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  • 1. Adolfsson, Daniel
    et al.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Robinson, Ryan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Cementitious phases in ladle slag2011Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 82, nr 4, s. 398-403Artikel i tidskrift (Refereegranskat)
    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.
    Menad, Nourreddine
    Viggh, Erik O.
    Bureau de Recherches Géologiques et Minières, Orléans.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hydraulic properties of sulphoaluminate belite cement based on steelmaking slags2007Ingår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 19, nr 3, s. 133-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Based on modified Bogue calculations, steelmaking slags were combined in order to produce a belite-rich clinker activated with sulphoaluminate. The experiments were conducted on two different mixtures based on steelmaking slags together with additives, namely MixA and MixB. The objective of the present study was to investigate the hydraulic properties of the specimens, using conduction calorimetry, X-ray diffraction and differential scanning calorimetry, and also to measure the mechanical strength of the specimens when hydrated for 2 and 28 days. The compressive strength was satisfactory in relation to the estimated compositions. Both mixtures behaved the same with regard to heat development as well as the amount of ettringite formed during the first 24 h of the hydration.

  • 3. Adolfsson, Daniel
    et al.
    Menad, Nourreddine
    Viggh, Erik O.
    Cementa AB, Malmö.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Steelmaking slags as raw material for sulphoaluminate belite cement2007Ingår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 19, nr 4, s. 147-156Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present study, slags from the steelmaking industry are described and considered as a potential raw material within the field of sulphoaluminate belite cement. The objective of the study was to investigate the possibility of using a substantial amount of steelmaking slags as raw meal in the manufacture of a sulphobelitic clinker. A further aim was to compare the influence of different slags in relation to the formation of sulphoaluminate and the other clinker phases required. The behaviour of high temperature reactions was investigated by using thermogravimetric analysis coupled with a quadrupole mass spectrometer. Mineralogical observations were carried out through X-ray powder diffraction, and scanning electron microscopy. Three different mixtures and a single ladle slag were prepared using modified Bogue calculations, which are characterised by the assessment of a potential phase composition in order to produce belite-rich cement activated with sulphoaluminate. The results so far prove that steelmaking slags have the potential to be used as raw material, since sulphoaluminate along with polymorphs of dicalcium silicate and ferrite phases were detected after firing at 1200 degrees C in an air atmosphere.

  • 4.
    Adolfsson, Daniel
    et al.
    SSAB Merox SE-61380 Oxelösund, Sweden.
    Robinson, Ryan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Influence of mineralogy on the hydraulic properties of ladle slag2011Ingår i: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 41, nr 8, s. 865-871Artikel i tidskrift (Refereegranskat)
    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.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Andersson, Anton
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    El-Tawil, Asmaa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lotfian, Samira
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Alternative Carbon Sources for Reduction2015Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Andersson, Anton
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    El-Tawil, Asmaa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lotfian, Samira
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Mousa, Elsayed
    Swerea MEFOS, Luleå.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Alternative Reducing Agents for Sustainable Blast Furnace Ironmaking2017Ingår i: ESTAD 2017, 2017Konferensbidrag (Refereegranskat)
    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.

  • 7.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Andersson, Charlotte
    LKAB, Research & Development, 983 81 Malmberget, LKAB Research and Development.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of olivine fineness and thermal profile on oxidation-sintering of magnetite concentrate pellets2015Ingår i: AISTech 2015: Proceedings of the Iron & Steel Technology Conference : 4-7 May 2015, Cleveland, Ohio, U.S.A / [ed] Ronald E Ashburn, Warrendale, PA: Association for Iron & Steel Technology , 2015, s. 379-388Konferensbidrag (Refereegranskat)
  • 8.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, Helwan, P.O. Box 87, Cairo, Egypt.
    Kumar, T. K. Sandeep
    Luossavaara Kiirunavaara Aktiebolag LKAB, S-97128 Luleå, Sweden.
    Alatalo, Johanna
    Luossavaara Kiirunavaara Aktiebolag LKAB, S-97128 Luleå, Sweden; AFRY AF Poyry, SE-97234 Luleå, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of carbon concentration and carbon bonding type on the melting characteristics of hydrogen- reduced iron ore pellets2022Ingår i: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 21, s. 1760-1769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decarbonization of the steel industry is one of the pathways towards a fossil-fuel-free environment. The steel industry is one of the top contributors to greenhouse gas emissions. Most of these emissions are directly linked to the use of a fossil-fuel-based reductant. Replacing the fossil-based reductant with green H2 enables the transition towards a fossil-free steel industry. The carbon-free iron produced will cause the refining and steelmaking operations to have a starting point far from today's operations. In addition to carbon being an alloying element in steel production, carbon addition controls the melting characteristics of the reduced iron. In the present study, the effect of carbon content and form (cementite/graphite) in hydrogen-reduced iron ore pellets on their melting characteristics was examined by means of a differential thermal analyser and optical dilatometer. Carburized samples with a carbon content 2 wt%, the molten fraction is higher in the case of carburized samples, which is indicated by the amount of absorbed melting heat.

  • 9.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Nurni, Viswanathan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Isothermal reduction kinetics of self-reducing mixtures2017Ingår i: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 44, nr 1, s. 66-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Isothermal reduction of haematite carbon mixtures was investigated at temperatures 750–1100°C under inert atmosphere. Mass loss curves proved the stepwise reduction of haematite to metallic iron. The non-linear feature of haematite to magnetite reduction kinetics was observed and an activation energy of 209 kJ mol−1 was calculated. Irrespective of carbon-bearing material type, reduction rate of magnetite was linear. Activation energy values were calculated to be 293–418 kJ mol−1. Significant increase in the reduction kinetics in the last step (Wustite reduction) was observed and explained by the catalytic effect of freshly formed metallic iron. During the initial stages of wustite reduction, the activation energy values were calculated to be in the range of 251–335 kJ mol−1 for all carbon-bearing materials.

