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  • 51.
    Lee, P.D.
    et al.
    University of Manchester.
    Ramirez-Lopez, Pavel Ernesto
    RISE, Swerea, Swerea MEFOS.
    Mills, K.C.
    Imperial College London.
    Santillana, B.
    Tata Steel RD and T.
    Review: The "butterfly effect" in continuous casting2012In: Ironmaking and Steelmaking, 2012, Vol. 39, no 4, p. 244-253Conference paper (Refereed)
    Abstract [en]

    The continuous casting (CC) mould may appear very peaceful when viewed from above, but the powder bed hides relentless fluctuations in the following phenomena: metal flow, thermal gradients, chemical reactions and multiple phase transformations. When observed separately, some of these phenomena seem to have a 'simple behaviour', which may appear easy to control through the main casting parameters (e.g. casting speed, pouring temperature and powder type) and associated control systems (e.g. mould level control, automatic powder feeding and mould oscillation). However, when combined, these phenomena exhibit periodic fluctuations in behaviour, which is both difficult to predict and control. For instance, the combination of casting speed, submerged entry nozzle design and slab size can cause the metal flow pattern to shift from double roll to single roll and back, which can cause unstable fluctuations in metal level, standing waves, etc. In this respect, the CC process closely resembles a meteorological system where both variations and local fluctuations in temperature, humidity, pressure, etc., can result in effects that are difficult to predict in the long term. This is equivalent to the famous Lorenz premise: 'Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?' In this paper, we give some examples of the 'butterfly effect' in CC discussed below by using a mathematical model able to predict the slab solidification inside the mould in which various factors affecting the process stability are analysed and the probable sources of fluctuation are identified. © 2012 Institute of Materials, Minerals and Mining.

  • 52.
    Leimalm, U.
    et al.
    Luleå University of Technology.
    Forsmo, S.
    LKAB R and D.
    Dahlstedt, A.
    LKAB R and D.
    Ökvist, Lena Sundqvist
    RISE, Swerea, Swerea MEFOS.
    Björkman, B.
    Luleå University of Technology.
    Blast furnace pellet textures during reduction and correlation to strength2010In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 50, no 10, p. 1396-1405Article in journal (Refereed)
    Abstract [en]

    The blast furnace is the most common means of producing hot metal. As the amounts of reduction agents increases, which influence in-furnace conditions such as ascending gas properties, temperature profiles and the ore-to-coke ratio, new demands are put on the iron-bearing material in terms of both reducibility and mechanical strength. To investigate the possibilities to use the Pellet Multi Press (PMP) equipment for compression strength measurements of reduced pellets and to gain a deeper understanding of the correlation between pellet texture and strength, an initial study of pellets taken from the LKAB Experimental Blast Furnace (EBF) was conducted. Furthermore, the pellet pieces generated after compression tests were characterized using light optical microscopy. In order to correlate the texture of pellet pieces to the pellet texture prior to breakage, a characterization of the chronological pellet texture development during reduction in the EBF was performed. The original pellet texture remained in the beginning of reduction and differences receded through the EBF shaft as wustite and Femet was formed. Occurrence of Femet in the pellet texture increased the compression strength, while less reduced and less sintered textures showed the reverse effect. So far, the results from compression strength tests indicate that disintegration of pellets takes place at a reaction front, at the transition between different texture types of iron oxide or at the location of a visible surface crack. © 2010 ISIJ.

  • 53.
    Leimalm, U.
    et al.
    SSAB Oxelösund.
    Lundgren, M.
    Luleå University of Technology.
    Ökvist, Lena Sundqvist
    RISE, Swerea, Swerea MEFOS.
    Björkman, B.
    Luleå University of Technology.
    Off-gas dust in an experimental blast furnace part 1: Characterization of flue dust, sludge and shaft fines2010In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 50, no 11, p. 1560-1569Article in journal (Refereed)
    Abstract [en]

    In blast furnace (BF) ironmaking, efforts are made to decrease coke consumption, which can be done by increasing the pulverized coal injection rate (PCR). This will cause changes in ¡n-furnace reduction conditions, burden distribution, demands on raw material strength, etc. In order to maintain stable operation, but also to obtain low amounts of material losses through the off-gas, it is important to understand fines generation and behaviour in the BF Off-gas dust and shaft fines generated in the LKAB Experimental Blast Furnace (EBF) were sampled during operation with olivine pellets and mixtures of acid pellets and sinter as iron-bearing materials. Characterization using XRD, SEM and LOM was focused on fines from iron-bearing materials, coke and slag formers. The results showed that flue dust, mainly <0.5 mm, was mechanically formed and created in the same manner for all investigated samples. Carbon-containing particles dominated in the fractions >0.075 mm and consisted mainly of coke particles from the shaft. Fe-containing particles, as Fe2O 3 from the top of the shaft, formed the major part of flue dust fractions <0.063 mm. Particles from slag formers such as quartzite and limestone were observed in flue dust when slag formers were utilized in the feed. Sludge consisted mainly of chemically formed spherical particles <1 μm precipitated from the ascending gas as the temperature decreased. © 2010 ISIJ.

  • 54.
    Lindblom, B.
    et al.
    Luleå University of Technology.
    Samuelsson, C.
    Luleå University of Technology.
    Sandström, Å.
    Luleå University of Technology.
    Ye, Gouzhu
    RISE, Swerea, Swerea MEFOS.
    Fine-particle characterization - An important recycling tool2002In: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 54, no 12, p. 35-38Article, review/survey (Refereed)
    Abstract [en]

    This paper summarizes the results from different research projects on fine-particle characterization of metallurgical residues, such as hydroxide sludge, electric-arc furnace dust, and copper-converter dust. These studies demonstrated that characterization is essential for developing new recycling strategies. The basic knowledge of the chemical and physical properties of the residues obtained by the characterizations also provides necessary information on potential problems that could be encountered during the processing of such materials.

  • 55.
    Lindvall, Mikael
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Gran, Jimmy
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sichen, Du
    KTH Royal Institute of Technology, Sweden.
    Determination of the vanadium solubility in the Al2O 3-CaO (25 mass%)-SiO2 system2014In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 47, p. 50-55Article in journal (Refereed)
    Abstract [en]

    Vanadium (V) solubility in the Al2O3-CaO (25 mass%)-SiO2 system was determined experimentally at 1873 K and at a fixed oxygen potential of 9.37×10-11 bar. EPMA microanalyses were employed to identify the phases and their compositions in the quenched samples. It showed that the solubility of V-oxide increased slightly with decreasing Al2O3-content in the interval from 3 mass% to 53 mass%. The maximum V-solubility was up to 7 mass% (as V). A solid solution rich in V-oxide was detected. The Al2O3 solubility in this solid solution was found to increase with increasing Al2O 3-content in the liquid.

  • 56.
    Lindvall, Mikael
    et al.
    RISE, Swerea, Swerea MEFOS.
    Rutqvist, E.
    LKAB Technology and Business Development.
    Ye, Guozhu
    RISE, Swerea, Swerea MEFOS.
    Björkvall, Johan
    RISE, Swerea, Swerea MEFOS.
    Sichen, D.
    Royal Institute of Technology.
    Possibility of selective oxidation of vanadium from iron and phosphorus in Fe-V-P melt2010In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 81, no 2, p. 105-111Article in journal (Refereed)
    Abstract [en]

    Experiments on a vanadium recovery method from vanadium containing BOF-slag using both a Tamman furnace (3 kg scale) and an induction furnace (150 kg scale) were conducted. The vanadium was extracted into the slag phase by bubbling oxidation gas into a metal bath consisting mainly of V (1-10 mass%), Si (less than 1 mass%) and P (about 1 mass%). The first experiments revealed that the slag formed during oxidation reaction had considerably high phosphate capacity. High phosphorus content would rule out the possibility of using the slag as a raw material for the production of ferrovanadium of high quality. In order to reduce the P-content in the slag, addition of slag former to reduce phosphate capacity was necessary. A suitable slag system (having the initial composition 40 mass% Al2O3 - 25 mass% CaO - 35 mass% SiO2) and a suitable atmosphere, by using CO2, that enhanced the oxidation of vanadium, but limit the oxidation of iron and phosphorus was found. However, more efforts should be put forward, e.g. study of the phase diagram, the viscosity of the slag and even oxide activities to gain more insight into the slag formed by selective oxidation. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 57.
    Lindvall, Mikael
    et al.
    RISE, Swerea, Swerea MEFOS.
    Rutqvist, S.
    SSAB Strip Products.
    Ye, Guozhu
    RISE, Swerea, Swerea MEFOS.
    Recovery of vanadium from v-bearing bof-slag using an eaf2010In: Proceedings of the 12th International Ferroalloys Congress: Sustainable Future, 2010, p. 189-195Conference paper (Refereed)
    Abstract [en]

    Experiments on a vanadium recovery method from vanadium containing BOF-slag using a 10 tons electric arc furnace (EAF) were conducted. The aim was not only to recover vanadium efficiently but also to make the treated BOF-slag useful for external markets. The vanadium and other valuable metals were extracted into a metal phase by pre-reduction using carbon-based reductants and finalreduction by injection of ferrosilicon- and/or aluminium powder. The results did show that in excess of 98% of vanadium could be recovered to the metal by this method, most of the iron and phosphorus was also successfully recovered to the metal. The reduced BOF-slag has a vanadium-content as low as 0.02mass% and thus has good opportunity to be used as construction material. The tested parameters important for the process are described and discussed in details in this paper.

