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Sundqvist Ökvist, LenaORCID iD iconorcid.org/0000-0003-3363-351x
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Publications (10 of 14) Show all publications
Sar, S., Sundqvist Ökvist, L., Sparrman, T., Engström, F. & Samuelsson, C. (2019). Characterization of Double Leached Waelz Oxide for Identification of Fluoirde Mineral. Metals, 9(3), Article ID 361.
Open this publication in new window or tab >>Characterization of Double Leached Waelz Oxide for Identification of Fluoirde Mineral
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2019 (English)In: Metals, ISSN 2075-4701, Vol. 9, no 3, article id 361Article in journal (Refereed) Published
Abstract [en]

Double leached Waelz oxide (DLWO), with 76% zinc, is a secondary zinc containing raw materials obtained by the treatment of electric arc furnace dust. The content of fluoride in DLWO is still too high for direct leaching, as fluoride has a detrimental effect on electrowinning for zinc production. Knowledge of the characteristics of DLWO, and especially on how a fluoride mineral might exist, can contribute to further improvement of the selective leaching for the removal of fluoride. In this study, DLWO was characterized using analytical techniques, such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), 19F liquid-state nuclear magnetic resonance (19F LS NMR), X-ray powder diffraction analysis (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and 19F solid-state nuclear magnetic resonance (19F SS NMR). This study showed that DLWO mainly consisted of zincite (ZnO), cerussite (PbCO3) and a spinel containing zinc, iron and manganese. The fluoride mineral identified was calcium fluoride (CaF2). In SEM analysis, fluorine was found in larger grains together with calcium and oxygen, which was possibly calcium carbonate.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
metal recycling, zinc secondary dust material, characterization of double leached Waelz oxide, halogens, fluoride identification
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73646 (URN)10.3390/met9030361 (DOI)000464321200002 ()2-s2.0-85064228809 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-04-16 (oliekm)

Available from: 2019-04-15 Created: 2019-04-15 Last updated: 2019-09-13Bibliographically approved
El-Tawil, A., Ahmed, H., Sundqvist Ökvist, L. & Björkman, B. (2019). Devolatilization Kinetics of Different Types of Bio-Coals Using Thermogravimetric Analysis. Metals, 9(2), Article ID 168.
Open this publication in new window or tab >>Devolatilization Kinetics of Different Types of Bio-Coals Using Thermogravimetric Analysis
2019 (English)In: Metals, E-ISSN 2075-4701, Vol. 9, no 2, article id 168Article in journal (Refereed) Published
Abstract [en]

The interest of the steel industry in utilizing bio-coal (pre-treated biomass) as CO2-neutral carbon in iron-making is increasing due to the need to reduce fossil CO2 emission. In order to select a suitable bio-coal to be contained in agglomerates with iron oxide, the current study aims at investigating the thermal devolatilization of different bio-coals. A thermogravimetric analyzer (TGA) equipped with a quadrupole mass spectrometer (QMS) was used to monitor the weight loss and off-gases during non-isothermal tests with bio-coals having different contents of volatile matter. The samples were heated in an inert atmosphere to 1200 °C at three different heating rates: 5, 10, and 15 °C/min. H2, CO, and hydrocarbons that may contribute to the reduction of iron oxide if contained in the self-reducing composite were detected by QMS. To explore the devolatilization behavior for different materials, the thermogravimetric data were evaluated by using the Kissinger– Akahira–Sonuse (KAS) iso-conversional model. The activation energy was determined as a function of the conversion degree. Bio-coals with both low and high volatile content could produce reducing gases that can contribute to the reduction of iron oxide in bio-agglomerates and hot metal quality in the sustained blast furnace process. However, bio-coals containing significant amounts of CaO and K2O enhanced the devolatilization and released the volatiles at lower temperature. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
devolatilization, torrefied biomass, bio-coal, volatile matter, iso-conversional method
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73181 (URN)10.3390/met9020168 (DOI)000460764700059 ()2-s2.0-85062329541 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-13 (johcin)

Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-04-12Bibliographically approved
Hu, X., Sundqvist Ökvist, L. & Ölund, M. (2019). Materials Properties and Liquid Flow in the Hearth of the Experimental Blast Furnace. Metals, 9(5), Article ID 572.
Open this publication in new window or tab >>Materials Properties and Liquid Flow in the Hearth of the Experimental Blast Furnace
2019 (English)In: Metals, E-ISSN 2075-4701, Vol. 9, no 5, article id 572Article in journal (Refereed) Published
Abstract [en]

