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  • 1. Adolfsson, Daniel
    et al.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Cementitious phases in ladle slag2011In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 82, no 4, p. 398-403Article in journal (Refereed)
    Abstract [en]

    Ladle slag is an internal by-product generated within the steelmaking industry during the refining of steel. The realisation of beneficial inherent properties of ladle slag as a binder supplement or substitute material is believed to be advantageous with respect to both economy and environment for steelmakers. For this reason, the current study has focused on highlighting the properties of ladle slag that are pertinent to the formation of calcium aluminate hydrates. Three fractions of ladle slag, two of which were based on different slag formers, have been characterised using XRF, XRD and calorimetric analysis. Commonly known hydraulic minerals such as mayenite, tricalcium aluminate and dicalcium silicate were detected during analysis. An important aspect in the utilisation of ladle slag is the slag handling methodology. Therefore, this study also highlights and discusses the need to reconsider slag handling procedures concerning unnecessary exposure to weathering and the possible need for further processing of the slag in order to better employ the inherent hydraulic properties of this material.

  • 2. Adolfsson, Daniel
    et al.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Blagojevic, J.
    SSAB Tunnplåt AB.
    Su, F.
    SSAB Tunnplåt AB.
    Assessment of ladle slag as binder alternative for cold bonded briquettes2008In: REWAS 2008: Global Symposium on Recycling, Waste Treatment and Clean Technology ; held October 12 - 15, 2008 in Cancun, Mexico / [ed] B. Mishra; C. Ludwig; S. Das, Minerals, Metals & Materials Society, 2008, p. 117-123Conference paper (Refereed)
    Abstract [en]

    Cold bonded briquetting of steel plant by-products has proven to be a viable recycling alternative concerning technology, economy and environment in both the traditional blast furnace route and the direct reduction process. A critical parameter in cold bonded briquettes is the type and amount of binder used during production. The binder material must meet certain quality requirements concerning low and high temperature strength, chemistry and economy. Currently, SSAB Tunnplåt uses ordinary Portland cement (OPC) as binder in their cold bonded briquettes. In order to improve binder quality and possibly decrease OPC dependency, a binder feasibility study has been conducted concerning an internal by-product, ladle slag, as a supplement and/or partial substitute for OPC. Several characterization techniques have been used to study the behaviour of ladle slag, these include: XRD, XRF, SEM, glass content analysis, calorimetric analysis, particle size distribution and thermochemical stability considerations concerning the CaO-Al2O3-SiO 2 system.

  • 3. Adolfsson, Daniel
    et al.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Blagojevic, J.
    Su, F.
    Assessment of ladle slag as bnder alternative for cold bonded briquettes2008In: REWAS 2008: Global Symposium on Recycling, Waste Treatment / [ed] B. Mishra; C. Ludwig; S. Das, Minerals, Metals & Materials Society, 2008, p. 117-124Conference paper (Refereed)
  • 4.
    Adolfsson, Daniel
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Influence of mineralogy on the hydraulic properties of ladle slag2011In: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 41, no 8, p. 865-871Article in journal (Refereed)
    Abstract [en]

    The present study is aimed at investigating the hydraulic characteristics of ladle furnace slag (LFS), under the pretence of using LFS as a cement substitute in certain applications. Furthermore, LFS has been considered as a possible activator in a blend containing 50% LFS, and 50% ground granulated blast furnace slag (GGBFS). Phases detected in LFS were quantified using Rietveld analysis. Calorimetric studies were performed at 20, 25 and 30 °C in order to calculate the apparent activation energy of hydration and thereby to suggest a kinetic model for the tested compositions within this temperature interval. In addition, compressive strength tests were performed on mortar prisms made with LFS, and LFS/GGBFS which had hydrated for 2, 7 and 28 days. Both compositions reached acceptable early strengths, (e.g. LFS, 33.1 MPa, and LFS/GGBFS, 17.9 MPa, after 2 days), but after 28 days hydration the blend was superior to neat LFS. Related apparent activation energies were determined using an Avrami–Erofeev model and gave Ea = 58 kJ/mol for neat LFS and Ea = 63 kJ/mol for the blend. The results imply that LFS or a LFS/GGBFS blend can be favourably used as supplement in binder applications such as binder in by-product metallurgical briquettes, which are used as recycle to the blast furnace or basic oxygen furnace depending on the specific briquette composition.