  • 10.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Persson, Amanda
    Swerea MEFOS AB.
    Sundqvist, Lena
    Swerea MEFOS AB.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Energy Efficient Recycling of in-Plant Fines2014Ingår i: Proceedings of World Academy of Science, Engineering and Technology, ISSN 2010-376X, Vol. 8, nr 6, s. 485-491Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    —Numerous amounts of metallurgical dusts and sludge containing iron as well as some other valuable elements such as Zn, Pb and C are annually produced in the steelmaking industry. These alternative iron ore resources (fines) with unsatisfying physical and metallurgical properties are difficult to recycle. However, agglomerating these fines to be further used as a feed stock for existing iron and steel making processes is practiced successfully at several plants but for limited extent. In the present study, briquettes of integrated steelmaking industry waste materials (namely, BF-dust and sludge, BOF-dust and sludge) were used as feed stock to produce direct reduced iron (DRI). Physical and metallurgical properties of produced briquettes were investigated by means of TGA/DTA/QMS in combination with XRD. Swelling, softening and melting behavior were also studied using heating microscope.

  • 11.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Persson, Amanda
    Swerea MEFOS AB.
    Sundqvist, Lena
    Swerea MEFOS AB.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Utilization of Steelmaking Industry Waste Materials in Producing Direct Reduced Iron2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The depletion of coke reserves and the raised environmental concerns motivated researchers to work on alternative iron-making processes. Large amount of metallurgical dusts and sludge containing iron and C are produced in the steelmaking industry. These alternative iron ore resources (fines) with poor hydrophilicity are difficult to recycle. The idea of briquetting such wastes containing iron to be used as a feed stock for steelmaking industry is practiced successfully at several plants.In the present study, agglomerates of integrated steelmaking industry waste materials were used as feed stock to produce direct reduced iron (DRI). The reduction behavior of blends of different waste materials (namely, BF dust and sludge, BOF dust and sludge) were investigated thoroughly utilizing TGA/DTA/QMS in combination with XRD.

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  • 12.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Persson, Amanda
    Swerea MEFOS AB, Sweden.
    Sundqvist-Ökvist, Lena
    Swerea MEFOS AB, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Reduction Behaviour of Self-reducing Blends of In-plant Fines in Inert Atmosphere2015Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 55, nr 10, s. 2082-2089Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large amount of dust and sludge recovered during cleaning of iron and steel making process gases are annually put on landfill or intermediate storage. These by-products have high contents of iron (Fe) and carbon (C) that potentially could be utilized in the steel industry. However, due to the presence of impuritycompounds as well as the unsuitable physical properties, these by-products cannot be recycled directly. The main objective of the present study is to investigate the possibilities to recover the valuable components Fe and C in these by-products and thereby decrease the need of landfills at the steel plants as well as reduce the consumption of virgin materials, including fossil coal, and reduce CO2 emissions. A recycling route has been investigated by means of laboratory trials and FactSage thermodynamic modeling. Four different blends of BF and BOF dusts and sludges are prepared in predetermined ratios. Reduction behavior of each blend is studied using TG/DTA/QMS and in-situ high temperature X-ray diffraction. High temperature physical properties like softening, swelling and melting are also investigated by means of heatingmicroscope. The obtained results indicate the feasibility of both minimizing the impurity elements as well as recovering of valuable components.

  • 13.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute (CMRDI).
    Semberg, Pär
    Luossavaara-Kiirunavara Aktiebolag (LKAB), Luleå.
    Andersson, Charlotte
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of added olivine on iron ore agglomerate during induration2018Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 58, nr 3, s. 446-452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Olivine is used extensively in iron-pellet production as an additive in LKAB blast furnace pellets, in order to improve the high temperature properties of the finished product during reduction. As the contribution of olivine into the process depends on the available surface area, the present study was designed to find out the effect of olivine and its fineness on the oxidation-sintering and subsequent dissociation of olivine in iron ore agglomerates. Agglomerates were exposed to different experimental conditions to study the effect of olivine on the behavior of magnetite and hematite at high temperatures. Olivine particles were found to react significantly only above 1 000°C. Porosity of the final product was found to depend largely on olivine fineness. The finer the olivine the lower the porosity of the final product. It is found also that irrespective of the starting iron oxide the ratio between hematite and spinel phase was the same after heating in air. Olivine fineness affects significantly the rate of hematite dissociation, the finer the olivine the higher the dissociation rate. Upon cooling the weight lost due to the dissociation was again regained

  • 14.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, P.O. Box 87, EG-114 21, Helwan, Egypt.
    Sideris, Dimitrios
    Luleå tekniska universitet.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Injection of H2-rich carbonaceous materials into the blast furnace: devolatilization, gasification and combustion characteristics and effect of increased H2–H2O on iron ore pellets reducibility2020Ingår i: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 9, nr 6, s. 16029-16037Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increasing the share of hydrogen in reduction of iron oxide in the blast furnace iron making will directly reduce the share of blast furnace greenhouse gas emissions. In the present study, injection of H2-rich biomass and plastic materials was studied in terms of its devolatilization, gasification and combustion characteristics. The released gases were identified using mass spectroscopy attached to a thermogravimetric analyzer and the corresponding kinetics parameters were estimated.

