PROJECT DESCRIPTION
BACKGROUND
In the European Union the use of batteries and rechargeable batteries is growing considerably. When these are used and discarded, they can become an important source of pollution as they contain substantial amounts of toxic heavy metals such as lead, cadmium, mercury or nickel. In order to protect the environment and save raw materials at the same time, it is necessary to initiate a recycling process that enhances the value of these metals. There are already processes working at high temperature, but they may simply lead to a pollution transfer through the emission of toxic gases, and the production of mixed oxydes or unsoluble calcinated waste. The process demonstrated by RECUPYL operates at low temperature (less than 100°C) and reduces the amount of liquid and gaseous effluents produced. It was developed and tested by the Department of Electrochemistry Studies at Grenoble National Polytechnic Institute. The RECUPYL process is based on total electrochemical processing and can be used for all kinds of batteries without prior sorting. Batteries are delivered loose and come from the various "battery banks" of nearby towns. The experimental plant was set up in Domène, near Grenoble. The system is composed of three production lines : · the mechanical processing line which includes a screening system, a mechanical processing device and a two-way magnetic separation device ; · the chemical processing line which includes selective chemical reactions, and whose aim is to separate liquid and solid elements and to purify the electrolyte ; · the electrolysis line which enables the separation through electrochemical means of zinc and manganese oxyde on the one hand and nickel on the other. The reactive-rich baths are recycled at the beginning of the line in order to facilitate the dissolution of non-ferric compounds. The process is adaptable to the evolution in the composition of batteries, and makes it possible to recover the mercury or the other compounds (such as alkylperfluorosulfonates) which are gradually coming into use.