rare earth elements. In a context of increasing scarcity of resources, recycling of rare earth elements is essential, as they are involved in a wide range of modern technologies, such as renewable energy production, defense, civil aviation and the automobile industry.