Browsing NTNU Open by Author "Tangstad, Merete"
Now showing items 21-40 of 145
-
Densification of Biocarbon and Its Effect on CO2 Reactivity
Kaffash, Hamideh; Tangstad, Merete; Surup, Gerrit Ralf (Peer reviewed; Journal article, 2021)Charcoal is an interesting reducing agent because it is produced from biomass which is renewable and does not contribute to global warming, provided that there is a balance between the felling of timber and growth of trees. ... -
Densification of charcoal by thermal decomposition of methane
Larsen, Marius (Master thesis, 2022)I dette prosjektet ble densifisering av trekull gjennom dekomponering av metan undersøkt. Totalt ble 6 prøvesett analysert, hver med en vekt på ca 350 g. De ulike gradene av densifisering var 10.3 , 11.1 , 24.0 og 29.7 ... -
Disintegration of Six Different Quartz Types during Heating to 1600 °C
Folstad, Marit Buhaug; Yu, Han; Wang, Haijuan; Tangstad, Merete (Journal article; Peer reviewed, 2023) -
Dissolution kinetics of carbon materials in FeMn
Kaffash, Hamideh (Doctoral theses at NTNU;2019:226, Doctoral thesis, 2019)Submerged electric arc furnace (SAF) is the main process for industrial production of ferroalloys, in which metal oxides are reduced by carbon. To decrease the production cost and reduce the CO2 emissions, a variety of ... -
Dissolution Rate and Wettability of SiO2-CaO-Al2O3 Slags on Quartz
Kristiansen, Save (Master thesis, 2023)Denne studien har som mål å undersøke fuktningsgraden og reaksjonskinetikken av SiO2 –CaO–Al2O3 slagg på industriell kvarts for å forstå interaksjonene mellom industrislagg og -kvarts i silisium- og ferrosilisiumproduksjon. ... -
Dynamic Current and Power Distributions in a Submerged Arc Furnace
Tesfahunegn, Yonatan; Magnusson, Thordur; Tangstad, Merete; Saevarsdottir, Gudrun (Journal article; Peer reviewed, 2019)Most submerged arc furnaces used for the production of ferroalloys run on three-phase alternating current. This affects the electrical operation of the furnace and thus it is of interest to study alternating current ... -
Dynamic Current Distribution in the Electrodes of Submerged Arc Furnace Using Scalar and Vector Potentials
Tesfahunegn, Yonatan; Magnusson, Thordur; Tangstad, Merete; Saevarsdottir, Gudrun (Journal article; Peer reviewed, 2018)This work presents computations of electric current distributions inside an industrial submerged arc furnace. A 3D model has been developed in ANSYS Fluent that solves Maxwell’s equations based on scalar and vector potentials ... -
Effect of Charge Basicity of Two Compositions on MnO Reduction During Smelting Ferromanganese
Mwana Bute Ngoy, D; Kalenga wa Kalenga, M; Tangstad, Merete (Journal article; Peer reviewed, 2018)The effect of basicity of two different basic charges for reduction of MnO by solid carbon during smelting ferromanganese is considered. The effect of different charge compositions on MnO reduction in the temperature range ... -
Effect of different SiO2 polymorphs on the reaction between SiO2 and SiC in Si production
Folstad, Marit Buhaug; Ringdalen, Eli; Tveit, Halvard; Tangstad, Merete (Peer reviewed; Journal article, 2021)This work investigates the phase transformations in silica (SiO2) during heating to a target temperature between 1700 °C and 1900 °C and the effect of SiO2 polymorphs on the reduction reaction 2SiO2 + SiC = 3SiO + CO in ... -
The Effect of Electrode Movements on Electrical Characteristics of a Submerged Arc Furnace
Tesfahunegn, Yonatan; Magnusson, Thordur; Tangstad, Merete; Sævarsdottir, Gudrun (Peer reviewed; Journal article, 2021)This work discusses the effect of electrode position on the electrical characteristics of a submerged arc furnace. A 3D model has been developed in ANSYS Maxwell using an eddy current solver that considers alternating ... -
