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10:15-12:15 Session 2A: Agglomeration-1

Agglomeration of iron ore

[Invited talk] Development in iron ore pelletizing for quality improvement

ABSTRACT. Hematite ore in India contains a high amount of gangue with a high ratio of alumina to silica due to which, Reduction degradation index (RDI) increases and it behaves adversely in blast furnaces and DRI making furnaces. To improve its performance in the blast furnace or DRI making, improvement of hematite pellet properties is required. Several innovative studies have been carried out at CSIR-NML to improve the metallurgical properties of hematite ore pellet which are discussed in this paper. In the current study, the RDI of the hematite pellet has been improved by several fluxes viz. Pure MgO, olivine, pyroxenite, magnesite. Their relative performance has been compared and found the best performance with olivine. Salt solution treatment of pellet after induration has been done to decrease RDI without using flux material. The use of Industrial wastes viz. mill scale and blast furnace flue dust (BFD) has also shown a very encouraging result to reduce RDI. Although the reducibility of a pellet depends upon the character of the ore from which it is made, its reducibility can be improved by optimizing several operating parameters. In the present study reducibility of a pellet has been improved up to 8 points by optimizing the physical parameters such as induration temperature, improving apparent porosity, and improving pore size distribution without any change in chemistry.

[Invited talk] Development of a Polymeric Organic Binder for Coal Briquetting process for recycling in COREX Iron Making Technology

ABSTRACT. Coal fines generation is a global problem in terms of handling and transportation. It is a source of Air, water and land pollution. COREX technology use semi-soft non coking coal as a primary source of energy. Unlike thermal coal, the coal for Corex needs to have good CSR and CRI, possess good thermal stability and thermo-mechanical stability inside the furnace. The coal is charged in the melter gasifier of the Corex at 1050 degrees. About 50% of coal is screened out as fines (< 6.3 mm) and has to be sold at lower price. Fines if converted into briquettes can be recycled back into the process, but the briquettes need to have the desired high temperature properties similar to the parent coal. The briquettes should not break down due to this thermal shock, the coal along with the binder should convert into stable char and form a char bed which is permeable and supports the counter current process. A polymeric binder was developed along with a process for coal briquetting for COREX Iron making technology which satisfied the above requirements of briquettes. A 500 TPD plant was established at AMNS steel plant Hazira that reduced the gross coal consumption in the process along with improved cost efficiency. This has also reduced the environmental footprint of iron making through COREX route.

[Invited talk] Use of high Alumina Indian iron ore in making super fluxed sinter for high pellet BF operation

ABSTRACT. Advantages of increasing pellets in blast furnace (BF) are well established. Due to their superior properties, regular shape & lower gangue content, increasing % pellet in BF helps in increasing permeability, productivity, reducing coke rate & overall Carbon foot print. However, to increase pellet percentage in BF, basicity & MgO content needs to be increased in pellet to meet BF’s slag chemistry requirement which leads to the deterioration of pellet’s cold strength. For increasing the pellet percentage in blast furnace (BF) and to compensate for the deterioration in cold strength of pellet on fluxing, use of super fluxed sinter was explored. Pot sinter trials were done to study the effect of increasing basicity (up to 2.9) & %MgO (up to 2.2%) using Indian iron ore containing higher Alumina (up to 4.0%). It was observed that with increasing basicity & MgO, sinter yield, tumbler index, productivity & RDI increases. This was attributed to the increase in slag bonding phases, which was confirmed by XRD and optical microscopy study. Further, plant scale implementation has confirmed the lab trends and helped in achieving stable BF operation with up to 60% pellets.

[Virtual mode] New Trends in Agglomeration Toward Next Generation Iron and Steel Making Technologies
PRESENTER: Elsayed Mousa

ABSTRACT. Agglomeration is an essential part in the steel industry aims at preparing the burden materials to fulfil the required mechanical and metallurgical characteristics for the implementation in ironmaking and steel making furnaces. The agglomeration not only helps in developing the quality of the primary raw materials to achieve efficient and stable operation in the furnaces, but it enables the recycling of the secondary and residual materials which are inevitably generated during the production processes. In this context this paper will address the latest trends in iron ore pelletising and briquetting to meet the modern iron and steel making technologies.

In Ironmaking, the next generation H2-based direct reduction technologies require an improvement in the pellets quality to reduce the gangue oxides, slag generation and energy consumption. In steelmaking, developing briquettes to enhance the recycling of lime rich residual is crucial to improve the overall efficiency of the process. In this aspect, this study will discuss the feasibility of using organic binders for partial and/or full replacement of bentonite in pelletizing of iron ore magnetite concentrates for H2-based ironmaking. Moreover, turning the unexploited lime and iron rich residues into briquettes with proper quality for steel making implementation will be addressed. The study will demonstrate the potential of agglomeration in improving the burden quality, resource efficiency and circular economy.

Processing of Iron Ores with High LOI for Pellet Making
PRESENTER: Rameshwar Sah

ABSTRACT. Gradual depletion of high grade iron ores coupled with physico-chemical and mineralogical variations in iron ore quality has significant impact on pellet plant performance and the pellet quality. The quality of the pellets is linked to the type of iron ores used as raw material and gangue minerals (primarily alumina and silica) present in it. In this study, the behaviour of the iron ore pellets with high loss-on-ignition (LOI) has been investigated during pelletization. Physical, chemical and microscopic analysis of iron ores with different LOI content were carried out to identify the mineral phases and their distribution. Thermo-gravimetric (TG) analysis of iron ore samples was carried out to understand the mechanism and kinetics of the thermal decomposition of mineral phases and release of chemically bonded water. The TG-DTA analysis revealed that the LOI in iron ore released in two steps in the temperature range of 250 to 800 °C. The pellet properties are significantly influenced by the presence of LOI. Higher LOI in pellets resulted in lower CCS and poor RDI. Proper understanding of iron ore mineralogy, characterization and optimized induration cycle can help in effective utilization of high LOI iron ores in pellet making.

