Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
  • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
  • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S277/00—Seal for a joint or juncture
  • Y10S277/935—Seal made of a particular material
  • Y10S277/936—Composite
  • Y10S277/938—Carbon or graphite particle or filament

Definitions

• An electrolysis cell generally comprises a pan made of sheet iron or steel, the bottom of which is lined with thermal insulation.
• cathode blocks made of carbon or graphite which are connected to the negative pole of a power source, form the bottom of another trough, the wall of which consists of side stones made of carbon, graphite or silicon carbide.
• a gap is formed between two cathode blocks in each case a gap is formed.
• the arrangement of the cathode block and possibly filled gap is generally referred to as the cathode bottom.
• the joints between the cathode blocks are conventionally filled by ramming mass of carbon and / or graphite based on coal tar.
• Expanded graphite has the following advantageous properties: It is harmless to health, environmentally friendly, soft, compressible, lightweight, resistant to aging, chemically and thermally resistant, technically gas and liquid-tight, non-combustible and easy to work. In addition, it does not form an alloy with liquid aluminum. It is therefore suitable as a filler material for a cathode bottom for an electrolytic cell for the production of aluminum.
• the pre-compressed graphite plate used according to the invention can be used in the areas of an electrolysis cell in which conventional ramming mass is used, ie in particular joints which are formed between cathode blocks, but also in intermediate spaces which are located between side walls of the electrolytic cell and cathode blocks.
• the precompressed graphite plate is used, in particular, as a sealing means between cathode blocks of a cathode bottom and between the cathode block and the side wall of a cathode bottom.
• the filling material and the cathode blocks or cathode block and side wall are non-positively connected and preferably terminate flush.
• the filler material and cathode block or side wall may optionally be glued together, for example by means of a phenolic resin.
• the terms sidewall and sidewall are used analogously.
• the precompressed graphite plate therefore has a thickness of 2 to 35 mm, preferably 5 to 20 mm, particularly preferably 10 to 15 mm.
• a minimum thickness of 2 mm is required to compensate for the sodium expansion of the cathode block or the side wall.
• the pre-compressed graphite sheet has a density from 0.04 to 0.5 g / cm 3, preferably 0.05 to 0.3 g / cm 3 particularly preferably 0.07 to 0.1 g / cm 3.
• the density must be less than 0.5 g / cm 3 in order to give a 2 mm thick graphite plate at a typical basis weight of 1000 g / m 3 .
• the filler material is disposed on two opposing surfaces of a cathode block adjacent the joint-forming surface and on and in the joint such that the filler material is flush.
• the cathode bottom in the above preferred embodiments with the at least two cathode blocks and / or at least one cathode block and at least one sidewall brick comprises regions which have a high conductivity, and with the filler material comprising the precompressed graphite plate, regions which are generally smaller conductivity have as the cathode blocks and / or sidewalls, but are able to seal the joints formed between the cathode blocks so that no bath components can penetrate into deeper areas of the cathode bottom in an electrolysis.
• the two components, ie cathode blocks or sidewalls, and precompressed graphite plate therefore perform various functions of the cathode bottom. Due to its multifunctional design, this cathode bottom is therefore dimensioned for large-scale use.
• the joints between the cathode blocks can optionally be filled with a precompressed graphite plate or with conventional anthracite ramming mass.
• Each joint of the cathode bottom can be filled differently.
• the cathode blocks are connected to the negative pole of a power source.
• At least one anode such as a Soderberg electrode or preheated electrode, hangs from a support frame connected to the positive pole of the power source and projects into the tub without touching the cathode bottom or sidewalls of the tub.
• the distance of the anode to the walls is greater than to the cathode bottom or the forming aluminum layer.
• Figures 4a to 4c is a schematic representation of a further process sequence for the production of a cathode floor according to the invention.
• the cathode blocks 27 each have a recess 29 which is suitable for receiving a bus bar (not shown), which can be connected to a negative pole of a current source (not shown).
• the electrolytic cell 213 has anodes 223, two of which are shown in FIG. 2, each attached to a support 225 connected to a positive pole of a power source (not shown).
• a solution 227 of alumina in molten cryolite In the electrolytic cell 213 is a solution 227 of alumina in molten cryolite. During the electrolysis, aluminum 229 collects between the solution 227 and the cathode bottom 21.
• FIGS. 3 a to 3 c show a schematic representation of a method sequence for producing a cathode bottom 31 according to the invention.

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• 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)

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• 2015
  • 2015-09-18 DE DE102015011952.4A patent/DE102015011952A1/de not_active Withdrawn
• 2016
  • 2016-09-16 RU RU2018113972A patent/RU2707304C2/ru active
  • 2016-09-16 UA UAA201804202A patent/UA120662C2/uk unknown
  • 2016-09-16 JP JP2018514359A patent/JP6629433B2/ja active Active
  • 2016-09-16 WO PCT/EP2016/072048 patent/WO2017046376A1/de active Application Filing
  • 2016-09-16 US US15/760,808 patent/US20180282888A1/en not_active Abandoned
  • 2016-09-16 EP EP16766325.1A patent/EP3350358B1/de active Active
  • 2016-09-16 CN CN201680066627.4A patent/CN108350587B/zh active Active
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