Fixation of carbon dioxide by producing carbonates from minerals and steelmaking slags

Dissertation

Sebastian Teir

    Research output: ThesisDissertationCollection of Articles

    Abstract

    Capture and storage of carbon dioxide (CO2) is internationally considered to be one of the main options for reducing atmospheric emissions of CO2. In Finland, no suitable geological formations are known to exist for storing captured CO2. However, fixing CO2 as solid carbonates using silicate-based materials is an interesting alternative. The magnesium silicate deposits in Eastern Finland alone could be sufficient for storing 10 Mt CO2 each year during a period of 200-300 years. Finnish steelmaking slags could also be carbonated, but the amounts produced provide a much smaller potential for CO2 storage (0.5 Mt CO2 per year) than magnesium silicates provide. The aim of this thesis was to study the possibility of reducing CO2 emissions by producing calcium and magnesium carbonates from silicate materials for the long-term storage of CO2 using multi-step processes. The production of carbonates from steelmaking slags and serpentinite, a magnesium silicate ore available from a metal-mining site, was studied both experimentally and theoretically. On the basis of the results, process concepts were developed and evaluated. Finally, the stability of synthetic calcium and magnesium carbonates as a medium for CO2 storage was assessed. Experiments with aqueous extraction and precipitation processes showed that magnesium and calcium can easily be extracted from steelmaking slags and natural silicate minerals using acids. Natural minerals seem to demand stronger acids for extraction than slags. Relatively pure calcium carbonate (80-90% calcite) was produced at room temperature and a CO2 pressure of 1 bar by adding sodium hydroxide to acetate solutions made from slag. Similarly, serpentinite was successfully converted into 93-100% pure hydromagnesite (a magnesium carbonate), using nitric acid or hydrochloric acid for the dissolution of serpentinite and sodium hydroxide for precipitation. The conversion of raw material to carbonate ranged from 60-90%. Although the results show that pure carbonates can be produced from industrial by-products and mining residues, the process concept suggested requires the recycling of large amounts of sodium hydroxide and acid, as well as low-grade heat for solvent evaporation. The methods suggested for recovering the spent chemicals were found to be expensive and cause more CO2 emissions than the amount of CO2 stored.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Helsinki University of Technology
    Award date2 Jun 2008
    Place of PublicationEspoo
    Print ISBNs978-951-22-9352-0
    Electronic ISBNs978-951-22-9353-7
    Publication statusPublished - 2008
    MoE publication typeG5 Doctoral dissertation (article)

    Fingerprint

    slag
    fixation
    magnesium
    carbon dioxide
    carbonate
    silicate
    mineral
    serpentinite
    hydroxide
    calcium
    sodium
    acid
    silicate mineral
    hydrochloric acid
    nitric acid
    calcium carbonate
    acetate
    calcite
    recycling
    evaporation

    Keywords

    • mineral carbonation
    • slag
    • carbon dioxide
    • dissolution
    • precipitation
    • carbonate

    Cite this

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    title = "Fixation of carbon dioxide by producing carbonates from minerals and steelmaking slags: Dissertation",
    abstract = "Capture and storage of carbon dioxide (CO2) is internationally considered to be one of the main options for reducing atmospheric emissions of CO2. In Finland, no suitable geological formations are known to exist for storing captured CO2. However, fixing CO2 as solid carbonates using silicate-based materials is an interesting alternative. The magnesium silicate deposits in Eastern Finland alone could be sufficient for storing 10 Mt CO2 each year during a period of 200-300 years. Finnish steelmaking slags could also be carbonated, but the amounts produced provide a much smaller potential for CO2 storage (0.5 Mt CO2 per year) than magnesium silicates provide. The aim of this thesis was to study the possibility of reducing CO2 emissions by producing calcium and magnesium carbonates from silicate materials for the long-term storage of CO2 using multi-step processes. The production of carbonates from steelmaking slags and serpentinite, a magnesium silicate ore available from a metal-mining site, was studied both experimentally and theoretically. On the basis of the results, process concepts were developed and evaluated. Finally, the stability of synthetic calcium and magnesium carbonates as a medium for CO2 storage was assessed. Experiments with aqueous extraction and precipitation processes showed that magnesium and calcium can easily be extracted from steelmaking slags and natural silicate minerals using acids. Natural minerals seem to demand stronger acids for extraction than slags. Relatively pure calcium carbonate (80-90{\%} calcite) was produced at room temperature and a CO2 pressure of 1 bar by adding sodium hydroxide to acetate solutions made from slag. Similarly, serpentinite was successfully converted into 93-100{\%} pure hydromagnesite (a magnesium carbonate), using nitric acid or hydrochloric acid for the dissolution of serpentinite and sodium hydroxide for precipitation. The conversion of raw material to carbonate ranged from 60-90{\%}. Although the results show that pure carbonates can be produced from industrial by-products and mining residues, the process concept suggested requires the recycling of large amounts of sodium hydroxide and acid, as well as low-grade heat for solvent evaporation. The methods suggested for recovering the spent chemicals were found to be expensive and cause more CO2 emissions than the amount of CO2 stored.",
    keywords = "mineral carbonation, slag, carbon dioxide, dissolution, precipitation, carbonate",
    author = "Sebastian Teir",
    note = "TK503 106 p. + app. 93 p.",
    year = "2008",
    language = "English",
    isbn = "978-951-22-9352-0",
    series = "TKK Dissertations",
    publisher = "Helsinki University of Technology",
    school = "Helsinki University of Technology",

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    Teir, S 2008, 'Fixation of carbon dioxide by producing carbonates from minerals and steelmaking slags: Dissertation', Doctor Degree, Helsinki University of Technology, Espoo.

