• A concept for electrowinning of aluminium using depolarized gas anodes 

      Mokkelbost, Tommy; Kjos, Ole Sigmund; Paulsen, Ove Bjørn; Øye, Bjarte Arne; Gudbrandsen, Henrik; Ratvik, Arne Petter; Haarberg, Geir Martin (Journal article; Peer reviewed, 2014)
      Aluminium is today commercially produced by the Hall-Héroult process using consumable carbon anodes. Consumable anodes have some concerns such as CO2 emission, continuous anodecathode distance adjustments and replacements ...
    • A multiscale numerical approach of the dripping slag in the coke bed zone of a pilot scale Si-Mn furnace 

      Letout, Sebastien Romain; Ratvik, Arne Petter; Tangstad, Merete; Johansen, Stein Tore; Olsen, Jan Erik (Chapter, 2017)
      The Si-Mn alloy process production in submerged arc furnaces (SAF) is investigated. The aim of the studies currently in progress is an enhancement of the knowledge about the key reactions and the mass transport phenomenon ...
    • A study of anode baking gas composition 

      Aarhaug, Thor Anders; Brandvik, Trond; Kjos, Ole Sigmund; Gaertner, Heiko; Ratvik, Arne Petter (Journal article; Peer reviewed, 2018)
      A method has been developed to measure gas composition inside the pit in open anode baking furnaces. The gas composition can be used to understand attack on and degradation of the refractory lining, baking behavior and ...
    • A XANES Study of Sulfur Speciation and Reactivity in Cokes for Anodes Used in Aluminum Production 

      Jahrsengene, Gøril; Wells, Hannah C.; Rørvik, Stein; Ratvik, Arne Petter; Haverkamp, Richard G.; Svensson, Ann Mari (Journal article; Peer reviewed, 2018)
      Availability of anode raw materials in the growing aluminum industry results in a wider range of petroleum cokes being used to produce carbon anodes. The boundary between anode grade cokes and what previously was considered ...
    • An EXAFS and XANES Study of V, Ni, and Fe Speciation in Cokes for Anodes Used in Aluminum Production 

      Jahrsengene, Gøril; Wells, Hannah C.; Sommerseth, Camilla; Ratvik, Arne Petter; Lossius, Lorentz Petter; Sizeland, Katie H.; Kappen, Peter; Svensson, Ann Mari; Haverkamp, Richard G. (Journal article; Peer reviewed, 2019)
      Lower-quality petroleum coke with higher levels of sulfur and metal impurities will have to be used for the manufacturing of anodes for aluminum production in the future. The sulfur and metallic impurities affect the anode ...
    • Assessment of the Thermodynamic Stability of Thermal Insulating Materials in Aluminium Electrolysis Cells 

      Luneng, Raymond; Grande, Tor; Ratvik, Arne Petter (Conference object, 2016)
      The cathode bottom lining in aluminium electrolysis cells serves as a thermal insulating barrier and is important for the overall thermal and dimensional stability of the cell. The thermal insulation layer ...
    • Autopsy of refractory lining in anode kilns with open and closed design 

      Brandvik, Trond; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article, 2018)
      Aluminosilicate refractory lining constitutes a major part of anode baking kilns, and during anode baking the lining is exposed to harsh conditions which limits the lifetime. Here, autopsies of refractory linings from both ...
    • Bubble evolution and anode surface properties in aluminium electrolysis 

      Thorne, Rebecca Jayne; Sommerseth, Camilla; Ratvik, Arne Petter; Rørvik, Stein; Sandnes, Espen; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article, 2015)
      One significant contribution to the anodic potential during aluminum electrolysis is the formation of CO2 bubbles that screen the anode surface. This effect creates an additional ohmic resistance as well as an increased ...
    • Calcination temperature dependent catalytic activity and stability of IrO2 – Ta2O5 anodes for oxygen evolution reaction in aqueous sulfate electrolytes 

      Xu, Wenting; Haarberg, Geir Martin; Sunde, Svein; Seland, Frode; Ratvik, Arne Petter; zimmerman, erik; Shimamune, T; Gustavsson, J; Åkre, Torjus (Journal article; Peer reviewed, 2017)
      In this work, commercial IrO2-Ta2O5 anodes with a certain composition calcined at three different temperatures were investigated. The results show that the calcination temperature has a significant influence on the ...
    • Carbon cathode wear in aluminium electrolysis cells 

