Basic Oxygen Furnace Research Articles

Enhanced post freeze-thaw stability of Zn/Pb co-contaminated soil through MgO-activated steel slag and fiber treatment

This study assessed the applicability of a novel stabilization/solidification (S/S) method to control re-release potential of heavy metal (HM) in remediated HMs-polluted soils experiencing freeze-thaw cycles (F-T). In so doing, MgO-activated basic oxygen furnace (M-BOF) slag alone and its combination with polypropylene fiber were added to a soil containing a wide range of Zn and Pb. The composites were then subjected to a series of macro and micro scale tests. It was found that, unlike treatment conditions with the same dosage of cement, in the samples with low levels of HMs, the application of 15% M-BOF could satisfy the S/S regulation limits even under the destroying impacts of acid leaching and F-T. In fact, as the results of XRD and SEM tests revealed, M-BOF would be much more influential than cement in the reactions which solidify the soil mass and improve its compactness, causing a notable reduction in the HMs-remobilization risks. However, the high levels of metals might negatively affect the binder performance, and thus the soil geo-mechanical characteristics particularly during the F-T scenario. The study showed that the incorporation of fiber in the S/S system would increase its efficiency in refining the pores network, wrapping the matrix against the structure defects upon the harsh conditions. As a result, the reinforced samples display a lower degree of strength damage and a marked decrease in the loss of HMs retention abilities with the progressing F-T. Overall, the findings indicate that the M-BOF/fiber mixture can effectively be used as a multi-functional S/S agent which, over time, can keep the toxic ions in a less mobile form.

Impact of Iron Ore Pre-Reduction Degree on the Hydrogen Plasma Smelting Reduction Process

To counteract the rising greenhouse gas emissions, mainly CO2, the European steel industry needs to restructure the current process route for steel production. Globally, the blast furnace and the subsequent basic oxygen furnace are used in 73% of crude steel production, with a CO2 footprint of roughly 1.8 t CO2 per ton of produced steel. Hydrogen Plasma Smelting Reduction (HPSR) utilizes excited hydrogen states with the highest reduction potentials to combine the simultaneous reduction and smelting of iron ore fines. Due to the wide range of iron ore grades available worldwide, a series of hydrogen plasma experiments were conducted to determine how pre-reduced iron ore and iron-containing residues affect reduction behavior, hydrogen consumption, overall process time, and metal phase microstructure. It was discovered that, during the pre-melting phase under pure argon, wet ore increased electrode consumption and hematite achieved higher reduction levels, due to thermal decomposition. The reduction of magnetite ore yielded the highest reduction rate and subsequent hydrogen conversion rates. Both hematite and magnetite exhibited high utilization rates at first, but hematite underwent a kinetic change at a reduction degree of 80–85%, causing the reduction rate to decrease. In comparison to fluidized bed technology, it is possible to use magnetite directly, and the final phase of the reduction can move along more quickly due to higher temperatures, which reduces the overall process time and raises the average hydrogen utilization. A combination of both technologies can be considered advantageous for exhaust gas recycling.

Soft sensor method of multimode BOF steelmaking endpoint carbon content and temperature based on vMF-WSAE dynamic deep learning

Abstract The difficulty of endpoint determination in basic oxygen furnace (BOF) steelmaking lies in achieving accurate real-time measurements of carbon content and temperature. For the characteristics of serious nonlinearity between process data, deep learning can perform excellent nonlinear feature representation for complex structural data. However, there is a process drift phenomenon in BOF steelmaking, and the existing deep learning-based soft sensor models cannot adapt to changes in the characteristics of samples, which may lead to their performance degradation. To deal with this problem, considering the characteristics of multimode distribution of process data, an adaptive updating deep learning model based on von-Mises Fisher (vMF) mixture model and weighted stacked autoencoder is proposed. First, the stacked autoencoder (SAE) and vMF mixture model are constructed for complex structural data, which can initially establish nonlinear mapping relationships and division of different distributions. Second, for each query sample, the basic SAE network will perform online adaptive fine-tuning according to its data with the same distribution to achieve dynamic updating. Moreover, each sample is assigned a weight according to its similarity with the query sample. Through the designed weighted loss function, the updated deep network will better match the working conditions of the query sample. Experimental studies with numerical examples and actual BOF steelmaking process data are provided to demonstrate the effectiveness of the proposed method.