  • 5.
    Engström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lidström-Larsson, Margareta
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Sandström, Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Leaching Behavior of Aged Steel Slags2014In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 85, no 4, p. 607-615Article in journal (Refereed)
    Abstract [en]

    Large amounts of slag are generated by the Swedish Steel Industry each year. The Electric Arc Furnace process generates about 200 000 ton of slag per annum, from which approximately 40% is deposited. An alternative to deposit is to use slag as road construction material. However, leaching of metals from the slag can be a reason to limit slag use in road construction. The aim of this work was to investigate how stable these materials are when aged, in an environment open to seasonable weather conditions, with respect to leaching and mineralogy. Three different EAF-slags from domestic steel plants were used in this study. The materials were characterized after 0, 6, 12, 18, and 24 months to evaluate the ageing process. The analytical techniques that were used to evaluate the effect of ageing are scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and a standard test for leaching. The changes in ageing behavior differ between the three materials. The conductivity and the pH decreases with time for all samples. The leaching of calcium, chromium as well as aluminum decreases with time while the leaching of magnesium increases. CaCO3 was formed on slag surfaces as CaO reacts with moisture and CO2 from the air.

  • 6.
    Kumpiene, Jurate
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Nordmark, Desiree
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Minskad mängd organiskt avfall på deponi: Effekt på redox-förhållanden, nedbrytning av organiskt material och utlakning av redox-känsliga ämnen2008Report (Other academic)
    Abstract [sv]

    I den nya EU-lagstiftningen angående deponering av avfall (2003/33/EC) finns krav på att den totala organiska halten kol (TOC) i avfall inte bör överstiga 3% för inert avfall, 5% för icke farligt avfall, 6% för farligt avfall och 18% för restprodukter från avfallsförbränning, vilket innebär en sänkning av tidigare gränsvärden. Förändringen kan få konsekvenser för bland annat mobiliteten hos redox-känsliga ämnen. Vid analys av TOC enligt europeisk och svensk standard (EN 13 137) går det inte att särskilja mellan organiskt kol och elementärt kol vilket är ett problem eftersom elementärt kol är inert i deponeringssammanhang. Genom biologiska, kemiska och termogravimetriska analyser har det här projektet försökt ge svar på hur stor andel av TOC som motsvaras av organiskt, lätt nedbrytbart kol och hur stor effekt halten organiskt material har på utlakningen av redox-känsliga ämnen från avfall. Tre olika avfall har ingått i undersökningen och som representerar aktuella avfallsströmmar till svenska upplag: en CCAförorenad jord, en bottenaska från biobränsleförbränning och ett restavfall. Nedbrytningen av organiskt material i avfallen och dess inverkan på utlakningen av redoxkänsliga ämnen har studerats i laboratorieförsök med metoder som BMP-försök (metanbildningspotential vid nedbrytning av organiskt material) och olika laktest i oxiderad och reducerad miljö, med och utan tillsats av organiskt material. Kolspeciering har gjorts dels med standardiserade analysmetoder för TOC men också med termogravimetrisk (TG) analys kopplad till differentiell termisk analys (DTA) och quadrupole masspektrometri (QMS). Resultaten från kolspecieringen med TG-analys visar på att den dominerade andelen kol i samtliga avfall var elementärt kol (ca 60%) medan standardiserad TOC-analys visar på att allt kol i askan och jorden var organiskt. Kolinnehållet i restfraktionen varierade stort och gav inga signifikanta skillnader mellan totalt och organiskt kol. Bestämningen av TOC, med standardiserad metod, i jorden och askan gav signifikant högre värden än analys med TG. Restfaktionen uppvisade ingen signifikant skillnad mellan de båda metoderna. Restfraktionen uppvisade den högsta gasbildningspotentialen medan nedbrytningen av organiskt material i askor kan vara svår att bedöma med biologiska metoder på grund av karbonatiseringsreaktioner i materialet. Utlakningen av redox-känsliga ämnen påverkades av mängden reaktivt organiskt material. En hög halt organiskt material sänkte redoxpotentialen i avfallen och krom och koppa visade på en minskad utlakning i reducerade miljö i samtliga avfall, zink även i jorden och restfaktionen. Utlakningen av arsenik och bly ökade i reducerande miljö från samtliga avfall. Från askan ökade också utlakningen av zink. Generellt ökar utlakningen av ämnen som till största delen är bundna till reducerbart material (t.ex. Fe-Mn-oxider) vid en högre halt organiskt material, medan det omvända gäller för ämnen som till största delen är bundna till oxiderbart material (organiskt material och sulfider). Andra faktorer som inverkar på mobiliteten hos kritiska ämnen är faktorer som pH och närvaron av ligander. Även materialens fysiska egenskaper som porositet och permeabilitet måste vägas in vid en bedömning av ändrad avfallssammansättnings effekt på utlakningen från deponier.

