Blast Furnace Pig Iron Research Articles

Rigorous environmental and energy life cycle assessment of blast furnace pig iron in Brazil: The role of carbon and iron sources, and co-product utilization

Iron and steel are valuable commodities worldwide. Pig iron is produced mainly by blast furnaces, being the primary raw material used in steel manufacturing. The ironmaking sector is intensive in energy use and greenhouse gas emission; however, detailed information on further environmental impacts concerning the blend of material sources and co-product utilization as well as a rigorous application of the life cycle assessment (LCA) method are scarce. This study aimed to assess the environmental and energy performance of the production of 1.0 t of pig iron from cradle-to-gate via LCA. Global warming potential (GWP), renewable and non-renewable cumulative energy demand (CEDR and CEDNR), fossil resource scarcity (FRS), mineral resource scarcity (MRS), blue water footprint (WF), and land use (LU) were assessed in five scenarios in the Brazilian context, being S0: the baseline scenario with coke as a carbon source; S1: partial utilization of by-/co-products (top gas and slag), representing the current industry practice; S2: carbon and iron input blends proportional to the current industry practice; S3: current industry mix (S1 and S2 combined); and S4: ex-ante (forecast) scenario with an enhanced blend of inputs and maximum utilization of co-products. Results show that, when evaluated against an unrefined but realistic fossil-based state of the technology (S0), the existing practice in co-product utilization (S1) provided more gains in terms of GWP, CEDNR, FRS, and MRS (11 % on average) than the current iron and carbon input blends (S2, 9 % on average) if compared side-by-side. The current industry mix (S3) showed further improvement in environmental and energy performance (22 % on average) compared with the baseline scenario (S0), while the forecasted scenario (S4) indicated additional gains, reducing GWP by 47 % (down to ~1 t CO2 eq), CEDNR by 69 %, FRS by 70 %, MRS by 12 %, and WF by 5 %. The GWP, CEDNR, and FRS presented the greatest improvements with a significant statistical difference, and using charcoal as a carbon source was key in that regard, despite the great increase in CEDR (3× for biomass) and LU (2×) indicators suggesting that a robust sustainable wood supply chain will be decisive for the sector strategy. The sensitivity analysis (SA) and benchmarking of the ex-ante scenario (S4) showed notable competitiveness of such pig iron in the global market, especially for carbon and energy footprints, reaching 0.69 t CO2 eq t−1 pig iron and 4.6 GJNR t−1 pig iron from 100 % sustainable charcoal and including rail logistics (SAiv), which are from 2× to 5× smaller than those of any conventional blast furnace pig iron reported in the consulted literature.

Cogeneration of energy in the reuse of blast furnaces gases in a steel manufacturing company / Cogeração de energia na reutilização gases de altos-fornos de uma empresa siderúrgica

In the present work, using the tools and the concepts of energy for the steelmaking process, a detailed study of the electric energy generation system (Cogeneration) in a non-integrated steel mill coupled with a thermoelectric plant was carried out, where the production process of this steel industry, which is located in a city in the Midwest region of Minas Gerais (Brazil), was analyzed. A pig iron producer that sells in the internal and external markets, this steel industry is continuously seeking to increase its competitiveness in the steel sector and to become an ecologically sustainable company. The intention is to propose a better utilization of the gases generated in the production of pig iron in a charcoal blast furnace. That is, since the gas flow from the blast furnace, which serves as fuel in the combustion process in the boiler, does not have a regular or constant flow, it is necessary to monitor the air/fuel ratio almost in real time, in order to obtain the highest power in the turbo-generator set of the steam system. Through the energy analyses performed for each of the components of the energy generation cycle of the steel mill, improvement proposals are suggested to increase the energy efficiency of the components and, consequently, of the cycle as a whole.

