(USUI) INTL. SYMP. ON ADVANCED SUSTAINABLE IRON AND STEEL MAKING

The industry of cassava represents an important source of residues commonly released in the environment. Special concerns are raised about the cassava bagasse and the waste water residue produced during the processing steps. In this study, we propose a sustainable route, which involves two steps of gas production. A first step uses the cassava bagasse in a thermal reactor to produce rich hydrogen gas suitable for use in the direct reduction processes. Then the waste water is treated in a biotechnological reactor using algae to produce hydrogen. To characterize the thermochemical processing step of the cassava bagasse decomposition, thermogravimetric analyses (TGA) and simultaneous differential scanning calorimetry (DSC) were carried out in a broader range of temperature and gas flow rates. This was done using the design of experiment techniques (DOE) to draw generalized correlations. In the second step of the waste water processing treatment, the concentrations and the culture conditions of the Chlorella minutissima microalgae were investigated. This was done to design feasible controllable parameters to maximize hydrogen production under the laboratory batch. Results indicated that gasification of the cassava bagasse presented high conversion rates in the temperature range of 600-700°C. Additionally, the microalgae conversion is proved possible in near environment temperatures under a controlled environment.

The 2018 IPCC report defined the goal to limit the global warming to 1.5°C by 2050. Accordingly, that would require “rapid and far-reaching transitions in land, energy, industry, buildings, transport, and cities”. The challenges fall on all sectors, but on energy and industry sectors they are most essential and explicitly measurable also. Iron and steel making is an energy-intensive industrial branch. It is playing a significant role in the global energy consumption, as it is largely based on fossil fuel and generates about 7% of overall carbon dioxide emissions. In order to conduct its own share in cutting CO2 emissions, great advancements must be achieved.
This contribution will highlight the present situation of steel industry and show plausible scenarios for the future. Potential methods to decrease CO2 emissions in current processes via improved energy efficiency, increasing recycling and alternative energy sources are surveyed. The role of recycled steel will considerably grow over the next few decades. These factors influence, that the specific energy consumption per ton steel and respective CO2 emissions will strongly decrease. The growth of emissions will be stopped and, in spite of the predicted growth of the steel production from the current 1.8 BT up to 2.5 BT/year, the total emissions from the steel sector can be significantly cut. However, these advancements are not sufficient for the final aim of carbon neutrality. That demands more radical changes in energy sources and systems as well as in iron & steel production technologies. Still today, energy systems are largely based on fossil fuel, but extensive transfer to renewable energy is coming true soon. Corresponding developments are taking place also in steel industry. Several on-going programs and initiatives for low-carbon and carbon-free ironmaking utilizing hydrogen are in progress. These projects as well as trends of future energy systems are surveyed. Finally, a simplified holistic model is shown demonstrating the steel´s contribution in solving the global CO2 emissions problem.

AUTHORS and AFFILIATION:
Camila Freitas de Araújo – Civil Engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (camilafr.eng@gmail.com).
Alex Milton Albergaria Campos – MSc Metallurgical Engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (alexcampos88@yahoo.com.br).
Adriano Corrêa Batista – Professor, DSc Instituto Federal de Minas Gerais, Ouro Preto, Brazil (adrianocorrea77@gmail.com).
Bernardo Antônio Perez da Gama – Professor, PhD UFF, Niterói, Brazil (bapgama@gmail.com).
Renato Crespo Pereira – Professor, DSc UFF, Niterói, Brazil (rcrespo@id.uff.br).
Rodrigo Pinheiro de Almeida Santos – Doctoral Student at UFF, Niterói, Brazil (pinheiro153@gmail.com).
Bruna Helena Malovini Loiola – Metallurgical Engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (malovinibruna@gmail.com).
Paulo Santos Assis –Professor, PhD REDEMAT/UFOP, Ouro Preto, Brazil (assis@ufop.edu.br).
Tateo Usui – Professor emeritus, DSc Osaka University, Suita, Japan (usui@mat.eng.osaka-u.ac.jp).

Abstract
The golden mussel (Limnoperna fortunei) is a species of bivalve mollusc introduced in Brazil via ballast water in the 1990s. Given the biological and ecological characteristics of the species, as well as the favorable environment in the country for its proliferation, the golden mussel has become an exotic invasive species that has caused several problems in the aquatic environment because of its ability to form colonies in structures. The species adheres on the surfaces by protein filaments, causing serious environmental, social and economic damages, provoking structural and functional alterations in the ecosystems and damages to the human activities.
The challenge presented consists of biological fouling combat through treating underwater surfaces with freshwater natural products, in particular those from red algae. Fouling control tends to arouse the interest of shipbuilders, marine vessel operators, fish farming in tanks and hydroelectric power plants. In Brazil, the chemical treatment against the incrustation of the golden mussel, for example, made only in three hydroelectric power plants in Minas Gerais, has annual cost of R$ 1,494,000.00 [1].
With the worldwide ban of TBT-based antifouling paints since 2008, alternative, environmentally safe treatments gain more appeal, considering the risk associated with the alternative products currently in use. Natural marine products have since been recognized as a promising alternative for the replacement of commercially used antifouling until the moment [2].
A selection of natural seaweed products with antifouling activity may provide effective results with little or no environmental impact compared to currently used products [3], while contributing to the understanding of ecological functions and mechanisms of metabolic production secondary. At least 18 different regulatory biocides are currently being used as an alternative to tributyltin free antifouling paints, but these also pose some threat to the aquatic environment. In fact, even biocide-free antifouling paints are toxic to marine organisms over a broad spectrum [4]. For this reason there is still an urgent demand for new low-impact anti-fouling products.
This article aims to disseminate this broad line of research and consolidate information about the potential of marine organisms as producers of secondary metabolites (natural products) with antifouling activity, in the light of scientific production.

