Browsing Institutt for materialteknologi by Author "Haarberg, Geir Martin"
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A concept for electrowinning of aluminium using depolarized gas anodes
Mokkelbost, Tommy; Kjos, Ole Sigmund; Paulsen, Ove Bjørn; Øye, Bjarte Arne; Gudbrandsen, Henrik; Ratvik, Arne Petter; Haarberg, Geir Martin (Journal article; Peer reviewed, 2014)Aluminium is today commercially produced by the Hall-Héroult process using consumable carbon anodes. Consumable anodes have some concerns such as CO2 emission, continuous anodecathode distance adjustments and replacements ... -
Adapting Modern Industrial Operation Parameters in a Standardized Laboratory Cell for Measuring Current Efficiency for Aluminium Deposition: Unexpected Challenges and Lessons Learned
Meirbekova, Rauan; Awayssa, Omar; Haarberg, Geir Martin; Saevarsdottir, Gudrun (Journal article, 2020)“Current efficiency” is an important cell parameter which shows how efficiently current is used to produce aluminium. Operational parameters that affect current efficiency have been widely studied in the aluminium industry, ... -
Anodeprosesser i elektrokjemisk fremstilling av sink
Skaftun, Siri Marie (Master thesis, 2013)Målet med denne oppgaven var å studere utfellingen av manganoksid fra en svovelsur elektrolytt inneholdende manganspesier. Syklisk voltametri, lineærsveip voltametri og potensialsteg ble utført på ulike elektrodematerialer. ... -
Anodic Behaviour of Ni-Fe-Cu electrode In Molten Fluoride Salts
Saevarsdottir, Gudrun; Singh, Kamaljeet; Haarberg, Geir Martin; Bourmaud, M; Padamata, Sai Krishna (Peer reviewed; Journal article, 2022)The anodic behaviour of NixFeyCuz alloy at different sodium- and potassium-cryolite based electrolyte compositions was examined by chronopotentiometry, galvanostatic polarisation, and linear sweep voltammetry at 1098 K. ... -
Calcination temperature dependent catalytic activity and stability of IrO2 – Ta2O5 anodes for oxygen evolution reaction in aqueous sulfate electrolytes
Xu, Wenting; Haarberg, Geir Martin; Sunde, Svein; Seland, Frode; Ratvik, Arne Petter; zimmerman, erik; Shimamune, T; Gustavsson, J; Åkre, Torjus (Journal article; Peer reviewed, 2017)In this work, commercial IrO2-Ta2O5 anodes with a certain composition calcined at three different temperatures were investigated. The results show that the calcination temperature has a significant influence on the ... -
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 ... -
Cation Nonstoichiometry of La2CoO4
Karlsen, Nini (Master thesis, 2017)In this thesis, the cation nonstoichiometry and composition range of the La2CoO4 phase in the La-Co-O system were investigated and compared to earlier studies. There is a controversy over the cation nonstoichiometry of ... -
Crystal Orientation of Iron Produced by Electrodeoxidation of Hematite Particles
Tokushige, Manabu; Kongstein, Ole Edvard; Haarberg, Geir Martin (Journal article, 2013)Electrowinning of iron was conducted in a 50 wt% NaOH-H2O electrolyte with suspended Fe2O3 particles at 110ºC and pure α-Fe films were obtained on a disk cathode with a higher current efficiency than 95%. The Fe2O3 particle ... -
Depolarized SnO2-based gas anodes for electrowinning of silver in molten chlorides
Xiao, S; Haarberg, Geir Martin (Journal article; Peer reviewed, 2013)SnO2-based porous anodes were prepared and the behavior of gas bubbles on the porous anodes with different original coarse grain size, immersed in ethanol to simulate molten chlorides, was primarily investigated. SnO2-based ... -
Direct electrochemical reduction of hematite pellets in alkaline solutions
Haarberg, Geir Martin; Yuan, Boyan (Journal article, 2014)Our previous studies on the electrowinning of iron from hematite particles suspended in sodium hydroxide solutions demonstrated that iron was produced through a direct solid phase electrochemical reduction of the oxide ... -
Direct Production of Aluminum Manganese and Silicon Alloys in Aluminum Reduction Cells: A Laboratory Test
Sævarsdottir, Gudrun Arnbjörg; Awayssa, Omar; Meirbekova, Rauan; Haarberg, Geir Martin (Journal article, 2022)Aluminum smelters produce pure aluminum in reduction cells by the Hall-Héroult process but supply a variety of alloys to their customers. The alloys are produced in the cast house, as master alloys containing the desired ... -
Direct Production of Aluminum Titanium Alloys in Aluminum Reduction Cells: A Laboratory Test.
