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  • 1.
    Ahmed, Hesham
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Andersson, Anton
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    El-Tawil, Asmaa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lotfian, Samira
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mousa, Elsayed
    Swerea MEFOS, Luleå.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Alternative Reducing Agents for Sustainable Blast Furnace Ironmaking2017In: ESTAD 2017, 2017Conference 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.

  • 2.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Andersson, Mats
    SSAB Europe, Luleå.
    Mousa, Elsayed
    Swerim AB, Luleå, Sweden; Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Kullerstedt, Adeline
    Swerim AB, Luleå, Sweden.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerim AB, Luleå, Sweden.
    The Potential of Recycling the High-Zinc Fraction of Upgraded BF Sludge to the Desulfurization Plant and Basic Oxygen Furnace2018In: Metals, ISSN 2075-4701, Vol. 8, no 12, article id 1057Article in journal (Refereed)
    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.

  • 3.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Gullberg, Amanda
    Swerea MEFOS, Luleå, Sweden.
    Kullerstedt, Adeline
    Swerea MEFOS, Luleå, Sweden.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerea MEFOS, Luleå, Sweden.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Upgrading of Blast Furnace Sludge and Recycling of the Low-Zinc Fraction via Cold-bonded Briquettes2019In: Journal of Sustainable Metallurgy, ISSN 2199-3823, no 3, p. 350-361Article in journal (Refereed)
    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.

  • 4.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Gullberg, Amanda
    Swerea MEFOS, Luleå, Sweden.
    Kullerstedt, Adeline
    Swerea MEFOS, Luleå, Sweden.
    Sandberg, Erik
    Swerea MEFOS, Luleå, Sweden.
    Andersson, Mats
    SSAB Europe, Luleå, Sweden.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerea MEFOS, Luleå, Sweden.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant2018In: Metals, ISSN 2075-4701, Vol. 8, no 10, article id 760Article in journal (Refereed)
    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.

  • 5.
    Andersson, Anton
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Gullberg, Amanda
    Swerim AB.
    Kullerstedt, Adeline
    Swerim AB.
    Wedholm, Anita
    SSAB Merox .
    Wikström, Jenny
    LKAB.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Recycling of Blast Furnace Sludge to the Blast Furnace via Cold-Bonded Briquettes: Evaluation of Feasibility and Influence on Operation2019In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 59, no 10, p. 1786-1795Article in journal (Refereed)
    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.

  • 6.
    El-Tawil, Asmaa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Central Metallurgical Research and Development Institute, Helwan,Cairo, Egypt.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerim AB, 97125 Luleå, Sweden.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Devolatilization Kinetics of Different Types of Bio-Coals Using Thermogravimetric Analysis2019In: Metals, E-ISSN 2075-4701, Vol. 9, no 2, article id 168Article in journal (Refereed)
    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. 

  • 7.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, SWERIM AB, Luleå, Sweden.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerim AB.
    Ölund, Martin
    Process Metallurgy Department, SWERIM AB, Luleå, Sweden.
    Materials Properties and Liquid Flow in the Hearth of the Experimental Blast Furnace2019In: Metals, E-ISSN 2075-4701, Vol. 9, no 5, article id 572Article in journal (Refereed)
    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.

  • 8.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, Swerea MEFOS.
    Sundqvist-Öqvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Eriksson, Johan
    Yang, Qixing
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Combined Chromium Reduction and Alloying of Steel2016In: Scanmet V, 2016Conference paper (Refereed)
  • 9.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, Swerea MEFOS AB.
    Sundqvist-Öqvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Process Metallurgy Department, Swerea MEFOS AB.
    Eriksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Yang, Qixing
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Direct alloying steel with chromium by briquettes made from chromite ore, mill scale, and petroleum coke2017In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, no 5, article id 1600247Article in journal (Refereed)
    Abstract [en]

