Browsing NTNU Open by Author "Rørvik, Stein"

Now showing items 1-13 of 13

    • 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 ...

    • 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 ...

    • 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 ...

    • 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 ...

    • Effect of Coke Properties on the Bubble Formation at the Anodes During Aluminium Electrolysis in Laboratory Scale 

      Gebarowski, Wojciech; Ratvik, Arne Petter; Rørvik, Stein; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article, 2017)
      The anodic reaction of aluminium electrolysis cells leads to the formation of CO2 bubbles, which partly screen the anode surface and leads to an increase in the cell voltage. An advantage of these bubbles is that the ...

    • Electrochemical Behaviour of Carbon Anodes Produced with Different Mixing Temperatures and Baking Levels—A Laboratory Study 

      Sommerseth, Camilla; Thorne, Rebecca Jayne; Gebarowski, Wojciech; Ratvik, Arne Petter; Rørvik, Stein; Linga, Hogne; Lossius, Lorentz Petter; Svensson, Ann Mari (Chapter, 2019)
      Anodes fabricated from a single source coke were used for investigations of effect of porosity and surface roughness on the electrochemical performance in laboratory scale cells. In order to fabricate anodes differing in ...

    • Electrochemical Reactivity and Wetting Properties of Anodes Made from Anisotropic and Isotropic Cokes 

      Sommerseth, Camilla; Thorne, Rebecca Jayne; Ratvik, Arne Petter; Sandnes, Espen; Rørvik, Stein; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article, 2016)
      High quality anodes require stable raw materials. As the quality of the coke available for production of anodes is changing, future production will rely on cokes that are more isotropic with higher impurity levels than ...

    • The Formation and Disintegration of Rafts from Different Aluminas and Fines 

      Gylver, Sindre Engzelius; Bekkevoll, Simen; Rørvik, Stein; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2022)
      Raft formation is a frequently encountered problem during alumina feeding in the Hall-Héroult-process and will delay alumina from being dissolved into the melt. The mechanisms for the formation and disintegration of rafts ...

    • Formation of Carbon Build-Up on the Flue Wall of Anode Baking Furnace 

      Wang, Zhaohui; Rørvik, Stein; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2017)
      A hard carbon build-up layer often forms on the flue wall surface in anode baking furnaces. The layer accumulates over thermal circles and needs to be mechanically removed regularly to ensure sufficient space for the anodes ...

    • Reactivity of Coke in Relation to Sulfur Level and Microstructure 

      Jahrsengene, Gøril; Rørvik, Stein; Ratvik, Arne Petter; Lossius, Lorentz Petter; Haverkamp, Richard G.; Svensson, Ann Mari (Journal article; Peer reviewed, 2019)
      The quality of coke materials available for anodes for the aluminium industry is changing and industrial cokes with higher impurity levels are now introduced. The cokes in the anodes must meet specifications with respect ...

    • Spatial methods for characterising carbon anodes for aluminium production 

      Sommerseth, Camilla; Thorne, Rebecca Jayne; Rørvik, Stein; Sandnes, Espen; Ratvik, Arne Petter; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article, 2015)
      Pilot test anodes were designed by Hydro Aluminium for laboratory studies using controlled blends of <2 mm aggregate from two single source cokes. Spa- tial and imaging methods were used to characterise anode surfaces with ...

    • The micro- and macrostructure of alumina rafts 

      Gylver, Sindre Engzelius; Nina Helene, Omdahl; Rørvik, Stein; Hansen, Ingrid; Nautnes, Andrea; Neverdal, Sofie Nilssen; Einarsrud, Kristian Etienne (Journal article; Peer reviewed, 2019)
      As alumina particles are fed to aluminium reduction cells, a frozen layer of bath is typically formed on the particle surface, due to the relatively low bath superheat. For particles in close proximity, platelets with ...