Sintering of low grade chromite fines for Ferrochrome production

ABSTRACT. India produced ~3.1 MT of chromite ore and ~ 1.0 MT of ferrochrome alloy in the calendar year 2021-22. Fe-Cr alloy is extensively used in producing different grades of alloy steels. In India chromite ore is mined from Sukinda valley in Odisha, which results in generation of > 90 % of mined ore as fine material (less than 10 mm). Chromite fine agglomeration is an effective measure to use them effectively. Normal agglomeration processes include briquetting, pelletizing or sintering, each process has its merits and demerits. Present study aims at producing sinter directly from the available chromite fines (-10 mm) without any grinding in presence of coke breeze (like iron ore sintering). Sintering was carried out in a pot sinter @1600 0C by breaking the spinel phase of chromite. Result indicated 18-20% molten phase formed for bonding the sintered mass, which reduces faster in subsequent electric arc furnace smelting. Reduction smelting experiments were carried out in 100 kg scale in the graphite lined 100 kVA electric arc furnace to produce Fe-Cr alloy. With optimum addition of fluxes and reductant & adjusting the slag composition, ferrochrome alloy was produced. Measured slag was sufficiently fluid having viscosity 1.1 poise, tapping temperature ~1719°C. The obtained Fe-Cr alloy has composition 50-54%Cr, 30-35% Fe, 7-8%C, 1-1.5% Si with 81% metallic yield and 88% chromium recovery.

Laboratory scale simulation of grate bar jamming of pallet car due to presence of Alkali in sinter feed mix by solid waste addition

ABSTRACT. Grate bar is an essential component of pallet cars in sintering process, whose primary function is to provide support to the sinter bed and facilitate uniform suction. JSW Steel Dolvi, consumes various in-plant iron bearing solid waste through sinter plant. Recently, a problem of grate bar clogging was faced by the sinter plant, affecting production rate severely. To understand the root cause & effect of clogging on grate bar, detailed characterization of the clogged material was done using XRF, AAS, XRD, which indicates presence of Alkali material. Further, source of Alkali was singled out and a series of experiments were done using pot sinter to simulate the grate bar clogging in the lab scale. Simulated lab scale study confirms the Alkali rich solid waste as the root cause of grate bar clogging. Furthermore, microstructure analysis of grate bar was done using optical microscope & SEM to assess corrosive impact of clogging material on the grate bar. Presence of Na & K was observed on the 40 to 50-micron thickness of top surface of grate bars which indicate the possibility of premature failure of grate bars, if the Alkali containing solid waste is continued.

10:15-12:15 Session 2B: Fluid flow in steelmaking
[Invited talk, virtual mode] Fluid flow simulation of an EAF with bottom gas injection comparing supersonic and coherent jets

ABSTRACT. In this work, a three – phase mathematical model for a 100 – ton electric arc furnace (EAF) with combined blown is presented. The combined blow consists of oxygen injection with three coherent jets, as well as bottom gas injection with three tuyeres. The model uses a volume of fluid (VOF) approach to simulate the multiphase flow. For simulating the fluid dynamics of this complex system, the coherent jet fluid flow is calculated apart from the rest of the metallurgical reactor. Then, the results of such calculation are coupled with the EAF simulation to enhance the computational time and increase the solution robustness. The model proves to predict the mean velocity reported by previous models correctly. The calculation results gave valuable information about the EAF combined blown fluid dynamics and can be used to make process decisions and improve their performance.

[Invited talk] Numerical simulation of temperature evolution in refractory side wall during the scrap melting in a lab-scale DC electric arc furnace

ABSTRACT. We numerically simulate arc plasma formation, scrap melting and evaporation in a lab-scale direct current electric arc furnace (DC-EAF). The Navier–Stokes and Maxwell's equations are solved for the arc plasma formation, the enthalpy–porosity technique is used to track the melting phenomenon, and the species equation is solved to incorporate the mixture of plasma species. The developed model was first validated against the previously published work for welding arc and then extended to the DC-EAF. The energy transfers from the arc to the anode, causing melting and metal evaporation. This energy transfer is dominated by electron enthalpy transport and convection. A part of arc energy transfers directly or indirectly to the refractory, mainly by radiation and convection mechanisms. In this study, we simulate the melting of scrap and the temperature change in the furnace's refractory walls. In the absence of post-combustion and electrode burning, radiation is the primary energy transfer mechanism to the refractory.

High-fidelity Multiscale Modelling and Simulation on Bubbles and Interface Behaviors for a Gas-Stirred Ladle
PRESENTER: Chris Pistorius

ABSTRACT. The gas-stirred ladle involves many multiphase/multiscale fluid-dynamics phenomena, including bubbles formation, deformation, coalescence and breakup, plume characteristics, slag eye and fluctuation behavior, slag entrainment into metal, et al. To insight into these features, a dispersed phase-resolved VoF method coupled with large eddy simulation (DPR-VOF-LES) was employed to track the small-scale bubbles and the large-scale interfaces between phases, especially the dispersed micro-bubbles in the sub-grid scale modeled by the Lagrangian bubble tracking technology. Each scale of the model is closed via the appropriate approach proposed by this study and the between-scales are bridged through a discrete-continuum-coupling transition model. The local mesh auto-refinement with dynamic load balance technology is applied to this model, cutting down the computational cost considerably compared to the traditional static mesh method to get the same resolution result. After the model is validated, it is applied to investigate targeted phenomena for an industrial-scale ladle with the actual physical properties and effects of critical operating parameters, such as the argon flow rate, configuration/number of bottom plugs, and so on, are also discussed.

Modelling of Hydrodynamics and Mixing Phenomena in an Inductively Stirred Ladle
PRESENTER: Krishna Avatar

ABSTRACT. Hydrodynamics and mixing phenomena in an inductively stirred ladle are modelled mathematically. In this, the effect of two types of electromagnetic stirrers on motion is simulated; one producing predominantly swirling motion (as in paddle stirred ladle) while the other generating an up-welling, toroidal motion (as in inert gas stirred ladle) within the bulk of the reactor. Two different ANSYS software namely, Maxwell-3D™ and FluentTM have been applied to carry out numerical simulations. In the former, three-dimensional Maxwell’s equations are solved to estimate a priori the distribution of magnetic field within the melt phase, due to the imposed, alternating current, while in the latter, RANS based magneto-hydrodynamic, turbulent flow equations are solved to yield the electromagnetically driven flow fields. Model predictions are evaluated against published results, and it is shown that electromagnetic as well as the turbulent flow model framework developed in this work perform sufficiently accurately. Finally, incorporating the computed velocities and turbulent viscosity, conservation equation for an inert species is solved to calculate homogenization or mixing time for both type of stirrers. Predicted results together with relevant published work indicate that at equivalent specific stirring power input, mixing is fastest for toroidal type electromagnetic stirrer followed by mechanical agitation, gas stirring and paddle type induction stirring.