Key words: Golden Mussel; red algae; anti-fouling products; secondary metabolites; tributyltin.

It is important to evaluate the reduction behavior of agglomerates as well as permeability for Blast Furnace analysis. Generally, rate-parameters of an agglomerate is used for several BF analysis. But, sinter has a different porosity in a different particle size. In radius direction of a blast furnace top, sinter particle size is different by burden distribution control. And also, sinter particle size changes by reduction degradation in a low temperature region of BF. In the high temperature region over 1100○C, porosity of sinter decreases by melt formation inside of sinter. It is needed to consider the change of particle size and porosity by above phenomena in the BF analysis
Here, Multi-Stage Zone Reaction model (MSZR) is used for analyzing the reduction of agglomerates. How to evaluate the rate-parameters is considered and the influence of agglomerate quality is analyzed.

The development of the raw materials supply is characterized by decreasing metal grades and still relatively low recycling rates. While the recycling of metallic scrap is nowadays state of the art, metal-containing by-products from the metallurgical industry represent a new potential secondary resource. Due to the genesis of the primary polymetallic ores, it is especially the metallurgical processes used in the copper, lead and zinc industries that offer a high potential in their by-products. Besides the base metals, also many minor metals declared as critical by the European Union regarding their supply will be recoverable. To allow a better assessment of these materials, a certification system similar to the ones already existing for primary resources needs to be established. Through special characterization of selected residues and the evaluation of possible recycling processes, a generally valid assessment scheme is to be developed. The optimized use of by-products as secondary raw materials helps to preserve valuable primary resources and to minimize landfilling of potentially hazardous wastes. An evaluation system followed by a certification step is beneficial for both continuously produced metallurgical by-products, and landfilled materials from the past. These resources will be opened to recycling step by step, offering new potentials that enlarge the present metal resource base.
A case study for zinc containing residues gives an insight on the ongoing research and development.

There are many articles and some reviews on inorganic [1] and organic binders [2] for agglomeration of ores. Most of them are related with obtaining enough strengths at green and dried stages (avoiding degradation during transport and processing) and after sintering (firing). For iron ore pellets, using 0.7% sodium bentonite as binder, the firing temperatures is around 1300oC and energy consumption represents highest cost of the pelletizing process. The cold agglomeration presents benefits for saving energy with consequences for environment. The cold agglomeration process using cement as binder is well known but presents two negative constraints: i) needs high (around 7%) content of the binder, resulting in slag increment; and ii) since the strength is given during curing by hydration, mainly of tri-calcium silicate, it starts the decompose at high temperatures and the strength of the pellets go down, reaching the minimum around at 950oC (increasing degradation). The objective of this paper is to analyze how may compose the organic and inorganic binders, in a synergetic effect, such that during reduction (temperature above 600oC) the agglomerates keeps its strength without much degradation. For carbon-ore composite agglomerates (self-reducing) the consolidated process is to use the properties of high fluidity coal and treat it thermally to serve as reducer and binder. The preliminary results, using bentonite and boric acid, are indicating hot strength of the pellets better than those obtained with the use of cement.

Tile: CO2 ultimate reduction in steelmaking process (COURSE50 project)
Author:Natsuo Ishiwata #1, Kazukuni Hase #1, Masaru Ujisawa#2, Kyouichi Araki#2
#1: Technology Planning Dept. JFE Steel Corporation,
2-3, Uchisaiwai-cho 2-chome, Chiyoda-ku, Tokyo 100-0011 Japan
#2:Ironmaking Technology Div., NIPPON STEEL CORPORATION,6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 100-8071 Japan
Abstract:
Four blast furnace steel makers and one engineering company in Japan have been engaged in the “CO2 Ultimate Reduction in Steelmaking Process by Innovative Technology for Cool Earth 50 (COURSE50) Project”, since FY2008. This project is a National Projects commissioned by New Energy and Industrial Technology Development Organization (NEDO).
The target of COURSE50 is a reduction of approximately 30% in CO2 emissions in the steel manufacturing process. Two technologies, which are a) Reduction of iron ore by using hydrogen-amplified coke oven gas to curb CO2 emissions from blast furnaces, and b) separation and recovery of CO2 from blast furnace gas by effective utilization of unused waste heat in the steel works are investigated.

