Blar i NTNU Open på forfatter "Sandnes, Espen"
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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 ... -
Bubble Evolution on Different Carbon Anode Designs in Cryolite Melt
Stanic, Nikolina; Jevremovic, Ivana; Martinez, Ana Maria Cuellar; Sandnes, Espen (Peer reviewed; Journal article, 2020)The anode potential has been shown to be highly dependent on anode geometry and orientation in the Hall–Héroult process. This work is an experimental laboratory scale study of the effect of anode geometry and orientation ... -
Bubble Phenomena and Bubble Properties for Different Carbon Anodes in Cryolite Melt
Stanic, Nikolina (Doctoral theses at NTNU;2022:333, Doctoral thesis, 2022)This doctoral work is an experimental laboratory scale study of the effect of anode geometry, anode orientation and carbon anode material on bubble behavior and bubble properties in cryolite melt. The increased knowledge ... -
Bubble Phenomena and Bubble Properties for Horizontal and Vertical Carbon Anode Surfaces in Cryolite Melt Applying a See‐Through Cell
Stanic, Nikolina; Martinez, Ana Maria Cuellar; Einarsrud, Kristian Etienne; Sandnes, Espen (Peer reviewed; Journal article, 2021)Gas bubble behavior on a carbon anode in a cryolite melt has been studied using a see-through cell. The phenomena studied have been growth, coalescence, detachment, and wetting during electrolysis. The surface orientation ... -
Carbon Capture and Recovery by Molten Salts Electrochemistry
Takahashi, Yukihiro (Master thesis, 2022)To mitigate global warming and climate change, it is an urgent mission for us to reduce the amount of CO2 in the atmosphere. One of the viable solutions to this challenge may be to capture, and preferably, to recover CO2 ... -
CO and CO2 Anode Gas Concentration at Lower Current Densities in Cryolite Melt
Stanic, Nikolina; Bø, Embla Knutsdotter Øi Tharaldse; Sandnes, Espen (Peer reviewed; Journal article, 2020)This work aims to study the CO-CO2 gas composition at low potentials and low current densities in cryolite melt with relatively low alumina content (≤2 wt%). There is a scarcity of data in the literature regarding the low ... -
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 ... -
Development of an electrochemical sensor for alumina concentration measurements and dissolution characteristics of alumina in cryolite melt
Bracamonte, Luis (Doctoral theses at NTNU, 2022:161, Doctoral thesis, 2022)The work studied the development and behaviour of an in-situ electromotive force (emf) based electrochemical sensor composed of a graphite probe during the addition and dissolution of alumina in cryolite-based melts. The ... -
Dispersion and dissolution of alumina in cryolite melts: impact of sulfur and carbon on dissolution behavior in see through cell
Aulie, Vegard (Master thesis, 2021)Aluminium blir produsert industrielt ved hjelp av Hall-Herôult metoden. Denne metoden produserer flytende aluminium fra aluminiumoksid (kalt alumina) og karbon i ett bad med flytende kryolitt. Denne prosessen krever høy ... -
Dissolution Characteristics and Concentration Measurements of Alumina in Cryolite Melts
Bracamonte, Luis Carlos Izaguirre; Aulie, Vegard; Rosenkilde, Christian; Einarsrud, Kristian Etienne; Sandnes, Espen (Peer reviewed; Journal article, 2021)Alumina dissolution is one of the most important processes in the Hall-Héroult process. In this work, video recording using a high-speed camera and a see-through cell and electromotive force (emf) based alumina sensor ... -
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 ... -
Electrochemical Study of Aluminum Chloride in Basic Chloride Melts with Oxide Additions
Bjørlo, Eirik (Master thesis, 2020)Hall-Héroult prosessen har dominert fremstillingen av aluminium i over et århundre. Flere alternative prosesser har blitt foreslått, hvorav “Alcoa Smelting Process” som ble utviklet på 70-tallet anses for å være den eneste ... -
Feeding of Alumina in Molten Cryolite Bath
Gylver, Sindre Engzelius (Doctoral theses at NTNU;2023:21, Doctoral thesis, 2023)Alumina is the principal raw-material used for the production of aluminum in the Hall- Héroult process and is fed to the electrolytic bath in batches regularly. Maintaining a stable concentration in the bath is important ... -
Interface resolved simulations of continuum scale electrochemical hydrogen evolution
Vachaparambil, Kurian J. (Doctoral theses at NTNU;2020:363, Doctoral thesis, 2020)An important aspect of improving the efficiency of water electrolysis is to remove the electrochemically generated hydrogen and oxygen bubbles. The evolution of these gases, which are associated with increased electrical ... -
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 ... -
Ionic Conductivity Measurements in Aqueous and Molten Salt Electrolytes
Tønneberg, Sophie; Strandheim, Marte Aarflot (Bachelor thesis, 2023)I en tid med stort fokus på det grønne skiftet, står aluminiumsindustrien overfor en sentral utfordring knyttet til mer klimavennlig aluminiumsproduksjon. Alcoas klorid- og elektrolyseprosess er et alternativ som kan bidra ... -
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 ... -
Oxide Sensor Measurements and Simultaneous Optical Observations During Dissolution of Alumina in Cryolite Melt
Bracamonte, Luis Carlos Izaguirre; Einarsrud, Kristian Etienne; Rosenkilde, Christian; Sandnes, Espen (Journal article; Peer reviewed, 2022) -
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. ... -
Pursuing Sustainable Cathodes with High Rate Capability
Finne, Per Håkon Pedersen (Master thesis, 2022)Litium-ionebatterier (LiBer) er forventet å bli en av fremtidens viktigste energilagringskilder, da de gir mulighet for å lagre og bruke energi uten å produsere drivhusgasser. CO2-fotavtrykket til LiBer er derimot i stor ...