    The devolatilization was found to occur through two or more steps. The first step is always associated with the release of CO2, CO, H2, H2O and hydrocarbons while only CO and H2 were detected during the later steps. Combustion and gasification starting temperatures of char of H2-rich carbonaceous materials were lower than that of pulverized coal char by ≥ 100 °C. The estimated activation energies suggested that, under the present conditions, devolatilization, gasification and combustion were chemically controlled. Carbon reactivity of the char of the studied H2-rich carbonaceous materials were higher than that of pulverized coal. Moreover, increased H2–H2O content in the blast furnace gas, due to injected H2-rich carbonaceous materials, was found to improve the iron ore pellets reduction kinetics.

  • 15.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, Helwan, P.O. Box 87, Cairo, Egypt.
    Sideris, Dimitrios
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lennartsson, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Prasad, Pande Nishant
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. SWERIM, Box 812, 971 25 Luleå, Sweden.
    From, Lars-Erik
    SWERIM, Box 812, 971 25 Luleå, Sweden.
    Orre, Joel
    SWERIM, Box 812, 971 25 Luleå, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of the Ash from H2‐Rich Carbonaceous Materials on the Physicochemical Properties of Raceway Slag and Coke Reactivity2020Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 91, nr 11, artikel-id 2000098Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The iron and steel industry is one of the most important sectors worldwide, and it has a great impact on the global economy; however, this sector is still highly dependent on fossil carbon. To decrease this dependency, approaches to partially replace the injected pulverized coal with secondary, highly reactive, renewable (biomass) and H2‐rich materials have been studied. The injection of such materials is expected to significantly decrease the emitted CO2 from blast furnaces. However, due to the different ash composition of these alternative materials (especially alkali and alkaline earth metals) compared to that of ordinary injected coal, these materials are expected to alter the raceway slag properties and affect the coke reactivity. In the present article, the effect of the ash from different hydrogen‐rich carbonaceous materials on the raceway slag physicochemical properties as well as coke reactivity is reported. The melting characteristics of the ash briquettes in contact with the coke and wettability of the melted ash on the coke surface are determined visually using an optical heating microscope. The effect of the ash on the coke reactivity is studied by means of thermogravimetry under a continuous flow of CO2.

  • 16.
    Ahmed, Hesham
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Viswanathan, Nurni
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Composite Pellets – A Potential Raw Material for Iron-Making2014Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 85, nr 3, s. 293-306Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Coke constitutes the major portion of iron-making cost and its production causes severe environmental concerns. In addition, lower energy consumption, lower CO2 emission and waste recycling are driving the Iron and steel making industry to develop “coke free, zero waste or green processes”. In the present article, an overview of possible ways to recognize a reasonable improvement in iron and steel making industry is summarized. The present discussion is focusing on the following approaches: 1. Replacing expensive coke with relatively less expensive alternate fuels having carbon as well as significant amount of hydrogen such as coal, waste plastic and biomass materials.2. Producing agglomerates from cheaper raw materials (secondary resources) as well as improving their performance in BF.3.Making the process towards higher carbon utilization by shifting the wustite equilibrium towards lower CO/CO2 ratio by using high reactive coke or catalytic activated one.4.Recycling the unused CO in the top gas by removing CO2 from the gas stream.Much attention has been paid to carbon composite agglomerates (CCA) as a promising raw material for future iron making. Production, mechanical and chemical suitability, reduction behavior, etc. are being elaborated. In addition, other possible ways to utilize CCA in alternate iron-making process has been explored.

  • 17.
    Albertsson, Galina Jelkina
    et al.
    Department of Materials Science and Engineering, Royal Institute of Technology, Division of Materials Process Science, Royal Institute of Technology (KTH).
    Teng, Lidong
    Division of Materials Process Science, Royal Institute of Technology (KTH).
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of basicity on chromium partition in CaO-MgO-SiO2-Cr 2O3 synthetic slag at 1873 K2014Ingår i: Mineral Processing and Extractive Metallurgy: Transactions of the Institutions of Mining and Metallurgy: Section C, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 123, nr 2, s. 116-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of the present work is to get an understanding of the phase relationships in the CaO-MgO-SiO2-Cr2O3 system with a view to control the precipitation of Cr-spinel in the slag phase. The equilibrium phases in CaO-MgO-SiO2-Cr2O3 slag system at 1873 K (1600°C) have been investigated experimentally and compared with the results from thermodynamic calculations. The Cr2O 3 and MgO contents in the slag were fixed at 6 and 8 wt-% respectively. The basicity (CaO/SiO2) of slag was varied in the range 1·0-2·0. A gas/slag equilibrium technique was adopted to synthesise the slag at a high temperature in air. The samples were heated to and soaked at 1873 K (1600°C) for 24 h in order to achieve the equilibrium state and subsequently quenched in water. The chromium distribution and phase compositions in the quenched slag were studied using scanning electron microscope wavelength dispersive spectroscopy and X-ray diffraction techniques. FactSage software was used for the phase equilibrium calculations. The experimental results obtained from the present work were compared with the calculation results from FactSage software. It was found that the spinel formation at 1873 K (1600°C) is favoured in the slag basicity range 1·0-1·4