  • 58.
    Lindvall, Mikael
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Sichen, Du
    KTH Royal Institute of Technology, Sweden.
    Determination of Vanadium Solubility in the Al2O3-CaO(30 Mass Pct)-SiO2 and Al2O3-CaO(35 Mass Pct)-SiO2 System2015In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 46, no 2, p. 733-740Article in journal (Refereed)
    Abstract [en]

    The solubility of vanadium oxide in the Al2O3-CaO(30 mass pct)-SiO2 system and Al2O3-CaO(35 mass pct)-SiO2 system was determined experimentally at 1873 K (1600 °C) and at a fixed oxygen potential of 9.37 × 10−11 bar. EPMA microanalyses were employed to identify the phases and their compositions in the quenched samples. The solubility of vanadium oxide in the liquid phase was found to decrease with increasing CaO content in the liquid. The vanadium oxide solubility was especially low when both CaO and Al2O3 contents were high in the liquid phase. The maximum solubility of vanadium oxide was up to 7 mass pct (as V). Two solid phases were found, a solid solution of Al2O3 and vanadium oxide and an Al2O3-rich solid phase with 16.7 mass pct V2O3. The Al2O3 solubility in the solid solution was found to increase with increasing Al2O3 content in the liquid, the impact of the CaO content in the liquid on the solubility of Al2O3 in V2O3 was found to be small. The Al2O3-rich solid phase was identified as the mineral hibonite with fractionation of V into the crystal structure.

  • 59.
    Lindvall, Mikael
    et al.
    RISE, Swerea, Swerea MEFOS.
    Ye, Guozhu
    RISE, Swerea, Swerea MEFOS.
    Experiences of using various metallurgical reactors for reduction of vanadium bearing steel slags and other wastes2012In: TMS Annual Meeting, 2012, p. 147-154Conference paper (Refereed)
    Abstract [en]

    Swedish iron ore contains about 0.1%V. The vanadium is reduced to the hot metal in a blast furnace and oxidised to the slag in a converter. The high V-content, up to 5% V, leads to a very limited external application of the steel slag in Sweden. Since 2004, MISTRA - the Swedish Foundation for Strategic Environmental Research has together with the steel and mining industry in Sweden and Finland initiated and supported a long term project aiming at efficient recovery of vanadium in the slag, and at the same time a useful slag product with low V-content. The proposed concept consists of a reduction step and a phosphorus removal step. This paper will highlight some of the results with focus on the various metallurgical reactors used for slag reduction, including results from recently performed pilot trials using a DC furnace for co-treatment of metallurgical slags and other wastes.

  • 60.
    Lingebrant, P.
    et al.
    Höganäs AB.
    Dahl, J.
    Luleå University of Technology.
    Larsson, Mikael
    RISE, Swerea, Swerea MEFOS.
    Sandberg, Erik
    RISE, Swerea, Swerea MEFOS.
    System optimization of an electric steel making plant with sequenced production and dynamic stock level2012In: Chemical Engineering Transactions, Italian Association of Chemical Engineering - AIDIC , 2012, Vol. 29, p. 523-528Conference paper (Refereed)
    Abstract [en]

    One third of the total steel production in the world today is produced by electrical steel making and is supposed to increase. It is a very energy intense process but for the production costs the scrap mix is nowadays clearly the most dominating cost factor. Because the ingoing raw material mix affects the energy consumption and the chemistry of the final product it is an important factor to control. A system optimization model for a generalized electric steelmaking plant has been developed. The vision has been to include a planned production sequence and a dynamic scrap stock level along with a full material- and energy balance connected to the processes. This gives the opportunity to run optimizations with restrictions similar to real production conditions. The generalized steelmaking plant produces hot rolled coils and five main processes are included in the model; a material pre-treatment process, an electric arc furnace, a ladle furnace, a continuous casting process and a hot rolling mill process. To estimate the chemical composition of the ingoing scrap grades, a regression model has been made based on process data from a Höganäs Sweden AB plant. Mixed Integer Linear Programming (MILP) has been used as the method for modeling the production system. Simulations and optimizations have been focused on changes in the chemical composition of certain scrap grades, restrictions of the availability of scrap grades and restrictions regarding the forecasted production sequence. The objectives used for the optimizations are production costs and total energy consumption. The model deliveries results in form of optimal raw-material mixes for the different steel grades defined in the model, optimal energy mix and optimal target temperatures for the sub-processes. Further it shows the effect on process parameters such as energy consumption, slag amount, off gas generation, injected carbon and oxygen etc. The model makes it possible to simulate scenarios that are expected for the future regarding new steel grades, availability of raw-materials and changed amount of tramp elements in the raw material used today. It is a good tool to find an optimal solution not only for a single heat but for a sequence of heats with varying chemical specifications. Copyright © 2012, AIDIC Servizi S.r.l.

  • 61.
    Liu, Shihhsien
    RISE, Swerea, Swerea MEFOS.
    Process selection for recycling dusts and sludges at China steel2010In: SEAISI Quarterly (South East Asia Iron and Steel Institute), ISSN 1295721, Vol. 39, no 1, p. 54-60Article in journal (Refereed)
    Abstract [en]

    In integrated steel works, dusts and sludges (commonly called residual materials) are inevitably generated with steel production. At China Steel Corporation (CSC), most of these residual materials were recycled as the raw materials of sintering plant to produce sinter. In order to reduce dioxins emission of sintering machines, CSC decided to remove the oily and chlorine-containing residual materials (9 kinds, approximately 0.22 million dry ton per year) away from the sinter mix and search other routes instead to recycle these residual materials in plant. Due to high iron oxides and carbon contents of the residual materials, the carbothermic reduction technology was recognized as the best achievable technologies (BAT) in CSC's survey work. Through studies on technology feasibility, equipment suitability, product quality, pollutants emission and operation cost, the combined process of one RHF (Rotary Hearth Furnace) process and one CBP (Cold-Bonded Pelletization) process was considered as the best solution to reach the goals of high efficient operation, high valorization, no secondary wastes and minimum pollutants emission. Products of the RHF process and CBP process are DRI (Direct Reduced Iron) and CBP (Cold-Bonded Pellets), respectively. At CSC, these products are charged into blast furnace to produce hot metal. The by-product of RHF process is the crude zinc oxide powder which is sold to zinc refinery. The combined process in CSC was constructed from January 2007, commissioned at the beginning of 2008, and reached the expected performance at the end of 2008.

  • 62.
    Liu, Zengjian
    et al.
    University of Science and Technology Beijing, China.
    Wang, Guangwei
    University of Science and Technology Beijing, China.
    Zhang, Jianliang
    University of Science and Technology Beijing, China.
    Lee, Jui-Yuan
    National Taipei University of Technology, Taiwan.
    Wang, Haiyang
    University of Science and Technology Beijing, China.
    Sun, Mimmin
    University of Science and Technology Beijing, China.
    Wang, Chuan
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. Åbo Akademi University, Finland.
    Study on CO2 Gasification Reactivity and Structure Characteristics of Carbonaceous Materials from the Corex Furnace2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 5, p. 6155-6166Article in journal (Refereed)
    Abstract [en]

    The gasification reactivities of four pretreated carbonaceous materials from the Corex furnace, including one coal char, two metallurgical cokes, and one recycling dust, were investigated by a thermogravimetric analyzer, in which the recycling dust came mainly from two metallurgical cokes and accounted for a mass fraction of 71.3%. The physicochemical properties of the different samples were tested systematically. The results showed that the recycling dust had a gasification reactivity similar to the coal char, of which the value was higher than those of the two metallurgical cokes. The structure analysis ascertained that the main factor that affected the gasification reactivity was the carbonaceous structure. Moreover, to characterize the reactive behavior of the different samples, three nth-order typical gas-solid reaction models were employed in this study. It has been found that the random pore model was the best model. The activation energies of different chars were in the range of 181.1-202.3 kJ/mol.

