Timo Fabritius

University of Oulu · Faculty of Technology

This study investigated lignin as a reducing agent instead of fossil carbon for the reduction of zinc oxide and zinc ferrite contained in steelmaking dusts. Three types of dusts from different steelmaking processes were considered: ferrochrome converter (CRC), electric arc furnace stainless steel (EAFSS) and electric arc furnace carbon steel (EAFCS...

There has been a rising interest in the iron and steel industry in replacing fossil-based carbon carriers in their processes because they are the main origin of the anthropogenic carbon emissions within the industry. The use of bio-based carbon carriers could be one solution to partly tackle this challenge. Conventionally, biocarbon is produced by...

Direct reduction of iron ores with hydrogen is envisioned to serve as a backbone of future low-CO2 steelmaking routes. In comparison with carbon monoxide- or methane-based direct reduced iron (DRI), the properties and composition, such as porosity and the absence of carbon, of H2-reduced DRI will be different. The change in the feed material will,...

Due to the ever‐increasing demand for high‐quality steel and the need to reduce CO 2 emissions, research and development of sustainable steelmaking processes have gained a lot of interest in the past decade. One of these processes is the hydrogen plasma smelting reduction (HPSR), which has proven to be a promising solution for iron ore reduction wh...

Electric steelmaking plays an important role in various scenarios for environmentally friendly steelmaking where the processes must be energetically and economically feasible. As electric furnaces’ capacities and low-grade recycled material usage can be expected to increase, optimizing the process practices and flexibility becomes paramount. The hi...

Slag foaming practice is employed widely in electric arc furnace steelmaking to improve the energy efficiency, protect the furnace structures and reduce noise pollution. Slag foaming is typically launched by injecting fossil-based carbonaceous material (e.g. coke dust) into the melt. In this study, a novel laboratory-scale experimental setup was us...

This work focused on the usage of bio-based and secondary iron and steelmaking raw materials. Auger pressing briquettes, cold-bonded agglomerates made from by-products, mainly mill scale (80%), were successfully tested in industrial-scale blast furnace (BF) trials. The briquettes from industrial production were studied in two different laboratory-s...

The formation of defects such as cracks in continuous casting deteriorates the quality of cast products and efficiency of steelmaking. To evaluate the risks and identify the root causes of defect formation, phenomenological quality criteria computed with a solidification and microstructure model known as InterDendritic Solidification (IDS) have pre...

The mitigation of CO2 emissions is one of the major areas of research in iron ore-based steelmaking. In this study, four simulated current and potential future reheating scenarios with different fuel and oxidizer gases were studied regarding the amount of oxide formation and the adhesion of the steel–oxide interface: (1) methane–air; (2) coke oven...

Final report of the Towards Carbon Neutral Metals (TOCANEM) project funded by Business Finland.

High‐aluminum advanced high‐strength steels have received increasing interest due to their excellent combination of strength and ductility. The control of non‐metallic inclusions in steel is among the most important issues for the production of high‐aluminum steel. This study proposes a model for the evolution of size distributions of AlN inclusion...

Slags are one of the postproduction wastes in iron and steel-making processes. Iron and steel production industries are looking for new technologies to recycle and reuse slags. There is a high potential for the recovery of iron from slags. Furthermore, the composition of slags should be adjusted to make them ready to be used in the cement and concr...

The evolution from natural gas usage to new technologies, such as the use of hydrogen as fuel or electricity‐based heating, strongly influences the oxidation of the stainless steel surface in the reheating furnace. Thermogravimetric tests using different simulated combustion and induction reheating conditions are performed for austenitic AISI 301,...

Biomass-based solutions have been discussed as having the potential to replace fossil-based solutions in the iron and steel industry. To produce the biocarbon required in these processes, thermochemical treatment, pyrolysis, typically takes place. There are various ways to produce biocarbon, alongside other products, which are called pyrolysis oil...

Defect formation in continuous casting is an issue that significantly undermines the material and energy efficiency of steelmaking. In previous work, a solidification and microstructure model known as IDS (InterDendritic Solidification) has been developed and implemented in various slab casters in Finland. Phenomenological quality criteria have bee...

The steel industry accounts for approximately 7 % of all the global CO2 emissions, where majority of these emissions are caused by carbon-based reduction of iron ores and fossil-based fuels. Due to the significant share of the CO2 emissions related to the steel industry, a transition toward environmentally sustainable steelmaking has a key role in...