The materials’ properties in the hearth of the blast furnace are very crucial for the hearthconditions. In this study, a number of coke, slag, metal, and aggregate samples were collected fromthe hearth of the LKAB’s experimental blast furnace (EBF). Subsequently, the coke, slag, and metalsamples were chemically analyzed by X-ray fluorescence (XRF) or optical emission spectrometer(OES); the aggregate samples were analyzed by scanning electron microscope combined withenergy-dispersive X-ray spectroscopy (SEM/EDS). The possible flow field of the liquid in the EBFhearth before quenching is depicted according to Cu tracers in the metal samples. Selected elementsin the coke, slag, and metal were mapped for two sampling layers in the hearth, as well as in one crosssection of the flow field. The results indicate that there exists an area beneath, and in front of, tuyere 3,where the flow resistance of the liquid was high. The high flow resistance contributed to the formationof a cold zone in the close-to-wall region and at the bottom of the EBF hearth. The temperaturedistribution in the EBF hearth has significant impacts on the chemical properties of the materials indierent positions of the EBF hearth, as well as on the radial and vertical distributions of certainelements/components.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
blast furnace, hearth conditions, materials properties
National Category
Metallurgy and Metallic Materials
Research subject
Centre - Centre for Advanced Mining & Metallurgy (CAMM); Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-74012 (URN)10.3390/met9050572 (DOI)000478818700089 ()2-s2.0-85066732596 (Scopus ID)
Projects
CAMM and RFCS Optiblafins
Note

Validerad;2019;Nivå 2;2019-06-10 (oliekm)

Available from: 2019-05-23 Created: 2019-05-23 Last updated: 2019-08-28Bibliographically approved
Andersson, A., Gullberg, A., Kullerstedt, A., Wedholm, A., Wikström, J., Ahmed, H. & Sundqvist Ökvist, L. (2019). Recycling of Blast Furnace Sludge to the Blast Furnace via Cold-Bonded Briquettes: Evaluation of Feasibility and Influence on Operation. ISIJ International, 59(10), 1786-1795
Open this publication in new window or tab >>Recycling of Blast Furnace Sludge to the Blast Furnace via Cold-Bonded Briquettes: Evaluation of Feasibility and Influence on Operation
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2019 (English)In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 59, no 10, p. 1786-1795Article in journal (Refereed) Published
Abstract [en]

Ore-based steelmaking generates various residues including dusts, sludges, scales and slags. Recycling of these residues within the process or via other applications is essential for sustainable production of steel. In blast furnace (BF) ironmaking, the gas-cleaning equipment generally recovers the particles in the off-gas as dust and sludge. Traditionally, the dry dust is recycled via the sinter or, in the case of pellet-based BF operation, via cold-bonded briquettes and injection. As the BF sludge mainly consists of iron and carbon, this residue is of interest to recycle together with the BF dust. However, depending on how the BF is operated, these two residues are more or less the major outlet of zinc from the furnace. Thus, to limit the recycled load of zinc, both materials cannot be recycled without dezincing the sludge prior to recycling. Dezincing and recycling of the low-zinc fraction of BF sludge via sinter have been reported whereas recycling via cold-bonded briquettes has not been performed. In the present study, cold-bonded briquettes containing the low-zinc fraction of dezinced BF sludge were charged as basket samples to the LKAB Experimental Blast Furnace (EBF). The excavated basket samples from the quenched EBF suggested that additions of up to 20 wt.% of upgraded BF sludge was feasible in terms of reducibility and strength. Based on these results, BF sludge were added to cold-bonded briquettes and charged in industrial-scale trials. The trials indicated that the annual generation of BF sludge, after dezincing, could be recycled to the BF.