  • 63.
    Luks, T.
    et al.
    Brno University of Technology, Czech Republic.
    Horský, J.
    Brno University of Technology, Czech Republic.
    Nilsson, Annika
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Jonsson, N.-G.
    Jernkontoret, Sweden.
    Lagergren, J.
    Åkers AB, Sweden.
    Contact stress distribution and roll surface temperatures in the roll gap analyzed with different sensors2014In: La Metallurgia Italiana, ISSN 0026-0843, Vol. 106, no 1, p. 19-25Article in journal (Refereed)
    Abstract [en]

    In this work, the contact stresses and temperatures during hot and cold rolling have been measured. A work roll containing three different sensors was used for the measurements. There were two contact devices for directly measuring forces and one temperature sensor. One sensor was the "ROLLSURF" sensor. Results obtained with this sensor have been presented earlier [1-3], The measurement principle is based on deformation measurements with strain gauges which were placed on an internal cradle-type roll insert. The second sensor was a friction pin sensor. The forces on the top of the pin were measured by three axis piezoelectric-transducers. The pin sensor was mounted inside the work roll opposite to the ROLLSURF sensor. The third sensor was a thermocouple placed next to the pin sensor. The temperatures were measured very close to the roll surface. The surface boundary conditions including the heat flux and surface temperatures were computed using inverse modelling calculations developed at Brno University of Technology. The main task of this paper is to show a comparison of the contact forces and contact length measured with the strain-gauge sensor and the pin-sensor.

  • 64.
    Lundgren, J.
    et al.
    Luleå University of Technology.
    Asp, B.
    Luleå University of Technology.
    Larsson, Mikael
    RISE, Swerea, Swerea MEFOS.
    Grip, C.-E.
    Luleå University of Technology.
    Methanol production at an integrated steel mill2008In: CHISA 2008 - 18th International Congress of Chemical and Process Engineering, 2008Conference paper (Refereed)
    Abstract [en]

    The technical and economic consequences of using coke oven gas (COG) to produce methanol (MeOH) to be used as automotive fuel were studied. In a case study of a steel mill, two of the four different production processes considered used COG, while the other two systems used biomass based synthesis gas to blend with the COG. With the assumed amount of available COG at the steel mill, nearly 300 Gw-hr/yr of MeOH could be produced, using the SMR production system. When 420 Gw-hr/yr of biomass for synthesis gas production were blended with the COG, another 270 Gw-hr/yr of MeOH can be produced. The use of COG to produce MeOH is cost efficient, and has the potential of reducing the specific CO2 emission in the range of 25-65% compared to fossil gasoline, depending on the amount of biomass included in the system setup. The integration of a motor fuel refinery in the steel industry may give benefits, e.g., better energy storage possibilities and increased incentives to utilize residual heat. This is an abstract of a paper presented at the 18th International Congress of Chemical and Process Engineering (Prague, Czech Republic 8/24-28/2008).

  • 65.
    Lundgren, J.
    et al.
    Luleå University of Technology, Sweden.
    Ekbom, T.
    Grontmij AB.
    Hulteberg, C.
    Nordlight, Sweden.
    Larsson, Mikael
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Grip, Carl Erik
    Luleå University of Technology, Sweden.
    Nilsson, L.
    SSAB EMEA, Sweden.
    Tunå, P.
    Lund University, Sweden.
    Methanol production from steel-work off-gases and biomass based synthesis gas2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 431-439Article in journal (Refereed)
    Abstract [en]

    Off-gases generated during steelmaking are to a large extent used as fuels in process units within the plant. The surplus gases are commonly supplied to a plant for combined heat and power production. The main objective of this study has been to techno-economically investigate the feasibility of an innovative way of producing methanol from these off-gases, thereby upgrading the economic value of the gases. Cases analyzed have included both off-gases only and mixes with synthesis gas, based on 300MWth of biomass. The SSAB steel plant in the town of Luleå, Sweden has been used as a basis. The studied biomass gasification technology is based on a fluidized-bed gasification technology, where the production capacity is determined from case to case coupled to the heat production required to satisfy the local district heating demand. Critical factors are the integration of the gases with availability to the synthesis unit, to balance the steam system of the biorefinery and to meet the district heat demand of Luleå. The annual production potential of methanol, the overall energy efficiency, the methanol production cost and the environmental effect have been assessed for each case. Depending on case, in the range of 102,000-287,000ton of methanol can be produced per year at production costs in the range of 0.80-1.1EUR per liter petrol equivalent at assumed conditions. The overall energy efficiency of the plant increases in all the cases, up to nearly 14%-units on an annual average, due to a more effective utilization of the off-gases. The main conclusion is that integrating methanol production in a steel plant can be made economically feasible and may result in environmental benefits as well as energy efficiency improvements. © 2013 Elsevier Ltd.

  • 66.
    Lundgren, M.
    et al.
    Luleå University of Technology.
    Leimalm, U.
    SSAB Oxelösund.
    Hyllander, G.
    LKAB RandD.
    Ökvist, Lena Sundqvist
    RISE, Swerea, Swerea MEFOS.
    Björkman, B.
    Luleå University of Technology.
    Off-gas dust in an experimental blast furnace part 2: Relation to furnace conditions2010In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 50, no 11, p. 1570-1580Article in journal (Refereed)
    Abstract [en]

    In the blast furnace process, material losses are caused by particles that are blown out of the furnace by the off-gas. In order to reduce these losses, it is important to understand the correlations between furnace conditions and off-gas dust formation. Off-gas dust, as flue dust and sludge, were collected during shaft probe sampling in LKAB Experimental Blast Furnace (EBF). Process data was used to evaluate the relationship between off-gas dust amounts and furnace conditions. The graphitization degree (Lc value) of shaft coke and coke in flue dust was determined using XRD measurements. Solution loss in the shaft had a negligible effect on coke degradation and the coke particles which ended up in the flue dust were mainly derived from abrasion at low temperatures. The amount of alkali and SiO2 in sludge increased with higher PCR and flame temperature, which confirmed that submicron spherical particles in sludge originated from the high temperature area around the raceway. Theoretical critical particle diameters of materials, which could be blown out with the off-gas, were estimated. Flow conditions in the top of the shaft as well as and the properties of fine particles in terms of size and density are important when outflow of mechanical dust, such as flue dust, is concerned. Low off-gas temperatures, and thus lower off-gas velocities, are favourable for low flue dust amounts expelled from the blast furnace. © 2010 ISIJ.

  • 67.
    Lundgren, Maria
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS. Luleå University of Technology, Sweden.
    Khanna, Rita
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Ökvist, Lena Sundqvist
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sahajwalla, Veena
    University of New South Wales, Australia.
    Björkman, Bo M.T.
    Luleå University of Technology, Sweden.
    The evolution of structural order as a measure of thermal history of coke in the blast furnace2014In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 45, no 2, p. 603-616Article in journal (Refereed)
    Abstract [en]

    Investigations were carried out on cokes heat treated in the laboratory and on cokes extracted from the experimental blast furnace (EBF) raceway and hearth. X-ray diffraction (XRD) measurements were performed to investigate changes in structural order (Lc), chemical transformations in coke ash along with comparative thermodynamic equilibrium studies and the influence of melt. Three data processing approaches were used to compute Lc values as a function of temperature and time and linear correlations were established between Lc and heat treatment temperatures during laboratory investigations. These were used to estimate temperatures experienced by coke in various regions of EBF and estimated raceway temperatures were seen to follow the profile of combustion peak. The MgAl2O4 spinel was observed in coke submerged in slag during laboratory studies and in cokes found further into the raceway. Coke in contact with hot metal showed XRD peaks corresponding to presence of Fe3Si. The intensity of SiO 2 peak in coke ash was seen to decrease with increasing temperature and disappeared at around 1770 K (1500 °C) due to the formation of SiC. This study has shown that the evolution of structural order and chemical transformations in coke could be used to estimate its thermal history in blast furnaces. 

  • 68.
    Lundgren, Maria
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Sundqvist Ökvist, Lena
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Brandell, Carina
    LKAB, Sweden.
    Development of nut coke activation for energy efficient blast furnace operation2015In: AISTech - Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2015, Vol. 1, p. 638-651Conference paper (Refereed)
  • 69.
    Lundgren, Maria
    et al.
    Luleå University of Technology.
    Ökvist, Lena Sundqvist.
    RISE, Swerea, Swerea MEFOS.
    Björkman, B.
    Luleå University of Technology.
    Coke reactivity under blast furnace conditions and in the CSR/CRI test2009In: Steel Research International, 2009, Vol. 80, no 6, p. 396-401Conference paper (Refereed)
    Abstract [en]

    The present work aims to study the high-temperature strength of coke. Mechanisms of disintegration were evaluated using basket samples charged into LKAB's experimental blast furnace prior to quenching and dissection. Coke charged into basket samples was analysed with CSR/CRI tests and compared with treated coke from the blast furnace. Results from tumbling tests, chemical analyses of coarse and fine material, as well as light optical microscopy studies of original and treated coke have been combined and evaluated. The results indicate a correlation between the ash composition and the CSR values. Differences in the texture of the coke were noted with light optical microscopy, and a significant change in the coke texture during the CSR/CRI test conditions was found. The results suggest that the main reaction between coke and CO 2 took place in isotropic areas, which was especially pronounced in coke with a low CSR. Signs of degradation were apparent throughout the coke pieces that have undergone CSR/CRI testing, but were less observable in coke reacted in the blast furnace. The results indicate that reaction with CO 2 is generally limited by the chemical reaction rate in the CSR/CRI test, while in the blast furnace the reaction is limited by the diffusion rate. Coke degradation is therefore mostly restricted to the coke surface in the blast furnace.