Hydrogen plasma smelting reduction (HPSR) has the potential to be a viable solution for both reducing metal-bearing oxides and treatment of metallurgical sidestreams for metal recovery. However, thermal plasmas are known for their erratic and sometimes unpredictable behavior. Plasmas are highly dynamic entities, as their properties change rapidly d...

Non-metallic inclusions have critical effects on the properties and manufacturing process of steels. The amount, composition, morphology, and size distribution of inclusions define the cleanliness of steel, which is the key to “clean steel”. In this work, a modelling framework for describing the evolution of amount, composition, and size distributi...

Reducing the CO2 burden of cement manufacturing can be achieved by increasing the ferrite content in cement as ferrite requires less calcium than other major clinker phases and thus reducing CO2 emission from limestone (mainly CaCO3) calcination. The steel industry produces vast and increasing amounts of EAF (electric arc furnace) slag that consist...

The reduction kinetics of cold‐bonded briquette prepared from return fines of sinter is studied. The results reveal that cold‐bonded briquettes with coke (CBBC) have a higher reduction velocity index (RVI) value than cold‐bonded briquettes without coke (CBB). Interfacial chemical reaction controls the early stages of the CBB reduction process at 90...

A dynamic one-dimensional mathematical model was developed for predicting the thermal state of a steelmaking ladle. The model is intended to be used in process control applications, in which fast computational times are desirable alongside model accuracy. The calculation domain was discretized using the finite difference method, and time integratio...

Hot metal desulfurization operates as an extraction process in steel production after the blast furnace. Mathematical modeling of the process provides the basis for control and optimization solutions. Owing to complex dynamics, an exhaustive physico-chemical description of the process is computationally infeasible. Thus, a model with a gray-box str...

Identification and characterization play an essential role in the study of non-metallic inclusions (NMIs) in monitoring the steel casting process and product quality. This study uses Raman spectroscopy, a versatile, relatively fast, and non-destructive technique for characterizing oxide and sulfide-based inclusion phases in steel samples. The relat...

Crack formation is an issue that undermines the quality and productivity of steel production significantly. In previous work, a solidification and microstructure model known as IDS (InterDendritic Solidification) has been developed and implemented in various slab casters in Finland. Numerous quality criteria have been derived from the model outputs...

The possibility of replacing methane with hydrogen as the fuel gas in an annealing furnace was studied in regard to the oxidation of both ferritic AISI 441 and austenitic AISI 304 stainless steels during simulated short‐term annealing. Oxide scale formation using the simulated atmospheres based on methane‐air, methane‐oxygen, and hydrogen‐oxygen co...

This work focuses on the properties of hydrolysis lignin biocarbons with a perspective on utilizing the biocarbons in pyrometallurgical processes. Even if the blast furnace and basic oxygen furnace (BF-BOF) process route was replaced by emerging technologies with lower CO2 emissions in the future, the need for carbonaceous materials in the iron and...

Scandium is currently classified as a critical raw material for the European Union, and several research projects focus on the search for new sources to supply to its expected increasing demand. The Kiviniemi mafic intrusion in Finland is a potential primary source for Sc; at Kiviniemi, Sc occurs mainly within the lattices of ferrous silicates, cli...

The static recrystallization characteristics and microstructure evolution in hot-deformed austenite were evaluated for a newly developed low-carbon CrNiMnB ultrahigh-strength steel with and without molybdenum addition. The time for 50% static recrystallization (t50%) over a wide range of strains and hot-deformation temperatures were obtained using...

The development of mold fluxes for continuous casting is one of major challenges to produce high aluminum steel. The CaO–Al2O3–B2O3 based mold flux is one of the potential candidates for casting high aluminum steel but its composition and properties still need to be optimized. In this work, the effect of silica and mass ratio of CaO to Al2O3 on the...

Burning of limestone is responsible of bulk of CO2 emissions from cement manufacture. Replacement of limestone with alternative raw materials could be a way to reduce CO2 burden. In conventional cement manufacture, iron is added to cement raw meal to enhance burnability during firing. The increase of iron in cement raw mix can lead to lower CO2 foo...

The utilization of bio-based side streams in metallurgical coke making promotes two major factors in the mitigation of climate impact in the steel industry. Circular economy as the waste material from biorefinery industry is utilized as a raw material in the steel industry, and mitigation of the production of fossil-based CO2 emissions. In this wor...

In contemporary steelmaking, burners are widely used for heating slabs in walking beam and annealing furnaces, heat-up of empty ladles, flame cutting of steel, as well as providing additional energy in electric arc furnaces. To facilitate the future of carbon-neutral steelmaking, a transition from natural gas-based burners toward hydrogen-based bur...