This work provides results of the author's activity in the field of application of sound and ultrasound waves for controlling interfacial phenomena in steelmaking and aluminum making processes. The corresponding investigations have been carried out using laboratory and industrial scale equipment. The physical basis for controlling interfacial phenomena is the fact that gaseous, liquid and solid phases differ greatly in acoustic impedance. Therefore, when a sound wave is incident on an interface between two phases, the major part of the wave’s energy is reflected from and/or absorbed by the interface, resulting in a number of effects beneficial for pyrometallurgical processes. In steelmaking processes, airborne sound/ultrasound waves provide the possibility to influence the interface mass transfer and thus, to control the rates of steelmaking reactions. Particularly, application of sound waves to the interphase between oxidizing atmosphere and molten Fe-C alloy causes enhanced oxidation of iron and influences thus the decarburization rate. Other examples of sound application effects are control of foaming phenomena and dust formation in steelmaking converters or electric arc furnaces.
In aluminum production, as the melting point of aluminum is much lower than iron, the ultrasonic vibrations can be introduced directly in the molten aluminum alloys using refractory metal or ceramics sonotrodes. This makes it possible to transmit the ultrasound energy directly to the liquid-solid interface and thus, to break and disperse various particulates in the melt before or during its solidification. Examples include, but are not limited to, dispersion of refiner particles and fragmentation of growing dendrites. This offers an attractive way to control macrostructure and microstructure of aluminum alloys in casting processes. Besides, this technique is applicable to the development of new aluminum alloys and composite materials.

One of the most important problems of the steelmaking industry is the recycling of galvanized steel scrap and the benefit or disposal of the powders produced in the Electric Arc Furnaces (EAFD) and LD / BOF converters. This issue is well-known worldwide. Transportation costs, disposal in appropriate places and increasing environmental demands are making many steel companies in the world look for ways to avoid, minimize and / or treat their powders and particulates correctly. The methodology of the project consists of collecting, sampling, selecting and molding the raw materials involved: powders from electric steelworksor Electric Arc Furnace Dust-EAFD, bentonite-Ben., refractory clay-AR and construction cements. Following that, these materials were characterized partially. Afterwards, heating tests were carried out on mixtures of EAFD and bentonitein, in the form of cylindrical briquettes, using electric ovens to evaluate how preset factors favorably influence the porosity response variable. This experience also provided the proportion in optimal weight of the mixtures. These proportions were used to form test bricks with all the aforementioned raw materials in order to evaluate the effect of their new factors on another variable responses to the resistance towards compression. All these tests were carried out according to experimental planning with the simple factorial method 23 that evaluated the effect of the factors using the COLMEIA software. It can be concluded that: A> B> AB, where the individual synergy of (A) EAFD / Ben. is more influential than the one of (B) Heating temperature. This in turn is more influential than the double synergy (A) EAFD / Ben. and (B) Heating temperature or AB in the porosity of the cylindrical briquettes formed of EAFD and bentonite. During the second run the result of A> AC explains that the individual synergy of (A) EAFD / Ben. is more influential than the dual synergy of (A) EAFD / Ben. and (C) Setting time or AC in the compressive strength of the set of test bricks. This compressive strength was based on electric steel, bentonite, refractory clay and construction cement powders.
Finally, it is concluded that in both experiences, the proportion PAE / Ben. = 7/3 is the optimal mixture and therefore, the factor most influential in the porosity-stabilization and resistance to compression or mechanical strength of the specimens was tested.

Demand for utilizing iron ore with high phosphorus content is increasing because of the depletion of the resource for high-grade iron ore. Utilization of oolitic hematite with very high phosphorus content [1] and development of the dephosphorization method by reduction and melting of iron ore-carbon composite are the main focus of this paper. It is known that most of phosphorus exists as calcium phosphate in oolitic hematite. It is known that calcium phosphate can reduce to phosphorus gas and moves into metallic iron in iron ore-carbon composites. In this study, the effect of the iron ore layout in composite on dephosphorization behavior is evaluated.
Four thin composite samples, using hematite reagent, coke and three compacts of oolitic hematite, were prepared. These samples (thickness=2mm) were then set in the alumina crucible, which is named as the layer sample. The mixing ratio of total carbon to oxygen in iron oxide was 0.8 in molar [2]. For comparison, a uniform mixing composite sample was prepared using oolitic reagent, hematite powders (Ore: Reagent = 2:1) and coke. The sample was heated up to different target temperatures at a heating rate of 0.167°C/s. Phosphorus content in oolitic hematite, reduced iron, and slag was measured by ICP-AES. Phosphorus content in oolitic hematite was 0.78%. After heating up to 1300°C, melted iron and slag were obtained, and phosphorus content in melted iron of the layer sample was estimated at approximately 0.04% while that of the uniform mixing composite was approximately 0.4%.