  • 70.
    Lundkvist, Katarina
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Brämming, Mats
    SSAB, Sweden.
    Larsson, Mikael
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Samuelsson, Caisa
    Luleå University of Technology, Sweden.
    System analysis of slag utilisation from vanadium recovery in an integrated steel plant2013In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 47, p. 43-51Article in journal (Refereed)
    Abstract [en]

    Vanadium in raw materials used in iron- and steelmaking, a particular challenge for Nordic steel producers, affects the composition of the generated slag from the steelmaking vessel, i.e. The basic oxygen furnace (BOF) adversely and reduces the potential for recycling and external utilisation. A process concept under development aims to enrich and extract the vanadium content of slag from the BOF, making use of the vanadium in the slag and also increasing the overall slag use potential. Applications of this concept affect slag compositions and internal material flows in the iron and steel production system, especially when recycling BOF slags as flux in the blast furnace (BF). This paper will present a case study, based on a Process Integration (PI) approach, using a designated system model to simulate the steel production system and the implementation of the process concept, thereby analysing how to obtain maximum usage of metallurgical slags without compromising the quality of the main product, i.e. liquid steel. Different approaches were studied to improve the environmental sustainability in the production system by maximising the material efficiency through vanadium recovery (as FeV alloy) and the use of slags, thereby minimising the stored/deposited slag amounts.

  • 71.
    Lundkvist, Katarina
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Brämming, Mats
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Riesbeck, Johan
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Wedholm, Anita
    SSAB Merox, Sweden.
    New methods for waste minimization in an integrated steel site2015In: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 45, p. 739-744Article in journal (Refereed)
    Abstract [en]

    Recycling of materials is of major interest in steel making for environmental reasons as well as economical. All process units produce by-products which are either recycled sold or put on landfill. The products have been selected into the categories slags, dusts and sludges. This work evaluates new methods for recycling of by-products in an integrated steel site. The study estimates how much material can be recycled and in which order that would be the most beneficial with respect to costs, energy and deposits. Main focus has been on by-products produced in significant quantities and those difficult to use because of their physical or chemical nature. The work show conflicting results and a pareto front was constructed comparing deposits with increased energy use and costs in the system. Chosen case studies have been tested in industrial scale and results from test periods have been used to compare modelling with process parameters. The results show that improved resource efficiency can be achieved by keeping the energy consumption constant or even receiving small energy credits. Major cost savings can be found if internal recirculation can replace raw material such as iron ore, coke and lime stone. Before the new methods will be implemented careful considerations will be made according to test results and predictions through modelling.

  • 72.
    Lundkvist, Katarina
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Larsson, Mikael
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Samuelsson, Caisa
    Luleå University of Technology, Sweden.
    Optimisation of a centralised recycling system for steel plant by-products, a logistics perspective2013In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 77, p. 29-36Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the optimisation of a recovery strategy for waste materials and thereby improved material efficiency in the iron and steel industry. A joint venture between four Nordic steel plants is considered in order to recycle materials otherwise mainly put to landfill, i.e. dusts and sludges from the steel production processes. Process integration (PI) was used to investigate the possibilities for recovering the materials by developing a system optimisation model of the steel plants and integrating a dedicated material upgrading process in the system. This work aims to develop a model suitable for analysing and finding a logistic solution needed to achieve a common recycling system by studying material supply, required material storage, shipping system and shipping frequency. The developed optimisation model is presented, using a case study of the steel production plants with the dedicated upgrading process and the logistics system. The prospect for shipping materials from the steel production sites to the material upgrading process site as well as the material supply to the upgrading unit is essential in the system analysis. A mathematical optimisation model based on mixed-integer linear programming (MILP) for the common system is presented. The integration of the dedicated material upgrading process show a system in balance regarding the materials generated and processed in the upgrading unit. Generated material amounts suitable for the upgrading process can be fully recovered thereby decreasing the landfilled amounts from the four steel production sites.

  • 73.
    Ma, P.
    et al.
    Luleå University of Technology.
    Lindblom, B.
    LKAB.
    Ye, Guozhu
    RISE, Swerea, Swerea MEFOS.
    Björkman, B.
    Luleå University of Technology.
    Experimental and theoretical study of the removal of sulphur and fluorine from pickling hydroxide sludge generated in the stainless steel industry2005In: REWAS'04 - Global Symposium on Recycling, Waste Treatment and Clean Technology, 2005, p. 2017-2026Conference paper (Refereed)
    Abstract [en]

    Pickling hydroxide sludge (pickling sludge for short) generated in the stainless steel industry in Sweden is currently dumped in special landfill areas. After filtration the sludge contains 50-60 wt-% moisture. After drying at 120̊C it contains about 26 wt-% of metal oxides, such as Fe 2O3, NiO and Cr2O3 and 43 wt-% of CaF2. In order to facilitate the recycling of pickling sludge and/or to recover fluorine as an HF acid, different scale experimental studies to remove sulphur and/or fluorine directly from the sludge have been carried out. Theoretical thermodynamic calculation results show that the simultaneous removal of both sulphur and fluorine is possible when the temperature is above 1500°C under the oxidizing condition and in the presence of water vapour in the system. Experimental results show that the elimination degrees of sulphur and fluorine for pickling sludge can reach 99 wt-% and 84 wt-%, respectively. These results demonstrate that potentially feasible methods for removing sulphur and/or fluorine from the sludge have been found.

  • 74.
    Magnelöv, Marianne
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Carlsson-Dahlberg, Anna
    SSAB EMEA AB, Sweden.
    Gustavsson, Lennart
    SSAB EMEA AB, Sweden.
    Björkvall, Johan
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Björkman, Bo
    Luleå University of Technology, Sweden.
    Iron losses during desulphurisation of hot metal utilising co-injection of Mg and CaC2 combined with nepheline syenite2015In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 42, no 7, p. 525-532Article in journal (Refereed)
    Abstract [en]

    Iron losses during hot metal desulphurisation using magnesium and calcium carbide have been studied by large scale investigations of slag from the slag pit as well as slag sampling during desulphurisation at SSAB EMEA in Luleå. The desulphurisation slag after co-injection is normally solid and contains a large amount of iron. An alkali containing mineral, nepheline syenite, was mixed with calcium carbide to enhance the separation of iron from the slag. Even though the addition of nepheline syenite resulted in a more fine grained slag, no reduction of the iron content in the slag was observed before slag skimming. Nepheline syenite has a positive effect on slag skimming; however, the total magnetic iron losses have not decreased significantly. The increased turbulence during injection of magnesium could explain the lack of improved iron yield. The addition of nepheline syenite does not have a negative influence on the reagent efficiency.

  • 75.
    Magnelöv, Marianne
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Eriksson, Johan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Drugge, J.
    SSAB, Sweden.
    Björkvall, Johan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Björkman, Bo
    Luleå University of Technology, Sweden.
    Investigation of iron losses during desulphurisation of hot metal utilising nepheline syenite2013In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 40, no 6, p. 436-442Article in journal (Refereed)
    Abstract [en]

    Iron losses during calcium carbide based hot metal desulphurisation have been studied via large scale investigations of slag from the slag pit as well as slag sampling during desulphurisation at SSAB EMEA in Luleå. The desulphurisation slag, after injection of calcium carbide, is normally solid and contains large amounts of iron. An alkali containing mineral, nepheline syenite, was mixed together with the calcium carbide to form a more fluid slag as the iron losses originate from enclosed metal droplets in the slag as well as drawn off hot metal during slag skimming. The slag amount after slag skimming decreased from 28.1 to 25.1 kg t-21 hot metal with addition of 5 wt-% nepheline syenite to the calcium carbide, and the magnetic fraction of the slag from the slag pit decreased from 2.5 to 1.9%. Finally, no negative effect on the reagent efficiency was observed during the trials with addition of nepheline syenite.