Low-carbon production of iron and steel: Technology options, economic assessment, and policy

Summary Given increased urgency to transition the global economy to net-zero CO2 emission, governments and industry have increased focus on decarbonizing hard-to-abate sectors, including steel making, which contributes roughly 6% of global CO2 emission and 8% of energy-related emission (including power consumption emission). This paper reviews current global iron and steel production and assesses available decarbonization technologies, including hydrogen injection, solid biomass substitution, zero-C electricity substitution, carbon capture and storage (CCS) retrofit, and combinations of these decarbonization approaches. Blast furnace-basic oxygen furnace (BF-BOF) dominates production (71%) and is particularly stubborn to any decarbonization technology. Direct reduced iron to electric arc furnace (DRI-EAF) production is 5% and growing, it appears to have better decarbonization potential to move toward net-zero. Secondary steel production using mainly steel scrap in electric arc furnace (EAF-scrap) is 24% of global production and has both the lowest energy consumption and is technically simplest to decarbonize through electrification but is limited in market share to recycled steel capacity. Of the options assessed, blue hydrogen, carbon neutral biomass, and CCS appear to have the lowest cost and highest technical maturity. However, no single approach today can deliver deep decarbonization to the iron and steel industry and all approaches lead to substantial production cost increase. No uniform ideal solution exists, and different geographies, infrastructure, and economies will determine the local optimum solution with viability and cost. Policy measures will be required to provide financial incentives for decarbonization and to avoid unwelcome outcomes such as emissions leakage or job loss.

Quantitative Analysis of Pig Iron from Steel Industry by Handheld Laser-Induced Breakdown Spectroscopy and Partial Least Square (PLS) Algorithm

One of the main objectives in the steel production process is to obtain a blast furnace pig iron of good quality and at the lowest possible cost. In general, the quality of pig iron is evaluated on the basis of its chemical composition determined by X-ray fluorescence laboratory equipment. In the present study, the performance of a handheld (h) laser-induced breakdown spectroscopy (LIBS) instrument in the identification and the quantification of the relevant elements C, Mn, P, Si, and Ti in forty-six blast furnace pig iron samples was tested successfully. The application of two different models, i.e., univariate and multivariate partial least square (PLS) calibration and validation, to the whole LIBS data set showed that the latter approach was much more efficient than the former one in quantifying all elements considered, especially Si and Ti.

Comparative Wear Behavior of Semicrystalline HVOF and Plasma Sprayed Phosphorous-Rich Pig Iron Coatings

The present work discusses the comparative wear behavior of composite (amorphous/nanocrystalline) blast furnace pig iron coatings deposited on a mild steel substrate using high velocity oxygen fuel and air plasma spray techniques. The study has been carried out using a ball-on-disk tribometer with the coated specimen and tungsten carbide ball as disk and counter body, respectively. A composite structure, consisting of both amorphous and nanocrystalline phases, has been confirmed by x-ray diffraction and transmission electron microscopy. It has indicatively been shown that the wear resistance of the mild steel substrate could be improved using composite coatings due to the higher micro-hardness of the coatings. Indirect tribo-oxidation involving oxidized debris has been found to be the dominant wear mechanism.

Amorphous/Nanocrystalline Composite Coatings Using Blast Furnace Pig Iron Composition by Atmospheric Plasma Spray and Their Electrochemical Response

The present study aims to develop composite (amorphous + nanocrystalline) coating using blast furnace (BF) pig iron composition with the help of atmospheric plasma spray process for the first time. The usage of cheap and lean chemical composition of pig iron for the development of economical composite coating on mild steel substrate has led to the improvement in its hardness as well as corrosion resistance in 3.5% NaCl solution. The corrosion resistance of the BF metal composite coating in 3.5% NaCl solution has rivaled that of the heavily alloyed (like Cr, Ni and Mo) 316L stainless steel coating. The as-sprayed coating has been characterized using x-ray diffraction, scanning electron microscope and transmission electron microscope. The improvement in corrosion resistance of composite coating can be attributed to the presence of amorphous, nanocrystalline phase and higher content of P and Si and protective rust phases.

