WO2018012981A1 - Electrolysis cell and a method for repairing same - Google Patents
Electrolysis cell and a method for repairing same Download PDFInfo
- Publication number
- WO2018012981A1 WO2018012981A1 PCT/NO2017/000018 NO2017000018W WO2018012981A1 WO 2018012981 A1 WO2018012981 A1 WO 2018012981A1 NO 2017000018 W NO2017000018 W NO 2017000018W WO 2018012981 A1 WO2018012981 A1 WO 2018012981A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- steel
- fss
- pot shell
- electrolysis cell
- accordance
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/011—Layered products comprising a layer of metal all layers being exclusively metallic all layers being formed of iron alloys or steels
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
-
- 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
- C25C3/10—External supporting frames or structures
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
Definitions
- the present invention relates to a pot shell of an electrolysis cell and more particularly a pot shell material for an aluminium electrolysis cell of Hall-Heroult type.
- the invention also relates to a method for repairing such a pot shell.
- Electrolysis cells for aluminium production based upon the Hall-H6roult principle commonly have prebaked anodes in its upper part and a cathode structure in its lower part.
- the cathode structure comprises mainly a steel pot shell formed as a pot with sides and a bottom and provided with vertical stiffeners and horizontal beams at its outside which are made out of steel too, the cathode structure further being provided with layers of protective and insulating lining materials inside its pot shell.
- In the mainly horizontal bottom part of the cathode structure there is commonly arranged electronic conducting carbon blocks.
- the cathode structure when in operation, contains a molten aluminium metal pad and above that molten bath material having temperatures that can be approximately 970° or even higher.
- the main feature of the steel pot shell including its stiffeners and beams is to maintain the geometric and dimensional configuration of the cathode structure during its lifetime of operation. Due to continuous chemical swelling of the cathode material and lining as well the high temperatures involved and the effect this has on the properties of lining and steel components involved, several attempts have been carried out to make the steel pot shell structure and the configuration of stiffeners able to withstand this influence in a long lasting manner. Further, the inner part of the steel pot shell is exposed to high temperatures and corrosive gases. The most exposed areas has shown to be in the area from the top of the steel pot shell structure, i.e. the deck plate and at the inside of the steel pot shell behind the sidewall lining, down to the bath / metal interface or even down to the level where collector bars are embedded in the cathode carbon blocks.
- the effect of this corrosion has a negative impact of the pot shell's ability to support the lining materials in an appropriate manner.
- the corrosion product has a thermal conductivity that differs from the originally installed steel plate. This may result in an altered thermal behaviour of the cell in affected areas. Still further, it is acknowledged that this kind of corrosion may involve high reparation costs.
- one solution could be to protect the mild steel quality that is applied today. In the upper side region this could be done by preventing corrosive gases passing through the solidified crust constituting the side ledge by making the sidelining more impermeable for such gases.
- Fig. 1 discloses a three dimensional view of a pot shell structure
- Fig. 2 discloses a theoretical imagination of the corrosion mechanism
- Fig. 3 discloses properties for various steel qualities
- Fig. 4 discloses metal weight gain/increase related to exposure and temperature of different materials.
- Fig. 1 there is shown in a 3 D view a cut-out of a pot shell structure 10 where first of all only the steel plates are shown, and no vertical stiffeners and horizontal beams. Still further, only one part of one long side 11 , one part of one short side 12 and a part of the bottom 6 is shown.
- the top of the long sidewall 11 comprises as a main constituent a deck plate 1
- the top of the short sidewall 12 comprises as a main constituent a short end deck plate 2.
- the upper parts of the long sidewall and the short sidewall comprise a part 3 and 4 respectively that is arranged beneath the deck plates 1 and 2. Between part 3 and the bottom there is arranged a lower part 7, showing openings 8, 8' for collector bars of the cathodic structure (not shown). Between part 4 and the bottom, there is a similar arrangement of a lower part 5, however without openings.
- One or more of the components 1 - 4 can be made out of ferritic stainless steel (FSS), either as a homogenous material or composite covered onto the existing shell material by lining or cladding.
- FSS ferritic stainless steel
- a suitable plate thickness will be between 15 and 25 mm, preferably 20 mm.
- a suitable plate thickness will be 1 to 5 mm, preferably 3 mm.
- the components 5-7 can be made out of a steel quality for pot shell structures that is commonly used, for instance a carbon steel.
- carbon steel may also be used in reference to steel which is not stainless steel; in this use carbon steel may include alloy steels.
- ferritic stainless steel has the following alloying composition in wt %:
- This chemical composition is based upon the finding that the most important alloying elements are Cr and to some extent Ni to provide the achieved corrosion resistance for this specific application in an electrolysis cell.
- the ferritic stainless steel has the following alloying composition in wt %:
- Fig. 2 discloses a theoretical imagination of the corrosion mechanism and that metal dusting is the corrosion mechanism acting on the steel shell causing a severe damage much faster than observed before.
- the temperature cycling resulted by anode changes are assumed to affect both the steel susceptibility to metal dusting and the environmental conditions. Due to repeating anode changes in primary aluminium production the environment beneath the deck plate may cycle between reducing and oxidizing gas conditions and thus maintain conditions favoring metal dusting reactions.
- Fig. 3 discloses physical properties for various steel qualities, among these carbon steels, ferritic stainless steels and austenitic stainless steels. It can be seen that the thermal expansion coefficient of ferritic stainless steel (Ferritic SS) and Carbon steels are very similar, as the thermal conductivity is a little bit less than the half. It can be seen that the austenitic steel is less suited for a low cost thermally loaded construction on the basis of the weight specific cost and coefficient of thermal expansion.