  • 76.
    Malmberg, Donald
    et al.
    RISE, Swerea, Swerea MEFOS.
    Hahlin, Pär
    RISE, Swerea, Swerea MEFOS.
    Nilsson, E.
    IDE Department.
    Microwave technology in steel and metal industry, an overview2007In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 47, no 4, p. 533-538Article, review/survey (Refereed)
    Abstract [en]

    In many metallurgical operations, effective analysis of the processes can be very difficult with available technology. This is especially true if the analysis is to be performed on-line and in a harsh environment characterized by high temperatures, dust and liquid metal. Protection of the equipment requires both rugged encapsulation as well as elaborate sampling systems and exposure of the equipment to the hazardous environment must be minimised. Often this result in an increased level of service and maintenance requirements and, in the worst case, the maintenance cost might be so high that the equipment is not installed. Microwave technology is a versatile and powerful tool with many different applications in the scientific community. It is insensitive to dust and fume and, for several years, the technology has been tested at MEFOS and evaluated for different metallurgical processes. It has been applied to slag thickness measurement and slag composition in an induction furnace, 3D imaging of the burden surface in a charging model on pilot scale as well as raceway depth measurements in a Blast Furnace. The idea of using microwave technology for gas analysis in metallurgical processes has also been explored. However, despite its many advantages, microwave technology is still not employed extensively in the steel and metal industries. © 2007 ISIJ.

  • 77.
    Malmberg, Kristofer J.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Karasev, Andrey Vladimirovich
    KTH Royal Institute of Technology, Sweden.
    Nzotta, Mselly M.
    Uddeholm AB, Sweden.
    Alexis, Jonas
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Jönsson, Pär Göran
    KTH Royal Institute of Technology, Sweden.
    Influence of final stirring treatment on inclusion number in tool steel2013In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 40, no 6, p. 407-412Article in journal (Refereed)
    Abstract [en]

    The focus was to study the elimination of non-metallic inclusions during the final part of the ladle refining of tool steel (AISI H13). More specifically, the final stirring treatment in a ladle before casting was modified to study how the number of inclusions could be decreased. The following three stirring treatments were tested: a conventional induction stirring with a 650 A current for 20 min, a short induction stirring with a 650 A current during 10 min, and a combined gas and induction stirring during 20 min (no open eye and a 600 A current). Steel samples were collected from the ladle before and after the final stirring period of the ladle treatment. Thereafter, the numbers of inclusions in steel samples were determined using a light optical microscope based on a classification according to the Swedish standard SS111116 (JK Scale II). Overall, the results showed that a combined gas and induction stirrings was the most efficient way of decreasing the number of DM, DH and DP inclusions. The decrease in the inclusion number in four heats was the following for the different size classes for a combined stirring procedure: 15-40% for DM type inclusions, 30-61% for DH type inclusions and 50-100% for DP inclusions. In addition, it should be mentioned that a stirring practice with induction stirring during 10 min resulted in a 67-100% decrease in the DH type inclusions. However, the results for a combined stirring case for DH type inclusions were more stable than those for a shorter induction stirring time.

  • 78.
    Mandova, H.
    et al.
    University of Leeds, UK; IIASA International Institute for Applied Systems Analysis, Austria.
    Leduc, S.
    IIASA International Institute for Applied Systems Analysis, Austria.
    Wang, C.
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. Åbo Akademi University, Finland.
    Wetterlund, E.
    IIASA International Institute for Applied Systems Analysis, Austria; Luleå University of Technology, Sweden.
    Patrizio, P.
    IIASA International Institute for Applied Systems Analysis, Austria.
    Gale, W.
    University of Leeds, UK.
    Kraxner, F.
    IIASA International Institute for Applied Systems Analysis, Austria.
    Possibilities for CO2 emission reduction using biomass in European integrated steel plants2018In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 115, p. 231-243Article in journal (Refereed)
    Abstract [en]

    Iron and steel plants producing steel via the blast furnace-basic oxygen furnace (BF-BOF) route constitute among the largest single point CO2 emitters within the European Union (EU). As the iron ore reduction process in the blast furnace is fully dependent on carbon mainly supplied by coal and coke, bioenergy is the only renewable that presents a possibility for their partial substitution. Using the BeWhere model, this work optimised the mobilization and use of biomass resources within the EU in order to identify the opportunities that bioenergy can bring to the 30 operating BF-BOF plants. The results demonstrate competition for the available biomass resources within existing industries and economically unappealing prices of the bio-based fuels. A carbon dioxide price of 60 € t−1 is required to substitute 20% of the CO2 emissions from the fossil fuels use, while a price of 140 € t−1 is needed to reach the maximum potential of 42%. The possibility to use organic wastes to produce hydrochar would not enhance the maximum emission reduction potential, but it would broaden the available feedstock during the low levels of substitution. The scope for bioenergy integration is different for each plant and so consideration of its deployment should be treated individually. Therefore, the EU-ETS (Emission Trading System) may not be the best policy tool for bioenergy as an emission reduction strategy for the iron and steel industry, as it does not differentiate between the opportunities across the different steel plants and creates additional costs for the already struggling European steel industry. © 2018 The Authors

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  • 79.
    Marston, H.F.
    et al.
    Swinden Technology Centre.
    Bolt, P.H.
    IJmuiden Technology Centre.
    Leprince, G.
    IRSID.
    Röder, M.
    Keiper GmbH.
    Klima, R.
    Betriebsforschungsinstitut.
    Niska, John
    RISE, Swerea, Swerea MEFOS.
    Jarl, M.
    University of Orebro.
    Challenges in the modelling of scale formation and decarburisation of high carbon, special and general steels2004In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 31, no 1, p. 57-65Article, review/survey (Refereed)
    Abstract [en]

    The oxygen bearing gases of the atmosphere in a reheating furnace oxidise the feedstock producing scale on the surface of the metal and, for high carbon steels, cause decarburisation of the surface layers. Modelling of these effects has to take into account the competitive nature of the two processes, scale formation and decarburisation, and complications that arise from changes in the controlling mechanism. Initially, the rate of scale formation may be controlled by effects in the gas phase, or nucleation of scale on the metal surface. Subsequently, scale growth is influenced by the gas composition and may be disturbed by the accumulation of oxidation products at the scale-metal interface. Voids and cracks within the scale may either inhibit solid state diffusion within the scale or provide channels for oxidising gas to access the scale-metal interface, For decarburisation, complications arise if a ferrite rim creates a step in the carbon profile or if retention of carbon monoxide within the scale provides a thermodynamic barrier to the reaction. This paper considers these complications and how they may be handled in mathematical models.

  • 80.
    Mellin, Pelle
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wei, Wenjing
    KTH Royal Institute of Technology, Sweden.
    Yang, Weihong
    KTH Royal Institute of Technology, Sweden.
    Salman, Hassan
    Sveaskog, Sweden.
    Hultgren, Anders
    SCA Energy, Sweden.
    Wang, Chuan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Biomass availability in Sweden for use in blast furnaces2014In: Energy Procedia, Elsevier Ltd , 2014, Vol. 61, p. 1352-1355Conference paper (Refereed)
    Abstract [en]

    Based on the type of BF operated in Sweden, the pulverized coal (PC) has primarily been considered replaceable. If replacing the PC, a reduction of 1.25 Mton CO2 annually is possible, which would require approximately 4 TWh charcoal (0.46 Mton) or 7.14 TWh of dry raw biomass. This amount of biomass is substantial and availability is the main concern discussed in this paper. Uncertainty of the future biomass supply makes predictions beyond 2030 difficult. However, the predictions used in this work indicate that there is an unused potential, which could cover the need of all PCI in Sweden. Other aspects could potentially limit the proportion of PCI replaced by biomass, which should be further investigated.

  • 81.
    Millman, M.S.
    et al.
    Tata Steel Research, UK.
    Overbosch, A.
    Tata Steel Europe Limited.
    Kapilashrami, A.
    Tata Steel Europe Limited.
    Malmberg, Donald
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Brämming, Mats
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Observations on BOS refining2013In: Transactions of the Indian Institute of Metals, ISSN 0972-2815, E-ISSN 0975-1645, Vol. 66, p. 525-534Article in journal (Refereed)
    Abstract [en]

    Selected IMPHOS (IMproving PHOSphorus refining) heats ([1], [2]: Millman et al. in Proc. Scanmet 3, 2008; and Millman et al. in Ironmak Steelmak 38:499, 2011), have been used to make observations on decarburizing and dephosphorising performance characteristics during BOS refining. If it is assumed that decarburization takes place solely in the slag/metal emulsion then maximum metal residence time in the emulsion is just under 9 sec and at peak decarburisation time, the maximum amount of metal in the emulsion is ∼ 50 % of the total metal content in the converter. To evaluate the effects of changes in slag component chemistry on phosphorus refining it is necessary to account for changes in slag weight, which can change substantially throughout a heat and be significantly different heat-to-heat. Dephosphorising performance depends on the thermodynamic stability of slag phases that are able to take-up phosphorus and the distribution of phosphorus between these thermodynamically stable phases. The application of proprietary thermodynamic models such as MTDATA and FACTSage has helped to clarify such events. The stability of the foamy slag/metal emulsion changes over the period of the blow. Slag height increases with an increase in FeO (tot) wt% and decreases with a decrease in decarburisation rate and the collapse of the foamy slag. © 2013 Indian Institute of Metals.

