Application de la biométallurgie dans le traitement des DEEE

The aim of this study is first to improve the comprehension of leaching and bioleaching processes in waste recycling – electric cables refuse mainly – and then to prove their feasibility. More specifically, this study provides a comparison between the two technologies to highlight their respective advantages and disadvantages in order to determine the one that could be developed on an industrial scale.

Different leaching and bioleaching tests where realized in the laboratory of the University of Liege. The sample used was the mechanical treatment refuse of electric cables supplied by the organism ARN, in the Netherlands. In addition to show the most suitable process for an industrial treatment, these tests’ aim was to determine the optimal parameters to solve copper (temperature, ferric iron concentration, bacteria). Some tests also develop the possibility to save reagents thanks to the use of pyrite as iron and sulphuric acid producer.

The different tests performances were judged on several parameters: lixiviation rate, sulphuric acid consumption and lixiviation efficiency. These parameters allow clearing up the respective advantages and disadvantages of each process. They also determine optimal temperature and oxidant concentration. A total and quick copper dissolution is interesting, of course, but other elements are important too. The plastics degradation, due to the presence of acid, can hinder the plastics recycling process.

Furthermore, this document proposes a bibliographical review in which current WEEE recycling processes are developed. Some information about the different bacteria used are given as well. Afterwards, the different tests and their results are presented in detail. They are followed by a general discussion that summarizes the main concepts mentioned in this thesis and is illustrated by an outline of several industrial flowsheets.