Abstract: In a process for recovering zinc from residues containing it, particularly rom ashes and hard-spelters coming from galvanizing baths, and which comprises the extraction by electrolysis of the zinc contained in the alkaline or acid solutions obtained. The solutions deriving from the ashes are obtained by dissolving their relatively low metallic zinc content granulometric fraction, the high metallic zinc content granulometric fraction of these ashes being re-introduced directly into the galvanizing bath advantageously after a leaching treatment and the solutions deriving from the hard-spelters are obtained by dissolving them either by having recourse to a corrosion cell or by forming by means of these hard-spelters the anodes of an electrolysis circuit.

Abstract: The invention relates to accumulators comprising halogen electrodes operating with fused halide based electrolyte.Such accumulators can include an electrochemical chain aluminium/mixture of aluminium halide and alkalin metal halide/metallic derivatives introduced into graphite.Application to the constitution of accumulators including halogen electrodes for considerable storage of halogen.

Abstract: The invention relates to an improved electrode for an electrochemical generator, said electrode enabling the electrochemical oxidation of hydrogen supplied of the interface of said electrode and an electrolyte. It comprises a nickel-based catalyst formed of particles or crystallites the sizes of which range from about 20 to about 130 Angstroms.

Abstract: The invention relates to electro materials based on lanthanum and nickel having a formula close to LaNi.sub.5 in which one of the components is partially substituted by a metal selected from those in groups Ia, II, III, IV and Va of the periodic table of elements, and other than lanthanides, in an atomic proportion which is not zero, being higher than 0.1% and lower than 25%, and preferbly from 0.5% to 15% with respect to the lanthanum.

Abstract: A process to detect toxic ions in the atmosphere or dissolved in water with n electrochemical cell which comprises an active electrode, a reference electrode and a counter electrode, connected by an electrolyte and to which a voltage is applied.The voltage alternates on each side of the thermodynamic potential. The cell, which is adapted to detect toxic gases in air, comprises a condensation chamber connected to a venturi for the admission of air and electrolyte, and to a measurement chamber. The electrolyte carrying the dissolved toxic gas is condensed in this chamber prior to passing through the measurement chamber.The invention is applicable in particular to check the atmosphere of workshops, and to check the pollution of bodies of water with an independent portable unit.