  • 7.
    Kumpiene, Jurate
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Robinson, Ryan
    Brännvall, Evelina
    Nordmark, Desiree
    Bjurstöm, Henrik
    ÅF-Engineering AB.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lagerkvist, Anders
    Ecke, Holger
    Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses2011In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 31, no 1, p. 18-25Article in journal (Refereed)
    Abstract [en]

    Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment.

  • 8.
    Nordmark, Désirée
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Kumpiene, Jurate
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Landfilled organic carbon: is it all organic?2008Conference paper (Other academic)
  • 9.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    High temperature properties of by-product cold bonded pellets containing blast furnace flue dust2005In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 432, no 1, p. 112-123Article in journal (Refereed)
    Abstract [en]

    In this investigation, the fundamental reactions occurring during the heat treatment of cold bonded pellets (CBP) comprised of iron and steelmaking by-products have been studied. Blast furnace (BF) flue dust, which contains fractions of coal and coke particles, has been included in the CBP blend as a source of solid reductant. Thermal analysis was performed on CBP samples in inert atmosphere at a heating rate of 10 °C/min in order to observe their high temperature properties, specifically, the mechanisms of self-reduction within CBPs. Both endothermic and exothermic reactions were observed during heating. The gases generated during thermal analysis were analyzed using a quadropole mass spectrometer (QMS). Furthermore, CBP samples heated to several different temperatures and quenched in argon were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results from this investigation demonstrate that the decomposition of hydrates and carbonates in CBP samples contribute, as gaseous intermediates, to an earlier reduction of contained iron oxides. The gaseous intermediates are responsible for an initial gasification of carbon contained in blast furnace flue dust leading to low temperature iron oxide reduction. The step-wise reduction of iron oxides in CBPs at the given conditions begins at ≈500 °C and is nearly completed at 1200 °C. This work can help to provide a fundamental understanding of the reduction characteristics of iron and steelmaking by-product agglomerates.

  • 10.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Recycling of metallurgical by-products within integrated iron and steelmaking: experimental studies of cold bonded by-product pellets2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years as costs for depositing dust and sludge generated in the iron and steel making industry have increased, due to lack of space and increasing environmental restrictions, the need to recycle these solid by- products to avoid depositing costs and to recover valuable metal fractions, is soon becoming a necessary reality. Cold bonded agglomeration is considered to be a well-suited alternative for recycling of steel industry by-product dust and sludge. The major objective of this work is to develop cold bonded pelletizing technology to increase the recycling of sludge and dust. Laboratory pelletizing tests were conducted based on a statistical procedure in order to later evaluate variables that effect cold strength, capacity and reduction of product pellets. The influence of BF flue dust, oily mill scale sludge, BOF fine and coarse sludge on the strength and capacity of cold bond pellets, using cement as binder, was studied experimentally. A related statistical procedure was used to conduct reduction experiments in inert gas over a temperature range of 20-1200 C. The results from cold strength and reduction tests have been evaluated using multivariate statistical analysis to model the experimental variables with given responses in order to help identify those variables that have most significance. Pellet blends with large fractions of particles in the size range of 10-40 microns promote good self-reduction while maintaining good cold strength. The fundamental reactions occurring during the heat treatment of cold bonded pellets have been studied. Blast furnace flue dust, which contains fractions of coal and coke particles, has been included in the cold bonded pellet blend as a source of solid reductant. Thermal analysis was performed on samples in inert atmosphere at a heating rate of 10 C/min in order to observe their high temperature properties, specifically, the mechanisms of self-reduction. The gases generated during thermal analysis were analyzed using a quadropole mass spectrometer. Furthermore, pellet samples were analyzed using X-ray diffraction, optical microscopy and scanning electron microscopy. Results demonstrate that the decomposition of hydrates and carbonates in cold bonded pellet samples contribute, as gaseous intermediates, to an earlier reduction of contained iron oxides. The gaseous intermediates are responsible for an initial gasification of carbon contained in blast furnace flue dust leading to low temperature iron oxide reduction. The step-wise reduction of iron oxides in the pellets at the given conditions begins at ~500 C and is nearly completed at 1200 C. The metallurgical characteristics of cold bonded pellets have been tested in additional laboratory tests i.e. isothermal reduction tests, blast furnace simulation and softening and melting tests. The test results indicate that cold bonded pellets can disintegrate during reduction at high temperature, are self-reducing to a high extent and, as a supplement to the normal ferrous burden, they show quite good softening and melting properties. Large scale trials with cold bonded pellets have been conducted in a commercial basic oxygen converter and a pilot scale blast furnace. Results from the basic oxygen furnace test show that charging of cold bonded pellets is feasible at levels up to 2.2% of the total charge weight. At these levels, cold bonded pellet addition resulted in no adverse disturbances to steel and slag chemistry and to the process in general. Results from the pilot scale blast furnace test show that the blast furnace operation was very stable during testing with 150 kg cold bonded pellets/tHM but the burden descent and gas distribution were disturbed during the periods with greater cold bonded pellet burden content. The rate of reducing agents was significantly decreased and slag amount was increased when cold bonded pellets were charged.