    Fixation of carbon dioxide by producing carbonates from minerals and steelmaking slags : Dissertation. / Teir, Sebastian.

    Espoo, 2008. 199 p.

    Research output: ThesisDissertationCollection of Articles

    TY - THES

    T1 - Fixation of carbon dioxide by producing carbonates from minerals and steelmaking slags

    T2 - Dissertation

    AU - Teir, Sebastian

    N1 - TK503 106 p. + app. 93 p.

    PY - 2008

    Y1 - 2008

    N2 - Capture and storage of carbon dioxide (CO2) is internationally considered to be one of the main options for reducing atmospheric emissions of CO2. In Finland, no suitable geological formations are known to exist for storing captured CO2. However, fixing CO2 as solid carbonates using silicate-based materials is an interesting alternative. The magnesium silicate deposits in Eastern Finland alone could be sufficient for storing 10 Mt CO2 each year during a period of 200-300 years. Finnish steelmaking slags could also be carbonated, but the amounts produced provide a much smaller potential for CO2 storage (0.5 Mt CO2 per year) than magnesium silicates provide. The aim of this thesis was to study the possibility of reducing CO2 emissions by producing calcium and magnesium carbonates from silicate materials for the long-term storage of CO2 using multi-step processes. The production of carbonates from steelmaking slags and serpentinite, a magnesium silicate ore available from a metal-mining site, was studied both experimentally and theoretically. On the basis of the results, process concepts were developed and evaluated. Finally, the stability of synthetic calcium and magnesium carbonates as a medium for CO2 storage was assessed. Experiments with aqueous extraction and precipitation processes showed that magnesium and calcium can easily be extracted from steelmaking slags and natural silicate minerals using acids. Natural minerals seem to demand stronger acids for extraction than slags. Relatively pure calcium carbonate (80-90% calcite) was produced at room temperature and a CO2 pressure of 1 bar by adding sodium hydroxide to acetate solutions made from slag. Similarly, serpentinite was successfully converted into 93-100% pure hydromagnesite (a magnesium carbonate), using nitric acid or hydrochloric acid for the dissolution of serpentinite and sodium hydroxide for precipitation. The conversion of raw material to carbonate ranged from 60-90%. Although the results show that pure carbonates can be produced from industrial by-products and mining residues, the process concept suggested requires the recycling of large amounts of sodium hydroxide and acid, as well as low-grade heat for solvent evaporation. The methods suggested for recovering the spent chemicals were found to be expensive and cause more CO2 emissions than the amount of CO2 stored.

    AB - Capture and storage of carbon dioxide (CO2) is internationally considered to be one of the main options for reducing atmospheric emissions of CO2. In Finland, no suitable geological formations are known to exist for storing captured CO2. However, fixing CO2 as solid carbonates using silicate-based materials is an interesting alternative. The magnesium silicate deposits in Eastern Finland alone could be sufficient for storing 10 Mt CO2 each year during a period of 200-300 years. Finnish steelmaking slags could also be carbonated, but the amounts produced provide a much smaller potential for CO2 storage (0.5 Mt CO2 per year) than magnesium silicates provide. The aim of this thesis was to study the possibility of reducing CO2 emissions by producing calcium and magnesium carbonates from silicate materials for the long-term storage of CO2 using multi-step processes. The production of carbonates from steelmaking slags and serpentinite, a magnesium silicate ore available from a metal-mining site, was studied both experimentally and theoretically. On the basis of the results, process concepts were developed and evaluated. Finally, the stability of synthetic calcium and magnesium carbonates as a medium for CO2 storage was assessed. Experiments with aqueous extraction and precipitation processes showed that magnesium and calcium can easily be extracted from steelmaking slags and natural silicate minerals using acids. Natural minerals seem to demand stronger acids for extraction than slags. Relatively pure calcium carbonate (80-90% calcite) was produced at room temperature and a CO2 pressure of 1 bar by adding sodium hydroxide to acetate solutions made from slag. Similarly, serpentinite was successfully converted into 93-100% pure hydromagnesite (a magnesium carbonate), using nitric acid or hydrochloric acid for the dissolution of serpentinite and sodium hydroxide for precipitation. The conversion of raw material to carbonate ranged from 60-90%. Although the results show that pure carbonates can be produced from industrial by-products and mining residues, the process concept suggested requires the recycling of large amounts of sodium hydroxide and acid, as well as low-grade heat for solvent evaporation. The methods suggested for recovering the spent chemicals were found to be expensive and cause more CO2 emissions than the amount of CO2 stored.

    KW - mineral carbonation

    KW - slag

    KW - carbon dioxide

    KW - dissolution

    KW - precipitation

    KW - carbonate

    M3 - Dissertation

    SN - 978-951-22-9352-0

    T3 - TKK Dissertations

    CY - Espoo

    ER -