Haarberg, Geir Martin; Awayssa, Omar; Saevarsdottir, Gudrun; Meirbekova, Rauan; Xu, Wenting (Journal article, 2022)Aluminum smelters produce pure aluminum in reduction cells by the Hall-Héroult process, however, aluminum is usually supplied as a variety of alloys to their customers. The alloys are produced in the casthouse, as desired ... -
Effect of composition and temperature on current efficiency for aluminium electrolysis from cryolite-based molten alumina electrolytes
Morishige, Taiki; Haarberg, Geir Martin; Gudbrandsen, Henrik; Skybakmoen, Egil; Solheim, Asbjørn; Takenaka, Toshihide (Journal article; Peer reviewed, 2017)The current efficiency (CE) for aluminium electrolysis in modern cells can be as high as 96 %. The main reason for loss in current efficiency is the so-called back reaction between dissolved metal and the anode product of ... -
Electrochemical Behavior of Tin in Molten LiCl-KCl at 450 ℃
Qin, Bo; Cui, Peng; Martinez, Ana Maria Cuellar; Haarberg, Geir Martin (Journal article; Peer reviewed, 2019)The electrochemical behavior of tin was studied with cyclic voltammetry at glassy carbon electrodes in the fused LiCl-KCl at 450 ℃. Metallic tin deposition on the glassy carbon electrode occurs at a potential of around ... -
Electrochemical behaviour of dissolved iron chloride in KCl+LiCl+NaCl melt at 550 ºC
Khalaghi, Babak; Kvalheim, Eirin; Tokushige, Manabu; Teng, Lidong; Seetharaman, S.; Haarberg, Geir Martin (Journal article, 2014)An electrochemical study of iron was carried out in KCl+LiCl+NaCl melt at 550ºC using a glassy carbon working electrode. Cyclic voltammetry showed that the Fe(II)/Fe(0) electron exchange is a soluble/insoluble reversible ... -
Electrochemical behaviour of dissolved titanium oxides during aluminium deposition from molten fluoride electrolytes
Haarberg, Geir Martin (Journal article, 2017)A small but significant amount of dissolved titanium is always present in the molten cryolite based electrolyte used during electrowinning of aluminium. The fact that titanium can appear in several oxidation states may be ... -
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 Co-Deposition of Alloying Elements during Aluminium Electrolysis in a Laboratory Cell
Awayssa, Omar Ratib (Doctoral theses at NTNU;2021:121, Doctoral thesis, 2021)Aluminium alloys are mainly produced by the so-called melt mixing at which an alloying element is added to the molten aluminium before casting. This approach suffers from several drawbacks such as the high requirements of ... -
Electrochemical Production of Al-Si Alloys in Cryolitic Melts in a Laboratory Cell
Awayssa, Omar Ratib; Sævarsdottir, Gudrun; Meirbekova, Rauan; Haarberg, Geir Martin (Peer reviewed; Journal article, 2021)Direct production of aluminium-silicon alloy during aluminium electrolysis in fluoride-based melts was studied. Experiments were carried out in a laboratory cell dedicated to current efficiency measurements. Electrolysis ... -
Electrochemical production of Al–Mn alloys during the electrodeposition of aluminium in a laboratory cell
Awayssa, Omar Ratib; Haarberg, Geir Martin; Meirbekova, Rauan; Sævarsdottir, Gudrun (Peer reviewed; Journal article, 2021)This study reports the direct production of an aluminium–manganese alloy during aluminium electrolysis in fluoride-based melts. Experiments were conducted in a laboratory cell dedicated for current efficiency measurements. ...