Place, publisher, year, edition, pages
Iron and Steel Institute of Japan, 2019
Keywords
blast furnace sludge, recycling, cold-bonded briquettes, pilot-plant scale blast furnace trials, industrial-scale blast furnace trials
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-75198 (URN)10.2355/isijinternational.ISIJINT-2019-080 (DOI)000493582600008 ()2-s2.0-85075167174 (Scopus ID)
Funder
Swedish Energy Agency, JK21069
Note

Validerad;2019;Nivå 2;2019-11-22 (johcin)

Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-11-25Bibliographically approved
Mousa, E., Lundgren, M., Sundqvist Ökvist, L., From, L.-E., Robles, A., Hällsten, S., . . . El-Tawil, A. (2019). Reduced Carbon Consumption and CO2 Emission at the Blast Furnace by Use of Briquettes Containing Torrefed Sawdust. Journal of Sustainable Metallurgy, 5(3), 391-401
Open this publication in new window or tab >>Reduced Carbon Consumption and CO2 Emission at the Blast Furnace by Use of Briquettes Containing Torrefed Sawdust
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2019 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 5, no 3, p. 391-401Article in journal (Refereed) Published
Abstract [en]

Lowering the carbon consumption and fossil CO2emissions is a priority in blast furnace (BF) ironmaking. Renewablebiomass is one option that can play an important role in future low-carbon ironmaking particularly in the countries rich inbiomass resources. In this study, full-scale trials to investigate the impact of briquettes containing torrefied sawdust on theBF efficiency and process stability have been conducted. Briquettes containing 1.8% of torrefied pelletized sawdust (TPS),86.2% of steel mill residues, and 12% cement with sufficient mechanical strength have been produced on industrial scale. Thebio-briquettes were charged at two different rates: 37% ( ~ 39 kg/tHM) and 55% ( ~ 64 kg/tHM) bio-briquettes to the SSABBF No. 4 in Oxelösund. The gas utilization was higher during bio-briquette-charging periods without change in pressuredrop up to 55% bio-briquettes, indicating sustained shaft permeability. BF dust generation or properties did not change significantly.Measurements of the top gas composition using mass spectrometry did not indicate release of hydrocarbon fromTPS in connection to the charging of bio-briquettes. Evaluation of process data has been carried out using a heat and massbalance model. The evaluation of operational data in the model indicated lowering of thermal reserve zone temperature by45 °C and reduction in carbon consumption by ~ 10 kg/tHM when charging 55% bio-briquettes compared to the referencecase. The total CO2emission was reduced by about 33–40 kg/tHM when using 55% bio-briquettes.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Ironmaking, Blast furnace, Bio-briquettes, CO2 emission, Torrefied sawdust
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-74276 (URN)10.1007/s40831-019-00229-7 (DOI)000483723600011 ()
Projects
Bioagglomerat (Project Number: 39150-1) and CAMM
Note

Validerad;2019;Nivå 2;2019-09-27 (johcin)

Available from: 2019-06-09 Created: 2019-06-09 Last updated: 2019-09-27Bibliographically approved
Andersson, A., Gullberg, A., Kullerstedt, A., Ahmed, H., Sundqvist Ökvist, L. & Samuelsson, C. (2019). Upgrading of Blast Furnace Sludge and Recycling of the Low-Zinc Fraction via Cold-bonded Briquettes. Journal of Sustainable Metallurgy (3), 350-361
Open this publication in new window or tab >>Upgrading of Blast Furnace Sludge and Recycling of the Low-Zinc Fraction via Cold-bonded Briquettes
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2019 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823, no 3, p. 350-361Article in journal (Refereed) Published
Abstract [en]

Depending on the operation of the blast furnace (BF), the main outlet of zinc from the furnace is more or less via the BF dust and sludge. As the dust is recycled to the BF, the sludge has to be de-zinced prior to recycling to prevent the accumulation of zinc in the BF. De-zincing and recycling of the low-zinc fraction via sinter have been reported. However, no research con-cerning recycling of upgraded BF sludge via cold-bonded briquettes has been performed. In the present study, a fine-grained BF sludge with low zinc content, generated by a BF operating on a ferrous burden of 100% pellets, was upgraded using the tornado process. The process simultaneously dried and separated the BF sludge into a high-zinc and a low-zinc fraction. The feasibility of recycling the low-zinc fraction to the BF using cold-bonded briquettes was studied on a laboratory-scale BF shaft simulator. On comparison with a reference briquette, the experiments indicated that 10 wt% of the upgraded BF sludge can be added to the briquette without negatively affecting the reducibility. Higher additions were found to render the briquette less reduced compared to the reference under test conditions corresponding to the central part of the BF. The strength of the briquettes was not compromised with the addition of the upgraded BF sludge, and a decision to study the briquettes in the LKAB experimental blast furnace was made in order to evaluate the behavior under actual BF conditions.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Blast furnace sludge, Recycling, Upgrading, De-zincing, Cold-bonded briquettes, Laboratory-scale blast furnace
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73899 (URN)10.1007/s40831-019-00225-x (DOI)000483723600008 ()2-s2.0-85065727551 (Scopus ID)
Funder
Swedish Energy Agency, JK21069
Note