Recently, due to increases in the price of ironmaking coal, low coke rate operations in the blast furnaces have been necessary. Because coke works as a spacer in the blast furnace, however, low coke ratio operation causes deterioration of furnace permeability [1]. This is remarkable in the cohesive zone. The results of measurements of the shape of the cohesive zone in dissected blast furnaces revealed that the ore layer and coke slit layer were alternately layered [2]. Therefore, in the cohesive zone, gas is expected to flow horizontally along the coke slit layer. Thus, the permeability of the coke slit layer in cohesive zone is important.
The authors developed a new simulator called the Cohesive Zone Simulator for quantifying the effect of the coke slit layer thickness on permeability. The authors revealed that this is because of the decrease in void fraction of the coke slit layer, caused by the increasing thickness of the penetration layer of melting the ore layer [3].
On the other hand, the effect of ore melting behavior on the permeability of the coke slit layer was not studied enough. Ore properties, i.e. reduction ratio and effect on the melting behavior, however, are known [4].
Based on the background outlined above, the effects of the contraction ratio of the melting ore layer to permeability were studied by using the cohesive zone simulator.

In high temperature material processes like iron & steelmaking, the thermodynamic parameters in liquid metals are the crucial guidelines for optimizing and improving the processes. Therefore, the thermodynamic data have been aggressively collected by a variety of sophisticated experimental techniques so far[1,2]. In addition, several researchers[3,4] have developed the estimation model for thermodynamic parameters in parallel with experimental researches because of the limitation of experimental data caused by difficulty of experiment at high temperature.
In the present work, the estimation method for the activity coefficient of element in liquid mental is proposed based on a predictive model for surface tension of liquid alloys with Butler’s equation[5] in order to realize the enlargement of thermodynamic data. The equation for calculating an activity coefficient of solute in infinite dilute liquid metal from the values of surface tension for liquid alloy is derived by focusing on infinite dilute liquid metal solution and modifying Butler’s equation. The estimation results in this work give a reasonable reproducibility in comparison with the literature values.

In recent years, development of innovative energy saving technologies for preventing global warming becomes more important for the steel industry. Ferro-coke is an innovative ironmaking process for energy saving in terms of realizing the low reducing agent ratio (RAR) operation in the blast furnace. In the Ferro-coke process, coal and iron ore were mixed and formed by a briquetting machine, and carbonized in a vertical type carbonization furnace. Ferro-coke causes lower thermal reserve zone temperature in a blast furnace because of its high gasification reactivity by Fe catalytic effect.
In this study, the reactivity of ferro-coke was measured under the condition simulated a blast furnace. As a result, it was found that ferro-coke has remarkably higher reactivity and lower reaction starting temperature than normal coke and in the case of mixing sinter, the reduction of sinter was enhanced.
In the former NEDO project, 2000 ton of ferro-coke was produced by the pilot plant with a capacity of
30 ton/day and the effect on RAR was confirmed in the actual blast furnace.
For the next step, NEDO began the project “Environmentally Harmonized Steelmaking Process Technology Development (Ironmaking Process Technology Using Ferro-coke)” with a 6 year schedule from FY 2017. In this project, a ferro-coke production technology is to be established through a medium-scale plant producing 300 ton/day of ferro-coke with the aim of a 10% reduction in energy consumption in the ironmaking process by around the year 2022.

FLOGEN Technologies Inc. has implemented and commissioned FLOGEN CONTOP, a Design/Decision-Making/Control/Optimization/Automation System at various blast furnaces of pig iron producers in Brazil.
The system instantaneously makes a complete optimization of all raw materials, including limestone, silica, air and oxygen volumes, in order to achieve specific targets according to the needs of the company. The main achievements of the implementation of the FLOGEN CONTOP system were the increase of the pig iron production by about 14% and the decrease of total consumption of charcoal (breeze and fines) by about 4%. Additionally, fines injected through the tuyeres were decreased, temperature and composition of slag and pig iron (including Si and P) were better controlled and silica addition as a flux was minimized. An overall instantaneous mass and energy balance helped fix various mechanical and procedural problems in the plant.
CONTOP system was also successfully used to determine the annual procurement strategies by predicting various raw material cost-based scenarios related to productivity and fuel consumption in short- and long-term future.
CONTOP increased productivity and reduced cost up to the highest designed limit of the technology. CONTOP also changed the way of operating from a reactive wait-the-lab-results-approach to a proactive forecast-and-act approach.

The Tatara furnace was the traditional method for steel production in ancient Japan. Tamahagane steel ("precious metal" in Japanese) obtained from the Tatara furnace was used for the manufacturing of Japanese swords.
These Japanese swords were produced with two types of steel: one with high carbon (kawagane) and another with low carbon (shingane). The high carbon steel was used for the blade region. The ductile low carbon steel was used for the interior part of the sword.
Japanese swords have a curvature, which is produced in the moment of the quenching. One of the interesting aspects of the Japanese sword is that the processing occurs in such a way that compression of residual stress is introduced on the side of the blade [1]. Thus, if a crack appears, it does not open. The Western swords with blades on both sides were much less reliable in combat. As for Western swords, existence of tensile residual stress on the surface of the swords makes them much easier to break.
Other details of the physical metallurgy of the steel employed in Japanese swords are also discussed.