      Senanu, Samuel; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2019)
      Autopsies of six spent potlinings with different carbon cathode block grades, amperage regimes and cell technologies were conducted at three separate smelters to reveal possible mechanisms causing cathode wear. Microstructure ...
    • Carbon Cathode Wear in Aluminium Electrolysis Cells 

      Senanu, Samuel; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Peer reviewed; Journal article, 2019)
      Autopsies of six spent potlinings with different carbon cathode block grades, amperage regimes and cell designs were conducted at three separate smelters to reveal possible mechanisms causing cathode wear. The microstructure ...
    • Cathode Wear Based on Autopsy of a Shutdown Aluminium Electrolysis Cell 

      Senanu, Samuel; Schøning, Christian; Rørvik, Stein; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2016)
      To investigate cathode wear, an autopsy of a shutdown aluminium electrolysis cell was conducted. The original lining consisted of a fully impregnated and graphitized carbon block and the cell was shut down after 2461 days ...
    • Cathode Wear in Aluminium Electrolysis Cells 

      Senanu, Samuel (Doctoral theses at NTNU;2019:317, Doctoral thesis, 2019)
      The increasing global demand for aluminium has resulted in growing production of aluminium metal through increased production capacity and improvement of the electrolysis technology. This has caused a development towards ...
    • Cathode Wear in Electrowinning of Aluminum Investigated by a Laboratory Test Cell 

      Wang, Zhaohui; Nobakhtghalati, Saeid; Støre, Anne; Solheim, Asbjørn; Tschöpe, Kati; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2016)
      The lifetime of an aluminum electrolysis cell is mainly determined by the cathode wear, especially for high amperage cells utilizing graphitized carbon cathodes. The cathode wear mechanisms are, however, complex and still ...
    • Chemical Durability of Thermal Insulating Materials in Hall-Héroult Electrolysis Cells 

      Luneng, Raymond; Bertel, Søren N.; Mikkelsen, Jørgen; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2019)
      The most common thermal insulating materials used in the cathode lining in aluminum electrolysis cells are Moler (diatomaceous earth), calcium silicate, or vermiculite based materials. The thermal insulation layer is ...
    • Chemical Stability of Thermal Insulating Materials in Sodium Vapour Environment 

      Luneng, Raymond; Bertel, Søren N.; Mikkelsen, Jørgen; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2017)
      The most typical thermal insulating materials used in the cathode lining in aluminium electrolysis cells are Moler, calcium silicate, or vermiculite. The thermal insulation is important for the overall thermal and dimensional ...
    • Coke Impurity Characterisation and Electrochemical Performance of Carbon Anodes for Aluminium Production 

      Jahrsengene, Gøril (Doctoral theses at NTNU;2019:352, Doctoral thesis, 2019)
      The aluminium production process uses consumable carbon anodes made from calcined petroleum cokes, recycled anode butts and coal tar pitch. The main ingredient is the coke, a side product from the petroleum refining industry. ...
    • Comparing Anodic Bubble Behavior of Anodes from Anisotropic and Isotropic Cokes in Laboratory Scale Aluminum Electrolysis Cells 

      Sommerseth, Camilla; Thorne, Rebecca Jayne; Ratvik, Arne Petter; Rørvik, Stein; Linga, Hogne; Lossius, Lorentz Petter; Svensson, Ann Mari (Journal article; Peer reviewed, 2019)
      During production of aluminum in Hall-Héroult cells, carbon anodes electrochemically oxidize to form mainly CO2. The CO2 bubbles block the anode working surface during growth and coalescence, leading to cell voltage loss ...
    • Correlation between coke type, microstructure and anodic reaction overpotential in aluminium electrolysis 

      Thorne, Rebecca Jayne; Sommerseth, Camilla; Ratvik, Arne Petter; Rørvik, Stein; Sandnes, Espen; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article; Peer reviewed, 2015)
      Although the anode process during aluminum electrolysis has a substantial overpotential that increases the energy demand and production cost of aluminum, properties of the coke that can influence the electrochemical ...
    • Degradation of Refractory Lining in Carbon Anode Baking Furnaces 

      Brandvik, Trond (Doctoral theses at NTNU;2019:340, Doctoral thesis, 2019)
      Primary aluminium metal is produced by electrochemical reduction of Al2O3 at ~960 ºC, during which large amounts of carbon anodes are consumed. The anodes are thus constituting an important part of the production process. ...