Validerad;2019;Nivå 2;2019-09-27 (johcin)

Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-09-27Bibliographically approved
Andersson, A., Gullberg, A., Kullerstedt, A., Sandberg, E., Andersson, M., Ahmed, H., . . . Björkman, B. (2018). A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant. Metals, 8(10), Article ID 760.
Open this publication in new window or tab >>A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant
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2018 (English)In: Metals, ISSN 2075-4701, Vol. 8, no 10, article id 760Article in journal (Refereed) Published
Abstract [en]

Ore-based ironmaking generates a variety of residues, including slags and fines such as dust and sludges. Recycling of these residues within the integrated steel plant or in other applications is essential from a raw-material efficiency perspective. The main recycling route of off-gas dust is to the blast furnace (BF) via sinter, cold-bonded briquettes and tuyere injection. However, solely relying on the BF for recycling implicates that certain residues cannot be recycled in order to avoid build-up of unwanted elements, such as zinc. By introducing a holistic view on recycling where recycling via other process routes, such as the desulfurization (deS) station and the basic oxygen furnace (BOF), landfilling can be avoided. In the present study, process integration analyses were utilized to determine the most efficient recycling routes for off-gas dust that are currently not recycled within the integrated steel plants of Sweden. The feasibility of recycling was studied in experiments conducted in laboratory, pilot, and full-scale trials in the BF, deS station, and BOF. The process integration analyses suggested that recycling to the BF should be maximized before considering the deS station and BOF. The experiments indicated that the amount of residue that are not recycled could be minimized.

Place, publisher, year, edition, pages
Basel: MDPI, 2018
Keywords
Recycling, Cold-bonded briquettes, Blast furnace, Desulfurization, Basic oxygen furnace, Dust, Sludge, Fines
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-71130 (URN)10.3390/met8100760 (DOI)000448658700024 ()2-s2.0-85054764975 (Scopus ID)
Funder
Swedish Energy Agency
Note

Validerad;2018;Nivå 2;2018-10-19 (marisr)

Available from: 2018-10-08 Created: 2018-10-08 Last updated: 2019-08-22Bibliographically approved
Sundqvist Ökvist, L., From, L.-E., Ölund, M., Orre, J., Sundelin, B. & Ahmed, H. (2018). Lowering of CO2 Emissions at the BF by Using Biocoa: Theoretical and Practical Possibilities and Limitations. In: Iron and Steel Technology Conference Proceedings: . Paper presented at AIS Tech Conference Proceedings, Philadelphia, USA, 7-10 May. Association for Iron and Steel Technology, AISTECH
Open this publication in new window or tab >>Lowering of CO2 Emissions at the BF by Using Biocoa: Theoretical and Practical Possibilities and Limitations
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2018 (English)In: Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2018Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Association for Iron and Steel Technology, AISTECH, 2018
Keywords
blast furnace, CO2 emission, injection, raceway monitoring, CFD modelling, heat and mass balance calculations, torrefied sawdust, bio-coal, raceway monitoring, PC
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73228 (URN)2-s2.0-85062567142 (Scopus ID)
Conference
AIS Tech Conference Proceedings, Philadelphia, USA, 7-10 May
Available from: 2019-03-18 Created: 2019-03-18 Last updated: 2019-03-18
Andersson, A., Andersson, M., Mousa, E., Kullerstedt, A., Ahmed, H., Björkman, B. & Sundqvist Ökvist, L. (2018). The Potential of Recycling the High-Zinc Fraction of Upgraded BF Sludge to the Desulfurization Plant and Basic Oxygen Furnace. Paper presented at 8th International Congress on Science and Technology in Ironmaking — 8th ICSTI 2018, September 25 to 27 2018, Vienna.. Metals, 8(12), Article ID 1057.
Open this publication in new window or tab >>The Potential of Recycling the High-Zinc Fraction of Upgraded BF Sludge to the Desulfurization Plant and Basic Oxygen Furnace
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2018 (English)In: Metals, ISSN 2075-4701, Vol. 8, no 12, article id 1057Article in journal (Refereed) Published
Abstract [en]