One significant operational problem in increasing pulverized coal rate and decreasing coke rate must be the increased pressure drop or the worsened gas permeability at the lower part of the blast furnace. In order to improve gas permeability around the blast furnace bird’s nest region during high pulverized coal injection rate operation, flux injection technology from the tuyere is surveyed with the purpose of decreasing slag hold-up. In this study, converter slag is focused on as the flux material. The advantages of converter slag are its low melting point due to high FeO content and its smaller endothermic quantity as a pre-melt slag. Results obtained by experiments and actual blast furnace tests are as follows:
(1) Converter slag was expected almost completely to be smelted during flight within the raceway and showed an excellent assimilation property with bird’s nest slag.
(2) A scheme is newly established which estimates the improvement degree of gas permeability using the operational conditions for the blast furnace and the converter slag injection conditions.
(3) A decrease in pressure drop at the lower part of the blast furnace was demonstrated by converter slag injection tests at Kobe No.3 blast furnace. The operational results showed fairly good agreement with those estimated by the scheme of the present study.

Gaseous reduction behavior of iron oxide pellets and iron ore sinter with CO and H₂ were studied experimentally. In reaction models for gaseous reduction of iron ore agglomerates, the formations of both unreacted-core shrinking (UCS) model for one interface and UCS model for three interfaces and the developments of multi-stage zone-reaction models without and with considering solid-state diffusion are summarized; these models were used mainly for pellets but sometimes used for sinter. UCS model for six interfaces in consideration of quaternary calcium ferrite reduction process was newly developed for sinter. Comparisons of these reaction models for pellets and sinter were carried out by using experimental data on gaseous reduction of these iron ore agglomerates.

The productivity of Blast Furnaces is largely impacted by fuel efficiency. Control of heat loss is one of the enabling parameters for achieving lower fuel rate. I-Blast Furnace is the latest and largest Blast Furnace of Tata Steel Jamshedpur with a working volume of 3230m³ and with rated capacity of 3.055 million tons per annum. Optimizing heat losses in Belly and Bosh zones remains a major challenge for blast furnace operators.
The I-Blast furnace has installed Cast Iron & Copper Staves cooling members where copper staves are installed in Belly, Bosh & Lower Stack, whereas cast iron staves are installed in the upper stack area. Stave cooled Blast Furnaces are prone to higher heat losses in the Belly and Bosh regions with increase in coal injection rate as Bosh gas volume increases. Under these conditions, managing gas flow patterns through proper burden distribution, casting techniques, and maintenance of desired raw material qualities are of upmost importance for sustaining high injection rates. This study details the burden distribution control by the Ore & Coke ratio adjustment at the wall and center of the Blast Furnace as the coal injection rates increase from 140 kg/thm to 220 kg/thm. Control of blowing parameters, casting philosophy, specification for raw materials, and division of operational practices for controlling heat losses is also elaborated with the model that is used to visualize heat loss patterns in different zones of the Blast Furnace.

AUTHORS and AFFILIATION:
Bruna Helena Malovini Loiola – Metallurgical Engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (malovinibruna@gmail.com);
Carlos Antônio da Silva – Professor, PhD REDEMAT/UFOP, Ouro Preto, Brazil (casilva@ufop.edu.br);
Henrique Silva Furtado – DSc. Eng. ArcelorMittal Global R&D South America, Vitória, Brazil (henrique.furtado@arcelormittal.com.br);
Camila Freitas de Araújo – Civil engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (camilafr.eng@gmail.com). Alex Milton Albergaria Campos – MSc. Metallurgical Engineer, Graduate Student at REDEMAT/UFOP, Ouro Preto, Brazil (alexcampos88@yahoo.com.br)

Paulo Santos Assis – Professor, PhD REDEMAT/UFOP, Ouro Preto, Brazil (assis@ufop.edu.br);
Tateo Usui – Professor emeritus, DSc Osaka University, Suita, Japan (usui@mat.eng.osaka-u.ac.jp).
ABSTRACT

Slopping is a phenomenon which is observed when the volume the emulsion inside of BOF (Basic Oxygen Furnace) is excessive and a fraction of slag and metal is then expelled. This phenomenon concerns steelmakers since it leads to material losses, health hazards, reduction of refining efficiency and, mainly, environmental issues. Big Data files from a steelmaking shop in Brazil have been analysed in order to identify the central causes of the slopping. Statistical techniques including Multivariate Analyzes have been employed in order to identify the main variables that affect slopping. Statistica, Genes and Rbio software were used to do so; also principal components, path analysis, and correlation network were chosen as tools. It was possible to identify and hierarchize the variables most affecting slopping in good agreement with literature. The resulting variables can be used to a model to generate anticipate slopping..


Key-words: Slopping; Emulsion; BOF; Multivariate Analyzes.

