• A method for comparing the HF formation potential of aluminas with different water contents 

      Sommerseth, Camilla; Osen, Karen Sende; Rosenkilde, Christian; Meyer, Astrid J.; Kristiansen, Linda; Aarhaug, Thor Anders (Chapter, 2012)
      In the aluminium industry today, smelters often have to rely on more than one alumina supplier. This creates diversity in the properties of smelter grade alumina (SGA). A method has been developed to compare the HF formation ...
    • 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 ...
    • Airborne Emissions from Mn Ferroalloy Production 

      Kero, Ida; Eidem, Per Anders; Ma, Yan; Indresand, Hege; Aarhaug, Thor Anders; Grådahl, Svend (Journal article; Peer reviewed, 2018)
      Airborne emissions from metal production represent a health, safety, and environmental challenge to which more and more attention is being directed. Industries worldwide, as well as authorities and others, are resolute in ...
    • Assessment of PEMFC Durability by Effluent Analysis 

      Aarhaug, Thor Anders (Doktoravhandlinger ved NTNU, 1503-8181; 2011:309, Doctoral thesis, 2011)
      A review of literature relevant for the understanding of chemical degradation in Polymer Electrolyte Membrane (PEM) systems was conducted. The proposed pathways to the formation of chemical species suspected of causing ...
    • Contribution of humidity and pressure to PEMFC performance and durability 

      Sørli, Jan Gregor Høydahl (Master thesis, 2008)
      In this work, a 23-1 designed experiment has been performed to evaluate the effect of selected operating conditions on PEMFC performance and durability. Relative humidity, clamping pressure and back pressure were studied ...
    • Impurity Elements in Raw Gas Ultra-Fines from Aluminium Electrolysis Cells 

      Gaertner, Heiko; Ratvik, Arne Petter; Aarhaug, Thor Anders (Journal article; Peer reviewed, 2012)
      The effect of alumina feeding and pot suction rate on the amount and composition of fine particles in raw gases has been investigated. Particle size distribution of ultra-fines (Di < 10 μm) were measured in real time and ...
    • In situ monitoring of pit gas composition during baking of anodes for aluminum electrolysis 

      Brandvik, Trond; Gaertner, Heiko; Ratvik, Arne Petter; Grande, Tor; Aarhaug, Thor Anders (Journal article; Peer reviewed, 2019)
      Carbon anodes, which are consumed in aluminum electrolysis, are fabricated in separate anode plants where coke and pitch are mixed and vibrocompacted to green anode blocks before being baked in anode baking furnaces. The ...
    • 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 ...
    • Online measurements of fluoride ions in proton exchange membrane water electrolysis through ion chromatography 

      Marocco, Paolo; Sundseth, Kyrre; Aarhaug, Thor Anders; Lanzini, Andrea; Santarelli, Massimo; Barnett, Alejandro Oyarce; Thomassen, Magnus (Peer reviewed; Journal article, 2021)
      This work investigates the online monitoring of fluoride ion concentration in proton exchange membrane water electrolysers (PEMWE) effluent water using an automated ion chromatography (IC) setup. Prototype catalyst coated ...
    • 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, ...
    • PFC Evolution in the Aluminium Production Process 

      Åsheim, Henrik (Doctoral theses at NTNU;2017:137, Doctoral thesis, 2017)
      Improvements in the Hall-Héroult process for electrowinning of aluminium have drastically reduced the anode effect duration, frequency and its associated perfluorocarbon (PFC) evolution, especially over the past 50 years. ...