  • 82.
    Millman, M.S.
    et al.
    Tata Steel Research.
    Overbosch, A.
    Tata Steel Europe Limited.
    Kapilashrami, A.
    Tata Steel Europe Limited.
    Malmberg, Donald
    RISE, Swerea, Swerea MEFOS.
    Brämming, Mats
    SSAB.
    Some observations and insights on BOS refining2013In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 40, no 6, p. 460-469Article in journal (Refereed)
    Abstract [en]

    Selected IMPHOS heats,1,2 have been used to make observations on decarburising and dephosphorising performance, scrap melting and slag foaming characteristics during BOS refining. If it is assumed that decarburisation takes place solely in the slag/metal emulsion then maximum metal residence time in the emulsion is just under 9 seconds and at peak decarburisation time, the maximum amount of metal in the emulsion is ∼50% of the total metal content in the converter. To evaluate the effects of changes in slag component chemistry on phosphorus refining it is necessary to account for changes in slag weight, which can change substantially throughout a heat and be significantly different heat-to-heat. Dephosphorising performance depends on the thermodynamic stability of slag phases that are able to take up phosphorus and the distribution of phosphorus between these thermodynamically stable phases. The application of proprietary thermodynamic models such as MTDATA and FACTSage has helped to clarify such events. Skull build-up on the scrap pile is at a maximum when the bulk bath temperature is ∼1460°C. At this time, the solid scrap and skull component of the bulk bath makes-up just over 60% of all the metal charged to the converter. All scrap and skull is melted out at a bulk bath temperature of ∼1610°C. The stability of the foamy slag/metal emulsion changes over the period of the blow. Slag height increases with an increase in FeO(tot)wt-% and decreases with a decrease in decarburisation rate and the collapse of the foamy slag. © 2013 Institute of Materials, Minerals and Mining.

  • 83.
    Millman, M.S.
    et al.
    Tata Research, UK.
    Overbosch, A.
    Tata Research, UK.
    Kapilashrami, A.
    Tata Research, UK.
    Malmberg, Donald
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Brämming, Mats
    SSAB Tunnplåt AB, Sweden.
    Study of refining performance in BOS converter2011In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 38, no 7, p. 499-509Article in journal (Refereed)
    Abstract [en]

    A unique in blow sampling system has been applied to a blowing converter to retrieve simultaneously representative bulk metal bath and slag/metal emulsion samples from seven specified positions and every 2 min from start of blow. Full sample datasets from 20 heats have been grouped according to differences in the bulk bath phosphorus removal profiles and analysed with respect to relative refining ability of the slag/metal emulsion and the bulk metal bath. The complexity of the thermokinetic relationships behind the removal of carbon and the transfer of silicon, phosphorus, manganese and sulphur between the metal and slag is highlighted and the metal circulation rate in the emulsion is derived. © 2011 Institute of Materials, Minerals and Mining.

  • 84.
    Mills, K.C.
    et al.
    Imperial College.
    Ramirez-Lopez, Pavel Ernesto
    RISE, Swerea, Swerea MEFOS.
    Lee, P.D.
    University of Manchester.
    Santillana, B.
    Tata Steel RD and T.
    Thomas, B.G.
    Morales, R.
    National Polytechnic Institute ESQIE.
    Looking into continuous casting mould2014In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 41, no 4, p. 242-249Article in journal (Refereed)
    Abstract [en]

    When you look into the continuous casting mould you can see very little. Consequently, steelmakers have had to rely on plant trials, simulation experiments and physical property measurements on fluxes and steels to gain an understanding of the mechanisms responsible for process problems and product defects. However, in recent years, mathematical modelling has advanced to the stage where they can provide us with great insight into these mechanisms. As a nonmathematical modeller, I was initially sceptical of some of the predictions of the mathematical models. However, I have been completely won over by the ability of these models to simulate accurately the mechanisms responsible for various defects, such as slag entrapment, oscillation mark formation, etc. Mathematical modelling literally allows us to 'see' what is happening in the mould. It is a remarkable tool. © 2014 Institute of Materials.

  • 85.
    Mousa, Elsayed Abdelhady
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. CMRDI Central Metallurgical Research and Development Institute, Egypt.
    Ahmed, Hesham Mohamed
    Lulea University of Technology, Sweden; CMRDI Central Metallurgical Research and Development Institute, Egypt.
    Wang, Chuan
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. Åbo Akademi University, Finland.
    Novel approach towards biomass lignin utilization in ironmaking blast furnace2017In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 57, no 10, p. 1788-1796Article in journal (Refereed)
    Abstract [en]

    Growing concerns over fossil CO2 emissions has created a considerable interest in an efficient utilization of renewable biomass in steel industry. Biomass lignin can be used as binder and reducing agent in the blast furnace briquettes. The traditional briquettes consist of various iron oxide-containing residues and cement is used as binder to give the proper mechanical strength. In the present study, cement (C) has been partially and totally substituted with lignin (L) to produce briquettes containing 0-12 wt.% lignin (L/C: 0, 10, 25, 50 and 100%). The mechanical strength has been evaluated based on drop test and tumbler index measurement. The partial replacement of cement with lignin up to 25% (3.0 wt.% lignin in briquettes) was exhibited adequate briquettes strength for blast furnace application. At higher substitution rate (L/C: 50 and 100%), the briquettes strength was sharply decreased. The briquettes with proper mechanical strength (L/C: 0, 10 and 25%) were subjected to self-reduction under inert atmosphere using thermogravimetric technique (TGA). The reduction rate of briquettes increased when increasing the cement substitution with lignin. The reduction took place in two main steps at 500-800°C and 800-940°C. Combined effect of gas diffusion and interfacial reaction were the rate determining step at the first stage while carbon gasification was controlling the second step of reduction. Interrupted reduction tests have been conducted to evaluate the compression strength after reduction. For all briquettes, the increased reduction temperature and lignin content deteriorated the briquette's mechanical strength due to the effect of dehydration and lignin gasification.

  • 86.
    Niemi, Jan
    et al.
    RISE, Swerea, Swerea MEFOS.
    Nilsson, Annika
    RISE, Swerea, Swerea MEFOS.
    Helkomaa, J.
    Rautaruukki Oyj.
    Rautiainen, J.
    Rautaruukki Oyj.
    Scale monitoring system tested at Ruukki metals plate mill in Raahe2013In: Materials Engineering Forum, 2013, Vol. 762, p. 644-648Conference paper (Refereed)
    Abstract [en]

    Some surface defects on hot rolled steels arise due to poor descaling. Generally reheated slabs are efficiently descaled but, now and then, residual scale remains on the slab after primary descaling. Commonly it is difficult to trace the few poorly descaled slabs since there often is no scale monitoring system. In the work presented here an image based primary scale monitoring- and evaluation system is presented. It is a stand-alone online vision system consisting of a camera connected to a computer. The camera is located directly after the descaling unit and the computer in the control room. The program automatically locates the boundaries of the top surface of a slab and calculates the quantity of residual scale on the top surface. The quantity of residual scale is logged and can afterwards be evaluated together with process parameters and downstream surface defects to identify problem areas. The system has been tested in industrial scale in the Ruukki plate mill. This work is a cooperation between Swerea MEFOS and Ruukki. The result of the test demonstrated the feasibility of using vision system for detection of residual scale. Some problems were identified and suggestions for solving them are reported. If the suggested modifications are carried out, it is believed that the vision system can be an on-line tool for the operator and also be an off-line resource for the ongoing quality work at the hot rolling mill. © (2013) Trans Tech Publications, Switzerland.

  • 87.
    Nilsson, Annika
    et al.
    RISE, Swerea, Swerea MEFOS.
    Melin, L.
    Luleå University of Technology.
    Magnusson, C.
    Luleå University of Technology.
    Finite-element simulation of V-die bending: A comparison with experimental results1997In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 65, p. 52-58Article, review/survey (Refereed)
    Abstract [en]

    A major problem in sheet bending is to compensate for springback. Analytical descriptions are not sufficiently general to accommodate influences from the material and the geometry due to the simplifications that have to be made. Practical experiments are still needed to be able to compensate for springback. The aim of this work has been to test the finite-element method on its abilities to predict springback for free bending in a V-die. The work shows that the finite-element method can be used to predict springback off-line. The true stress-true strain curve from a tensile test is used as the material description. Springback has been studied for eight different materials of varying thickness. The process has been simulated with the code Nike2d and the results from the simulations compared with those from experiments, good correlation between the simulations and the experiments being achieved. © 1997 Elsevier Science S.A.