China, a country with a total industrial energy consumption ranking in the forefront of the world. China's steel industry has a large energy consumption and low energy recycling rate, which is one of the reasons for the limited development of Green & Low-Carbon metallurgy. BOF gas, with an annual output of more than 100 billion standard cubic meters, is one of the main by-product energy resources in the steelmaking process. However, the up to 34.7% abandoned rate of BOF gas has caused a lot of carbon emissions and energy resources waste. The abandoned BOF gas, with a high temperature of 1773~1873K and 20~40%(vol.%) CO and 20~30%(vol.%) CO₂, has a huge physical sensible heat and chemical latent heat. It means there is a predictable recyclable value and comprehensive utilization prospects to achieve the ultra-low carbon emissions, reduction of energy consumption, resources recovery and energy conversion in iron and steel making process. The paper has carried out detailed calculation and analysis of the energy value of abandoned BOF gas, and the feasibility analysis and program design of the overall resource recycling and energy utilization in iron and steel making process that include blast furnace (BF) smelting of vanadia-titania magnetite (VTM), Combined blowing in BOF and vanadium-extracting converter, Co-production of steel-chemicals industry.

The use of Hydrogen and natural gas promise a revolution in Syderurgy.
At the present time, the cost of wind and solar energy are decreasing [1] and also, new sources of natural gas have been discovered [2,3].
As a consequence, cheap electric energy can be available in a near future, as well as natural gas. This opens new possibilities for the energy use in Steelmaking [4].
Electric energy can be used for generating hydrogen, for use in reduction processes.
In this talk, the many possibilities for application of hydrogen and natural gas in Syderurgy are discussed.
Direct reduction processes based on shaft furnaces can open new possibilities for mini mill facilities.
A detailed model for the direct reduction of iron oxides in the shaft furnace was developed [5]. This model can be used to simulate the steady state condition of a commercial shaft furnace for pellets and lump ore reductions.
The model is able to predict the productivity and efficiency of the gas shaft furnace.

The reduction of pellets and lump ores in the shaft furnace process is widely used to produce direct reduced iron (DRI). The traditional process of DRI production uses a gas reforming system based on catalytic reactions and demands high amount of fossil source energy from natural gas. A new hydrogen-based process has been proposed. In this study, we propose to combine self-reducing characteristics with hydrogen technology with self-catalytic reactions to avoid the natural gas-based reforming step. We analyzed this new technology using an in-house computational code. The computational analysis is a numerical model based on transport equations of momentum, energy and chemical species for gas and solid phases to reproduce the inner phenomena in the direct reduction of the shaft furnace process for producing DRI. The model is used to investigate promising scenarios of hydrogen-based technology. Four cases were considered using partial replacement of the burden by bio-self-reducing agglomerates combining with hydrogen and oxygen injections on the bustle level. The inner temperature, pressure and phase composition distributions are discussed for the selected scenarios. The simulation results indicated that the efficiency of the process can be improved with the adequate choice of operational parameters and raw materials burden.

Volumetric expansion during low temperature reduction of hematite to magnetite causes disintegration of iron ore burden in the upper part of blast furnace (1). The extent of such a property is generally evaluated by ISO11258/JISM8720 as a Reduction Disintegration Index (RDI) at low temperatures, where test samples are reduced with the constant gas composition at a constant temperature followed by the strength test after cooling. It is difficult, however, to observe detailed behaviors of crack formation during the test operation. Therefore, we have applied an acoustic emission (AE) method for an RDI test equipment (2). AE is an in-situ non-destructive technique that enables detection of the incidences of the generation and propagation of the crack (3)-(6).
In a single particle reduction, the sinter emitted a large number of AEs during cooling, and the AE energy of the sinter was higher than that of the pellet. Furthermore, lump ores containing high combined water emitted a large number of AEs during heating. The latter result implies that this method is useful for the evaluation the decrepitation of iron ore lumps.
In the packed bed tests, the effective AE signals were obtained against noise probably caused by frictions between the sample and the wave guide. The guide represents the average properties of the iron ore burden. The measurements revealed that thermal energy stress during cooling was higher than during reduction at 823 K for 30 min.
The results show that the value of the standard RDI is affected by the cooling operation, which is different from blast furnace conditions. The AE method will be applied as a unique measure to observe real disintegration behaviors of iron ore burden during reduction.

Since reducibility of iron oxide in iron ore directly affects the amount of CO₂ from BF, the enhancement of reducibility of iron oxide is important to reduce CO₂ emissions. The iron ore grade, however, becomes lower year by year. Gangue in iron ore is increasing especially in Al₂O₃. It is observed that the reducibility of sintered iron oxide pellets decreases with the increase of Al₂O₃ content in softening and melting zones over 1373 K in BF. Besides, it is reported that the initial melt formation temperature drops and the amount of melt increases with the increase of Al₂O₃ content [1]. Since molten oxide formed inside sintered iron oxide pellets causes pore occlusion [2], melt formation can affect reducibility in the softening and melting zones. Therefore, it is required to determine the effect of melt on reduction behavior to enhance reducibility of sintered iron oxide pellets.
We focused on the reduction behavior and rate of sintered iron oxide pellets on the initial melt formation stage and investigated the effect of melt on the reducibility of iron oxide. The sample was prepared by sintering a mixture of Fe₂O₃, CaO, SiO₂, and Al₂O₃ regent powder. Reduction experiments were carried out to clarify the reduction behavior of a sample from 1273 K to 1473 K and to determine the effect of melt on reduction rate of a sample at 1473 K. The microstructure of a sample was observed by a scanning electron microscope (SEM) and porosity was estimated by an image analysis technique.