Utilization of Bauxite Residue: Recovering Iron Values Using the Iron Nugget Process

ABSTRACT Red mud waste from aluminum processing was utilized as a material for extraction of iron. Red mud contains a high amount of iron, comparable to feedstock to North American iron mines, and extracting this iron value is paramount. The iron nugget process can extract iron from the iron minerals in red mud. The nugget process is a one-step alternative to the blast furnace which simultaneously reduces and separates metallic iron from the red mud. A mixture of powdered hardwood and softwood was used as the reducing agent. Resulting iron nuggets have an iron grade that is comparable to blast furnace pig iron.

Composite (glass + crystalline) coatings from blast furnace pig iron by high velocity oxy-fuel (HVOF) process and their electrochemical behavior

The present study is the first report on the possibility of blast furnace (BF) pig iron-based corrosion resistant and very hard composite (glass + crystalline) coating on a mild steel. The BF metal is of very lean and cheap alloy chemistry and its coating on the mild steel has been found to show similar corrosion resistance as shown by the stainless steel (SS) coating on the mild steel. The BF coating has been made through high velocity oxygen fuel (HVOF) thermal spray process at different powder feed rates of 30, 40, 50 and 60 g/min. The microstructural characterization of coatings reveals good inter-splat bonding with low porosity in the range of 3 to 5%. The corrosion potential of the BF coatings is significantly negative than that of the mild steel substrate as well as the SS coating suggesting that the BF coatings could provide sacrificial protection to the mild steel substrate in addition to the comparable corrosion resistance as shown by the SS coating in freely aerated 3.5% NaCl solution. It has been found that the corrosion resistance of these BF coatings is significantly higher than the conventional galvanized coating, allowing them to be a promising and better sacrificial coatings than the galvanized one. The high corrosion resistance of the BF coatings could be attributed to its partially amorphous structure, presence of high C, Si and P, and relative portion of the insoluble α-FeOOH phase compared to the soluble γ-FeOOH phase in the rust, indicated protection parameter of the rust (α/γ*).

Glassy blast furnace pig iron and design of other glassy compositions using thermodynamic calculations

Formation of metallic glass largely depends on the composition of the alloy system and inherent glass forming ability (GFA). Among all the relevant GFA criteria, GFA parameter, PHSS, gives better quantitative description to explain higher GFA in multicomponent systems. Present work shows a set of glass forming alloys designed with the help of some GFA parameters including PHSS using a raw blast furnace (BF) grade metal, popularly known as pig iron, in the range of 75–100 wt% of the total alloy weight and addition combination of alloying elements (B, P, Nb, Cr, Mo). Good glass forming ability of the blast furnace hot metal (direct from blast furnace containing impurities) as determined by thermodynamic calculation has been experimentally validated by making its glassy ribbons by melt spinning in air as well 1 mm diameter partially glassy rod as confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) studies.

Manipulation of slag separation properties from pig iron nuggets with flux additions to dried greenball mixture

ABSTRACTPig iron nugget process is one of the direct smelting processes developed as an alternative to the traditional blast furnace process. Throughout the process, slag-free pig iron nuggets, which have similar properties to the blast furnace pig iron and white cast iron, are produced by single-stage heat treatment of dried greenballs. During the process, slag separation from the metallized areas can be enhanced by adjustment of the slag’s chemical and physical properties. The objective of this research was to investigate the effects of flux addition rates (basic to acid ratio) to the dried greenball mixture on pig iron nugget production and slag separation. Thus, this study involved the heat treatment of six different greenball mixtures, which contained various amounts of limestone addition (basic to acid ratios, 0, 0.63, 1.02, 1.42, 1.85, and 2.29) utilizing a laboratory-scale resistance box furnace or simultaneous differential scanning calorimetry and thermalgravimetric analyzer. The samples produced by heating in the box furnace were analyzed for their morphological and chemical properties utilizing optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), macroscopic observations, iron titrations, and atomic absorption spectroscopy. It was determined that the highest percentage of iron yield in the nugget for the process and the highest distribution of iron in magnetic slag were obtained when utilizing the greenball mixture, which contained 7.5 wt% limestone as flux (basic to acid ratio of 1.42).