  • 18.
    Albertsson, Galina
    et al.
    Division of Materials Process Science, Royal Institute of Technology (KTH).
    Teng, Lidong
    Division of Materials Process Science, Royal Institute of Technology (KTH).
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Seetharaman, Seshadri
    Division of Materials Process Science, Royal Institute of Technology (KTH).
    Effect of low oxygen partial pressure on the chromium partition in CaO–MgO–SiO2–Cr2O3–Al2O3 synthetic slag at elevated temperatures2013Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 84, nr 7, s. 670-679Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of the present work is to get an understanding of the impact of Al2O3 addition on the phase relationships in the CaO–MgO–Al2O3–SiO2–Cr2O3 slags at low oxygen partial pressures ( = 10−4 Pa), with a view to control the precipitation of Cr-spinel in the slag. The equilibrium phases in CaO–MgO–Al2O3–SiO2–Cr2O3 slag system in the range on 1673–1873 K have been investigated. The compositions close to the industrial slag systems were chosen. The Cr2O3 content was fixed at 6 wt% and MgO at 8 wt%. Al2O3 contents in the slag were varied in the range of 3–12 wt%. The basicity (CaO/SiO2) of slag was set to 1.6. Gas/slag equilibrium technique was adopted. The samples were heated to 1873 K and soaked at this temperature for 24 h. The samples were then slow cooled to 1673 K and equilibrated for an additional 24 h. The oxygen partial pressure was kept at 10−4 Pa. A gas mixture of CO/CO2 was used to control the oxygen partial pressure. After the equilibration, the samples were quenched in water. The chromium distribution and phase compositions in the quenched slags were studied using SEM–WDS and XRD techniques. The results were compared with the phase equilibrium calculations obtained from FACTSAGE software and the samples equilibrated in air. The size of spinel crystals increased drastically after slow cooling followed by annealing compared to samples being quenched after soaking at 1873 K. It was also found that low oxygen partial pressure had a strong impact on chromium partition. The amount of spinel phase increases with increased Al2O3 content.

  • 19.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, P.O. Box 87-Helwan, Cairo, Egypt.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Characterization and Upgrading of a Low Zinc-Containing and Fine Blast Furnace Sludge: A Multi-Objective Analysis2017Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 57, nr 2, s. 262-271Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ore-based steelmaking generates a variety of residues including dusts, sludges and slags. Recycling of these residues within the process or via other applications is essential for sustainable production from both environmental and economic aspects. In blast furnace (BF) ironmaking, there are generally two residues leaving the gas cleaning equipment; namely, BF dust and BF sludge. Traditionally, the dust is recycled via the sinter or, in the case of pellet based BF, via cold bonded agglomerates and injection. As the main output of zinc from the BF is the top gas, the sludge has to be dezinced prior to recycling to prevent accumulation of zinc in the furnace. Although dezincing of BF sludge has been successfully accomplished using e.g., hydrocycloning, the studied sludges are generally coarse sized and high in zinc. Furthermore, information is lacking regarding the efficiency of separation of different hydrocyclone setups. In the present work, hydrocycloning of a fine sludge, with low zinc content, generated by a pellet based BF has been studied. The gas cleaning equipment used to produce the sludge was running a primary aerocyclone and a scrubber. A characterization of the sludge has been conducted together with an evaluation of the separation efficiency of the hydrocyclone in order to assess the hydrocyclone performance and limitations. Furthermore, the dezincing using the hydrocyclone has been compared to that of sulfuric acid leaching. The results suggest that 51 to 93% of the sludge can be recycled depending on the demand on zinc removal and the chosen dezincing route.

  • 20.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Characterization and Upgrading of Ore Based Steelmaking Sludges2015Ingår i: COM 2015: Conference of Metallurgists, 2015Konferensbidrag (Övrigt vetenskapligt)
  • 21.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Characterization of Blast Furnace Sludge and Upgrading Using Physical Separation and Leaching2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The on-site sinter plants of the Swedish ore based steel industry are all closed. Instead of using sinter, the blast furnaces (BF) operate on iron ore pellets and the major part of the recycling of in-plant residues is realized via cold bonded briquettes charged to the BF. Cost of raw materials and energy continuously drives the work towards an increased recycling of in plant residues. The major part of the zinc entering the BF leaves through the top gas ending up in the BF dust and sludge. The recycling of all the BF dust back to the BF leaves the BF sludge as the main bleed of zinc out of the system. In order to utilize the iron and carbon content of the sludge, means to remove zinc is required prior to recycling via the briquette. In the present work, blast furnace sludge has been characterized. Using the characterization as standpoint, different operations for zinc removal was suggested and studied in laboratory scale. Zinc was successfully removed using a hydrometallurgical and physical separation route, respectively. A successful dezincing operation would enable the recycling of the sludge. This would improve the material- and energy efficiency and substantially decrease the amount of sludge being landfilled.

  • 22.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Feasible routes of blast furnace sludge upgrading in the light of its properties2016Ingår i: SCANMET V: 5th International Conference on Process Development in Iron and Steelmaking, Luleå, 12-15 June 2016, 2016Konferensbidrag (Övrigt vetenskapligt)
  • 23.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, P.O. Box 87, 114 21 Cairo, Egypt.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Swerim AB, Box 812, 971 25 Luleå, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the present work, a full factorial design of experiments with three factors was performed studying the evaporation of potassium (K) from synthetic blast furnace (BF) slag. The experiments showed that slag temperature and B2 basicity (%CaO/%SiO2) had the greatest effect on the evaporation kinetics, while the effect of the MgO content was comparatively less. The regression model developed based on the experimental design could describe the evaporation of K from actual BF slags fairly well, provided that they were within the experimental matrix of the design of experiments.