In the world of ever-increasing demand for carbon-free steel, hydrogen and recycling have an undeniable role in achieving net-zero carbon dioxide emissions for the steel industry. However, even though steel is one of the most recycled materials globally, the quantity of steel that can be made from recycled steel will probably not match the demand i...

Briquetting is a process in which fine materials unsuitable for use as such are agglomerated to achieve a larger particle size. Auger pressing is a novel briquetting method to efficiently improve the recycling of by-products from iron and steelmaking. The high-temperature properties of auger pressing briquettes mainly consisting of blast furnace sl...

The operational conditions, including temperature and gas composition, vary along the radial position in a blast furnace. Nevertheless, very few studies can be found in the literature that discuss how the reduction behavior of the ferrous burden varies along the radial position. In this study, the effect of the radial charging position on the reduc...

IDS is a thermodynamic-kinetic software combined with a microstructure tool developed to simulate the non-equilibrium solidification of steels. The present work introduces its main calculation module, SOL, and presents some essential results of that module, such as the formation of ferrite and austenite in different types of steels during their sol...

Complex TiN + oxide inclusions which nucleate and grow on the surface of the primary oxide inclusions, e.g. MgO, have been frequently observed in various steel grades after solidification. To describe the precipitation kinetics of TiN and TiN + MgO inclusions, a model accounting for both heterogeneous and homogeneous nucleation was proposed in this...

Plastic waste of different origin has been proposed and used as an additive in coal blends in metallurgical coke production for trace amounts for about two decades. Previous studies have suggested that high-density polyethylene (HDPE) can be used as an additive in coking blends for small quantities (2–3 wt% of the blend) without considerably damagi...

The crystallization in glasses is a paradoxical phenomenon and scarcely investigated. This work explores the non-isothermal crystallization of a multicomponent alumino-borosilicate glass via in situ high-energy synchrotron X-ray diffraction, atomic pair distribution function, and Raman spectroscopy. Results depict the crystallization sequence as Ca...

Several research projects are currently focused on the search for new sources of scandium due to its expected increasing demand in advanced technology applications. The Kiviniemi Fe-Sc-enriched mafic intrusion is a potential primary source for Sc. According to the recent investigations on the FeO component reduction in the Kiviniemi magnetic Sc con...

The occurrence of non-deformable, non-metallic inclusions is the dominant reason for failure of wire during drawing and degrades service life for some steel grades, e.g., tire cord steel. To investigate the deformability of glassy inclusions in CaO-Al2O3-SiO2 and MnO-Al2O3-SiO2 systems, experimental and numerical methods were used. Young’s modulus...

The upgradation of the ilmenite ore, using a pyrometallurgy method, is performed using a carbothermic reduction of the ilmenite. A high titania slag is obtained which is used as a feedstock for the TiO2 pigment production. The slag is cooled after tapping in big molds and can take ten days to cool. This cooling method has remained the same since th...

The recycling of steel plant side streams through cold-bonded briquettes has become quite common. However, Portland cement is mainly used as a binder in the briquettes, contributing significantly to the energy consumption, costs, and carbon footprint associated with the production of cold-bonded briquettes. This paper reports on a more sustainable...

Iron ore pellets are small and hard spherical particles agglomerated from a fine iron ore concentrate. They are used in the blast furnace process to produce hot metal. The diameter of blast furnace pellets is usually between 8 and 16 mm. In this study, a batch of magnesia iron ore pellets was first sieved into particle sizes of 8–10 mm, 10–12.7 mm,...

Scandium provides technological advantages particularly in solid oxide fuel cells and aluminum alloys. Potential new sources are investigated to respond to the expected increasing demand of this rare earth metal, which is currently classified as a critical raw material for the European Union. The recently discovered Kiviniemi mafic intrusion in Fin...

The in‐plant recycling routes of several side streams produced in Electric Arc Furnace (EAF) steelmaking remain under‐explored. In article 2100472, Abdelrahim and co‐workers characterize eight side streams and use them to produce seven different briquettes. Briquettes are assessed for their suitability to be used in EAF through a series of mechanic...

Despite the common challenge of investigating non-metallic inclusions within ultra-high-strength-steel (UHSS) at sub-micrometer scale via conventional methods, probing nitride inclusions at elevated temperatures is vital for guiding steel’ performance. Herein, an in-situ spectro-microscopic determination using advanced Synchrotron X-ray absorption...

Aimed for improved business opportunities and digitalisation in the steel industry, the project consisted of work concerning measurements and monitoring, modeling and artificial intelligence (AI), as well as development of the platform economy business model. The benefits of digitalisation by means of computational methods and novel technologies...

