Now showing items 21-34 of 34

    • Influence of Mg Concentration on the Inhibiting Effect of CO2 on the Rate of Oxidation of Aluminum Alloys 5182 and 6016 

      Solem, Cathrine Kyung Won; Solberg, Egil; Tranell, Gabriella; Aune, Ragnhild Elizabeth (Peer reviewed; Journal article, 2021)
      Oxidation of aluminum alloys during production is a well-known problem and contributes to significant metal losses. As small additions of CO2 in the oxidizing atmosphere has proven to inhibit the oxidation rate for ...
    • Interfacial Boundary between Carbon Anodes and Molten Salt Electrolyte 

      Gebarowski, Wojciech; Sommerseth, Camilla; Ratvik, Arne Petter; Sandnes, Espen; Lossius, Lorentz Petter; Linga, Hogne; Svensson, Ann Mari (Journal article, 2016)
      The properties of calcined petroleum cokes (CPC), used in the anodes in the Hall-Héroult process, are important for the electrochemical behaviour of the anodes. CPCs from different sources vary not only in impurity level ...
    • Investigation of Sodium Sulfate Additions into Cryolite-Alumina Melts 

      Meirbekova, Rauan; Haarberg, Geir Martin; Aarhaug, Thor Anders; Sævarsdóttir, Gudrun A. (Journal article, 2016)
      In the Hall-Héroult process, sulfur impurities may not only emit harmful gases but also reduce current efficiency. To better understand this process, the behaviour of sulfur compounds in a cryolite-alumina melt at 1253 K ...
    • Investigation of Spent Refractory Lining in an Anode Baking Furnace 

      Brandvik, Trond; Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2017)
      The refractory lining in anode baking furnaces is exposed to harsh chemical environment and thermal cycling. Spent refractory lining from an anode baking furnace after 4000 days in operation was investigated. Variation in ...
    • On Gaseous Emissions During Alumina Feeding 

      Gylver, Sindre Engzelius; Follo, Åste Hegglid; Aulie, Vegard; Granlund, Helene Marie; Sørhuus, Anders; Sandnes, Espen; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2021)
      Aluminium electrolysis involves feeding of alumina into a cryolite-based bath. Water originating from alumina as well as from air reacts with fluorides and results in HF evolution. Untreated HF gas is a significant ...
    • Online monitoring of aluminium primary production gas composition by use of Fourier-transform infrared spectroscopy 

      Aarhaug, Thor Anders; Ferber, Alain Marc C; Kjos, Ole Sigmund; Gaertner, Heiko (Journal article; Peer reviewed, 2014)
      Online monitoring of aluminium primary production raw gas is challenging due to the high concentration of HF in the presence of water. Tunable Diode Laser (TDL) analyzers retrofitted with sapphire optical windows allow for ...
    • Particulate emissions from electrolysis cells 

      Gaertner, Heiko; Ratvik, Arne Petter; Aarhaug, Thor Anders (Journal article; Peer reviewed, 2011)
      In the dry cleaning of the exhaust gas from the aluminium cells impurities are accumulated in the finer fractions of secondary alumina from the dry scrubbers. The present work describes new methods for the determination ...
    • Perfluorocarbon Formation During Rare Earth Electrolysis 

      Osen, Karen Sende; Martinez, Ana Maria Cuellar; Gudbrandsen, Henrik; Støre, Anne; Sommerseth, Camilla; Kjos, Ole Sigmund; Aarhaug, Thor Anders; Gaertner, Heiko; Chamelot, Pierre; Gibilaro, Mathieu; Massot, Laurent (Journal article; Peer reviewed, 2018)
      A challenge during rare earth (RE) electrolysis is to avoid emissions of perfluorocarbon (PFC) green-house gases. The objective of this work was to study how to operate the RE electrolysis process with neither PFC formation ...
    • PFC evolution characteristics during aluminium and rare earth electrolysis 

      Kjos, Ole Sigmund; Solheim, Asbjørn; Aarhaug, Thor Anders; Osen, Karen Sende; Martinez, Ana Maria Cuellar; Sommerseth, Camilla; Gudbrandsen, Henrik; Støre, Anne; Gaertner, Heiko (Journal article; Peer reviewed, 2018)
      In addition to aluminium electrolysis, the electrolysis of rare earth (RE) metals from fluoride melts is a significant source of perfluorocarbon (PFC) emissions to the atmosphere. These processes have many similarities, ...
    • 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 ...
    • Understanding Anode Overpotential 

      Thorne, Rebecca Jayne; Sommerseth, Camilla; Svensson, Ann Mari; Sandnes, Espen; Lossius, Lorentz Petter; Linga, Hogne; Ratvik, Arne Petter (Journal article, 2014)
      In aluminium electrolysis cells the anodic process is associated with a substantial overpotential. Industrial carbon anodes are produced from a blend of coke materials, but the effect of coke type on anodic overpotential ...
    • Utilization of waste heat for pre-heating of anodes 

      Einarsrud, Kristian Etienne; Grimstad, Martin; Elstad, Kim Ronny; Solheim, Asbjørn (Peer reviewed; Journal article, 2020)
      Carbon anodes are replaced on a regular basis in Hall–Héroult cells as they are consumed by electrochemical reactions. Upon insertion of new anodes, bath will freeze locally as a result of low bath superheat and comparatively ...