  • 88.
    Olofsson, David
    et al.
    RISE, Swerea, Swerea MEFOS.
    Bellqvist, David
    RISE, Swerea, Swerea MEFOS.
    Karlsson, J.
    LuleKraft AB.
    Johansson, M.
    Luleå Energi AB.
    Optimising the operation of a district heating system2013In: Chemical Engineering Transactions, Italian Association of Chemical Engineering - AIDIC , 2013, Vol. 35, p. 637-642Conference paper (Refereed)
    Abstract [en]

    A system with several actors will increase the possibilities for collaboration and therefore, in many cases also increase the possibilities to affect the operation with economic and environmental benefits. In this paper a district heating system is studied with purpose to create economic and environmental operation guidelines in favour of the involved actors. The company LuleKraft owns a combined heat and power plant, while the four heating stations together with the DH network are owned by Luleå Energi. District heat is produced from the CHP plant and the four heating stations which are fired with process gases from an integrated steel plant, oil, wood pellets or electricity. The heat demand in the system is strongly depending on the outdoor temperature. In this paper, the system is modelled with Mixed Integer Non Linear Programming in order to optimise the profit and CO2 emission. A comparison between actual process data and modelled results is performed. A pareto front is derived to show the trade-off between economic benefits and CO2 emissions. It is found that the main suggestions, under conditions for optimised profit, are (1) to prioritize effective heat production instead of electricity production at cold outdoor temperatures and (2) redistribution of the accessible process gases between the CHP plant and one of the heating stations. This will lead to an improved operation strategy, resulting in increased profit and reduced energy consumption. Copyright © 2013, AIDIC Servizi S.r.l.

  • 89.
    Orre, Joel
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Bellqvist, David
    SSAB EMEA, Sweden.
    Nilsson, Leif
    SSAB EMEA, Sweden.
    Alström, Linus
    LuleKraft AB, Sweden.
    Wiklund, Stefan
    LuleKraft AB, Sweden.
    Optimised integrated steel plant operation dependent on seasonal combined heat and power plant energy demand2018In: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 70, p. 1117-1122Article in journal (Refereed)
    Abstract [en]

    The steel industry is energy intensive with large corresponding contributions of fossil CO2 emissions, which accounts to around 7 % of the global emissions. This presents great challenges, and continuous work is therefore done to reduce energy consumption and CO2 emissions. This work evaluates ways of decreasing the total energy demand and CO2 emissions in a system containing integrated steel plant connected to a combined heat and power plant (CHP), through optimised production operation with respect to seasonal-dependent energy demands. The studied system, which includes SSAB EMEA Lulea (integrated steel plant) and LuleKraft (CHP), is located in the municipality of Lulea in northern Sweden. The CHP produces the base demand of district heat (DH) for the community, with process gases from the integrated steel plant as its main fuel. Oil is used as an extra energy source when the amounts of process gases are insufficient to meet the DH demand, which happens mainly in the cold winter periods. Therefore, this study aims to find production guidelines to minimise the additional energy consumption of oil through matching cold winter periods with high production of process gases. Optimisation of the system is performed with a mixed integer linear programming (MILP) model based on process data for a normal year. The year is divided into periods based on varying DH demand, to give the model possibility to choose how the integrated steel plant is best operated in each period. The main variables in the integrated steel plant for the study are coke production and usage of recirculated materials, which are bound by yearly demand and availability. Optimisation of this setting is then evaluated in comparison to an optimisation where the integrated steel plant is operated in a constant manner the whole year. Results show that an optimised use of recirculated materials and coke production decreases yearly oil consumption with up to 8 GWh and increases yearly electricity production with up to 8 GWh.

  • 90.
    Orre, Joel
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Wang, Chuan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Larsson, Johan
    SSAB, Sweden.
    Olsson, Erik T.
    SSAB, Sweden.
    Potential impacts on the energy system at the integrated steelwork by changing injection coal types to the blast furnace2013In: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 35, p. 973-978Article in journal (Refereed)
    Abstract [en]

    Pulverized coal is often injected into the blast furnaces (BFs) at the integrated steelworks as reducing agent for the hot metal production. The BF process will behave different depending on the injection coal used. The objective of this study is to investigate how different types of coal will influence the BF, and the total energy system atan integrated steel plant. The major process units covered in the model are coking plant, BF, reheating furnace at the rolling mill and a power plant. They are all linked to each other via the main products as well as process gases (i.e. blast furnace gas (BFG)and coke oven gas (COG)) and oxygen network. At the studied plant, the mixed gas of BFGand COG is used within the coking batteries at the coking plant and hot stoves at the BF. The fuel used at the reheating furnace is COG and oil with high heating values. In total, 13 different types of coal and one biomass charcoal are included in the study. Possible impacts on energy and CO 2 emission from a holistic view have been analyzed for different types of coal and injection rates. The different strategies on pulverized coal injection to BF are presented and discussed.

  • 91.
    Presz, W.
    et al.
    Warsaw University of Technology.
    Wanheim, T.
    Proconsult.
    Lagergren, J.
    Åkers Sweden AB.
    Jonsson, Nils-Göran
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Application of surface load - A new calibration method2011In: Proceedings of the 10th International Conference on Technology of Plasticity, ICTP 2011, 2011, p. 1265-1269Conference paper (Refereed)
    Abstract [en]

    A special kind of transducer making it possible to measure normal and tangential contact stresses during rolling has been developed. As normal stresses are approximately ten times larger than the tangential, and since cross signals must occur, a proper calibration of the sensor is essential. Calibration must consist of a number of simultaneous applications of known normal and tangential loads. This problem was solved with an especially designed apparatus called Surface Loader (SL). The design makes it possible to apply a force of known value and direction to a small area of the surface. If the value and direction of force is known it might be treated as applying normal and tangential load using the force components. The contact end of the force actuator has a low carbon steel nose, making it possible to reach high friction coefficients. A precise determination of the applied force direction is possible by the invented method of loading. It is applied by a special construction of SL, controlling of the bending moment acting on the actuator by measuring the reaction force and using a special loading procedure: (i) Applying normal force on the sensor surface - a lateral support is used, (ii) Removing the lateral support, (iii) Developing friction by horizontally moving the platform until the moment in the actuator disappears. © 2011 IBF (RWTH Aachen) & IUL (TU Dortmund).

  • 92.
    Ramirez Lopez, Pavel Ernesto
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Jalali, Pooria Nazem
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Björkvall, Johan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sjöström, Ulf
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Nilsson, C.
    SSAB EMEA.
    Recent developments of a numerical model for continuous casting of steel: Model theory, setup and comparison to physical modelling with liquid metal2014In: ISIJ International, Iron and Steel Institute of Japan , 2014, Vol. 54, no 2, p. 342-350Conference paper (Refereed)
    Abstract [en]

    Recent developments of an advanced numerical model for Continuous Casting of steel unveiled at the previous 2010 CSSCR Conference in Sapporo, Japan are presented. These include coupling of the existing multiphase, heat transfer and solidification model to argon injection for tracking bubble trajectories in the SEN, metal bulk and across the slag bed after passing through the metal surface. Hence, description of a method for adding gas injection in combination with a multiphase model for tracking metal/slag interfaces (Discrete Phase Model + Volume Of Fluid, DPM+VOF) is given. Validation is supported by tests on a revamped Continuous Casting Simulator (CCS-1) based on a low melting point alloy, which can realistically replicate the flow conditions in the caster. Metal-slag-argon flow predictions were compared to observations in the physical model showing good agreement on features such as discharging jets, rolls, standing waves and argon distribution measured through a variety of techniques such as ultrasound, electromagnetic probes and video sequences. Ultimately, the model makes possible the prediction of stable or unstable flows within the mould as a function of different argon flow-rates and bubble sizes. Application to industrial practice is an ongoing task and preliminary results are illustrated. The robustness of the model combined with direct observations in CCS-1 make possible the description of phenomena difficult to observe in the caster (e.g. argon injection and metal flow), but critical for the stability of the process and the quality of cast products. © 2014 ISIJ.