  • 24.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, P.O. Box 87, 114 21, Helwan, Egypt.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Swerim AB, Box 812, 971 25, Luleå, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    The Quantitative Effect of Blast Furnace Slag Composition and Temperature on the Kinetics of Potassium Evaporation2020Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 51, nr 6, s. 2711-2723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increased in-plant recycling and lower quality raw material in terms of alkali content drive the alkali load in the blast furnace (BF) to higher levels. Excessive load of alkalis, primarily potassium, has several negative effects on the BF operation, which necessitates means to control the removal of potassium from the BF. One method to improve the removal is by increasing the potassium retention in the slag, which is controlled by the evaporation kinetics of potassium. Although several authors have studied factors affecting the evaporation rate, none of these studies have quantitatively investigated the effect of these parameters and attempted to relate these effects to slags from the industry. In the present work, a full-factorial design of experiments with three factors (B2 basicity, MgO content, and temperature) was performed, studying the evaporation of potassium from synthetic BF slag. The results suggested that multiple linear regression is suitable to describe the evaporation kinetics of potassium within the boundaries of the design of experiments. However, extrapolating to industrial slags of different compositions and additional slag components is best performed utilizing the corrected optical basicity. The corrected optical basicity showed a linear relation to the evaporation kinetics of potassium, which was related to the correlation between diffusivity and corrected optical basicity.

  • 25.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Swerim AB, Luleå, Sweden.
    The Potential of Recycling the High-Zinc Fraction of Upgraded BF Sludge to the Desulfurization Plant and Basic Oxygen Furnace2018Ingår i: Metals, ISSN 2075-4701, Vol. 8, nr 12, artikel-id 1057Artikel i tidskrift (Refereegranskat)
    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.

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  • 26.
    Andersson, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute, Cairo, Egypt.
    Sundqvist Ökvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Swerea MEFOS, Luleå, Sweden.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A Holistic and Experimentally-Based View on Recycling of Off-Gas Dust within the Integrated Steel Plant2018Ingår i: Metals, ISSN 2075-4701, Vol. 8, nr 10, artikel-id 760Artikel i tidskrift (Refereegranskat)
    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.

  • 27.
    Andersson, Charlotte
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Thermal diffusivity measurements in magnetite based iron ore pellets2011Ingår i: Proceedings: METEC InSteelCon 2011 : Düsseldorf, Germany, CCD Congress Center Düsseldorf, 27th June - 1st July, 2011 ; it unites for international congresses/conferences under one roof: ECIC, 6th European Coke and Ironmaking Congress; ECCC, 7th European Continuous Casting Conference; EECRsteel, 1st International Conference on Energy Efficiency and CO2 Reduction in the Steel Industry; STEELSIM, 4th International Conference on Modelling and Simulation of Metallurgical Processes in Steelmaking, Düsseldorf, 2011Konferensbidrag (Refereegranskat)
  • 28. Andersson, Charlotte
    et al.
    Björkman, Bo
    Engström, Fredrik
    Mostaghel, Sina
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    The need for fundamental measurements for a sustainable extraction of metals2010Konferensbidrag (Refereegranskat)
  • 29.
    Andersson, Charlotte
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Mostaghel, Sina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    The need for fundamental measurements for a sustainable extraction of metals2011Ingår i: Mineral Processing and Extractive Metallurgy: Transactions of the Institutions of Mining and Metallurgy: Section C, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 120, nr 2, s. 199-204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increased need for efficient material processing and efficient utilisation of more complex raw materials and the need for recycling or reusing byproduct and waste streams, are all increased challenges in material processing. To cope with these challenges, there is a need for new basic physical and thermodynamic data. The present paper gives four examples, as well as preliminary data, of areas where increased knowledge of fundamental parameters will increase the possibility for a sustainable extraction of metals. The examples include measurement of solubility of pure individual slag minerals, determination of distribution of leachable elements between different mineralogical phases in slag, influence of alumina on liquidus temperature of a copper slag and thermal diffusivity measurements in magnetite based iron ore pellets, all important in different ways to increase the sustainability of the respective materials involved

  • 30.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Activity: European Slag Conference; Euroslag 20102010Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 31.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Djupförvar av högaktivt avfall: miljö och säkerhet1994Rapport (Övrigt vetenskapligt)
  • 32.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    MIMER, minerals and materials recycling research centre: pågående och planerade forskningsaktiviteter1996Ingår i: Konferens i mineralteknik: Luleå 13-14 february 1996 / [ed] Marianne Thomaeus; Eric Forssberg, MinFo , 1996, s. 17-32Konferensbidrag (Övrigt vetenskapligt)
  • 33.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Thermodynamic modelling1988Ingår i: Technological advances in metallurgy: proceedings, September 20-21, 1988, Luleå Sweden, Luleå: MEFOS , 1988Konferensbidrag (Refereegranskat)
  • 34.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Degerstedt, U.
    Lindblom, Bo
    Luleå tekniska universitet.
    Samuelsson, Caisa
    Kinetics of Impurity Elimination During Roasting1994Ingår i: Extraction and processing for the treatment and minimization of wastes, 1994: Proceedings of an International Symposium [on Extraction and Processing for the Treatment and Minimization of Wastes] / [ed] Johm P. Hager, Warrendale, Pa: Minerals, Metals & Materials Society, 1994, s. 825-842Konferensbidrag (Refereegranskat)
    Abstract [en]

    Four different arsenic containing dusts from the Boliden plant, Boliden Mineral AB, Sweden have been examined. A kinetic study of the arsenic elimination was performed in a laboratory scale roasting furnace for roasting furnace ESP dust and smelting furnace ESP dust. Characterisation and thermodynamic calculations were carried out to determine the mineralogy, and the stability of compounds in the dusts studied. The characterisation methods used were chemical analysis, X-ray diffraction analysis and microprobe analysis. It was found in the experiments that a high degree of As elimination was obtained for roasting furnace ESP dust and a low degree for smelting furnace ESP dust. Derived kinetic models are given. A prediction of the As-elimination for settling furnace dust and converter ventilation dust is presented

  • 35.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik. Umeå University, Umeå, Sweden;TMS.
    Eriksson, Johan
    Luleå tekniska universitet.
    Nedar, Lotta
    Luleå tekniska universitet.
    Samuelsson, Caisa
    Luleå tekniska universitet. TMS.
    Waste reduction through process optimization and development1996Ingår i: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 48, nr 3, s. 45-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article, the possibilities of optimizing metallurgical processes based on minimization for waste reduction and application requirements for the reuse of waste products are discussed together with the possibilities of treating existing waste in direct connection with the process involved. Some results from ongoing projects on controlled dust generation and an outline of an ongoing research program are also described.