Modeling the effect of SEN design on fluid flow in thin-slab casting.
PRESENTER: Chandan Kumar

ABSTRACT. Compact Strip Production (CSP®) caster technology is an ever-evolving process because of its complexity, high-speed flow field region and high casting speed. Improving fluid dynamics inside mould reduces number of breakouts and improves heat flux removal from mould walls. To cater this, many geometrical modifications in Submerged Entry Nozzle (SEN) is being carried out by different steel makers across globe. To this end, a three-dimensional, two-phase flow field model of the fluid in SEN-mould region was developed, taking two SEN designs (SEN-I & SEN-II), to investigate the impact of its design on the fluid dynamics inside mould. CFD modelling was carried out using VOF (Volume of Fluid) model in Ansys® Fluent to study the velocity profile, flow pattern and meniscus behaviour in SEN-mould configurations. Transient fluid flow simulation results showed large scale asymmetric flow in the mould for SEN-I while a better symmetric flow region was observed for SEN-II. SEN-II was observed to be performing better than SEN-I but meniscus fluctuation observed for SEN-I was of the order of ±11mm while it was around ±20 mm for SEN-II.

Effect of Internal Gas Injection in Various Shroud Geometry and Influence on Tundish Hydrodynamic Performance
PRESENTER: Abhinav Maurya

ABSTRACT. Flow of molten steel through a shroud, with or without inert gas injection, can influence the flow in tundish and has a considerable influence on metallurgical performance of steelmaking tundish system. In continuous slab casting, large throughput rates may promote refractory wear, slag entrainment, and large tundish eye which are known to seriously impair steel cleanliness. In the present work, a numerical investigation has been carried out using commercial CFD package ANSYS FLUENT. The numerical investigation has been done for two cases, without inert gas injection (homogeneous system) and with inert gas injection (two phase system) for two different ladle shrouds namely, conventional and bell-shaped ladle shroud have been considered to investigate the influence of inert gas injection with 10% gas loading ratio on the hydrodynamic performance of a slab casting tundish system.

10:15-12:15 Session 2C: Blast Furnace-1
[Invited talk] Powder holdups in 2-D and 3-D packed beds with lateral and bottom injection of gas-powder

ABSTRACT. Experimental study of gas-powder flow in a two dimension (2-D) rectangular and three dimension (3-D) in cylindrical bed is carried out to find out the static and dynamic powder holdups behaviour. The system simulates the lower and middle part of an ironmaking blast furnace (BF). Two types of gas-powder injection system have been used i.e. lateral (as in the BF) and bottom. A drastic change was observed in powder static holdup values in two systems than dynamic holdup. This phenomenon was present in all experimental conditions (i.e. it was not affected by variables like gas flow, powder flux & its size and packing materials & its size). Pressure profile across the bed length in both the system was also recorded. The various phenomena, which have been observed during the experiments, are explained based on fluid dynamics of both the phases (gas and powder) and elutriation velocity of the powder. Relevance of the results to the blast furnace is discussed.

[Invited talk] An experimental investigation of slugging phenomenon in 2D binary gas-solid tapered fluidized beds
PRESENTER: Sabita Sarkar

ABSTRACT. The gas-solid fluidized beds are widely employed in metallurgical industries for producing Direct Reduced Iron (DRI). For such practical applications, generally, particles with wide-size distribution are charged in the fluidized bed reactor. It is reported that the tapered fluidized beds are most suitable for particles with wide size distribution due to the velocity gradient in the axial direction. Typically, in gas-solid fluidized beds, bubbles are formed, and tapered beds are no exceptions. These bubbles transform into slugs when their size becomes comparable to bed diameter at high gas velocities. Slug behavior in binary tapered beds has not been reported in the literature. Therefore, in the present work, the slug behavior in binary tapered fluidized beds has been captured using a high-speed camera and further analyzed using the digital image analysis method. The influence of taper angle, air velocity, and the fraction of fines on slug size and rise velocity have been investigated. It was found that the slug size and rise velocity increase with taper angle, air velocity, and fine fraction.

[Invited talk] Advancements in Blast Furnace Burden Distribution Control in Tata Steel

ABSTRACT. Burden distribution inside a blast furnace is a key dictator of stable operations of the same. Tata Steel has invested a significant amount of research in this area to tackle the various problems associated with it and subsequent blast furnace performance. In the present paper, a brief overview of methods for quantifying and utilizing data to enhance burden distribution control has been presented. Experiments performed in lab scale cold models of a blast furnace along with trials during burden material filling in of actual furnaces have enabled to build robust burden distribution models capable of predicting the burden layer specifics according to different operational parameters. With the advancement of technology in the past few decades, focus has increased on non-invasive measurement technologies which facilitate continuous monitoring of the top burden surface 24 X 7 to provide real-time insights to operators and inputs to models. Numerical modelling of burden material flow from material storage locations to blast furnace top using high-speed computational simulations has provided an insight into changing burden behavior with changing burden material qualities. These advancements have helped achieve more stability in blast furnace operations with a drop in coke consumption compared to a decade ago.

