Blar i NTNU Open på forfatter "Tangstad, Merete"

Viser treff 81-100 av 144

    • Phase transformation in quartz at elevated temperatures 

      He, Jiali; Jusnes, Karin Fjeldstad; Tangstad, Merete (Peer reviewed; Journal article, 2021)
      Natural quartz is a raw material in Si production. During heating, it will go through a series of phase transformations before melting in the furnace, from quartz to an intermediate amorphous phase and further to cristobalite. ...

    • Phase transformations and thermal degradation in industrial quartz 

      Jusnes, Karin Fjeldstad (Doctoral theses at NTNU;2020:205, Doctoral thesis, 2020)
      Quartz is used as the silicon source for silicon and ferrosilicon production. Together with various carbon materials, the quartz is added to a submerged arc furnace. Energy is supplied through three carbon electrodes, which ...

    • Phase Transformations from Quartz to Cristobalite 

      Jusnes, Karin Fjeldstad; Tangstad, Merete; Ringdalen, Eli (The Minerals, Metals & Materials Series;, Chapter, 2018)
      Two quartz types used in the silicon and ferrosilicon industry were heated to temperatures of 1600 and 1700 °C. The parameters varied were the temperature and the holding time at maximum temperature. The amount of quartz, ...

    • Phase transformations in quartz used in silicon and ferrosilicon 

      Jusnes, Karin Fjeldstad; Tangstad, Merete; Ringdalen, Eli (Peer reviewed; Journal article, 2021)
      Different quartz types are used as raw material for silicon and ferrosilicon production. Upon heating, the quartz will experience phase transformations to other silica polymorphs. In this study the phase transformation ...

    • Phases and Zones in the Silicon Process 

      Bø, Siri Marie (Master thesis, 2016)
      Different zones and materials formed during the production of silicon in a silicon furnace has been examined in this thesis. Samples from two industrial scale silicon furnaces have been have been studied. The excavations ...

    • Pilot Scale Production of Manganese Ferroalloys Using Heat-Treated Mn-Nodules 

      Tangstad, Merete; Ringdalen, Eli; Manilla, Edmundo; Davila, Daniel (Journal article; Peer reviewed, 2017)
      Pilot-scale experiments are one way to investigate the process patterns and the reaction mechanisms of processes and raw materials. To understand a process fully, both theoretical considerations as well as small-scale ...

    • Pre-reduction Behaviour of Manganese Ores in H2 and CO Containing Gases 

      Ngoy, Didier; Dmitry, Sukhomlinov; Tangstad, Merete (Peer reviewed; Journal article, 2020)
      This paper presents results of a study conducted on the pre-reduction of Assmang and Comilog ores with gases of CO+CO2 and CO+H2+CO2 up to 1 000°C. Non-isothermal experiments were carried out in a vertical thermogravimetric ...

    • Pre-reduction of United Manganese of Kalahari Ore in CO/CO<inf>2</inf>, H<inf>2</inf>/H<inf>2</inf>O, and H<inf>2</inf> Atmospheres 

      Davies, Emlyn John; Tangstad, Merete; Schanche, Trygve Lindahl; du Preez, Preez (Peer reviewed; Journal article, 2023)
      The incorporation of hydrogen, which is a relatively unexplored reductant used during ferromanganese (FeMn) production, is an attractive approach to lessen atmospheric gaseous carbon release. The influence of hydrogen on ...

    • Prereduction Behavior of Manganese Ores With Solid Carbon and in CO/CO<inf>2</inf> Gas Atmosphere 

      Mukono, Tichaona; Reiersen, Henrik Stensdal; Schanche, Trygve Lindahl; Wallin, Maria; Tangstad, Merete (Peer reviewed; Journal article, 2022)
      The prereduction reactions in the submerged arc furnace (SAF) are highly decisive of the total carbon, and energy consumption of the ferromanganese process. Therefore, understanding the dependency of prereduction behavior ...

    • Prereduction of Comilog- and Nchwaning ore 

      Larssen, Trine Asklund (Doctoral theses at NTNU;2020:415, Doctoral thesis, 2020)
      Manganese ferroalloys are mainly used as an alloying element in steel production and are normally produced in submerged arc furnaces. Raw materials such as manganese ore, metallurgical coke and fluxes (and quartz for SiMn) ...

