Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/042—Electrodes formed of a single material
  • C25B11/045—Mercury or amalgam

Definitions

• the support for the mobile cathode in horizontal mercury cells is constituted in a large number of cases by a steel or iron plate.
• mercury cells of the vertical type with or without a support for the mobile cathode, iron is usedpractically exclusively.
• the metal support must be perfectly amalgamated in order to ensure the best possible circulation and distribution of the mercury and in order to avoid premature corrosion of the metal support by the electrolysis. The Wetting of the metallic surface thus attains considerable importance especially when the cell is put into service.
• It has been proposed to cover the cathode support German Patent No. 692,- 954), especially if it is of iron, with a very thin layer of another metal such as tin, copper, lead or the like.
• This metal deposit has as its object the favouring of the wetting by the mercury, the met-a1 deposited having the well known property of easy amalgamation.
• the invention is based on the observation that the quality of the iron used as supporting metal for the mercury cathode of the electrolytic cell has a marked influence on the ease of amalgamation of this support; thus, electrolytic iron amalgamates more easily and maintains its amalgamation far longer than in the case of ordinary iron or steel.
• the invention consists in a process for making supports for mobile cathodes of electrolytic cells of the vertical type which is characterised in that there is electrolytically deposited on a metallic plate, preferably of iron, a layer of pure iron, this layer being several tenths of millimetre in thickness.
• the added electrolytic iron of which the purity may be very high does not dissolve in the mercury as the readily amalgamated metals do.
• This addition to the base metal is carried out once and for all since the life of the layer is very long compared with that of the other metals referred to.
• Electrolytic deposition of iron correctly carried out, provides a very finely roughened surface which, particularly in the case of the vertical mobile mercury cathode cells, retains mercury and amalgam, thus assuring efficient and regular operation of the apparatus.
• a known bath containing for example 300 grams of FeCl .2l-I O and 150 grams of CaCl per litre of solution, having a atent C pH value of 1.5 to 2 with or without further additions; the current density being between 4 and 4.5 amperes per square decimeter of cathode surface and the temperature being of the order to C.
• the invention is not limited to the formation of a mercury cathode support with a uniformly polished surface. It comprises likewise the manufacture of grooved supports and embossed supports such as those which form the object of U.S. patent application 479,746 filed January 4, 1955, in the names of Charles Deprez and lean Clement, now Patent No. 2,849,393.
• a network of lines is traced on the supporting plate with the aid of an insulating varnish and an electrolytic deposit of iron is obtained on the surface not covered by varnish, up to a thickness of some tenths of millimeter after which the varnish is dissolved away from the grooves thus formed.
• the supports thus formed present, apart from the advantage 'already stated, that of a lower cost of replacement than in the case of a grooved cathode prepared by mechanical means. Furthermore, it is possible to obtain a groove-design as complicated as can be desired whereas this is difficult to achieve by mechanical means. Likewise one can treat surfaces of any size or shape.
• the deposits of electrolytic iron can be obtained in the electrolytic cell itself. To this end it is suflicient to replace the graphite anodes by iron anodes and to replace the electrolyte by an appropriate solution having the composition indicated above. Operating in this way permits economy in the use and with special respect to special installations which are generally undesirable.
• a support for said mercury comprising a metallic base plate having upon its mercury-contacting surface an electro-deposited coating of soft iron having a thickness up to 0.9

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrolytic Production Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=3868419

Family Applications (1)

Country Status (5)

Cited By (3)

Citations (10)

• 0
  • BE BE548025D patent/BE548025A/xx unknown
• 1957
  • 1957-04-20 DE DES53228A patent/DE1038012B/de active Pending
  • 1957-05-09 CH CH360977D patent/CH360977A/fr unknown
  • 1957-05-14 US US658965A patent/US3002914A/en not_active Expired - Lifetime
  • 1957-05-16 FR FR1175278D patent/FR1175278A/fr not_active Expired

Patent Citations (10)

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