The paper discusses (1) gaseous reduction of iron oxides and ores, (2) reduction of manganese, chromium and titanium oxides using methane-containing gas, (3) constraints in the reduction of manganese, chromium ores, ilmenite and quartz, and (4) the effect of the gas atmosphere in the carbothermal reduction of stable metal oxides. Reduction of metal oxides was studied using a fixed-bed reactor. Reduction of iron oxides and ores was also examined using high-temperature XRD.
Under standard conditions, methane is thermodynamically unstable above 550°C and decomposes to solid carbon and hydrogen. At appropriate CH₄/H₂ ratio and temperature, carbon activity in the methane-containing gas phase can be well above unity relative to graphite, which provides favorable thermodynamic conditions for reduction. To maintain these conditions, the rate of reduction/carburisation should be higher than the rate of solid carbon deposition. This condition is difficult to maintain in the reduction of stable oxides and ores. Carbothermal reduction of stable oxides in hydrogen is a promising avenue for processing of manganese ores and ilmenites.

Although boron (B) is well known as one of the effective elements to prevent slag dusting [1], there is the possibility that B concentration and its leaching amount of steelmaking slag exceed the limit of environmental standards [2]. Therefore, it is important to understand the leaching behavior of B in slag. There are, however, few reports on the behavior and mechanism of B leaching from slag.
The leaching behavior of steelmaking slag, modified by B-containing flux, has been reported [3]. Although the effect of the particle size was investigated in the publication, the effect of the component condition of the slag on the leaching behavior of B has not been understood.
In this study, the leaching test has been performed using the steelmaking slag with a different basicity. In addition, the chemical structure of B in slag before leaching has been analyzed by solid-state ¹¹B NMR and FIB-TOF-SIMS.
The leaching amount of B decreased with increasing slag basicity and calcium (Ca) concentration in water. The effect of slag basicity should be related to the leaching amount of Ca because the slag with higher basicity increases free-CaO and Ca concentration in water. From NMR and FIB-TOF-SIMS results, B is found to coexist primarily with Ca in the slag. Consequently, it is considered that B leaches with Ca. The slag with higher basicity decreases the leaching amount of B due to the common-ion effect by calcium.

The distribution of the burden plays a key role for the operation of the blast furnace [1], as it affects the thermal and chemical phenomena in the lumpy zone. Through these, the efficiency of heat and mass transfer and chemical reactions in the shaft are also affected. It also influences the level and shape of the cohesive zone, which has considerable impact on process stability and fuel rate. Therefore, many mathematical models (e.g., [2]) have been developed to gain understanding of the complex burden layer-formation process.
A mathematical model of the distribution of burden in a blast furnace with bell-less charging has been developed. Special attention was paid to the computation efficiency to make the model fast enough to allow for real-time simulation and interactive planning of charging programs. The model, which describes the formation of burden layers and their descent in the shaft of the furnace, has been verified by charging experiments at a small scale [3] and has been applied for automatic generation of charging programs satisfying certain criteria concerning the radial distribution of the burden [4].
The present paper presents some results where the model is applied to study new charging programs and the resulting distribution of coke and ore in the furnace shaft. Furthermore, the model's predictions of the distribution of burden layers are validated by comparison with measurements from a 3D top scanner in an operating furnace, through which the radial distribution of the layers can be measured. The model has been proven as a valuable tool in the design of charging programs and in the simulation of the distribution and descent of the burden layers in the throat and shaft regions of the blast furnace.

The shaft furnace process is widely used to produce DRI from pellets and lump ore. One of the largest shortcomings of the process is the need for a reforming gas station for producing reducing gas. This study proposes the enhancement of the efficiency of the process using self-reducing burden with poor reducing gas. A numerical model based on transport equations of momentum, energy and chemical species for gas and solid phases is proposed to simulate the inner phenomena in the direct reduction of the shaft furnace process for producing direct reducing iron (DRI). The model is verified using industrial data of productivity, raw materials and final composition of the DRI product. The model is used to evaluate operational practices using new raw materials and composition of reducing gas in the process. Five cases were considered which correspond to available raw materials and operational conditions on the process. The effects on the gas and solid inner temperature, pressure and phase compositions distributions are quantified. The simulation results indicated that good agreement for overall parameters of the process could be achieved. Afterwards, detailed features of the inner conditions of the process are predicted.

Charcoal is an existing alternative to the use of coal and coke in the metallurgical industry, but it has inherently low mechanical strength. The existing methods to evaluate charcoal compression strength rely on preparing test specimens free of defects and compress it in the direction of the fibres. Since charcoal is anisotropic, these tests may not reveal the behaviour of charcoal, as a whole, when suffering compressive loads. As a consequence, such approach may not relate to industrial conditions, where the load on charcoal is not only on the direction of the fibres. This paper proposes a new method to quantify the effects of applying a compressing load on randomly distributed bulk charcoal, simulating what would be expected in industrial conditions, such as in a blast furnace, rather than the analysis of individual pieces of charcoal. It is shown that the results are normally distributed when analysed by means of the friability index proposed by ASTM D440.