End‐Point Dynamic Control Model for 260 Tons BOF Steelmaking Based on PWWTSVR and LWOA

The control of end‐point carbon content and temperature is very important for basic oxygen furnace (BOF) steelmaking. Herein, to improve the control precision of the BOF end‐point, a new dynamic control model of the BOF end‐point is proposed. First, based on the samples of low‐carbon steel collected from the steel plant, a prediction model of BOF end point is established by using projection wavelet weighted twin support vector regression (PWWTSVR). It is indicated in the simulation results that the error bound of carbon content and temperature are 0.005 wt% and 10 °C, respectively, and the hit rates of the prediction models are 92% and 90%. Moreover, a double hit rate of 84% is higher than the other five prediction models. Based on the PWWTSVR prediction model, a Lévy‐flying whale optimization algorithm (LWOA) is used to optimize the objective function to establish the control model. The control model shows that the mean absolute error of the end‐blow oxygen volume calculated by the model is 75.0201 Nm3, which is smaller by comparing the other two control models. The proposed control model can provide efficient guidance for on‐site smelting personnel.

Production of low phosphorous steel from low silicon high phosphorous hot metal in BOF

ABSTRACT Production of low phosphorous (≤0.015%) steel in Basic Oxygen Furnace (BOF) using high phosphorous (average 0.17%) and low silicon (≤0.5%) hot metal with Si/P ratio <3 is a challenging task. In addition to temperature, slag basicity and FeO, the quantity of slag becomes important which is achieved by higher lime addition. However, how much lime is appropriate need to be understood. A detailed analysis of plant data indicated that a scope exists for lowering lime addition from existing level. Accordingly, systematic trials were conducted with reduction in lime which showed that lowering 12% lime had no effect while 19% reduction increased end blow (EB) P by 20 ppm. SEM-EDX studies of slag samples revealed chemical and morphological changes in trial heats. Lime addition pattern was also found to impact EB P. Addition of lime in a small batch during 10–25% of the oxygen blow resulted lower EB P.

Quantitative analysis and phase assemblage of basic oxygen furnace slag hydration

Basic oxygen furnace (BOF) slag from steelmaking could be applied as a binder in building materials, reducing the CO2 footprint and solid waste, which is relevant for industrial waste management and circular economy. However, its use is mostly restricted because its hydraulic activity is poorly understood. The BOF slag was hydrated in this study, and its reaction products were systematically characterized using XRD, QXRD, and SEM/EDX-based phase mapping. Internal consistency checks of the data were performed between the analytical techniques. The results revealed that the composition of the amorphous hydration products could be identified and quantified, and the main hydration products were hydrogarnets and C-S-H gel. An extended milling process significantly improved the reactivity, and all the major slag phases, including wüstite, participated in the reaction. Brownmillerite formed hydrogarnets during the first 7 days of hydration. The new hydration products contributed to the immobilization of vanadium and chromium. Particle size played an important role in the amount of C2S reacting, the composition of the hydrogarnets and C-S-H gel, their proportions, and the immobilization capacity. Based on the findings, an overall hydration reaction was developed.

Utilisation of aged and unaged basic oxygen furnace steel slag aggregates in pavement quality concrete

ABSTRACT The study presented in the paper evaluated the properties of pavement quality concrete (PQC) containing coarse aggregates made from aged and unaged basic oxygen furnace (BOF) slag. Workability, air content, strength, drying shrinkage, expansion, abrasion resistance and expansive potential of PQC were evaluated. Air content and workability of fresh slag concrete increased marginally. Compressive and flexural strength of the concrete containing aggregates of aged and unaged slag was observed to be less than the strength of normal concrete. The reduction in strength of concrete containing aged slag aggregates was more as compared to the concrete containing unaged slag aggregates due to the presence of a dusty coating around the aged aggregates. The drying shrinkage of the concrete increased with the content of steel slag aggregates. The abrasion resistance of the slag concrete was found to be better than the abrasion resistance of conventional concrete. Deterioration of slag concrete was not observed due to normal water curing up to 90 days. However, accelerated aging of concrete in water at 70°C resulted in the localised cracking and eruptions due to expansion. The study showed that, aged as well as unaged slag aggregates may be used for the preparation of concrete mixtures of required properties for road construction.