  • 36.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Holmström, Åke
    Luleå tekniska universitet.
    A Quantitative Comparison of the Impurity Capacity in Some Copper Making Routes1989Ingår i: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 18, nr 1, s. 2-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A metallurgical comparison of alternatives to increase the capacity to treat contaminated raw materials was made. The comparison was made by calculating the material balances at different Cu contents in mattes during Cu making and considering the effects of removal of impure intermediate products like dusts and slag for separate treatment. The most efficient methods included the removal of dust from the smelting furnace and the avoidance of reducing conditions in the matte smelting operation. By separating dust and slag produced in the Cu converters, an improved capacity could also be obtained. The removal of impurities made it possible to significantly increase the use of contaminated raw materials but, to drastically increase the impurity capacity, the introduction of pretreatment processes like roasting or leaching was necessary.

  • 37. Björkman, Bo
    et al.
    Jacobsson, E.
    Boliden Metall AB.
    New thermodynamic tools1986Ingår i: Scaninject IV: 4th International Conference on Injection Metallurgy, Luleå, Sweden, June 11-13, 1986, Luleå: MEFOS , 1986, Vol. 1Konferensbidrag (Refereegranskat)
  • 38.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Lindblom, Bo
    Luleå tekniska universitet.
    Toppslagg: avskiljning av desoxiadationsprodukter1993Rapport (Övrigt vetenskapligt)
  • 39.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Menad, Nourreddine
    Thermodynamic conditions for the reduction of dioxins during combustion of the organic parts contained in electronic wastes1999Ingår i: REWAS '99: Global Symposium on Recycling, Waste Treatment and Clean Technology ; proceedings of the "REWAS'99: Global Symposium on Recycling, Waste Treatment and Clean Technology", held in San Sebastián, Spain, September 5 - 9, 1999 ; TMS Fall 1999 Extraction and Process Metallurgy Meeting / [ed] I. Gaballah, 1999, s. 937-648Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electric and Electronic scrap contains about 30% plastics which are treated with halogenated flame retardants. During the combustion of these wastes, halogenated flame retardants can produce dibenzo-p-dioxins and dibenzo-furans. Their reduction can be performed by optimization of combustion parameters e.g. temperature in the combustion chamber, concentration of oxygen, temperature of flue gas at exit, residence time in the cooler, and HCl and H2O mixed in secondary air. The thermodynamic calculations show that, with an oxygen content of 0.1 mole, the total amount of dioxins/furans starts to reduce at 700°C and no formation of these isomers can be observed at 1000°C. However, these molecules are formed even at high temperature and the influence of chlorine on their reduction is negligible with an oxygen content of 1E-5 mole. On the other hand, the presence of SO2 in the gas mixture minimizes the dioxin emissions and the high concentration of water reduces the ratio of dioxins and furans in a given system

  • 40.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Samuelsson, Caisa
    Dust forming mechanisms in the copper converting process1996Ingår i: Second International Symposium on Extraction and Processing for the Treatment and Minimization of Wastes, 1996: proceedings of an international symposium /c sponsored by the Extraction and Processing Division (EPD) of TMS, and held in Scottsdale, Arizona, October 27-30, 1996 / [ed] V. Ramachandran; C.C. Nesbitt, Warrendale, Pa: Minerals, Metals & Materials Society, 1996, s. 105-114Konferensbidrag (Refereegranskat)
    Abstract [en]

    A controlled dust generation whereby the dust generated would be enriched with specific metals would considerably facilitate the possibilities of recovering metals from such dusts. A basic understanding of the dust forming mechanisms is of fundamental importance to achieve a controlled dust generation. The present study deals with dust formation in a copper converting process. Dust samples collected from various places in the gas cleaning system were characterised for chemical and mineralogical composition using chemical analysis as well as microprobe analysis. Thermodynamic calculations were used to predict the formation of chemically formed dust at various temperatures and amounts of leakage air to the gas system. The results show that a separation of mechanically formed dust, e.g. SiO sub 2 , Cu and chemically formed dust, e.g. Pb, Zn, As, Bi, could, to some extent, be obtained due to their different particle sizes. A selective condensation of Pb, Zn and As at a various temperatures could, according to thermodynamic calculations, be possible at high temperature. A selective condensation of metals requires an airtight gas cleaning system or a gas cleaning system with a limited amount of leakage air in order to maintain the desired temperature level.