Enhanced Hydrogen in Blast Furnace and Its Effect on Reduction Behavior of Iron Oxides
PRESENTER: Pritesh Garg

ABSTRACT. Use of hydrogen bearing injectants in blast furnace as an alternate reductant is one of the capable options to lower greenhouse gas emissions of steel making units. Since blast furnace is traditionally operated primarily with carbon-based reductant, use of hydrogen bearing gases alters the burden material behavior and in turn, the process dynamics. In this work, reduction behavior of iron oxides (sinter and pellet) is evaluated by conducting high temperature experiments in simulated blast furnace conditions with different levels of hydrogen content (3.5 – 16.5 %) in reducing gas. It is found that there is an increase in reduction kinetics of both sinter and pellet with increasing hydrogen in reducing gas. The reduction degree of pellets and sinter for case containing 16.5 % hydrogen in bosh gas is found to be 1.3 times and 1.6 times higher respectively than that for case containing 3.5 % hydrogen. The reduced samples were subjected to characterization analysis to identify the phases, to capture the morphological changes and identification of different constituents in reduced samples under different conditions.

Productivity improvement of large Blast Furnace (4554 m3) at Jindal Steel and Power Angul, India
PRESENTER: Ritesh Mishra

ABSTRACT. Jindal Steel and Power, Angul commissioned its first blast furnace of 4554 m3 in May 2017 at Odisha, India. This Blast Furnace has achieved productivity of 3.16 t/m3 of working volume/day by producing more than 12000 tons of hot metal in a day. Productivity improvement of large blast furnace is achieved by improving permeability inside the cylindrical structure of furnace by changing Sinter chemistry based on alumina percentage as higher alumina deteriorate the physical properties of Sinter, reducing fines and moisture input in terms of kg/thm, Modifying burden mix blending in main charging conveyor. This approach helped to increase oxygen enrichment with coal injection in the furnace to increase productivity.

[Cancelled] Ferrous Burden Performance for Reduction and Degradation using Advanced Experiment and Characterization Methods

ABSTRACT. Substantial CO2 emissions contribution from Iron and steel making can be reduced to Thermodynamically lowest possible emission level by bringing efficient use of Raw materials in such a way to reduce the Carbon Rate (RAR). Reducibility and Disintegration of Ferrous Burden are two of the important parameters constantly monitored to improve the blast furnace operating conditions. Conventional testing methods for Blast furnace operation follows iso-thermal and Gases with constant reduction potential can only give partial information about the performance and impact of additives live effect of fluxing agents and coatings at different temperatures. Customized advanced testing methods HOSIM using the RIST operating line of actual Operating furnace data and its internal features like temperature changes from Zone to Zone to achieve targeted CO utilization efficiency. These Methods has the capability to Improve the Ferrous metallics preparation processes and their impact on Carbon rate. Additionally, these tests combined with advanced characterization methods revealed details about performance at different temperatures the insights about the role of secondary oxides on reduction performance of iron oxides. Development of Alternative fluxes and their impact on Reducibility and disintegration are some of the applications applied for regular operations to optimize at the material preparation stage.

[Cancelled] Development of Scaled-Down Pulverized Coal Combustor to replicate Raceway conditions of Blast furnace through numerical simulations

ABSTRACT. Pulverized Coal Injection (PCI) technology plays a critical role in controlling the performance of the blast furnace process. However, combustion performance of pulverized coal inside the raceway is difficult to predict owing to the lack of measurements. Hence, there is a need to develop and study the combustion behaviour in lab scale reactors. In this work, scaled-down pulverized coal combustors are designed using different approaches based on Constant Residence Time (CRT) and Constant Velocity (CV). In this study, numerical predictions of the scale down reactors are carried out. Governing equations of particle laden reacting flow are solved in ANSYS-Fluent® platform. Discrete Phase Model (DPM) is used for predicting the coal particle flow and its interaction with the gas phase. Devolatilization rate is calculated using an Arrhenius type single step kinetic model and its conversion to products is modelled through Eddy-dissipation model. Reaction of char with the oxygen is modelled using kinetic/diffusion-controlled mechanism. Subsequently, a few crucial combustion parameters are compared between lab scale and original reactor. It is found that modified CRT and original flame dynamics to be same in the appropriate non-dimensional coordinates. This indicates that similar processes occur at both scales, indicating the validity of the modified CRT scaling method for further studies.

14:00-14:45 Session 3: Plenary Talk-1 (Uttam Singh)

Plenary talk

Transformation in Ironmaking, Tata Steel: A Journey of Last 10 Years

ABSTRACT. Tata Steel Jamshedpur is the oldest integrated steel plant in India with a current annual capacity of 11Mn Tonnes crude steel production. Its ironmaking division constitutes agglomeration, coke making, hot metal logistics and blast furnaces. Last decade of ironmaking has witnessed major process shifts focusing on super-efficient processes, circular economy and sustainability with significant improvements through technical engagements, innovative trials and adoption of industry 4.0 technologies. This has created new benchmarks in productivity, cost and sustainability amidst the constraints of use of low grade iron ore with high alumina, high ash coke and varying raw materials qualities. With significant interventions in process optimization and implementation of multiple digital models right from raw material tracking to output predictions, bigger furnaces have significantly reduced coke rates from 450 to ~300 kg/thm and increased productivity beyond 3 t/m3/day. Agglomerates being the units most prone to emissions, efforts on digital and hardware interventions have resulted in considerable reduction in stack emissions. Coke plants have pioneered usage of non-coking indigenous coal in coke making with blend optimisation for cost reductions and sustaining coke properties required for operating at higher coal injection rate in blast furnaces. As ironmaking contributes to 80% of the overall CO2 footprint of any steel industry, many trials have been either been conducted or are planned in future for meeting decarbonisation goals.

15:00-15:45 Session 4A: Agglomeration-2
[Invited talk] Agglomeration of iron and steel making residues using organic binders
PRESENTER: Hesham Ahmed

ABSTRACT. Developing a cement-free iron ore agglomerates for fossil-free steelmaking is one of the challenges in decarbonizing the steel industry. The present study aims at enabling the fossil-free residues recirculation in steel industry through cement-free agglomerates. This is achieved by smart design of agglomerates using novel binders followed by hydrogen reduction. The impact of different parameters on the mechanical strength and reducibility of the developed/reduced agglomerates are evaluated. In this work, the agglomeration of two different types of residues were tested, namely mill scale and pellet fines. The influence of binder type, binder dosage, moisture content, compaction pressure on the agglomeration process and the agglomerates quality will be investigated. The agglomerate quality will be characterized through their mechanical strength and reduction behavior. The mechanical strength is measured by using a compressive tester machine and the reduction behavior is studied by thermogravimetric analysis (TGA).