    In this work, the effectiveness of using briquettes made from chromite ore, mill scale, and petroleum coke for direct chromium alloying is tested by induction furnace trials carried out in three different scales. The experimental results show that steel scrap can be alloyed with chromium by the chromite ore in the briquettes and the Cr yield from the chromite ore increases with the increase in mill scale addition to the briquettes: the more mill scale is added to the briquettes, the lower the mass ratio of Cr to (Cr+Fe) would be, leading to a higher Cr yield from the chromite ore. Specifically, the maximum Cr yield from the chromite ore is 99.9% when the mass ratio of Cr to (Cr+Fe) in the briquettes is 0.05, and being 93.0% when the ratio is 0.10. However, when the ratio of Cr to (Cr+Fe) in the briquettes reaches 0.20, the maximum Cr yield is only 67.1%. The reduction of chromite ore under the present experimental conditions is promoted by a solid-state reduction mechanism

  • 10.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, Swerea MEFOS AB, Sweden.
    Sundqvist-Öqvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Process Metallurgy Department, Swerea MEFOS AB, Sweden.
    Åström, Elin
    LKAB R&D.
    Forsberg, Fredrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics. LKAB R&D.
    Checchia, Paolo
    INFN Sezione di Padova, Padova, Italy.
    Bonomi, Germano
    Universita degli Studi di Brescia, Brescia, Italy.
    Calliari, I.
    Universita degli Studi di Padova, Padua, Italy.
    Calvini, Piero
    Universita degli Studi di Genova, Genoa, Italy.
    Donzella, Antonietta
    Universita degli Studi di Brescia, Department of Mechanical and Industrial Engineering, Brescia, Italy.
    Faraci, Eros
    Centro Sviluppo Materiali S.p.A., Roma, Italy.
    Gonella, Franco
    Istituto Nazionale Di Fisica Nucleare, Frascati, Frascati, Italy.
    Klinger, Joel
    Istituto Nazionale Di Fisica Nucleare, Frascati, Frascati, Italy.
    Pagano, Davide
    Universita degli Studi di Brescia, Brescia, Italy.
    Rigoni, Andrea
    Consorzio Rfx, Padua, Italy.
    Zanuttigh, Pietro
    Universita degli Studi di Padova, Padua, Italy.
    Ronchese, Paolo
    Universita degli Studi di Padova, Padua, Italy.
    Urbani, Michele
    Universita degli Studi di Padova, Department of Physics and Astronomy, Padua, Italy.
    Vanini, Sara
    Universita degli Studi di Padova, Department of Physics and Astronomy, Padua, Italy.
    Zenoni, Aldo
    Universita degli Studi di Brescia, Department of Mechanical and Industrial Engineering, Brescia, Italy.
    Zumerle, Gianni
    Universita degli Studi di Padova, Department of Physics and Astronomy, Padua, Italy.
    Exploring the capability of muon scattering tomography for imaging the components in the blast furnace2018In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 58, no 1, p. 35-42Article in journal (Refereed)
    Abstract [en]

    Knowing the distribution of the materials in the blast furnace (BF) is believed to be of great interest for BF operation and process optimization. In this paper calibration samples (ferrous pellets and coke) and samples from LKAB’s experimental blast furnace (probe samples, excavation samples and core-drilling samples) were measured by the muon scattering tomography detector to explore the capability of using the muon scattering tomography to image the components in the blast furnace. The experimental results show that it is possible to use this technique to discriminate the ferrous pellets from the coke and it is also shown that the measured linear scattering densities (LSD) linearly correlate with the bulk densities of the measured materials. By applying the Stovall’s model a correlation among the LSD values, the bulk densities and the components of the materials in the probe samples and excavation samples was established. The theoretical analysis indicates that it is potential to use the present muon scattering tomography technique to image the components in various zones of the blast furnace.

  • 11.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, Swerea MEFOS.
    Teng, Lidong
    Division of Materials Process Science, KTH-Royal Institute of Technology.
    Wang, Haijuan
    State Key Laboratory of Advanced Metallurgy, University of Science and Technology .
    Sundqvist-Öqvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Yang, Qixing
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Seetharaman, Seshadri
    Division of Materials Process Science, KTH-Royal Institute of Technology .
    Carbothermic Reduction of Synthetic Chromite with/without the Addition of Iron Powder2016In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 56, no 12, p. 2147-2155Article in journal (Refereed)
    Abstract [en]