The modification of basic oxygen furnace (BOF) slag by adding silica can improve the properties of BOF slag for applications in the cement industry. The rapid dissolution of silica is essential to hot slag modification. In this work, the dissolution behavior of silica in the molten CaO–SiO2–Fe2O3–MgO–MnO system as synthetic BOF slag was investigate...

The production of ferrite-rich calcium sulfoaluminate belite (CSABF) cement clinker, also containing MgO, from ladle slag, Fe-slag, and phosphogypsum was translated from a lab-scale to a pilot demonstration in a 7-metre kiln at 1260C. An account of the pilot trials/manufacturing is presented, and the process was robust. Laboratory tests prior to sc...

The steel industry is on its way towards more environmentally friendly steelmaking. To achieve the ambitious goals of significant CO2 emissions reduction, new processes, practices, sources of on-line data, and digitalization together with automation will be required. To address these issues, this paper discusses optical emission spectroscopy (OES)...

Non-metallic inclusions play a decisive role in the steel's performance. Therefore, their determination and control over their formation are crucial to engineer ultra-high-strength steel. Currently, bare experimental approaches are limited in the identification of non-metallic inclusions within microstructural phases of complex steel matrices. Here...

A clean energy revolution is occurring across the world. As iron and steelmaking have a tremendous impact on the amount of CO2 emissions, there is an increasing attraction towards improving the green footprint of iron and steel production. Among reducing agents, hydrogen has shown a great potential to be replaced with fossil fuels and to decarboniz...

Electric arc furnaces and ladle furnaces have an important role in the future of steelmaking, where CO2 emissions have to be mitigated to an acceptable level. One way to address this goal is to optimize and improve the current practices by adjusting the chemistry and reactions with material additions or gas injections. These procedures would greatl...

Large amounts of slags are formed in the production of ferrochrome and stainless steels. Although there are many suitable applications for ferrochrome slag products, some chromium is lost with the slag. On the other hand, utilisation of some stainless steel slags are hindered by the volumetric changes of the dicalcium silicate, which is formed duri...

A synergetic valorization method was proposed to convert the basic oxygen furnace (BOF) slag and stone coal into ferroalloy and glass-ceramic in this work. Effects of reduction time, temperature, and the mass ratio of BOF slag to stone coal on the reduction were studied. The reduction mechanism was investigated by in-situ observation and dissolutio...

The in-plant recycling routes of several side streams produced in Electric Arc Furnace (EAF) steelmaking remain under-explored. Briquetting is an attractive technique to enable recycling of in-plant side streams. Briquettes introduced into EAF must possess certain mechanical and chemical properties. However, no standard is available to determine th...

The defects forming in continuously cast steel take place typically due to the cumulative impacts of the steel grade, machine design, and the casting practices. The steel grade alone is associated with many physical aspects affecting the sensitivity to defects. As an example, the formation of transverse corner cracks depends strongly on the type, s...

An existing and in-use online transient three-dimensional heat transfer model (3DHTM), combined with a solidification and microstructure model (interdendritic solidification model – IDS) for the continuous casting of steel is presented. The 3DHTM and IDS are integrated into a single online software entity and this has been installed in the automati...

Argon-oxygen decarburization (AOD) is the main process for refining stainless steel. During the AOD process, the composition and properties of the slag undergo great changes owing to changes in composition and temperature. Decarburization slag contains large amounts of solid phases, particularly chromium-containing oxide phases and sometimes undiss...

CaO and CaF2 are important slag constituents and additive materials in secondary metallurgy. Optimization of the quantity of these compounds has a key role in adjusting the slag chemistry for optimal refining properties. In this study, the CaO and CaF2 content of the slag has been analyzed with optical emissions from an industrial ladle furnace mea...

Steel quality and properties can be affected by the formation of complex inclusions, including Ti-based inclusions such as TiN and Ti2O3 and oxides like Al2O3 and MgO·Al2O3 (MA). This study assessed the prospective use of Raman spectroscopy to characterize synthetic binary inclusion samples of TiN–Al2O3, TiN–MA, Ti2O3–MA, and Ti2O3–Al2O3 with varyi...

In blast furnaces it is desirable for the burden to hold a lumpy packed structure at as high a temperature as possible. The computational thermodynamic software FactSage (version 7.2, Thermfact/CRCT, Montreal, Canada and GTT-Technologies, Aachen, Germany) was used here to study the softening behavior of blast furnace pellets. The effects of the mai...