For preserving the environment and preventing the resource depletion, it is important to extend the allowance of recycling low grade ferrous scraps in iron- and steel-making. It is well known that the recycling also contributes to the reduction of carbon dioxide emissions from iron- and steel-making processes. However, lower grade ferrous scraps generally contain more tramp elements, such as copper and tin. It is difficult to remove such tramp elements from molten iron in iron- and steel-making processes. Highly-concentrated tramp elements negatively affect the quality of steel. For example, it is well known that copper in steel causes hot shortness by concentrated melting of copper onto the surface in hot-rolling process.
In this work, the possibilities of removing impurities from molten iron by oxidation and evaporation, which are usual methods in metal refining, are firstly investigated. Of all the elements which are dissolved in molten iron, Cu, Sn Ni, Co, Mo and W are found to be difficult to be removed by such usual methods as oxidation and evaporation [1].
Subsequently, the prospective methods to remove such tramp elements are discussed. Copper, which is one of the most important tramp elements in iron, can be removed by evaporation [2] or by sulfurization [3]. As the other methods, the possibilities to remove copper in molten iron by oxidation [4] and by reduction are considered, and the lowering limits by these methods have been investigated.

In recent years, many approaches have been made to reduce the environmental impact of iron and steelmaking industries. Replacement of reducing agents and reaction control of blast furnace are expected to decrease the greenhouse gas emission. Under such operation, internal states of the blast furnace changes drastically, thus the operation conditions should be carefully adjusted. Kinetic-based mathematical simulation is one of the useful tools for design and optimization of blast furnace operation. This paper first summarizes the outline of the blast furnace model and the reaction sub-models for reduction of iron ore and gasification of coke. Then the characteristics and utilizing methods of these models are introduced. Namely effect of coke substrate reactivity on intra-particle reaction progress of coke, and the effect of reducing gas on the form of reaction of iron oxide reduction. Finally, the recent approaches to the iron ore reduction under the scales of particle and burden layer are introduced.

The rapid increase in world steel output during the last three decades has been accompanied by a growing geographical distribution of production, especially among developing countries. There have been tendencies towards both larger and more efficient units for achieving high production and less environmental impact. Currently, about 40% of steel is manufactured from recycled scrap, which uses only 15-20% of the energy needed to make steel from virgin ore. The cut throat competition from the electric furnaces and environmental norms is getting more stringent. The very sustenance of Blast Furnace is chiefly dependent on the level of optimized usage of available raw material. Apart from the regular raw materials, like coke, coal, iron bearing materials and fluxes, the blast furnaces also consume many utilities such as nitrogen, steam, water and consumables for safe and efficient operation. This paper elaborates the actions taken to reduce the raw materials, utilities and consumables, thereby saving over USD 30 M.

Unlike the available mineral resources, the steel-making processes require raw material with lower phosphorous content in order to decrease the costs, energy use and the residue generated within the steel plant. One alternative is to develop pre-treatment of the iron ore concentrates, achieving raw materials with lower phosphorous. Depending on the mineral structure, a heat treatment combined with leaching can be an efficient way to achieve concentrates with low phosphorous (less than 0.01%). A fast and efficient way of applying energy to iron ore particles is the use of microwave energy to heat the particles. Thus, we propose a treatment using microwave heating while admixing low concentration sulfuric acid, followed by quenching during leaching with water as a feasible route for phosphorus removal from iron ore particles. We performed a design of experiment (DOE) to investigate the optimal conditions of heating and leaching which maximize the rate of phosphorous removal. The structure of the iron ore particles after their treatment with microwave energy was observed using scanning electron microscopy (SEM). Disclosing results must be presented here: the optimal conditions for heating and leaching, how the structure of the iron ore particles is affected and which is the mechanism to which it corresponds, as well as the equations and the controlling mechanism.
We demonstrated that, under the most favorable combination of heating and leaching conditions proposed in this study, the reduction of the phosphorus content in the iron ore sample could reach 100%.

Biomass is generated in agro industry and it was proved by some authors that the generation of residues is high and relevant to be used in the iron and steel making processes. In this sector there is interest to reduce the Green House Gas and biomasses appear as a new idea on renewable source of energy, replacing a part of the material injected on blast furnaces. Brazil has a huge production of biomass, for example, last year was produced around 300 Million ton of grains making it a major agricultural producers, while rich in natural resources. Brazil has an important role in the steel industry, these two activities now represent the largest contributors to greenhouse gases responsible for the greenhouse effect. Looking at this point, the purpose of this paper is analyze the technical, economic and environmental aspects of replacing part of the coal, commonly used in blast furnace, for some agribusiness waste as sugarcane bagasse, moringa oleifera husk and maize cob and straw. Some researches appointed that is possible to replace around 40% of the coal without change the process and bring some economics and environmental gains.