The invention relates to a method for recycling used or discarded portable electrical batteries which comprise recyclable components such as iron, zinc, manganese, copper and fixed and volatile carbon, as well as heavy metals and hazardous compounds. The method is characterized in that the used or discarded batteries are introduced as a load into a metal-melting, smelting type furnace (1,40,44), such as a cupola furnace, a free electric arc furnace or induction furnace, and for which a gas purification device (16,23) is provided in the hot gas evacuation channel after the melting furnace to capture and eliminate harmful elements such as mercury, chlorides or fluorides and heavy molecules such as dioxins, furans and aromatics. The invention can be used for recycling used and rejected batteries.