  • 11.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Studies in low temperature self-reduction of by-products from integrated iron and steelmaking2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Within the last decade, the landfill tax in Sweden has increased over 70% with comparable rates in the UK and elsewhere in EU. This development, among others, highlights the incentive for increased recycling efforts of fine particulate solid by-products in the iron and steel making industry in order to avoid depositing costs and to recover valuable metal fractions. As pre-treatment is necessary for recycling fine particulate material, cold bonded agglomeration is considered to be a well-suited alternative for recycling of steel industry by-product dust and sludge. The major objective of this work has been to provide insight to help further the development of cold bonded agglomeration technology in order to increase the recycling of iron and steelmaking by-products. Laboratory pelletizing tests were conducted based on a factorial design test plan to help identify those variables that most influence the cold strength and capacity of product cold bonded pellets (CBPs). The design variables were the individual components of the by-product pellet mix; i.e blast furnace (BF) flue dust, oily mill scale sludge, both fine and coarse basic oxygen furnace (BOF) dust and Portland cement as binder. A related statistical procedure was used to plan reduction experiments in inert gas over a temperature range of 20-1200¢XC. The results from cold strength and reduction tests have been evaluated using multivariate statistical analysis to model the experimental variables with chosen responses in order to help identify those variables that have most significance. For agglomerate dimensions used in this study, pellet blends with large fractions of particles in the size range of 10-40 ƒÝm promote good self-reduction while maintaining good cold strength. The fundamental reactions occurring during the heat treatment of CBPs have also been studied. BF flue dust, which contains fractions of coal and coke particles, has been included in the CBP blend as a source of solid reductant. Thermal analysis was performed on samples in inert atmosphere at a heating rate of 10¢XC/min in order to observe their high temperature properties, specifically, the mechanism(s) of self-reduction. The gases generated during thermal analysis were analyzed with a mass spectrometer. Furthermore, raw and heat treated pellet samples were analyzed using X-ray diffraction and scanning electron microscopy. Results demonstrate that the decomposition of hydrates and carbonates in CBP samples contribute, as gaseous intermediates, to the prereduction of contained iron oxides. The gaseous intermediates are responsible for an initial gasification of carbon contained in BF flue dust leading to low temperature iron oxide reduction. The step-wise reduction of iron oxides in the pellets at the given conditions begins at roughly 500¢XC and is nearly completed at 1200¢XC. Detailed studies of the system Ca(OH)2-C-Fe2O3 have also been conducted because of the inherent importance of this system in the self-reduction of by-product agglomerates. Experiments have confirmed that carbon gasification does occur during the dehydration of lime and kinetic results highly correlate to behavior in CBPs. Hematite reduction in the simplified chemical system is controlled by either carbon gasification or availability of direct contact with graphite depending on hematite grain size. These results have less correlation with CBP behavior. After dehydration of Ca(OH) 2, calcium ferrite formation begins at temperatures below 600¢XC. Furthermore, the varying composition of this system has been studied in order to optimize self-reduction and low temperature bonding characteristics. The metallurgical characteristics of CBPs have been tested in additional laboratory tests; i.e. isothermal reduction tests, BF simulation and softening and melting tests. These test results indicate that CBPs; can disintegrate during reduction at high temperature, are self-reducing to a high extent and, as a supplement to the normal ferrous burden, show good softening and melting properties. Large-scale trials with CBPs have been conducted in a commercial BOF and a pilot scale BF. Results from BOF testing show that charging of CBPs is feasible at levels up to 2.2 wt% of the total charge. At these levels, CBP addition resulted in no adverse disturbances to steel and slag chemistry and to the process in general. Results from pilot scale BF tests show that operation was very stable during testing with 150 kg CBPs/tHM but that the burden descent rate and burden gas distribution were disturbed during periods with more CBP burden. The rate of reducing agents was significantly decreased and slag amount was increased when CBPs were charged.