Studies on Mechanical and Metallurgical characteristics of Fluxed Composite Pre Reduced pellets made with high ash coal
PRESENTER: Avash Kumar Saha

ABSTRACT. Many researchers are pushing the efficiency of blast furnaces to new heights, and every effort is being made to keep them running for as long as coking coal is accessible. There are enormous proven techniques and tested methods to slice down the use of coke rate in blast furnaces using composite pre reduced (CPR) pellets. To meet the said objectives efforts were made to develop fluxed composite pre-reduced (FCPR) pellets which consist of a metallised sponge iron pellet encased in a sintered shell of iron ore. It was found that pellet with 1mm and 2mm coating thickness show high percent of degree of reduction but they does not withstand its original shape even at lower temperature (900 & 1000°C) and melts at higher temperature (1100 & 1200°C). But 3mm thickness layer shows approx 60% reduction and it shows maximum strength (~300 kg/pellet) at 1100°C for basicity 3 without forming a separate coating layer. So according to the result 3mm thick iron coating was found suitable for preparing good FCPR pellets which acts as a single pellet. The major achievement of the present study has been to optimise the thickness layer to get a remarkable amount of reduction and better strength pellets which could help in promoting its use as blast furnace feed.

Development of an Automated Property Prediction System for Iron-ore Agglomeration Processes

ABSTRACT. In an integrated steel plant, the agglomeration processes are highly dynamic and are affected by the raw materials composition and process variables, which cause fluctuations in the properties of the produced agglomerates. This mandates multiple sampling and testing routines in each shift, which is tedious and involves long testing procedures resulting in delay in corrective action at the operator’s end. Machine learning techniques can be deployed for quick prediction of the desired properties and features without any delay and help in improving the process control systems. In the present work, an online fully automated machine learning-based prediction system was developed through Python and R programming languages for the prediction of key pellet and sinter quality parameters like cold crushing strength, reducibility index, reduction degradation index, tumbler index etc. using ensemble machine learning techniques. The developed model showed good prediction accuracy of 90-95%. It was implemented on the plant scale by incorporating a novel ‘incremental updating dataset’ approach that helped the model to ‘self-learn’ from the deviations and ongoing trends in the fresh datasets to deliver more accurate predictions. Post-deployment, the model helped in reducing manual sampling frequency leading to better manpower utilization and enabled the operators to take quick corrective actions for improved process control resulting in significant monetary savings.

15:00-15:45 Session 4B: Optimization
A Candid Perspective from a Highly Productive, Modern Mini-Mill: Fundamentals of Value-In-Use Modelling and Optimization of Raw Materials (Scrap, Pig Iron and HBI)
PRESENTER: Kamalesh Mandal

ABSTRACT. Steel Dynamics (SDI) Flat Roll Group, operates Electric Arc Furnace (EAF) based modern mini mills in the USA that serve customers in appliance, automotive, construction, HVAC, energy, pipe & tube, agriculture, and service center markets with Hot Rolled, Cold Rolled, Pickled, Galvanized, Galvalume®, Aluminized Type 1, Painted, and digital printed products. SDI’s EAF-based mini-mills are successfully producing advanced versions of these products with low-residuals, particularly low-copper, by using an optimized mix of prime scrap, HBI, and pig iron. This paper will focus on fundamentals of Value-In-Use (VIU) modeling and optimization of scrap mix, and production experience with pig iron and HBI.

Optimization of Reagents Consumption in hot metal Desulphurisation
PRESENTER: Aditya Nema

ABSTRACT. External desulphurization, or hot-metal pre-treatment is an important unit operation in the integrated route for iron and steel manufacturing, particularly, with the ever-increasing requirements of lower and lower Sulphur contents in the final steel product. The price of fluxes (Mg and CaO) used in a DeS station can be ~10,00,000 per heat for a 150-200 ton vessel ! Thus, optimization of the amount of Mg and CaO in DeS can result in significant amount of cost savings for the steel industry. Such studies, however are limited and the amounts of fluxes added are often determined based on the experience of the operators. This study, therefore, in an important step in developing a predictive model for flux additions in DeS. based on process and consumption data collected and classified in different buckets for different Reagents data science based models were trained and deployed to optimize the Reagents added in various DS units at Tata Steel Ltd. Under normal process conditions, accuracy of model is around ~75 %.

Integrated Process Optimization strategy at LFs to reduce energy consumption and superheat delays
PRESENTER: Gaurav Kumar

ABSTRACT. Treatment of steel at the Ladle furnace is an important step towards achieving a desired steel quality. The objective of the process is to achieve a desired chemistry and temperature for smooth casting operation through arcing and ferro alloy additions. The current work describes the process models which have been developed and deployed to control the two critical aspects of LF treatment process at LD3, Tata Steel, Jamshedpur. The first one is to predict the steel temperature in a real time (every 10 seconds) and advice the operators the optimum arcing pattern i.e. arcing duration and tap number to be used. The second aspect is the recommendation of a suitable LF out temperature to meet the desired superheat based on the dynamic shop conditions. These two models work in tandem and complement each other. The recommended LF out temperature derived from one model is used as an input to the other model so that an optimum arcing advice profile is predicted by the other model. The models are heuristic in nature with the core as some data science based algorithm and supported by different business logics and self-learning features to handle the unusual or unforeseen scenarios like lead heat, new steel ladle or some interruptions.

15:00-15:45 Session 4C: Casting and Solidification-1
Sliver defects in low carbon Nb-V-Ti microalloyed steel caused by edge crack in continuous cast slab
PRESENTER: Santosh Kumar

ABSTRACT. Sliver is a common defect observed in hot rolled coils applied for linepipe making. Linepipe steel is a Low carbon Nb-V-Ti micro-alloyed steel. Transverse cracks generated on the edge of slab lead to sliver generation during hot rolling. Manifestation of the scale (FeO) and internal oxidation associated with the defect indicates that the cracks were pre-existing at the subsurface locations in the cast product. Subsequently, during reheating of the slab before rolling, oxygen ingress in the reheating furnace through the crack opening reacted with the carbon of the steel resulted in partial decarburization around the crack confirming it to be a casting defect. Detailed study has been carried out which composed of multiple variables such as steel composition, casting conditions to diagnose the occurrence of cracking on Low carbon Nb-V-Ti micro-alloyed steel slabs and propose countermeasures to prevent them. The diagnostic approach consisted on plant monitoring, including direct temperature measurements in the strand with pyrometers, restriction of carbon level below peritectic range.

