Abstract: An electrical connection system between an electrochemical cell and a printed circuit having a copper layer, the system comprising at least one connection piece welded to the cell, wherein the layer of copper is of a thickness greater than 70 &mgr;m and wherein a metal piece electrically connected to the connection piece is fixed to the layer of copper by welding without any filler metal.

Abstract: A process is disclosed for recovering metallic constituents of spent or waste catalysts containing metallic compounds fixed on an aluminous support. The process is particularly applicable for the recovery of metals such as Al, Mo, V, Ni and Co, contained in spent catalyst. The process comprises transforming the metals to be recovered into volatile chlorides by carbochlorination and then separating the chlorides obtained by dry means and fixing them successively in a selective manner. The separation of AlCl.sub.3 is accomplished by passage through granules of anhydrous NaCl, and the separation of MoCl.sub.5 by passage through granules of crystallized KCl. The process is particularly suitable for the treatment of waste catalyst from the catalytic hydrocracking or hydrodesulfurization of oils.