Thermodynamic analysis of vanadium distribution behavior in blast furnaces and basic oxygen furnaces

Abstract Production data from a vanadium (V)-containing titaniferous magnetite (VTM) smelting blast furnace (BF) ironmaking plant and a V-recovering basic oxygen furnace (BOF) shop were collected over a period of 1 year. The corresponding thermodynamics was analyzed in terms of V reduction in the BF operation and V oxidation in the BOF operation. The thermodynamic calculations were performed using the software Multi-Phase Equilibrium (MPE), in which generalized central atom model was introduced into the description of molten slag and applied for the slag database. The effects of operating conditions on V distribution ratios between slag and hot metal/semi-steel were analyzed and compared with the plant data. The simulated results could reproduce the variation of V distribution ratios with slag temperature and composition and provide the guidance for operators to control V distribution behavior for the better process operation.

Softening–Melting Properties and Slag Evolution of Vanadium Titano-Magnetite Sinter in Hydrogen-Rich Gases

Blast furnace–basic oxygen furnace (BF–BOF) process is the predominant method for smelting vanadium titano-magnetite (VTM) in China. Hydrogen-rich (H2-rich) gas injection in BF is considered as an important way to reduce CO2 emission under the background of low carbon metallurgy. In this paper, the softening–melting behaviors of VTM sinter in H2–rich gases were investigated by the method of determination of its reduction softening drippinger performance under load. The experimental results indicated that the permeability of VTM sinter during the softening–melting process was improved by increasing the H2 content of the reducing gases. The maximum pressure drop of the burden decreased gradually from 29.76 kPa to 19.97 kPa, and the total characteristic value (representing the comprehensive softening–melting property) also decreased obviously from 2357.52 kPa·°C to 630.94 kPa·°C with the increase in H2 content. The softening interval of the samples was widened, while the melting–dripping interval increased firstly and then decreased. In that case, the position of the melting–dripping zone in BF would move downwards, which was beneficial to smelting smoothly. The thermodynamic analysis indicated that Ti- and Fe-bearing phases were more difficult to be reduced than iron oxides, and H2-rich gas is beneficial to the reduction of that kind of oxides. Titano-magnetite will be reduced stepwise to form Fe2TiO4, and then in the order of FeTiO3→TiO2→Ti(C,N). Wustite (FeO) was an important component during the slag-forming process, whose content increased firstly and then decreased. Perovskite and silicate were the main phases in the dripping slag samples.

Numerical Simulation of Motion and Distribution of Powder Particles Injected from a Nozzles-Twisted Oxygen Lance in BOF Steelmaking

The pulverized lime/limestone injection by top oxygen blowing lance during the basic oxygen furnace (BOF) process has gained much interest in recent years due to its advantages in helping slag formation and consequently in promoting refining reactions such as dephosphorization. In this pneumatic process, understanding the motion behavior and distribution of the powder particles in the furnace is of importance for regulating and designing this refining system reliably and efficiently. In this study, limestone powder top blowing through a novel nozzles-twisted oxygen lance during a BOF process is proposed and the process is simulated by establishing a multi-fluid flow model. The coupled fluid flow of gaseous oxygen and liquid steel is predicted by the volume of fluid (VOF) method, and the motion of the limestone particles is tracked by the discrete phase model (DPM). The results show that the powder injection has little effect on cavity depth of the oxygen-powder mixture jets of the nozzles-twisted lance, but decreases cavity width. During the blowing process, most of the powder particles gather around hot spots while the rest are taken out of the furnace by the reflecting oxygen stream or penetrate into the molten bath. The generated swirling flow of the nozzles-twisted oxygen lance enables a decrease in the amount of the powder particles carried by the reflecting stream and going into the molten bath, through changing the motion paths of the powder particles. As a result, the concentration distribution of the powder particles in the molten bath varies. It could be suggested that for the limestone powder injection the preferred nozzle twist angle of the oxygen lance is 10° due to the favorable conditions for dephosphorization.

Use of steel slag and LAS-based modifying admixture in obtaining highly eco-efficient precast concrete products

This paper presents a study on improving the eco-efficiency of no-slump concrete for precast elements using Basic Oxygen Furnace Slag (BOFS). Recycled BOFS powders and aggregates have been produced to obtain mixtures with better particle size distribution and improved packing density based on a particle packing method. A comprehensive experimental investigation was carried out on mixtures with different cement contents (5%, 10%, and 15% vol.) and compaction energy levels (6, 10, and 20 blows in a sand rammer). A modifying admixture based on Linear Alkyl Benzene Sodium Sulfonate (LAS) has also been evaluated as a workability and cohesiveness enhancer for steel slag concretes. In addition, concrete eco-efficiency was evaluated by measuring the binder intensity (bi) and waste consumption. The highest compaction energy provided packing densities ranging from 0.78 to 0.80, and BOFS aggregates led to better mechanical performances. The BOFS concrete containing 15% cement obtained the best strength (52.1 MPa) and bi value (7.0 kg/m³/MPa), with a waste consumption of 2356.57 kg/m³. The mixture with the lowest cement consumption (5% - 121.56 kg/m³) and the highest consumption of waste (2637.82 kg/m³) reached 16 MPa, delivering a bi of 7.6 kg/m³/MPa.