Use Of Mould Heat Flux As A Tool To Prevent Off Corner Longitudinal Breakouts in Slab Casters

ABSTRACT. Off corner longitudinal cracks and subsequent breakouts in mould arise due to incorrect mould taper and uneven shell growth in the solidifying shell. The uneven shell growth is linked to uneven heat flux extraction from different faces of the mould. A mathematical model was devised to calculate the mould heat flux for broad and narrow faces of the copper mould plate. The heat flux from individual plates was calculated based on the cooling water flow rate and the temperature rise in cooling water. Real time calculation of the heat flux and comparison between narrow and broad side heat flux trends provided an assessment for the stability in the casting process.The trends were used to analyse the casting conditions and generate alarms for unstable casting conditions and prevent breakouts during continuous casting. The tool has been implemented in two old slab casters of a SAIL plant. The number of incidences of breakouts owing to off corner longitudinal cracks has been completely eliminated helping the shop to achieve high productivity.

Hydrogen behaviour in continuously cast and hot rolled low alloy steels
PRESENTER: M. Vidhyasagar

ABSTRACT. Hydrogen is an interstitial impurity in alloy steels that causes delayed failure known as hydrogen flaking. A series of hydrogen sensitive steel grades were examined for hydrogen distribution from tundish to the final hot rolled product. It is observed that the hydrogen content decreases significantly during the solidification. The solubility difference of hydrogen between the liquid and solid steel results in hydrogen loss during solidification in the form of gas. In the solid state, the hydrogen partition takes place from the surface to the center by progressive conversion of decreasing austenite phase fraction with higher hydrogen solubility to ferrite phase fraction with lower solubility. The hydrogen content in the as cast stage is further decreased, when the cast product is converted to a rolled product. Apart from this the present study briefs about the hydrogen behavior in the as cast and rolled steel with respect to the initial hydrogen at tundish and the final rolling cross section.

16:00-17:30 Session 5A: Coal and coke
Studies on increasing utilization of Indian high ash coal in coke oven
PRESENTER: Kashi Nath Malik

ABSTRACT. Coke production in the Indian steel industries depends primarily on imported coal because Indian coal has a very high ash content (~18-23%). Ever-increasing prices and long transportation of imported coal create a considerable problem for coke makers. Therefore, various investigators are making efforts to reduce the dependence on imported coal, which reduces the cost of coke production. This work aims to increase the Indian coal percentage in the coal blend. Two typical Indian high ash coal in reference to one imported low-ash Australian coal were taken under the present investigation. Grinding of various Indian coals and, subsequently, ash distribution was evaluated among different particle size ranges. Reducing the particle size up to 0.15mm can reduce ash content from (18-23 %) to (14-15%), which is generally considered the ash content of the blended coal mixture used for coke making in the coke-oven battery. With this reduced ash-containing fraction, more percentage of Indian coal can be incorporated into the blend (~8-10%). Efforts were also made to evaluate the economics of the coking process by considering 100% imported low ash coal or blended with 3, 5, 8, and 12% Indian high ash coal. It was observed that 8-10% blending will be economical for coke making without hampering the final coke chemistry.

Study on push force measurement technique and operational difficulties in stamp charge coke making
PRESENTER: Deepak Kumar

ABSTRACT. Push force is a key operational parameter in stamp charge coke making. In general, high push force reflects high resistance in coke oven walls which is not desirable and can be caused by many process and operational parameters. Poor shrinkage, coal blend quality, high battery temperature, sticky ovens are some of the known factors which may cause high push force during operation. In this work a detailed study has been done on various operational factors affecting push force profile during the pushing of hot coke at Battery 10 & 11. Eighty push force data points are captured for each oven from pusher ram and data has been analyzed in level II. The study also concluded that the stamping charging and pushing (SCP) machine which is used for pushing the hot coke itself has significant role. The paper describes importance of push force, measurement technique and automation support for level II analysis to know major factors affecting push force.

Recycling of Waste Plastics in Coke Ovens

ABSTRACT. Economic growth and changing lifestyle patterns are resulting in rapid increase in generation of waste plastics in the world. Effective disposal of waste plastic is an area being seriously explored as a part of environmental initiatives. An attempt is made to assess the impact of waste plastics in coal blend on the coke properties at pilot scale studies. The present study explores addition of up waste plastic in the coal blend. Experimental trials were conducted in a 120kg pilot-scale coke oven. The coal maximum fluidity at 1% plastic addition was found to be in line with the base composition. Results show that up to 1% plastics can be effectively recycled in the coal blend without any detrimental effect on coke quality. Addition of higher percentages of plastics resulted in deterioration in coke properties e.g. Coke Strength after Reaction (CSR) and Coke Reactivity Index (CRI) and coke yield. The waste plastic utilisation at coke ovens aims at a cleaner and greener environment around us. Based on the lab-scale results, plastic shredding system was installed at JSW Steel Ltd., Vijayanagar Works. During the period Jan’21 to May’22, ~135 tonnes of waste plastic has been consumed in Coke Oven-3. The addition of waste plastics to coal blend in coke making can be attributed as one of the effective ways of waste plastic recycling.