  • 12. Robinson, Ryan
    et al.
    Menad, Nourreddine
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Low temperature behavior of the Ca(OH)2-C system and it's significance on the self-reduction of cold bonded by-product agglomerates2006In: The 4th international congress on the science and technology of ironmaking (ICSTI '06): proceedings : November 26-30 2006, Osaka, Japan, Tokyo: The Iron and Steel Institute of Japan , 2006Conference paper (Refereed)
  • 13. Robinson, Ryan
    et al.
    Pattison, Fabrice
    LSG2M, Nancy-Université, Parc de Saurupt.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Low temperature reactivity in agglomerates containing iron oxide: Studies in the Ca(OH)2-C-Fe2O3 system2011In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 103, no 1, p. 185-193Article in journal (Refereed)
    Abstract [en]

    In this study, we have attempted to explain the complex reactions that occur during the dehydration of Ca(OH)2, in the presence of solid carbon and Fe2O3, in order to clarify their role as eventual precursors to the reduction and high temperature strength characteristics in feedstock agglomerates of iron and steelmaking by-products. A series of simultaneous thermo-gravimetric (TG), differential thermal analytic (DTA), and mass spectrometric (MS) tests were performed on agglomerated sample mixes of Ca(OH)2, C, and Fe2O3 to test the influence of heating rate and particle size on the transformations occurring below 1,073 K in inert atmosphere. The overall transformation begins with calcium hydroxide dehydration. Nucleation and growth of CaO grains during dehydration, as well as subsequent gasification of solid carbon, are highly dependent on the governing interstitial particle porosity and mildly dependent on the heating rate in and around agglomerates. The reduction of hematite in current agglomerates is, by association to preceding reactions, partly dependent on porosity and heating rate, but the mechanism of reduction was also found to be highly dependent on the particle size of iron oxides. Furthermore, in areas of intimate contact between CaO and iron oxide, a calcium ferrite phase appears in the form of angular and calcium-rich particles.

  • 14.
    Robinson, Ryan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Ökvist, Lena Sundqvist
    High temperature properties of iron and steelmaking by-product cold bonded pellets2005In: Proceedings, 5th European Coke and Ironmaking Congress, Jernkontoret , 2005, p. Tu3:2/1-Tu3:2/15Conference paper (Refereed)
  • 15.
    Robinson, Ryan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Ökvist, Lena Sundqvist
    Luleå tekniska universitet.
    Recycling of by-product pellets as burden in the blast furnace process: a lab and pilot scale investigation2004In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 75, no 2, p. 99-105Article in journal (Refereed)
    Abstract [en]

    Cold bonded by-product briquettes have been recycled in the blast furnace at SSAB Tunnplat in Lulea since 1993. Recently, much effort has been made to increase the recycling of by-products. One such project deals with the development of a cold bonded by-product pellet (CBP) agglomerated from very fine dusts. The pellets used in these tests are produced from a blend containing BF flue dust, filter dust, briquette fines and BOF coarse dust as well as cement binder. The pellets were tested in the laboratory by reduction tests, softening and melting tests, thermo gravimetric analysis, differential thermo analysis, and mass spectrometry measurements. The test results indicate that the CBPs can disintegrate during reduction in the BF shaft, are self-reducing to a high extent and, as a supplement to the normal ferrous burden, they show quite good softening and melting properties. A pilot scale test in LKAB's experimental blast furnace was performed. CBPs were charged with rates of 150 kg/tHM, 299 kg/tHM and 344 kg/tHM respectively during test periods 1, 2 and 3. The blast furnace operation was very stable during test period 1 with 150 kg CBP/tHM, but the burden descent and gas distribution were disturbed during the periods with greater CBP burden content. The rate of reducing agents was significantly decreased and slag amount was increased when CBPs were charged.