A novel path towards limiting non-exhaust particulate matter emissions of a commercial friction material through the addition of metallurgical slag

Keeping recycling and the circular economy in mind, this study explores the reduction in emission of a highly optimized, commercially employed friction material formulation through the addition of metallurgical slags from a basic oxygen furnace in varying quantities from 6 to 38 wt%. The various compositions were paired with a pearlitic grey cast iron counterface and tested on a pin on disc tribometer. The friction coefficient and pin wear increased with the slag addition but were still within the permissible limit when compared to the original formulation. Specimens with higher slag content observed extremely compacted and extended secondary contact plateaus, which also recorded significant slag presence. The extended plateaus detached in the form of chunks from the mating surfaces, which settled on the equipment hardware and restricted the production of airborne particles. From an industrial symbiosis perspective, the addition of metallurgical slags proved to be a promising way of obtaining green friction materials with reduced emissions.

Air granulated basic Oxygen furnace (BOF) slag application as a binder: Effect on strength, volumetric stability, hydration study, and environmental risk

This study evaluates the air granulated BOF slag potential as a cementitious material by comparing the granulated and conventionally cooled slags. The mechanical performance of the cement-slag composites is correlated with the hydration behaviour through thermal, mineralogical, and microstructural analysis. The findings show that the granulation improved the grindability, reactivity, and compressive strength till 28 days. The ∼5% slag can be substituted as a binder and ∼35% as an inert filler. The performance decline upon 20–50% replacements is attributed to the absence of brownmillerite reactivity. Overall, the granulation did not improve the cement-slag composite performance significantly till 90 days.

Oxidative modification of industrial basic oxygen furnace slag for recover iron-containing phase: Study on phase transformation and mineral structure evolution

Basic oxygen furnace (BOF) slag is the main co-product in the steelmaking process, its recycling within the iron and steel enterprises is crucial for the industry to ensure greater sustainability. According to the composition characteristics of BOF slag, a method of separating and recovering iron resources by regulating the composition of BOF slag with silica as an additive at high temperature was proposed. In this study, the growth of iron-containing phase during oxidative modification of BOF slag was in-situ observed by ultra-high-temperature confocal scanning laser microscope, and the phase transformation and mineral structure evolution were analyzed by chemical analysis, X-ray diffraction and field emission scanning electron microscopy. The results demonstrated that the increase of oxidation temperature effectively promoted the transformation of iron oxides to (Mg,Fe2+)O·Fe2O3, but too high temperature could lead to the increase of iron-containing melilite phase and reduce the iron recovery. In the oxidative modification process, the appropriate holding time and cooling mode facilitated the growth and development of (Mg,Fe2+)O·Fe2O3 particles, which was conducive to the separation and recovery of iron resources. After BOF slag was oxidized at 1300 ℃ for 240 min and cooled in the furnace (1 ℃/min), the grade of magnetic slag obtained by magnetic separation had a grade of 40.26%, a recovery of 70.95%, and a P and S content of 0.042 and 0.456, respectively, which may be used as an important supplement to the raw materials for sintering. The regulated secondary slag may be used to diversify into higher value-added production. Therefore, the systematic research and development of oxidative modification-crushing-magnetic separation technology may promote the efficient utilization of BOF slag components and heat energy.

Electricity and Heat Demand in Steel Industry Technological Processes in Industry 4.0 Conditions