The Effect of Hydrogen and Methane Containing Gases on SiC and SiO formation
Aarnæs, Trygve Storm (Doctoral theses at NTNU;2023:48, Doctoral thesis, 2023)The production of silicon is currently done in a submerged arc furnace where quartz react with carbon. This emits large amounts of CO2to the atmosphere. From a global warming perspective this is far from ideal, and ... -
Effect of Moisture, Hydrogen, and Water–Gas Shift Reaction on the Prereduction Behavior of Comilog and Nchwaning Manganese Ores
Larssen, Trine Asklund; Tangstad, Merete (Peer reviewed; Journal article, 2022)The ore–gas reactions in the prereduction zone in a ferromanganese furnace are largely decisive of the overall energy efficiency, carbon consumption, and climate gas emissions in ferromanganese production. An increased ... -
The Effect of Pre-Oxidation on the Reducibility of Chromite Using Hydrogen: A Preliminary Study
Davies, Jamey; Tangstad, Merete; Ringdalen, Eli; Beukes, Johan Paul; Bessarabov, Dmitri; du Preez, Stephanus Petrus (Peer reviewed; Journal article, 2022)The majority of ferrochrome (FeCr) is produced through the carbothermic reduction of chromite ore. In recent years, FeCr producers have been pressured to curve carbon emissions, necessitating the exploration of alternative ... -
Effect of Raw Materials on Temperature Development during Prereduction of Comilog and Nchwaning Manganese Ores
Larssen, Trine Asklund; Tangstad, Merete (Peer reviewed; Journal article, 2023)The effect of raw materials on the temperature development and prereduction behavior of Comilog and Nchwaning manganese ores (3.33–4.00 mm or 11.20–15.00 mm) were investigated in a CO-CO2 atmosphere. Experiments were ... -
Electrical Resistivity in Carbon Materials Converting to SiC
Pedersen, Tommy André (Master thesis, 2020)Målet med dette arbeidet har vært å undersøke hvordan ledningsevnen i karbonmaterialer endres som følge av interaksjon med SiO gass ved høye temperaturer. Dette har blitt gjort som et ledd i å øke forståelsen av hvordan ... -
Electrical Resistivity of Carbonaceous Bed Material at High Temperature
Surup, Gerrit Ralf; Pedersen, Tommy Andre; Chaldien, Annah; Beukes, Johan Paul; Tangstad, Merete (Peer reviewed; Journal article, 2020)This study reports the effect of high-temperature treatment on the electrical properties of charcoal, coal, and coke. The electrical resistivity of industrial charcoal samples used as a reducing agent in electric arc ... -
Electrical Resistivity of Materials in the Silicon Furnace
Hoover, Haley (Doctoral thesis, 2023)Silicon is becoming an increasingly important part of the modern world through its applications in electronics, solar cells, and silicones, to name a few. Norway is a significant producer of silicon, competing with much ... -
Electrical Resistivity of Transformed Carbon Materials in the Silicon Furnace
Hoover, Haley; Sævarsdottir, Gudrun; Tangstad, Merete (Chapter, 2022)Optimal current paths through the silicon furnace depend on the electrical properties of the charge materials. It is essential for good tapping conditions that sufficient current is supplied to the arc and lower part of ... -
Electrode paste behaviour in Søderberg electrodes in ferroalloys production
Skjeldestad, Aslak (Doctoral theses at NTNU, 2019:325, Doctoral thesis, 2019)The main goal of this work has been to study the melting behavior of electrode paste used in Søderberg electrodes in ferroalloy production. It has been done by first measuring temperatures in an industrial electrode and ... -
Elektrisk resistivitet i industrielle SiC-lag
Krokstad, Magnus Austheim (Master thesis, 2014)Det antas at 1% av strømmen som går gjennom en ovn som produserer silisiumslegeringer vil gå gjennom chargen mellom elektrodene, resten vil gå gjennom lysbuen som går fra elektroden og til metallbadet. Det er ukjent hvor ...