  • 93.
    Ramirez Lopez, Pavel Ernesto
    et al.
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS.
    Jalali, Pooria Nazem
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS. KTH Royal Institute of Technology, Sweden.
    Sjostrom, Ulf
    RISE - Research Institutes of Sweden, Swerea, Swerea MEFOS.
    Jonsson, Par Goran
    KTH Royal Institute of Technology, Sweden.
    Mills, Kenneth C.
    Imperial College London, UK.
    Sohn, Il
    Yonsei University, South Korea.
    Key Lubrication Concepts to Understand the Role of Flow, Heat Transfer and Solidification for Modelling Defect Formation during Continuous Casting2018In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 58, no 2, p. 201-210Article in journal (Refereed)
    Abstract [en]

    Surface defects are recurrent problems during Continuous Casting of steel due to the introduction of new grades that are often difficult to cast, as well as the everlasting pursuit for higher quality and improved yield. Accordingly, numerical modelling has become a ubiquitous tool to analyse the formation mechanisms of such defects. However, industrial application of simulations is often hampered by oversimplifications and omissions of important process details such as variations in material properties, specific casting practices or shortcomings regarding fundamental metallurgical concepts. The present manuscript seeks to create awareness on these issues by visiting key notions such as slag infiltration, interfacial resistance and Lubrication Index. This is done from a conceptual point of view based on industrial observations and numerical modelling experiences. The latter allows a re-formulation of outdated concepts and misconceptions regarding the influence of fluid flow, heat transfer and solidification on lubrication and defect formation. Additionally, the manuscript addresses common challenges and constraints that occur during industrial implementation of numerical models such as the lack of high -temperature material data for slags. Finally, the manuscript provides examples of improvements on product quality and process stability that can be achieved through a holistic approach which combines modelling with laboratory tests, experiences from operators and direct plant measurements.

  • 94.
    Ramirez Lopez, Pavel Ernesto
    et al.
    RISE, Swerea, Swerea MEFOS.
    Mills, K.C.
    Imperial College London.
    Lee, P.D.
    Imperial College London.
    Santillana, B.
    Tata Steel Research Development and Technology.
    A unified mechanism for the formation of oscillation marks2012In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 43, no 1, p. 109-122Article in journal (Refereed)
    Abstract [en]

    Oscillation marks (OMs) are regular, transverse indentations formed on the surface of continuously cast (CC) steel products. OMs are widely considered defects because these are associated with segregation and transverse cracking. A variety of mechanisms for their formation has been proposed (e.g., overflow, folding, and meniscus freezing), whereas different mark types have also been described (e.g., folded, hooks, and depressions). The current work uses numerical modeling to formulate a unified theory for the onset of OMs. The initial formation mechanism is demonstrated to be caused by fluctuations in the metal and slag flow near the meniscus, which in turn causes thermal fluctuations and successive thickening and thinning of the shell, matching the thermal fluctuations observed experimentally in a mold simulator. This multiphysics modeling of the transient shell growth and explicit prediction of OMs morphology was possible for the first time through a model for heat transfer, fluid flow, and solidification coupled with mold oscillation, including the slag phase. Strategies for reducing OMs in the industrial practice fit with the proposed mechanism. Furthermore, the model provides quantitative results regarding the influence of slag infiltration on shell solidification and OM morphology. Control of the precise moment when infiltration occurs during the cycle could lead to enhanced mold powder consumption and decreased OM depth, thereby reducing the probability for transverse cracking and related casting problems. © The Minerals, Metals & Materials Society and ASM International 2011.

  • 95.
    Ramirez Lopez, Pavel Ernesto
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sjöström, Ulf
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Jonsson, Thomas
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Lee, P.D.
    University of Manchester, United Kingdom.
    Mills, K.C.
    Imperial College London, United Kingdom.
    Petäjäjärvi, Marko
    Outokumpu Tornio Works, Finland.
    Pirinen, Jarno
    Rautaruukki Oy, Finland.
    Industrial application of a numerical model to simulate lubrication, mould oscillation, solidification and defect formation during continuous casting2012In: IOP Conference Series: Materials Engineering and Engineering, 2012, Vol. 33, no 1, article id 012013Conference paper (Refereed)
    Abstract [en]

    In recent years, the addition of the slag phase to numerical models of the Continuous Casting (CC) process has opened the door to a whole new range of predictions. These include the estimation of slag infiltration and powder consumption (lubrication), heat transfer and cooling through the cooper mould (solidification) and investigating the effect of operational parameters such as mould oscillation and powder composition on surface quality / defect formation. This work presents 2D and 3D CC models capable of describing the dynamic behaviour of the liquid/solid slag in both the shell mould-gap and bed as well as its effects on heat extraction and shell formation. The present paper also illustrates the application of the model to a variety of casters and the challenges faced during its implementation. The model attained good agreement on the prediction of mould temperatures and shell thicknesses as well as slag film formation and heat flux variations during the casting sequence. The effect of different oscillation strategies (sinusoidal and non-sinusoidal) was explored in order to enhance powder consumption and surface quality. Furthermore, the modelling approach allows one to predict the conditions leading to irregular shell growth and uneven lubrication; these are responsible for defects such as, stickers, cracking and, in the worst case scenario, to breakouts. Possible mechanisms for defect formation are presented together with strategies to enhance process stability and productivity of the CC machine.

  • 96.
    Ramirez Lopez, Pavel Ernesto
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sjöström, Ulf
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Lee, Peter D.
    University of Manchester, United Kingdom.
    Mills, Kenneth C.
    Imperial College London, United Kingdom.
    Jonsson, Björn
    Outokumpu Stainless AB, Finland.
    Janis, Jesper
    Outokumpu Stainless AB, Finland.
    A novel approach for coupling slag infiltration to metal flow, solidification and mold oscillation on a 3d model for continuous casting of slabs2012In: AISTech - Iron and Steel Technology Conference Proceedings, 2012, p. 1259-1267Conference paper (Refereed)
    Abstract [en]

    This work presents a novel modeling methodology which allows one to predict slag infiltration in a 3D slab model by coupling the slag behavior with the metal flow, heat transfer, oscillation and solidification within the mold. The model is able to describe the dynamic behavior of liquid/solid slag in the shell mold gap and the bed, as well as its effects on heat extraction and shell formation. This paper also illustrates both the application of the model to industrial practice and the challenges faced during its implementation. Furthermore, the model allows one to predict the conditions leading to irregular shell growth, which is likely to generate defects such as cracking and bulging. It also provides, at the same time, a more fundamental understanding of the mechanisms responsible for defect formation.

  • 97.
    Riesbeck, Johan
    et al.
    RISE, Swerea, Swerea MEFOS.
    Sandberg, J.
    LKAB.
    Wang, Chuan
    RISE, Swerea, Swerea MEFOS.
    A system analysis of LKAB malmberget heating system to centralisation and substitution of fossil fuels to biofuels2012In: Chemical Engineering Transactions, Italian Association of Chemical Engineering - AIDIC , 2012, Vol. 29, p. 793-798Conference paper (Refereed)
    Abstract [en]

    An industrial heating system connected to an iron ore mine and iron ore upgrading processing system is presented. The profitability of introducing measures for increased energy efficiency and improved waste heat utilisation has been investigated. The results show that a full centralisation of the system with increased heat recovery and densified wood based boilers is the most financial solution of a life span over twenty years. The system will be more flexible and easy to connect with external users if a centralisation is made. To minimise the risk of increased energy prices it is recommended to increase waste heat utilisation which will be most profitable if the system is centralised. Use of bio based boilers will make the system free from fossil fuels. Copyright © 2012, AIDIC Servizi S.r.l.

  • 98.
    Riesbeck, Johan
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    Sandberg, Johan
    LKAB, Sweden.
    Wang, Chuan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, MEFOS.
    A system analysis of LKAB Malmberget heating system to centralisation and substitution of fossil fuels to biofuels2012In: CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference PRES, 2012Conference paper (Refereed)
    Abstract [en]

    The profitability of shifting from a current decentralized and oil- and electricity-based heat production to a centralized system was evaluated. Existing decentralized system with upcoming retrofit investment was not efficient. Three cases showing the investment costs, energy costs, maintenance costs, and CO2 used are presented. The financial evaluation of this work was made considering 10% discount rate. Sensitivity analysis should be made for various energy costs and discount rates. In Malmberget, the heat demand varies significantly from winter to summer. This means the system needs a high maximal capacity but only a part time of the year. The waste heat recovery cannot cover for the maximum heat load in winter, so extra heat capacity is required. This extra heat can be made from different sources, e.g., electricity, oil, coal, biomass, and heat, from district. Thus, a centralized system will, in several ways, make the heat deliveries and future improvements more flexible. It will be able to increase the life time of boilers, which is not needed all year around. It is easier to connect new buildings and processes to the system and control of the system will be easier when most of the heat is produced in the same building. This is an abstract of a paper presented at the CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (Prague, Czech Republic 8/25-29/2012).

  • 99.
    Riesbeck, Johan
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Wedholm, Anita
    SSAB Merox AB, Sweden.
    Lundkvist, Katarina
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Brämming, Mats
    RISE - Research Institutes of Sweden, Materials and Production, Swerea MEFOS.
    Systematic study on recycling of waste materials in an integrated steel site2015In: AISTech - Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, AISTECH , 2015, Vol. 2, p. 2022-2030Conference paper (Refereed)
  • 100.
    Ryman, Christer
    RISE, Swerea, Swerea MEFOS.
    2nd international conference on process development in iron and steelmaking2004In: Nordic Steel and Mining Review, 2004, no 3, p. 11-oktConference paper (Refereed)
    Abstract [en]

    [No abstract available]

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