Blar i NTNU Open på forfatter "Ratvik, Arne Petter"

Viser treff 21-40 av 48

    • Diffusion of alkali metals in the first stage graphite intercalation compounds by vdW-DFT calculations 

      Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor; Selbach, Sverre Magnus (Journal article; Peer reviewed, 2015)
      Diffusion of alkali metal cations in the first stage graphite intercalation compounds (GIC) LiC6, NaC6, NaC8 and KC8 has been investigated with density functional theory (DFT) calculations using the optPBE-vdW van der Waals ...

    • 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 ...

    • Effects of Water Cooling of Green Anodes on Anode Furnace Operation 

      Brandvik, Trond; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2018)
      Water can be present in significant amounts in green anodes due to cooling with water after the forming process. The chemical environment in the pit can potentially be affected by the presence of water and may cause ...

    • 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 Behaviour of Industrial IrO2-Ta2O5 Anodes for Copper Electrowinning 

      Xu, Wenting; Haarberg, Geir Martin; Sunde, Svein; Seland, Frode; Ratvik, Arne Petter; Zimmerman, Erik; Åkre, Torjus (Journal article; Peer reviewed, 2017)
      In this work, industrial IrO2-Ta2O5 anodes calcined at different temperatures were investigated. The results show that the calcination temperature has significant influence on the surface microstructure including the ...

    • 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 ...

    • Formation of aluminium carbide in Hall-Héroult electrolysis cell environments 

      Novák, Bronislav; Ratvik, Arne Petter; Wang, Zhaohui; Grande, Tor (Journal article; Peer reviewed, 2018)
      The formation and dissolution of aluminium carbide under conditions similar to the chemical and electrochemical environments in the Hall-Héroult process were studied in laboratory cells, including cells with reversed ...

    • 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 ...

    • 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 ...

    • 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 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 ...

    • 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 ...

    • Pitting on Carbon Cathodes in Aluminium Electrolysis Cells 

      Senanu, Samuel; Ratvik, Arne Petter; Grande, Tor (Journal article; Peer reviewed, 2018)
      Uneven cathode wear is one of the key challenges for the lifetime of aluminium electrolysis cells. Here we report on autopsy of several potlinings with focus on the surface morphology of the carbon cathodes. The surface ...

    • 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 ...

    • Role of Pitting in the Formation of Potholes in Carbon Cathodes - A Review 

      Senanu, Samuel; Grande, Tor; Ratvik, Arne Petter (Journal article, 2016)

    • Sandblasting effect on performance and durability of Ti based IrO2 –Ta2O5 anode in acidic solutions 

      Xu, Wenting; Haarberg, Geir Martin; Sunde, Svein; Seland, Frode; Ratvik, Arne Petter; Holmin, Susanne; Gustavsson, J; Afvander, Åsa; Zimmerman, Erik; Åkre, Torjus (Journal article; Peer reviewed, 2018)
      The effect of applying sandblasting during pretreatment while preparing titanium based IrO2 – Ta2O5 anodes by the conventional method was investigated. It was observed that sandblasting influences the surface morphology ...

    • 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 durability of the thermally decomposed IrO2-Ta2O5 coated titanium anode in a sulfate solution 

      Xu, Wenting; Haarberg, Geir Martin; Seland, Frode; Sunde, Svein; Ratvik, Arne Petter; Holmin, Susanne; Afvander, Åsa; Gustavsson, John; Zimmerman, Erik; Årke, Torjus (Journal article; Peer reviewed, 2019)
      In this work, series of IrO2-Ta2O5 anodes were investigated. The catalytic activity towards oxygen evolution reaction (OER) of these anodes are determined by calcination temperature, coating loading (coating thickness), ...

    • The Effect of Production Parameters on the Performance of Carbon Anodes for Aluminium Production 

      Sommerseth, Camilla (Doctoral thesis at NTNU;2016:108, Doctoral thesis, 2016)
      Carbon anodes are essential when producing aluminium. Oxygen from dissolved aluminium oxide reacts electrochemically on the carbon anode forming CO2. The carbon anode is consumed during the process. The production of ...