- Fig. 4 discloses metal weight gain/increase related to exposure and temperature of different materials. Starting from left in the diagram:
- EN/DIN 1.4003 has a significantly lower corrosion rate when applied in the corrosive environment of the cells compared to other materials in use today, the factor is approximately 10 times lower.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Prevention Of Electric Corrosion (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ749316A NZ749316A (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
EA201990280A EA035328B1 (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
AU2017297124A AU2017297124B2 (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
CA3030237A CA3030237C (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
BR112018076872-3A BR112018076872B1 (en) | 2016-07-13 | 2017-06-01 | ELECTROLYSIS CELL, AND, METHOD FOR REPAIRING A CATHODE STRUCTURE |
EP17828028.5A EP3491174A4 (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
ZA201900087A ZA201900087B (en) | 2016-07-13 | 2019-01-07 | Electrolysis cell and a method for repairing same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO20161170 | 2016-07-13 | ||
NO20161170A NO20161170A1 (en) | 2016-07-13 | 2016-07-13 | Electrolysis cell and a method for repairing same |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2018012981A1 true WO2018012981A1 (en) | 2018-01-18 |
Family
ID=60952140
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NO2017/000018 WO2018012981A1 (en) | 2016-07-13 | 2017-06-01 | Electrolysis cell and a method for repairing same |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP3491174A4 (en) |
AU (1) | AU2017297124B2 (en) |
CA (1) | CA3030237C (en) |
EA (1) | EA035328B1 (en) |
NO (1) | NO20161170A1 (en) |
NZ (1) | NZ749316A (en) |
WO (1) | WO2018012981A1 (en) |
ZA (1) | ZA201900087B (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4608135A (en) * | 1985-04-22 | 1986-08-26 | Aluminum Company Of America | Hall cell |
US7678244B2 (en) * | 2002-10-14 | 2010-03-16 | Aluminum Pechiney | Electrolytic cell leak limiter |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB225494A (en) * | 1923-11-30 | 1925-02-26 | Aluminum Co Of America | Improvements in or relating to methods of operating and lining electrolytic cells for electrolytic refining |
GB596066A (en) * | 1944-07-31 | 1947-12-29 | Ind De L Aluminium Sa | Improvements relating to cells for the electrolytic production or refining of aluminium |
LU29922A1 (en) * | 1971-03-18 | |||
US3783121A (en) * | 1972-03-24 | 1974-01-01 | Aluminum Co Of America | Magnetic field control in electrolysis cells |
CH643602A5 (en) * | 1979-10-17 | 1984-06-15 | Alusuisse | ELECTROLYSIS PAN. |
NO158882C (en) * | 1985-11-01 | 1988-11-09 | Mosal Alu Elkem Spigerverk | CATO BOX FOR ELECTROLYCLE CELLS AND PROCEDURES FOR THE MANUFACTURE OF CATALOG FOR ELECTROLYCLE CELLS. |
DE10122326A1 (en) * | 2001-05-08 | 2002-11-14 | Norddeutsche Affinerie | Process for repairing electrolysis cathodes |
CN102230186B (en) * | 2011-06-29 | 2012-12-12 | 东北大学设计研究院(有限公司) | Cell shell device of aluminum electrolytic cell |
-
2016
- 2016-07-13 NO NO20161170A patent/NO20161170A1/en unknown
-
2017
- 2017-06-01 EA EA201990280A patent/EA035328B1/en not_active IP Right Cessation
- 2017-06-01 EP EP17828028.5A patent/EP3491174A4/en active Pending
- 2017-06-01 AU AU2017297124A patent/AU2017297124B2/en active Active
- 2017-06-01 WO PCT/NO2017/000018 patent/WO2018012981A1/en unknown
- 2017-06-01 CA CA3030237A patent/CA3030237C/en active Active
- 2017-06-01 NZ NZ749316A patent/NZ749316A/en unknown
-
2019
- 2019-01-07 ZA ZA201900087A patent/ZA201900087B/en unknown
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4608135A (en) * | 1985-04-22 | 1986-08-26 | Aluminum Company Of America | Hall cell |
US7678244B2 (en) * | 2002-10-14 | 2010-03-16 | Aluminum Pechiney | Electrolytic cell leak limiter |
Non-Patent Citations (2)
Title |
---|
CHUN, C. M. ET AL.: "Metal dusting corrosion of ferritic steels with varying chromium content", HIGH TEMPERATURE CORROSION AND MATERIALS CHEMISTRY V, 2005, pages 101 - 115, XP009518213, ISSN: 0161-6374, ISBN: 1-56677-469-1 * |
SLABBERT, G.A. ET AL.: "The effect of the matrix structure on the metal dusting rate in hydrocarbon environments", JOURNAL OF THE SOUTHERN AFRICAN INSTITUTE OF MINING AND METALLURGY, vol. 113, no. 2, 2013, pages 81 - 90, XP055457536, ISSN: 2225-6253 * |
Also Published As
Publication number | Publication date |
---|---|
CA3030237A1 (en) | 2018-01-18 |
ZA201900087B (en) | 2019-10-30 |
CA3030237C (en) | 2023-08-08 |
EA035328B1 (en) | 2020-05-28 |
NO20161170A1 (en) | 2018-01-15 |
BR112018076872A2 (en) | 2019-04-02 |
EA201990280A1 (en) | 2019-07-31 |
AU2017297124B2 (en) | 2022-07-14 |
EP3491174A4 (en) | 2020-08-19 |
AU2017297124A1 (en) | 2019-01-03 |
EP3491174A1 (en) | 2019-06-05 |
NZ749316A (en) | 2019-08-30 |
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