16:00-17:30 Session 5B: Primary Steelmaking
[Invited talk] Slag conductivity and it’s effect on Oxygen Transport and interfacial reaction kinetics
PRESENTER: Jayasree Biswas

ABSTRACT. Pyrometallurgical refining typically involves slag-metal reactions which are many times controlled by transport of reactants in the slag or metal phase. For the simplicity of analysis, mass transport in slag is generally treated on a phenomenological basis as transport of molecules. Although this approach works well for many of the reaction systems over narrow ranges of conditions, it fails in some systems. In many refining processes, transport of oxygen determines the kinetics of major reactions. Transport of oxygen in slag is strongly influenced by the electrical conductivity of slag. Whilst this has been well understood since 1950s, there have been relatively few attempts to quantify the effects of slag electrical properties on the refining kinetics. In this paper, an overview is presented focusing on the electrical properties of slags and their effects on the transport kinetics in steelmaking reactors. Examples from the authors’ laboratory will be discussed and presented along with an evaluation of literature data on oxygen transport.

[Invited talk] A Study on Altering Flux in BOF Steelmaking and Its Impact on Sustainability
PRESENTER: Tapas Kumar Roy

ABSTRACT. Production of steel in sustainable manner has been gaining significant importance day by day. Altering usage of flux in BOF steelmaking such as partial replacement of lime with limestone could be a small step towards this. The heat available in the converter can meet the need of limestone calcination and thus avoid energy required from fossil fuel for calcination in the lime kiln. The challenge arises in the use of limestone is due to inadequate knowledge of calcining limestone inside converter and problems associated with it such as slopping, uncalcined limestone, formation of hard burnt lime, abnormal blowing, fines generation etc. Therefore, size, quantity, and time of addition of limestone in BOF converter are important parameters to be studied to minimize the stated impact. Accordingly, laboratory scale experiments were carried out by varying temperature, time, and size of limestone to understand high temperature behaviour and decide the parameters for plant trials. Based on experimental results, plant trials were conducted in a converter by replacing a part of lime with limestone without any process abnormalities. The paper will highlight results obtained from laboratory studies as well as plant trials and its impact on sustainability.

Study of Slag Formation and Foaming in Early Stages of Direct Reduced Iron (DRI)-Hot Metal (HM) based Electric Arc Furnace (EAF) Operation
PRESENTER: Sumanta Maji

ABSTRACT. EAF charge materials and operations vary substantially from plant to plant. This study examines the early stages of slag formation and foaming behaviour in an industrial electric arc furnace which uses direct reduced iron, hot metal and scrap as primary iron-bearing raw materials. While scrap and hot metal are charged in batches, DRI, flux materials and oxygen are added continuously. Arcing is also carried out continuously. The addition of oxygen leads to oxidation reactions which in the initial stages are dominated by the oxidation of silicon, carbon and iron. Initial slag components from the bath are FeO and SiO2. The dissolution of lime and dolo and the gangue materials from the melting of DRI provide CaO, MgO, SiO2, Al2O3 and other components of the evolving slag. With the evolution of CO, the foaming of slag starts in the early stage of the process. Most heats begin slag flushing within five minutes after oxygen blowing. Several models of oxidation and foaming, cited in the literature, are used in the analysis. A process model is developed that explains the dynamic evolution of slag chemistry and foam height in the early phases of the industrial process.

Effect of CaO content on crystallization behavior of EAF slag under different cooling environment

ABSTRACT. In the present scenario, the world’s utilization rate of steel slag is comparatively very low and primarily used for landfills only which affects the environment adversely and loss to the economy as well. Compare to ironmaking slags, there are no such suitable techniques available to recycle and extract valuable products from steel slag. At present, India is the second-largest producer of crude steel consisting a handsome fraction through DRI-EAF route. In the present study, we are mainly focusing on steel slag through the later one. The mineralogy of primary slag ensures the presence of various constituent ranges, Fe2O3/FeO (18-30%), CaO (23-48%), SiO2 (2-6%), MgO (4-17%), and Al2O3 (2-15%), mainly depends on the quality of raw material as well as processing. One of the major components of steel slag with a large variety of ranges is calcium oxide. It is seen, that the presence of calcium oxide is responsible for enhancing the crystallization ability in steel slag. The main crystalline phases found during phase cooling are diopside (CaMgSi2O3) and anorthite (CaAl2Si2O3). The present study focused on the physical and chemical properties of steel slag. This investigation is based on the CaO content and different cooling environment. The different Calcium oxide content of fresh slags are taken from the industries and cooled for understanding the effect of calcium oxide in slag crystallization.

Investigating the melting behavior of a CaO-MnO-SiO2-Al2O3 flux for use in fusion welding of low carbon steel

ABSTRACT. CaF2 has been commonly used as a constituent in oxide fluxes for welding of low carbon steel plates, owing to its strong ability to lower the liquidus temperature as well as viscosity of the molten flux. But, the adverse impact of fluorides on the health of the operating personnel and the environment has prompted a worldwide effort to replace CaF2 with more benign constituents. The CaO-MnO-SiO2-Al2O3 compositions, identified in the current work, have shown promise in terms of controlling oxygen transfer and inclusion generation in the molten metal, and can potentially be used as fluxes for welding of low carbon low alloy steels. However, the melting behaviour of the flux needs to be established before recommending its use. In addition to experimental measurements using High Temperature Microscopy (HTM) and Differential Thermal Analysis (DTA), and comparison with simulations from commercially available thermodynamic packages like FactSage™, this work also aims to understand the final composition and potential inclusions that could form in the weld pool using the selected CaO-MnO-SiO2-Al2O3 flux.

Injection of Plastics in Electric Arc Furnace
PRESENTER: Mukund Manish

ABSTRACT. With the increasing use of plastics, its sustainable re-use and recycling has become a serious environmental challenge. At JSW steel a new technology to inject plastics in electric arc furnace (EAF) as a foaming agent has been developed and implemented. EAF utilizes coal /coke fines to increase the foaming behavior of its slag for stable arcing and reduced arcing time. In the present work the in-house generated plastics were shredded to < 5 mm size and pneumatically injected into the EAF slag as a replacement of coke fines. For handling these fine shredded plastics, a unique pneumatic conveying system for has been developed which is first of its kind where different types of plastic particles are fully suspended in the conveying air and transported at controlled low pressure and high velocity into the furnace without choking from a single unit. The controlled burning inside the furnace takes advantage of the generated gases. This method of recycling plastics has huge potential to get consumed in large steel making furnaces. India’s first EAF plastic injection system has been commissioned at SMS-3 in JSW Steel Vijayanagar works and is injecting 70 -100 kgs in each heat. The use of plastics has reduced the equivalent coke fines consumption and shown improvements in slag foaming and furnace efficiency along with over all CO2 emission reduction.