    Carbothermic reduction of chromite is an important industrial process for extracting chromium from the chromite. To have a better understanding of the effect of iron on the carbothermic reduction of chromite, the reduction of synthetic chromite (FeCr2O4) by graphite with/without the addition of iron powder was investigated in this paper by Thermogravimetric Analysis (TGA) in argon atmosphere. The fractional reduced samples were examined by SEM/EDS and XRD analysis, and the reduction process was thermodynamically and kinetically evaluated. The experimental results show that the iron powder addition enhances the reduction of FeCr2O4 and this effect increases when increased amounts of iron powder are added. This phenomenon is attributed to the in situ dissolution of chromium into the iron and mixed carbide (Cr,Fe)7C3, which can decrease the activity of the nascent chromium formed by the reduction of the FeCr2O4. The experimental results indicate that the reduction of FeCr2O4 with up to 80 wt.% iron powder addition is likely to be a single-step process and the kinetic analysis suggests that the reduction reaction is likely to be either (a) chemical reaction at the surface of FeCr2O4 or (b) diffusional dissolution of the product (FeCr2) into the iron/alloy particles or the mixed control of (a) and (b). 

  • 12.
    Mousa, Elsayed
    et al.
    Swerim AB, Luleå. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Lundgren, Maria
    Swerim AB, Luleå.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerim AB, Luleå.
    From, Lars-Erik
    Swerim AB, Luleå.
    Robles, Astrid
    Swerim AB, Luleå.
    Hällsten, Siv
    SSAB Merox AB, Oxelösund.
    Sundelin, Bo
    SSAB EMEA AB, Oxelösund.
    Friberg, Hanna
    SSAB EMEA AB, Oxelösund.
    El-Tawil, Asmaa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Reduced Carbon Consumption and CO2 Emission at the Blast Furnace by Use of Briquettes Containing Torrefed Sawdust2019In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 5, no 3, p. 391-401Article in journal (Refereed)
    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.

  • 13.
    Sar, Suchandra
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Sundqvist Ökvist, Lena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Sparrman, Tobias
    Umeå University.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Characterization of Double Leached Waelz Oxide for Identification of Fluoirde Mineral2019In: Metals, ISSN 2075-4701, Vol. 9, no 3, article id 361Article in journal (Refereed)
    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.

  • 14.
    Sundqvist Ökvist, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Swerea MEFOS AB, Luleå, Sweden.
    From, Lars-Erik
    Swerea MEFOS AB, Luleå, Sweden.
    Ölund, Martin
    Swerea MEFOS AB, Luleå, Sweden.
    Orre, Joel
    Swerea MEFOS AB, Luleå, Sweden.
    Sundelin, Bo
    SSAB Special Streels, Oxelösund, Sweden.
    Ahmed, Hesham
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Lowering of CO2 Emissions at the BF by Using Biocoa: Theoretical and Practical Possibilities and Limitations2018In: Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2018Conference paper (Refereed)
  • 15.
    Sundqvist Ökvist, Lena
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Process Metallurgy Department, Swerea Mefos AB, Luleå.
    Lagerwall, Per
    Ironmaking Department, SSAB Europe, Luleå.
    Sundelin, Bo
    Strategic Production Development, SSAB Special Steels, Oxelösund.
    Orre, Joel
    Process Metallurgy Department, Swerea Mefos AB, Luleå.
    Brämming, Mats
    Process Integration Department, Swerea Mefos AB, Luleå.
    Lundgren, Maria
    Process Metallurgy Department, Swerea Mefos AB, Luleå.
    Low CO2 ironmaking in the blast furnace: Roheisenerzeugung im Hochofen mit niedrigen CO2 Emissionen2017In: Stahl und Eisen (1881), ISSN 0340-4803, Vol. 137, no 9, p. 29-37Article in journal (Refereed)
    Abstract [en]

    The steel industry contributes to the global emissions of fossil CO2 by ~ 7 %, mainly related to coal and coke used in the BF. At the same time the BF is, and will be in a foreseeable future, the most energy efficient method for ore based hot metal production. Several R&D teams have investigated concepts to minimise CO2 emission as e.g. the ULCOS top gas recycling BF, high injection of H2, use of bio-mass products and HBI. In this paper these different options, and in some cases combination of these are analysed relative the BF conditions and their possible impacts on fossil CO2 emission are compared.

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