  • 16. Robinson, Ryan
    et al.
    Ökvist, Lena Sundqvist
    SSAB Tunnplåt AB.
    Recycling of by-product pellets as burden in the blast furnace process: a lab and pilot scale investigation2003In: Proceedings: 3rd International Conference on Science and Technology of Ironmaking; 3rd ICSTI 2003 : Düsseldorf, 16 - 20 June, 2003; METEC Congress 03, Dûsseldorf: Verl. Stahleisen , 2003Conference paper (Other academic)
  • 17.
    Su, Fenwei
    et al.
    SSAB Tunnplåt AB.
    Lampinen, Hans-Olof
    SSAB Tunnplåt AB.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Recycling of sludge and dust to the BOF converter cold bonded pelletizing2004In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 44, no 4, p. 770-776Article in journal (Refereed)
    Abstract [en]

    With the aim to increase the recycling of fine sludge and dust disposed normally in landfill, cold bonded pelletizing of the sludge and dust using cement as binder was investigated in laboratory scale as well as in the pilot scale pelletizing plant. The influence of BF flue dust, BOF fine sludge and oily mill scale sludge on the cold strength, capacity and reduction degree of cold bond pellets was studied experimentally on the basis of a statistical procedure. With a coarser representative particle size, oily mill scale sludge has the greatest effect on the cold strength. BF flue dust has a negative effect for increasing both the cold strength and capacity for levels of over 25% of the mixture. The BOF fine sludge has the positive effect on cold strength, while its interaction with BF flue dust has the negative effect on reduction degree. The results of pelletizing tests in pilot scale show that the maximum cold strength (TTH 94%) and capacity (13-15 t/h) of products is obtained at the conditions given by the optimal mixture design and cure time. The industrial tests on charging cold bonded pellets as burden material in the BOF converter were described. The charging weight of cold bonded pellets varied from 0.5 to 2.5 tons. The results of industrial tests indicated that the converter process was not subject to any adverse disturbances due to the addition of 2.5 tons of cold bonded pellets.

  • 18.
    Su, Fenwei
    et al.
    SSAB Tunnplåt AB.
    Lampinen, Hans-Olof
    SSAB Tunnplåt AB.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Eriksson, L-E
    SSAB Tunnplåt AB.
    Recycling of sludge and dust through the BF and BOF by cold bonded pelletizing at SSAB Tunnplat2002In: TMS fall 2002 Extraction and Processing Division Meeting on Recycling and Waste Treatment in Mineral and Metal Processing: technical and economic aspects / [ed] Bo Björkman; Caisa Samuelsson; Jan-Olov Wikström, Luleå: MEFOS , 2002, Vol. 2, p. 139-148Conference paper (Other academic)
  • 19.
    Su, Fenwei
    et al.
    SSAB Luleå.
    Lampinen, Hans-Olov
    SSAB Luleå.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Industrial tests on charging cold bonded pellets as part of burden materials in the BOF converter2005In: Global Symposium on Recycling, Waste Treatment and Clean Technology (REWAS'04), Minerals, Metals & Materials Society, 2005, p. 1943-1952Conference paper (Refereed)
    Abstract [en]

    Industrial tests on recycling of iron-bearing sludges through BOF converter in the form of cold bonded pellets were carried out at the S SAB Tunnplat. The total amount of about 400 tons of cold bond pellets was produced in a pilot scale pelletizing plant on the basis of the results of experimental studies concerning cold strength and reduction behaviour. The charging weight of cold bonded pellets in the BOF converter with 114 tons varied from 0,5 to 2,5 tons. The effect of charging cold bonded pellets on the amount of sludge and the composition of slag generated in the BOF converters was studied. The slopping problem occurred in the industrial tests is discussed. According to the results of industrial tests, in general the converter process was not subject to any adverse disturbances due to the addition of cold bonded pellets. Dust, sludge, recycling, cold bonded pellets, pilot scale tests and industrial tests.

1 - 19 of 19
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