The publication presents heat and electricity management in the Polish steel industry. The paper is based on actual data on heat and electricity consumption and intensity by processes in the steel industry in Poland in Industry 4.0 conditions. Two steel production processes are used in Poland: EAF Electric Arc Furnace and BOF Basic Oxygen Furnace. The analysis is an analysis of actual data is used to characterise the electricity and heat consumption by processes in the Polish steel industry. The analysis shows that the EAF technology is always more electricity intensive and the BOF technology more heat intensive. On the basis of conducted analysis, it can be concluded that pro-environmental innovations in the steel industry should first aim to reduce the electricity consumption of EAF technology and the heat consumption of BOF. An analysis of data for Poland for the period 2004–2020 shows that both cases occurred. The study shows that the heat consumption of BOF technologies has been steadily decreasing since 2010, and the electricity consumption of EAF technologies has been decreasing throughout the period under review. It can be concluded from this that the Polish steel industry is adapting to pro-environmental requirements and, through the introduction of technological innovations, is moving towards the concept of sustainable steel production according to green steel principles. The decrease in energy intensity (means electricity) of steel produced according to EAF technology is an important issue, as the high energy intensity of EAF processes affects the overall energy intensity of the steel production in Poland. In the future, the use of new innovative technological solutions, including solutions based on Industry 4.0 principles, should help the Polish steel industry to further reduce the level of electricity and heat consumption. The driving force behind the investment is the boom in the steel market. The authors made a short-term forecasts of steel production (2022–2025). The annual forecasts determined and analyses made were used to determine the heat and energy consumption of the Polish steel industry up to 2025.

Cost effective decarbonisation of blast furnace – basic oxygen furnace steel production through thermochemical sector coupling

We present here a first-principles study of the sector coupling between a thermochemical carbon dioxide (CO2) splitting cycle and existing blast furnace – basic oxygen furnace (BF-BOF) steel making for cost-effective decarbonisation. A double perovskite, Ba2Ca0.66Nb0.34FeO6, is proposed for the thermochemical splitting of CO2, a viable candidate due to its low reaction temperatures, high carbon monoxide (CO) yields, and 100% selectivity towards CO. The CO produced by the TC cycle replaces expensive metallurgical coke for the reduction of iron ore to metallic iron in the blast furnace (BF). The CO2 produced from the BF is used in the TC cycle to produce more CO, therefore creating a closed carbon loop, allowing for the decoupling of steel production from greenhouse gas emissions. Techno-economic analysis of the implementation of this system in UK BF-BOFs could reduce steel sector emissions by 88% while increasing the cost-competitiveness of UK steel on the global market through cost reduction. After five years, this system would save the UK steel industry £1.28 billion while reducing UK-wide emissions by 2.9%. Implementation of this system in the world's BF-BOFs could allow the steel sector to decarbonise in line with the Paris Climate Agreement to limit warming to 1.5 °C.

Applications and Developments of Thermal Spray Coatings for the Iron and Steel Industry.

The steel making processes involves extreme and harsh operating conditions; hence, the production hardware is exposed to degradation mechanisms under high temperature oxidation, erosion, wear, impact, and corrosive environments. These adverse factors affect the product quality and efficiency of the steel making industry, which contributes to production downtime and maintenance costs. Thermal spray technologies that circumvent surface degradation mechanisms are also attractive for their environmental safety, effectiveness and ease of use. The need of thermal spray coatings and advancement in terms of materials and spray processes are reviewed in this article. Application and development of thermal spray coatings for steel making hardware from the molten metal processing stages such as electric arc and basic oxygen furnaces, through to continuous casting, annealing, and the galvanizing line; to the final shaping process such as cold and hot rolling of the steel strips are highlighted. Specifically, thermal spray feedstock materials and processes that have potential to replace hazardous hard chrome plating are discussed. It is projected that novel coating solutions will be incorporated as awareness and acceptance of thermal spray technology grows in the steel making sectors, which will improve the productivity of the industry.

ФОРМУВАННЯ МІЖНАРОДНОЇ СТРАТЕГІЇ РОЗВИТКУ РИНКУ СТАЛІ

The article examines the structure of strategic consumers of the metallurgical industry. The most important industries in the structure of consumption of the metallurgical sector are: industrial and civil construction, machine building (mechanical equipment and automobile industry). The integrated types of steel production are identified: based on blast furnace (BF) and basic oxygen furnace (BOF) and electric arc furnace (EAF) steel production technology type. The structural components of the operating cycle of the main types of steel production (iron ore, coal, limestone, scrap, energy), as well as the components of commercial products (main industrial products and related products): steel, sludge, dust, blast furnace gas, converter gas, recovered steam are defined, energy. The cost norms of the material and energy supply sector of the metallurgical sector and the results of metallurgical production in average quantitative terms are substantiated. The trend of global steel production was analyzed and analytical indicators of dynamics were determined (average absolute growth, growth rate, growth rate). In order to ensure further analytical forecasting of industrial product markets, the selection of an approximating curve was made using the method of trend formation. Based on the obtained logarithmic curve, a smoothed estimate of the trend was made and a forecast of world steel production for the period 2023–2027 is formed. The forecast volumes of the metallurgical industry supply markets (iron ore market (iron ore and agglomerate); limestone market, scrap market, energy market), as well as the greening market (recovered steam, converter gas, blast furnace gas) and related products (slag, dust) are determined for the period 2022–2027 The forecast indicators of the growth of markets for industrial products of the metallurgical sector are substantiated. The main principles of the international strategy for the development of the steel market are determined: efficiency and sustainability of development, designing the product life cycle, stimulating the reuse of industrial products; maximum use of scrap, acceleration of decarbonization processes and transition to green steel production, effective and efficient processing of by-products. Proposed areas of the international steel development strategy: ensuring sustainable growth; promoting the development of security markets; development of effective use of related products.