  • 41.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Recycling of Steel2014Ingår i: Handbook of recycling: state-of-the-art for practitioners, analysts, and scientists, Waltham, Mass: Elsevier, 2014, s. 65-83Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Steel is perhaps the most important construction material in the world, providing services for the well-being of mankind. An increased demand for steel services creates demand for steel consumption, and the lifetime of the products in use determines the recycling potential and the need for replacement. At the same time the steel sector contributes 9% to global energy consumption and process-related carbon emissions. This is a figure that is very much dependent on the amount of steel recycled, because production of steel from recycled material can be carried out with much less energy and CO2 emissions.Considering volume, steel is already the most recycled metal, and there is a well-functioning business structure for the recycling of steel. Currently about 40% of the steel produced comes from recycled material. If and when the increase in world consumption of steel decreases, there will be numerous possibilities of producing a large amount of the steel from recycled scrap.Based on the existing process technology for scrap sorting and steel processing and on what is known about scrap quality, possible limitations and possible actions, the chapter discusses possibilities to reach a truly sustainable steel recycling. The greatest challenge for the steel and scrap processing industry to obtain long term sustainable steel recycling is perhaps the question of scrap quality and the need to avoid quality losses when recycling steel. As the share of steel produced from ore has increased in the last decade, accumulation of tramp elements has not been an issue of high importance recently, but it is an issue that has to be tackled in the future.

  • 42.
    Björkman, Bo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Samuelsson, Caisa
    Lindblom, Bo
    Luleå tekniska universitet.
    Kinetics of impurity elimination during roasting1993Rapport (Övrigt vetenskapligt)
  • 43.
    Brämming, Mats
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Avoiding sloppy BOS process behavior2010Ingår i: Proceedings of the Iron & Steel Technology Conference: May 3 - 6, 2010, Pittsburgh, Pennsylvania, U.S.A / [ed] Ronald E. Ashburn, Warrendale, Pa: Association for Iron & Steel Technology , 2010, s. 1037-1047Konferensbidrag (Refereegranskat)
    Abstract [en]

    Extreme BOS processing conditions may sometimes lead to excessive slag foaming and slopping, resulting in considerable amounts of metallic losses, equipment damage and un-necessary production disturbances. Control of slag formation without slopping is primarily accomplished by taking preventive measures. If static control measures are not effective then in-blow control measures are required and for these to be successful, it is necessary to employ a method for predicting slopping events. Such a system, utilizing BOS vessel vibration measurement, is presently being re-introduced at SSAB's BOS plant in Luleå, Sweden. A deep study into the causes of slopping has been carried out for a 114 tonne LD/LBE vessel, equipped with an automatic system for slopping registration using image analysis. Improved slopping control was achieved by developing a novel lance control scheme, with a new approach to the adjustment of lance position according to scrap quality and ore additions

  • 44. Brämming, Mats
    et al.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Avoiding sloppy BOS process behavior2010Ingår i: Iron & Steel Technology, ISSN 1547-0423, Vol. 7, nr 11, s. 66-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    SSAB EMEA's BOS plant in Luleå, Sweden installed a new system in April 2009 for slopping registration in order to raise the level of metallurgical process control. An excellent and well-documented tool for investigating the causes behind slopping is image analysis. The system scans each received camera image (25 per second) and counts the number of light pixels above a set threshold within a designated area of the camera frame. The scanning output is a 1-second number called the slopping value (in %). A 2-second average value is stored for a period of up to 14 days. Data for a complete year of production on BOS vessel LDI (over 11,000 heats) were collected and scrutinized. The multivariate analysis showed that main static causes behind slopping are the large additions of scrap of lower quality, mainly recycled large-size skulls and pig iron, but also purchased scrap, high ratio of dolomitic fluxes and high Si content in hot metal in the case of HS blowing regime.

  • 45.
    Brämming, Mats
    et al.
    Department of Process Integration, Swerea MEFOS AB.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    BOF Process Control and Slopping Prediction Based on Multivariate Data Analysis2016Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 87, nr 3, s. 301-310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A complex industrial batch processes such as the top-blown BOF steelmaking process, it is a complicated task to monitor and act on the progress of several important control parameters in order to avoid an undesired process event such as “slopping” and to secure a successful batch completion such as a sufficiently low steel phosphorous content. It would, therefore, be of much help to have an automated tool, which simultaneously can interpret a large number of process variables, with the function to warn of any imminent deviation from the normal batch evolution and to predict the batch end result. One way to compute, interpret, and visualize this “batch evolution” is to apply multivariate data analysis (MVDA). At SSAB Europe's steel plant in Luleå, new BOF process control devices are installed with the purpose to investigate the possibility for developing a dynamic system for slopping prediction. A main feature of this system is steelmaking vessel vibration measurements and audiometry to estimate foam height. This paper describes and discusses the usefulness of the MVDA approach for static and dynamic slopping prediction, as well as for end-of-blow phosphorous content prediction.

  • 46.
    Brämming, Mats
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    BOF slopping prediction based on multivariate data analysis2012Ingår i: Scanmet IV: 4th International Conference on Process Development in Iron and Steelmaking, Luleå: MEFOS , 2012, Vol. 1, s. 461-470Konferensbidrag (Refereegranskat)
  • 47.
    Brämming, Mats
    et al.
    Swerim AB, Luleå, Sweden.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Characterization of Slag‐Metal Emulsion and Its Impact on Foaming Behavior and Slopping in the LD Process2019Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 90, nr 2, artikel-id 1800269Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the Basic Oxygen Steelmaking (BOS) process, a heterogeneous emulsion‐solid mix will form, consisting of an emulsion of liquid slag and metal droplets, in which 2nd phase particles of undissolved fluxes and solid in‐blow precipitates are suspended. When the carbon in the metal droplets reacts with iron oxide, small bubbles of CO gas are formed. If the upward movement of these bubbles is obstructed by the physical properties of the emulsion‐solid mix, foaming will occur. Certain process conditions may lead to an excessive foam growth, in the worst case forcing foam out of the vessel. This undesired process event is known as “slopping”. Extensive studies during recent decades have shown that emulsion characteristics strongly connected to foaming are: viscosity, surface tension, and density. The extent of foaming is also dependent on bubble size; foaming increasing with smaller bubble size. However, investigations into the influence of the mineralogy and morphology of the emulsion‐solid mix on foaming in basic oxygen steelmaking are scarce. In this work, samples from trials in a 6‐tonne pilot plant BOS vessel are examined by XRD and with SEM for the determination of emulsion‐solid mix mineralogy and morphology at different stages of the oxygen blow. The study confirms the importance of tight process control in order to minimize the emulsion‐solid mix apparent viscosity and, hence, the foam height, but this without over‐oxidizing the liquid slag phase, which would result in increased gas generation within the slag‐metal emulsion.