    • Prereduction of Nchwaning Ore in CO/CO2/H2 Gas Mixtures 

      Schanche, Trygve Lindahl; Tangstad, Merete (Peer reviewed; Journal article, 2021)
      Prereduction of Nchwaning manganese ore was investigated by isothermal reduction between 600 and 800 °C to optimize the conditions for industrial pretreatment of manganese ores. Experiments were conducted in CO/CO2 gas ...

    • Pretreatment of manganese ores in CO/CO2/H2 atmospheres 

      Schanche, Trygve Lindahl (Doctoral theses at NTNU;2022:401, Doctoral thesis, 2022)
      During industrial production of manganese ferroalloys, the manganese raw materials are prereduced in the low temperature zone of the submerged arc furnace (SAF). The endothermic Boudouard reaction (CO2 + C = 2CO) consumes ...

    • Production of Silicomanganese from Comilog Ore - Reduction Behavior 

      Holtan, Joakim (Master thesis, 2016)
      The reduction behavior of silicomanganese (SiMn) charges based on Comilog ore was investigated. The charges were heated up to to different temperatures by using a thermogravimetric graphite tube furnace. The weight loss ...

    • Production Rate of SiO Gas from Industrial Quartz and Silicon 

      Sindland, Caroline; Tangstad, Merete (Peer reviewed; Journal article, 2021)
      The production rate of SiO gas from industrial quartz and silicon has been investigated by isothermal heat treatment experiments. Mixtures of silicon and different quartz samples have been heated to temperatures ranging ...

    • Production Rate of SiO Gas from Industrial Quartz and Silicon 

      Sindland, Caroline (Master thesis, 2020)
      Reaksjonshastigheten til den SiO produserende reaksjonen, reaksjon mellom silisium og silika er undersøkt ved isoterm varmebehandling. Flere blandinger av silisium og silika har blitt varmet opp til temperaturer fra 1650 ...

    • A Raman-Structure Model for the Viscosity of SiO2- CaO-Al2O3 System 

      Haghdani, Shokouh; Tangstad, Merete; Einarsrud, Kristian Etienne (Peer reviewed; Journal article, 2022)
      The relationship between structure and viscosity of molten slags is investigated using the Raman spectroscopy technique. To this end, a group of 20 synthetic slags in the SiO2-CaO-Al2O3 ternary system is considered. The ...

    • Reaction Rate Analysis of Manganese Ore Prereduction in CO-CO2 Atmosphere 

      Larssen, Trine Asklund; Senk, Dieter Georg; Tangstad, Merete (Peer reviewed; Journal article, 2021)
      Variations in energy efficiency and climate gas emissions in production of manganese ferroalloys are largely related to the solid-state reduction of the manganese ores used as raw material in the production. The gas-solid ...

    • Reactivity assessment of charcoal for use in silicon production 

      Ramos, D.C.; Carneiro, A.C.O.; Tangstad, Merete; Pereira, B.L.C.; Saadieh, Raghed; Oliveira, A.C.; Vital, B.R. (Peer reviewed; Journal article, 2021)
      As charcoal is used in the silicon metal process, reactivity towards SiO is one of the most important properties that has strong effects on silicon recovery. The purpose of this study was to analyze anatomical properties ...

    • Reactivity of silicomanganese slag towards carbon materials - A comparison of coke and charcoal as reducing agents 

      Haugli, Ine Mariell Fagerbakk (Master thesis, 2019)
      Silikomangan produseres ved karbotermisk reduksjon med koks som reduksjonsmiddel. Mens koks er laget av kull og er en fossil karbonkilde, er trekull laget av trær og er en fornybar karbonkilde som ikke slipper ut ekstra ...

    • Recycling of Glass Wool Waste 

      Rudjord, Fredrik (Master thesis, 2018)
      The importance of environmentally friendly solution is an ever-increasing concern of industries all over the country. The glass wool industry has for a long time had a problem regarding waste from their production process. ...