Abstract: The invention relates to a method and a device for regenerating exhausted tin-plating solutions which contain tin and copper ions, free complexing agent and complexing agent bound to the copper ions, as well as expended and unexpended reducing agent. By means of a suitable rinsing technique, the rinse water of the tin-plating process is concentrated to a 10 to 15 percent dilution of the process solution. The regenerating solution thus produced is fed to an electrolytic cell. The electrolytic cell comprises a cathode chamber, a middle chamber and an anode chamber. The cathode chamber is separated from the middle chamber by an anion-exchange membrane and the anode chamber is separated from the middle chamber by a cation-exchange membrane. The regenerating solution is initially provided in the cathode chamber. Here, the interfering copper component is cathodically deposited.

Abstract: Process for hot dip galvanizing workpieces of steel or iron materials wherein a treatment with fluxing agent is omitted. After being cleaned, the workpieces are coated with a thin metal layer which replaces the previously customarily applied fluxing agent layer and are immersed into the zinc melt with their surfaces in the dry state.

Abstract: Method for the recovery of lead from lead sulfide containing materials such as ores and concentrates wherein the materials are initially leached in a leaching vessel containing a chloride solution and iron (III) chloride as an oxidation agent to form an iron (II) chloride solution containing lead chloride. The latter solution is then conducted to an electrolytic cell comprising at least one insoluble anode and at least one cathode for the cathodic deposition of lead. The electrolyte containing iron (III) ions formed by the oxidation of iron (II) ions at the anode is returned to the leaching vessel for the further leaching of lead sulfide containing materials.

Abstract: Method for treating metal containing waste water employing a vessel containing the waste water in which there is provided at least one anode and a cathode comprised of a plurality of electrically conductive elements and in which the waste water is subjected to electrolysis during which the cathode elements are being moved. The cathode elements are provided in the form of rods which are arranged in the vessel by means of at least two holding devices so that the rods extend parallel to one another and can be moved in the holding devices relative to one another. The holding devices are moved during the electrolysis process so that the rods strike one another again and again at spaced intervals. An apparatus is provided for practicing the method.

Abstract: Method for treating metal containing waste water employing a vessel containing the waste water in which there is provided at least one anode and a cathode consisting essentially of electrically conductive particles and in which the waste water is subjected to electrolysis during which the waste water and the particles of the cathode are being moved. The particles of the cathode are arranged in a cage closed on all sides whose walls are perforated. The cage is moved by an external force during the electrolysis in order to move the particles. The waste water is simultaneously moved by producing a forced flow through the particles. An apparatus is provided for practicing the method.

Abstract: Method for treating metal containing waste water employing a vessel containing the waste water in which there is provided at least one anode and a cathode comprised of a plurality of electrically conductive elements and in which the waste water is subjected to electrolysis during which the cathode elements are being moved. The cathode elements are provided in the form of rods which are arranged in the vessel by means of at least two holding devices so that the rods extend parallel to one another and can be moved in the holding devices relative to one another. The holding devices are moved during the electrolysis process so that the rods strike one another again and again at spaced intervals. An apparatus is provided for practicing the method.

Abstract: Method for treating metal containing waste water employing a vessel containing the waste water in which there is provided at least one anode and a cathode consisting essentially of electrically conductive particles and in which the waste water is subjected to electrolysis during which the waste water and the particles of the cathode are being moved. The particles of the cathode are arranged in a cage closed on all sides whose walls are perforated. The cage is moved by an external force during the electrolysis in order to move the particles. The waste water is simultaneously moved by producing a forced flow through the particles. An apparatus is provided for practicing the method.

Abstract: A coating applied to a workpiece is removed therefrom and measured to determine the surface area of the workpiece.