The Use of the D-Optimal Mixture Design to Develop a Novel Refractory Ramming Mix of the MgO–SiO2–SiC–C System for Blast Furnace Pig Iron Runners

In this study, to develop a ramming mix, the D-optimal mixture design method was used, which makes it possible to achieve in the new type of ramming mix the optimal concentration of carbonaceous raw materials – silicon carbide, graphite, pitch. Using the expert-design software and a special preparation methodology, 16 samples of varying compositions were prepared, and their physical properties, such as dried and fired strength, were evaluated. In order to determine the optimal formulation, 12 models were studied. The model with the highest percentage of desired properties at 78.5% contained 11.7 wt.% silicon carbide, 2.6 wt.% graphite, and 5.7 wt.% pitch. Thus, this is the optimal composition of a ramming mix of the MgO–SiO2–SiC–C system for a blast furnace pig iron runner.

Life cycle assessment of the comprehensive utilisation of vanadium titano-magnetite

This study describes the life cycle assessment (LCA) of the comprehensive utilisation of vanadium titano-magnetite (VTM) through the integrated steel production and valuable element (V and Ti) extraction route. The major sources of environmental impacts are described and pollution prevention methods are proposed. The LCA methodology is based on the ISO 14044 standard, which uses GaBi 6.0 software and the Ecoinvent database, and the life cycle inventory (LCI) data (input and output) are from Pan. Steel. Impact assessment results indicate that production of pig iron in blast furnace (BF) exerts the most extensive impacts on global warming potential for the time horizon of 100 years (GWP100) and fossil fuel consumption. By contrast, iron ore mining dressing and sintering contribute the most to acidification potential (AP), eutrophication potential (EP) and photochemical ozone creation potential (PCOP) because of dust and pollutant gas emissions. When indicator contributions are considered, the observed impacts on AP (50.88%), GWP100 (24.25%) and photochemical ozone creation potential (POCP) (19.51%) are higher than those on EP, human toxic potential (HTP) and abiotic depletion potential (ADP). Therefore, when processes with environmental impacts are taken into account, the iron mining and dressing, iron ore sintering and BF iron-making processes must be considered, when category indicators are taken into account, AP, GWP100 and POCP must be considered.

USE OF WASHING BRIQUETTES FOR IMPROVEMENT OF THE BLAST-FURNACE HEARTH OPERATION

The use of washing pellets in the amount of 30 – 60 kg/t of pig iron in blast furnace with useful volume of 3000 m3 has contributed to the quite effective flushing of the horn and preservation of the smooth furnace operation. The estimated reduced productivity of the blast furnaces increased by 3,5 % while reducing the specific con-sumption of coke reduced by 0,69 %.

Life cycle inventory processes of the Mittal Steel Poland (MSP) S.A. in Krakow, Poland—blast furnace pig iron production—a case study

Purpose The goal of this paper is to describe the life cycle inventory (LCI) approach of pig iron produced by Mittal’s Steel Poland Blast Furnace (MSPBF) in Krakow, Poland. The present LCI is representative for the reference year 2005 by application of PN-EN ISO 14040: 2009 (PN-EN ISO 2009). The system boundaries were labeled as gate-to-gate (covering a full chain process of pig iron production). The background input and output data from the blast furnace (BF) process have been inventoried as follows: sinter, several types of pellets, ore (from Brazil or Venezuela), limestone, coke, and from 2005 coal powder, pig iron, blast furnace gas, blast furnace slug, consumption of energy and fuels, including: pulverized coal, natural gas, blast furnace gas and coke oven gas, and emission of air pollutants.