16:00-17:30 Session 5C: Ladle refining
Influence of Slag Carryover on the Non-Metallic Inclusion and Magnetic Property in Electrical Steel

ABSTRACT. The high-temperature experiments were planned to study the influence of slag carryover on non-metallic inclusion evolution during the production of high silicon electrical steels. It was also observed that the binary oxide inclusions are modified to CaO-based complex oxides in the presence of synthetic slag. Further, at the end of the refining treatment, complex oxide inclusions are modified to MnS-free oxy-sulfide inclusions in the high Si steel with an increase in the amount of carryover slag. Such complex oxides have been found to be detrimental to the magnetic behavior of electrical steels. The magnetic property confirms the detrimental magnetic behavior of the steel treated using the top slag with the excess amount of SCO (10 kg/t). The increase in coercivity is due to a higher fraction of sub-micron inclusions in the steel matrix. The evolution of detrimental inclusions in functional grade (electrical) steels due to the slag carryover call for strict process control in the upstream processes to maintain the product quality for transformer core applications.

Application of FactSage based kinetic process model to diagnose ladle refining process for controlling impurity concentration in liquid steel
PRESENTER: Sk Wasim Haidar

ABSTRACT. Ladle furnace (LF) is one of the key secondary steelmaking process unit where liquid steel is treated to achieve desired steel quality. Typical processes performed during secondary steelmaking process include deoxidation, inclusion removal, inclusion modification, desulphurization, alloy addition, homogenization and temperature adjustment. Therefore, understanding of ladle refining process is very crucial. In the present study, a kinetic LF process model has been developed considering Effective Equilibrium Reaction Zone (EERZ) model using the FactSage macro processing code to know the effect of steelmaking parameters on impurity concentration in liquid steel. Liquid steel-slag interaction, flux additions to slag, various metallic additions to steel and refractory dissolution to slag were taken into account to develop the model. Equilibrium reaction between liquid steel and atmospheric oxygen has also been considered in this model to replicate the reoxidation process during ladle refining. These considerations can be helpful to analyse the effect of reoxidation process on desulphurization rate. Model results show that predicted final liquid steel and slag chemistry are in good agreement with the experimentally measured values.

thermodynamic and kinetic based process simulation of Ladle refining process (LF) and validation with plant data
PRESENTER: Manas Paliwal

ABSTRACT. In the present work, we present a process model that explains the change in melt and slag composition as a function of complex process conditions in Ladle refining process. The multiphase kinetics of the process are captured using an “Effective reaction zone model” by linking the ChemApp thermodynamic library with the FactSage databases. Slag former addition, alloying, steel/melt interaction, arcing, purging, inclusion evolution is incorporated in the model. The simulation results are compared against an industrial LF process and accuracy of the model is judged by comparing the measurements with the melt, slag and inclusion compositions obtained from model.

Improving Titanium Recovery during Ladle Furnace Steelmaking
PRESENTER: Albin Rozario

ABSTRACT. Titanium or niobium alloying is done in micro-alloyed steels to improve the mechanical properties by grain refinement. Contrary to niobium, titanium addition gives additional advantages of (i) lower rolling load in the mill and (ii) low ferroalloy cost. However, the recovery of titanium, owing to its high affinity towards oxygen, is highly inconsistent and depends mainly on secondary steelmaking process parameters. In the present work, a large amount of process data has been analysed and correlated to the chemical composition of steel and slag to understand the influence of various process parameters on titanium yield. Based on this study, industrial plant trials have been conducted with a modified ferrotitanium (FeTi) addition practice. FeTi wire injection was done in 7 heats with different wire injection speed and bottom argon purging rate. It has been found that 200 m/min of injection speed along with differential flow rate of argon from porous plug with 35 Nm3/hr and 6 Nm3/hr respectively yielded better recovery of titanium. The titanium recovery was increased by 4% compared to the earlier practice of wire injection and argon purging.

[Cancelled] Ingenious silico-thermic chemical heating for high quality low aluminum grade electrical steels

ABSTRACT. The current paper highlights development of silico-thermic heating process for increasing steel temperature at CAS-OB route. Typical electrical steels with restrictions of Al<0.005% successfully developed calculating heat balance for silico-thermic reaction. Aluminum pickup in Aluminothermic heating is avoided after investigations with Si-heating and a correlation between Si and Al content in steel with SiO2 and Al2O3 in slag established. Subsequently, the modified method has resulted in elimination of chemistry diversion due to high Al and has proved to be an economical way of production of low Al containing Si killed electrical steel using CAS-OB route.

[Cancelled] Reduction in nitrogen absorption in HSLA steels during electrical arcing process by increasing nitride capacity of slag

ABSTRACT. The current work focuses on reduction of nitrogen pickup during electrical arcing process at ladle furnace (LF) by increasing nitrogen holding capacity of slag. Nitrogen pickup in CaO-Al2O3-MgO-SiO2 slags system at 1860 k during LF treatment of high strength low alloy (HSLA) steels was evaluated. The effect of SiO2 on nitrogen pickup during arcing was also investigated. The plant trail confirms the reduction of nitrogen pickup from ~11 ppm to ~5 ppm during arcing at LF by SiO2 in the slag and finishing N below 40 ppm. Furthermore, XRD analysis of slag was carried out to study to phases in slag contributing to low nitrogen pickup (~5 ppm).

Dynamic Model Based upon Multiple Reactors Approach
PRESENTER: Prasenjit Singha

ABSTRACT. The electric arc furnace steelmaking process accounts for more than 25% of world steel production. Electric arc furnace steelmaking converter contains three main bulk phases such as gas, slag, and metal. The reaction takes place in gas-metal, slag-metal, and solid-slag interfaces. In real cases, all reactions occur in a single converter. In the present work, It is assumed the volume close to the interface is the reaction zone, and it is considered the mass inside the reaction zone to attain a thermodynamic equilibrium at any processing time.Transient metal compositions are in good agreement with plant data.