A Novel Operation Optimization Method Based on Mechanism Analytics for the Quality of Molten Steel in the BOF Steelmaking Process

This paper investigates a dynamic analytics and operation optimization method for the basic oxygen furnace (BOF) steelmaking process, which is a multi-stage process. First, based on reaction kinetics, fluid dynamics and conservation of mass, that a novel discrete-time nonlinear system with process disturbance, time delay and the constrained operation input is established characterizes the dynamics of the quality (the carbon content and the temperature) of molten steel in the BOF steelmaking process. It is difficult and complicated to realize analytics and operation optimization for the BOF steelmaking process by using the established nonlinear system directly, so a surrogate-model-based discrete-time switched system with time delay and actuator saturation is given to describe the multi-stage BOF steelmaking process. Then, sufficient conditions are derived under which the stability is guaranteed and the tracking performance is achieved. The parameters of analytics-based operation optimization algorithm can be obtained by solving linear matrix inequality problems (LMIPs). Finally, the effectiveness of the proposed method is verified by a BOF steelmaking numerical experiment example. Note to Practitioners—This paper deals with the problem of dynamic analytics and operation optimization arising from the BOF steelmaking process. Based on the real-time estimation of the carbon content and the temperature of molten steel, the plan for the operation of oxygen lance and the addition of auxiliary materials is given to produce the qualified molten steel. This paper establishes a system model based on the mechanism, and the model parameters are derived from papers verified by a large amount of data to ensure the correctness of the model. In addition, actuator saturation is applied to describe the phenomenon of restricted operation variables. Through a surrogate model approximation and theoretical analysis, the parameters of dynamic analytics and operation optimization algorithm can be obtained by solving LMIPs, which is a convex optimization problem that is easy to solve. The numerical experiment results show that the proposed method can give operators some desired references.

Синтез модельно-прогнозуючого регулятора режиму дуття киснево-конвертерного процесу

The purpose of the research was to find a solution for a decrease in the cost price of the basic oxygen furnace steel. It is conditioned by an increase in the scrap metal portion due to an increase in the СО to CO2 afterburn degree in the basic oxygen furnace cavity according to the optimal model predictive control of the parameters of the blowing mode. The optimal parameter control system was synthesized for the blowing mode of the oxygen-converter melting on the basis of the feedback based on the model-predictive control using the linear-quadratic functional and it enabled a simultaneous control of the blowing intensity and the lance position when programmatically changing the task for the oxygen consumption and CO2 content improving also the control quality and energy saving during the melting process due to an increased afterburn degree during the CO to CO2 conversion that is a consequence of an increased portion of the scrap metal. Closed CO to CO2 afterburn degree control systems were improved by the synthesis of the model-predictive controller taking into consideration process limitations imposed on the shifting rate of controlling mechanisms, improving thus the process control quality in the case of the limitations. The suggested solution enables certain process control quality improvement under the conditions of process limitations. A comparative investigation of the operation of the model – predictive controller and combined control system with PID–controllers showed that the obtained transition processes of the automatic control of the blowing mode for the basic oxygen furnace melting using the automatic model-predictive controller provided ISE values for the oxygen consumption loop equal to 5577 and the CO2 content equal to 43 in basic oxygen furnace gases with a maximum dynamic deviation of the CO2 content in converter gases equal to 0.95 %. The use of the model-predictive controller allowed us to improve the control quality for the oxygen consumption loop by a factor of 1.63 CO2 and by a factor of 32.5 for the CO2 content control loop in converter gases. A maximum dynamic deviation of the CO2 content in converter gases was reduced by 16.55 % in comparison to that in the combined control system equipped with PID-controllers.