The Microstructure of the Pig Iron Nuggets

The pig iron nugget process (referred to as the Iron Technology Mark 3, or ITmk3, process by Kobe Steel) was developed as an alternative to the traditional blast furnace process. Throughout this process self reducing–fluxing dried greenballs are reduced and smelted in to nuggets of metal. The objective of this research was to produce pig iron nuggets at laboratory scale, then characterize and compare them with the blast furnace pig iron. Pig iron nuggets were characterized utilizing apparent density measurements, optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, and bulk chemical analysis. It was determined that pig iron nuggets had high apparent density (6.7–7 g/cm3); had a high iron content (95–97%); and exhibited microstructures similar to white cast iron, which is essentially the same as pig iron from a blast furnace.

Methods of extending the campaign of a blast furnace

As before, the main trends in world blast-furnace smelting in this century have been a decrease in coke use, an increase in furnace productivity, and lengthening of the furnace campaign. Over the last few decades, metallurgical companies have paid an increasing amount of attention to extending the life of blast furnaces through the use of various technical, technological, and organizational measures. This article generalizes those companies’experiences in this area and analyzes the results of studies conducted by the world’s largest producers of blast-furnace pig iron.

Carburization effects on pig iron nugget making

The iron nugget process is an economical, environmentally friendly, cokeless, single-step pig iron making process. Residence-time dependent process requirements for the production of pig iron nuggets at a fixed furnace temperature (1,425°C) were investigated. Depending on the residence time in the furnace, three chemically and physically different products were produced. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI) and pig iron nuggets (PIN). The increase in the carbon content of the structure as a function of residence time was detected by optical microscopy and microhardness measurements. Sufficient carbon dissolution for the production of pig iron nuggets was obtained after a residence time of 40 minutes. The pig iron nuggets produced had chemical and physical properties similar to blast furnace pig iron. They were liquid-state products, and the slag was completely separated from the metal.

Investigation of the kinetics of ferrous oxide reduction in the slurries of metallurgical processes

The present paper is devoted to investigations of the reduction kinetics of ferrous oxides contained in the slurry mixtures of metallurgical products at the Kremikovtzi‐AD firm. The mixtures are selected to permit pellets and agglomerates to be obtained which are suitable for blast furnace pig iron production. As a reducing agent in the laboratory investigations, a small fraction of coke with 88% carbon is used. The experimental results are recorded within the temperature range 293–1183 K. The kinetic curves can be described by the following function: where α is the degree of reduction (%), x is the temperature (K), and b0–b6 are model coefficients. The degree of ferrous oxide reduction is found (α = 43.14%) for a mixture containing 40% converter slurry, 40% blast furnace slurry and 8% electric steelmaking slurry The highest degree of reduction (α = 46.88%) is possessed by ferrous oxides in the mixtures containing 68% converter slurry and 22% blast furnace slurry. When the kinetic dependencies of industrial slurries are compared with those of synthetic slurries, they are seen to be very similar. This should be taken into account when choosing an effective technology for utilizing the slurry.

Modernizing the cable drive of desulfurization-unit lances

The increasingly stringent quality criteria for steel, under conditions of extensive progress in oxygen converter production in combination with continuous casting machines, has significantly tightened the requirements for blast-furnace pig iron with respect to its content of harmful impurities, especially sulfur. For example, to make converter steel, the sulfur content of the pig should be within the range 0.010-0.015%. It should be within 0.005-0.008% for ultralow-sulfur steel. Such steel is needed to satisfy the growing national demand for metal products with improved physical properties, particularly pipes for major pipelines in the Far North.

銑鉄中Si濃度に及ぼす高炉操業要因の影響に関する反応工学的解析

銑鉄中Si濃度に及ぼす高炉操業要因の影響に関する反応工学的解析