Recycling of solid waste generated from metallurgical industries will avoid disposal of wastes, enhance the use of secondary raw material fines and save costs. Numerous hydrometallurgical and pyrometallurgical processes, or a combination of both, have been proposed for the utilization of metallurgical waste. A growing interest in microwave heating...

The electric arc furnace (EAF) is the main unit process in scrap-based steelmaking. This work aimed at developing a fundamental mathematical model of the EAF process for online use. The model is based on stand-alone modules for 1) scrap melting, 2) gas-phase reactions in the freeboard, and 3) metal–slag reactions. The description of scrap melting i...

Oxide scale formation during short-term annealing and electrolytic pickling behavior of ferritic EN 1.4622 and austenitic EN 1.4828 stainless steels were investigated. The annealing was performed at temperatures between 1000-1100 °C for ferritic and 1100-1200 °C for austenitic steel grade under humid atmospheres in simulated industrial process. Neu...

Alite–ye’elimite–ferrite (AYF) cement is a more sustainable alternative to Portland cement (PC) that may offer improved mechanical, rheological, and chemical performance. Using traditional raw materials and conventional clinker processing conditions, alite (C3S) and ye’elimite (C4A3$), the major phases in PC and calcium sulfoaluminate (CSA) cements...

The thermodynamic Iron Alloy Database (IAD) has been developed since 2000 to provide consistent thermodynamic data for modeling the solidification of steels. This work presents the carbon containing thermodynamic descriptions of the Fe–Cr–Cu–Mo–Ni–C system, extending the two earlier publications on that database. The results suggest a good agreemen...

Electric arc furnace is the main process in scrap-based steelmaking and accounts for roughly 30% of total crude steel production. Over the years, numerous mathematical models have been proposed for the EAF process, ranging from models focusing on different aspects of the process to comprehensive process models, which aim to account for all the main...

The structure of CaO–Al2O3–B2O3–BaO glassy slags with varying mass ratio of BaO to CaO has been investigated by Raman spectroscopy, ¹¹B and ²⁷Al magic angle spinning nuclear magnetic resonance (MAS‐NMR) spectroscopy and atomic pair distribution function (PDF). ¹¹B MAS‐NMR spectra reveal the dominant coordination of boron as trigonal. Both simulatio...

Blast furnace is the most used process for production of iron in the world. It is charged mainly with metallurgical coke and ferrous materials. When descending inside the blast furnace, iron bearing materials start reducing and melting with other burden materials. This melting leads into formation of so called primary slags from which the final sla...

Cyanide, among with NOx, CO2, and CO, is one of the adverse compounds that form in the ironmaking and steelmaking industry. High-temperature processes are suitable environments for cyanide formation, and cyanide can form as a result of recombination in electric arc plasma. Even though the cyanides might not survive e.g. the post-combustion process,...

Utilising the oxyfuel practice for CH4-fuelled combustion has positive effects on the emissions, efficiency and cost of high temperature furnace practices. However, especially in older installations, oxyfuel usage requires retrofitting and alters the atmosphere in which the oxidation of the steel occurs, when compared to using air as the oxidiser....

Recent inclusion models are mainly focused on the compositional evolution of inclusion, steel and slag. Due to the importance of inclusion size distribution to steel properties, the evolution of inclusion size distributions should also be accounted for. As the first step to establish a model to predict the evolution of inclusion size distribution,...

The aim of this work was to derive new quality criteria based on steel composition and cooling pattern for continuous casting and for the subsequent cooling and reheating processes. The criteria were devised based on the outputs of multiphysics simulation tools for casting applications. The criteria were found to be good predictors of whether a ste...

Different properties are required from metallurgical slags in different stages of their life cycle: from slag formation to their use in metallurgical processes, cooling and solidification, and finally utilisation or landfill. Whereas some properties are important in process control itself, some properties are more useful when modelling and simulati...

Chromium-containing calcium-silicate slag is a by-product of the AOD process. During cooling in the slag yard, the phase composition of the slag is subject to changes that affect its properties. A previously proposed 1-dimensional model for slag cooling was coupled with computational thermodynamics calculations to study the phase composition of the...

Determining non-metallic inclusions (NMIs) are essential to engineer ultra-high-strength steel as they play decisive role on performance and critical to probe via conventional techniques. Herein, advanced Synchrotron X-ray absorption coupled with photoemission electron microscopy and first-principles calculations are employed to provide the structu...

Carbonaceous reductants for pyrometallurgical applications are usually obtained from fossil-based sources. The most important properties of the reductants greatly depend on the application and the feeding of the reductant into the process. However, the mechanical strength, calorific value, fixed carbon content, and reactivity of the reductant are t...