In ore-based steelmaking, blast furnace (BF) dust is generally recycled to the BF via the sinter or cold-bonded briquettes and injection. In order to recycle the BF sludge to the BF, the sludge has to be upgraded, removing zinc. The literature reports cases of recycling the low-zinc fraction of upgraded BF sludge to the BF. However, research towards recycling of the high-zinc fraction of BF sludge within the ore-based steel plant is limited. In the present paper, the high-zinc fraction of tornado-treated BF sludge was incorporated in self-reducing cold-bonded briquettes and pellets. Each type of agglomerate was individually subjected to technical-scale smelting reduction experiments aiming to study the feasibility of recycling in-plant residues to the hot metal (HM) desulfurization (deS) plant. The endothermic reactions within the briquettes decreased the heating and reduction rate leaving the briquettes unreduced and unmelted. The pellets were completely reduced within eight minutes of contact with HM but still showed melt-in problems. Cold-bonded briquettes, without BF sludge, were charged in industrial-scale trials to study the recycling potential to the HM deS plant and basic oxygen furnace (BOF). The trials illustrated a potential for the complete recycling of the high-zinc fraction of BF sludge. However, further studies were identified to be required to verify these results.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
recycling, blast furnace sludge, smelting reduction, desulfurization, basic oxygen furnace, cold-bonded briquettes, cold-bonded pellets, low-sulfur binders
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-72426 (URN)10.3390/met8121057 (DOI)000455072100081 ()2-s2.0-85058575555 (Scopus ID)
Conference
8th International Congress on Science and Technology in Ironmaking — 8th ICSTI 2018, September 25 to 27 2018, Vienna.
Note

Konferensartikel i tidskrift

Available from: 2019-01-02 Created: 2019-01-02 Last updated: 2019-08-22Bibliographically approved
Ahmed, H., Andersson, A., El-Tawil, A., Lotfian, S., Mousa, E., Sundqvist Ökvist, L. & Björkman, B. (2017). Alternative Reducing Agents for Sustainable Blast Furnace Ironmaking. In: ESTAD 2017: . Paper presented at 3rd European Steel Technology and Application Days, Vienna, Austria, 26-29 June 2017.
Open this publication in new window or tab >>Alternative Reducing Agents for Sustainable Blast Furnace Ironmaking
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2017 (English)In: ESTAD 2017, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Lowering of CO2 emission from the integrated steel industry as well as minimizing theneed for landfill are important challenges in the focus for the integrated steel industry. With thisaim collaborative research projects have been conducted and are on-going on the possible useof renewable reducing agents or such with high content of H2 as well as for enabling recyclingof 1in-plant fines so far not possible to use. Due to contents of undesired impurities the blastfurnace (BF) sludge has to be pre-treated in an appropriate way before carbon and iron oxidecan be valorized. In order to understand the impact of alternative reducing agents as injectedthrough the tuyeres or part of top charged agglomerates containing iron oxide, samples oftorrefied biomass, plastic and in-plant fines have been analyzed by means of thermogravimetricanalyzer coupled with a mass spectrometer (TGA-MS).The results proved that effective utilization of carbon bearing BF dust and sludge as analternate reducing agent could be realized and can be implemented into BF after adequateupgrading. Plastic materials and biomass based reductants decomposition is associated with therelease of volatiles. The main contents of these volatiles are CO, H2 and hydrocarbon which areall known for their reduction potential. Moreover, injection of such materials is expected toimprove process efficiency and sustain the gas permeability along the BF cohesive zone. Onthe other hand, top charging of these materials would improve the energy and materialefficiency in the BF due to their higher reactivity compared to conventional carbon.

Keywords
biomass, iron and steel making wastes, waste plastic materials, reducing agents, reduction metallurgy.
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-70064 (URN)
Conference
3rd European Steel Technology and Application Days, Vienna, Austria, 26-29 June 2017
Available from: 2018-07-04 Created: 2018-07-04 Last updated: 2018-08-14Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3363-351x

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