  • 48.
    Brämming, Mats
    et al.
    SSAB EMEA, Luleå.
    Millman, Stuart
    Tata Steel Research, D & T, Teesside Technology Centre, Middlesbrough.
    Overbosch, Aart
    Tata Steel Research, D & T, IJmuiden Technology Centre.
    Kapilashrami, Abha
    Tata Steel Research, D & T, IJmuiden Technology Centre.
    Malmberg, Donald
    Swerea MEFOS AB.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    BOS vessel vibration measurement for foam level detection2011Ingår i: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 51, nr 1, s. 71-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the BOS process liquid slag together with dispersed metal droplets, solid particles and process gases form an expanding foam. Certain process conditions may lead to excessive foam growth, forcing foam out through the vessel mouth, an event commonly known as 'slopping'. Slopping results in loss of valuable metal, equipment damage and lost production time. In the early 1980s a system for foam level and slopping control was installed at SSAB's steel plant in Lulea, a system based on the correlation between BOS vessel vibration in a narrow low frequency band and foam development. The technique, in this case with an accelerometer mounted on the trunnion bearing housing, soon showed its usefulness, for example when adapting existing lance patterns to a change in oxygen lance design from a 3-hole to a 4-hole nozzle. Estimating the actual foam height in the BOS vessel was of great importance in the recently completed RFCS funded research project "IMPHOS" (Improving Phosphorus Refining). Based on the earlier positive experiences, it was decided to further develop the vessel vibration measurement technique. Trials on an industrial size BOS vessel type LD/LBE have been carried out, this time with a tri-axial accelerometer mounted on the vessel trunnion. FFT spectrum analysis has been used in order to find the frequency band with best correlation to the foam level development. The results show that there is a correlation between vessel vibration and foam height that can be used for dynamic foam level and slopping control

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  • 49.
    Brämming, Mats
    et al.
    SSAB EMEA, Luleå.
    Parker, Gareth
    Tata Steel Europe - Long Products.
    Millman, Stuart
    Tata Research, D & T, Teesside Technology.
    Kapilashrami, Abha
    Tata Research, D & T, IJmuiden Technology Centre.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Comparison between vessel vibration and audiometry for slopping control in the top-blown BOS process2011Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 82, nr 6, s. 683-692Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Excess slag foam growth is a frequent problem in the BOS process. In the worst case, foam is forced out of the vessel and this phenomenon, commonly called slopping, not only results in loss of valuable metal yield but also in equipment damage and lost production time. In order to minimize slopping, accurate estimation of the foam level inside the vessel is an important part of BOS process control. In the top blown BOS vessel, slopping control is achieved using both static and dynamic measures. The most common implemented technique for dynamic foam height estimation and slopping control is the audiometer system. An alternative method, vessel vibration monitoring, has been investigated as part of the work in a RFCS funded research project called IMPHOS. In order to judge the usefulness of this method, parallel vibration and audio measurements have been carried out on 130 tonne as well as on 300 tonne BOS vessels. The results show that during stable process conditions there is good agreement between the two methods with regard to foam height estimation and, as vessel vibration and audiometry are largely independent of each other, a combination of the two is likely to increase significantly the accuracy of slopping prediction

  • 50.
    Durinck, D.
    et al.
    Katholieke University of Leuven.
    Engström, Fredrik
    Arnout, S.
    Katholieke University of Leuven.
    Heulens, J.
    Katholieke University of Leuven.
    Jones, P.T.
    Katholieke University of Leuven.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Blanpain, B.
    Katholieke University of Leuven.
    Wollants, P.
    Katholieke University of Leuven.
    Hot stage processing of metallurgical slags2008Ingår i: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 52, nr 10, s. 1121-1131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Slags are an indispensable tool for the pyrometallurgical industry to extract and purify metals at competitive prices. Large volumes are produced annually, leading to important economical and ecological issues regarding their afterlife. To maximise the recycling potential, slag processing has become an integral part of the valorisation chain. However, processing is often directed solely towards the cooled slag. In this article, the authors present an overview of the scientific studies dedicated to the hot stage of slag processing, i.e. from the moment of slag/metal separation to complete cooling at the slag yard. Using in-depth case studies on C2S driven slag disintegration and chromium leaching, it is shown that the functional properties of the cooled slag can be significantly enhanced by small or large scale additions to the high temperature slag and/or variations in the cooling path, even without interfering with the metallurgical process. The technology to implement such hot stage processing steps in an industrial environment is currently available. No innovative technological solutions are required. Rather, advances in hot stage slag processing seem to rely primarily on further unravelling the relationships between process, structure and properties. This knowledge is required to identify the critical process parameters for quality control. Moreover, it could even allow to consciously alter slag compositions and cooling paths to tailor the slag to a certain application.

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