Improvements in or relating to methods for the electro-chemical treatment of metal electrodes for electrolytic cells and apparatus for carrying out such processes

摘要

756,039. Electrolytic treatment of electrodes. KILCHLING, K. March 13, 1953 [March 13, 1952; April 21, 1952], No. 7100/53. Drawings to Specification. Class 41. A method of electrochemically preparing metallic electrodes for electrolytic cells comprises electrically connecting an electrode to be prepared, the surface of which is free from a locally insulating layer, with a second metal externally of an aqueous electrolyte in which the electrode and second metal are immersed, the second metal being chosen so that. its position relative to the electrode metal in the displacement series is such that the greater part of the electrolytic preparation takes place by utilization of the self-produced current. The electrode to be prepared may be of aluminium and may be electrically connected to a second electrode of carbon, copper, lead or iron, externally of an electrolyte which may be hydrochloric acid, aluminium chloride, sodium chloride, or a fluoride, to increase the surface area of the aluminium electrode by roughening as it serves as an anode. The self-produced current may be augmented by connecting an external source of current between the electrodes. The electrolyte may be one which also roughens the aluminium by chemical action. The roughened aluminium electrode is then cleaned by being made a cathode by connection to another electrode, such as one of magnesium, in an electrolyte, so that the self-produced current flows in the opposite direction to that in the roughening process. The electrolyte may be water, since substances adhering to the electrode from the roughening process are sufficient for a current to be produced, and may contain glycerin or glycol; the electrolyte may also contain acetic or oxalic acid. An external source of current may also be added to the self-produced current in the cleaning process.