Browsing NTNU Open by Author "Haarberg, Geir Martin"
Now showing items 41-60 of 71
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Influence of electrode gas flow rate and electrolyte composition on thermoelectric power in molten carbonate thermocell
Kandhasamy, Sathiyaraj; Calandrino, Luca; Burheim, Odne Stokke; Solheim, Asbjørn; Kjelstrup, Signe Helene; Haarberg, Geir Martin (Journal article, 2016)A thermocell (thermo-electrochemical cell) is an electrochemical system with two identical electrodes placed at different temperatures in an electrolyte solution. Ion transport between the electrodes due to the temperature ... -
Influence of Electrode Gas Flow Rate and Solid Oxide Ratio in Electrolyte on the Seebeck Coefficient of Molten Carbonate Thermocell
Kandhasamy, Sathiyaraj; Calandrino, Luca; Burheim, Odne Stokke; Solheim, Asbjørn; Kjelstrup, Signe; Haarberg, Geir Martin (Journal article; Peer reviewed, 2017)Thermocells represent a promising way to utilize heat as a power source. The aim of this work is to develop a thermocell with identical gas electrodes using molten carbonate-based electrolytes. The cell can generate power ... -
Influence of phosphorus on current efficiency in aluminum electrolysis at different current densities
Meirbekova, Rauan; Haarberg, Geir Martin; Thonstad, Jomar; Saevarsdottir, Gudrun (Journal article; Peer reviewed, 2017)Many factors may contribute to loss of current efficiency (CE) in aluminum reduction and one of them is a presence of impurities. In this work, the effect of phosphorus on CE is studied in a laboratory cell at different ... -
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 ... -
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 ... -
Manganese Oxide in Zinc Electrowinning: Deposition and removal at platinum, gold and IrO2-Ta2O5/Ti anodes in sulphuric acid
Skaftun, Siri Marie (Doctoral theses at NTNU;2021:242, Doctoral thesis, 2021)An environmentally friendly and energy efficient replacement for lead anodes in zinc electrowinning is highly desired. Oxygen evolution reaction (OER) is the desired anode reaction in acidic sulphate electrolytes. However, ... -
Molten Carbonate Electrolyte Based Thermocell for High Temperature Waste Heat Recovery
Kandhasamy, Sathiyaraj (Doctoral theses at NTNU;2018:321, Doctoral thesis, 2019)Industrial processes for the production of metals and alloys by metallurgical and electrochemical methods generate a lot of waste heat due to irreversible losses. This waste heat could be used as a power source to produce ... -
Natural Gas Anodes for Aluminium Electrolysis in Molten Fluorides
Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy (Journal article; Peer reviewed, 2016)Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse ... -
Natural Gas Anodes of Porous Graphite for Aluminium Electrolysis
Khalaghi, Babak (Doctoral theses at NTNU;2017:266, Doctoral thesis, 2017)Aluminium is the second metal produced in the world in terms of quantity. It is produced in a multistage process. First, aluminium ore is converted to pure aluminium oxide. The second stage is an electrolysis process. In ... -
The performance change of aluminum electrolysis in standard cryolite electrolyte with cathodic current density
Silva, Pedro (Master thesis, 2017)A series of experiments were performed to verify the effect of current density in current efficiency of aluminum electrolysis in molten salts. To avoid interference of other parameters, a special designed laboratory cell ... -
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. ... -
Porous Carbon Anodes for the Supply of Methane during Electrowinning of Aluminium
Khalaghi, Babak; Gudbrandsen, Henrik; Kjos, Ole Sigmund; Osen, Karen Sende; Mokkelbost, Tommy; Haarberg, Geir Martin (Chapter, 2016)One of the major downsides of the current aluminium production process is the high amount of CO2 e mission. One alternative is to replace the consumable carbon anodes with inert anodes so that oxygen evolves instead of CO2 ... -
Preparation of diboride coatings by electrophoretic deposition in nanoparticle-containing molten inorganic salts
Jin, Weiliang; Xiao, Saijun; Kou, Qian; Ding, Desheng; Zhang, Jun; Fang, Xiaohong; Ge, Chuntao; Zhong, Cong; Zhu, Hongmin; Haarberg, Geir Martin (Peer reviewed; Journal article, 2022)Electrophoretic deposition is a type of significant method for preparing coatings and films, which has been widely investigated in aqueous and organic suspensions. However, electrophoretic deposition in molten inorganic ... -
Preparation of ZrB<inf>2</inf>coatings by electrophoretic deposition in NaCl-KCl-AlCl<inf>3</inf>molten salts
Ge, Chuntao; Kou, Qian; Pang, Jie; Zhang, Jun; Jin, Weiliang; Zhu, Hongmin; Haarberg, Geir Martin; Xiao, Saijun (Peer reviewed; Journal article, 2022)Fabrication of transition metal diboride coatings via electrophoretic deposition in molten salts has been recently proposed, however, the influence of the process parameters on the coating has not yet been studied extensively. ... -
Primary Production of Aluminium and Its Alloys in Molten Salts with Oxygen Evolving Anodes: Overview
Padamata, Sai Krishna; Singh, Kamaljeet; Haarberg, Geir Martin; Saevarsdottir, Gudrun (Peer reviewed; Journal article, 2022)Due to environmental and economic concerns, carbon-free aluminium production has been an ultimate target for aluminium industries. For the last few decades, a considerable amount of research has been conducted to find a ... -
Production of Iron Alloy by Direct Electrolytic Reduction Using Suspension Electrolysis in an Alkaline Electrolyte
Tokushige, Manabu; Kongstein, Ole Edvard; Haarberg, Geir Martin (Peer reviewed; Journal article, 2022)Iron alloys were produced by suspension electrolysis in a 50 wt% NaOH–H2O electrolyte at 383 K, and Fe–Cr and Fe–Ni alloys were obtained using a suspension of Fe2O3+Cr2O3 and Fe2O3+Ni(OH)2 particles, respectively. Highly ... -
Production of tib2 coatings on graphite substrates by electrophoretic deposition in NaF-AlF3 melt
Zhang, Jun; Pang, Jie; Jin, Weiliang; Chu, Shaojun; Haarberg, Geir Martin; Xiao, Saijun (Peer reviewed; Journal article, 2023)In this paper a novel method for fabrication of TiB2 coatings on graphite substrates by electrophoretic deposition of TiB2 nanoparticles in NaF-AlF3 melt at 980°C has been explored. With an applied cell voltage of 1.2 V ... -
Removal and recovery of indium from ITO coated glass and scraps using molten salt electrolysis
Cui, Peng; Qin, Bo; Martinez, Ana Maria Cuellar; Haarberg, Geir Martin (Peer reviewed; Journal article, 2019)Indium is an important strategic resource due to the scarcity for the metal. In the present study, molten salt electrolysis is used to reduce indium from ITO coated glass and scraps in order to seek a new way to recycle ... -
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 ... -
Seebeck coefficients of cells with lithium carbonate and gas electrodes
Børset, Marit Takla; Kang, Xue; Burheim, Odne Stokke; Haarberg, Geir Martin; Xu, Q.; Kjelstrup, Signe (Journal article; Peer reviewed, 2015)The Seebeck coefficient is reported for thermoelectric cells with gas electrodes and a molten electrolyte of one salt, lithium carbonate, at an average temperature of 750 °C. We show that the coefficient, which is 0.88 mV ...