Sinter Production Research Articles

A novel deep learning method for on-line monitoring of grate bar defects in sintering machine system

The defective grate bars at the bottom of the sintering machine system pose a serious safety risk to steel enterprises. Cracking and missing of these grate bars lead to severe production accidents and economic losses. Implementation of an efficient defect monitoring system plays a crucial role in ensuring continuous and stable sintering production. This paper presents a novel on-line grate bar defects monitoring method to address the following two key challenges. Firstly, a light-weight location model called Multi Scale Separated Convolutional Attention Network-LiteSeg (MSSCAN-LiteSeg) is proposed to identify the optimal shooting position of the moving trolley and simultaneously segment the horizontal and vertical grate bars. By separating the attention calculation into independent channel spaces, MSSCAN-LiteSeg can effectively handle the imbalanced sample distributions. Secondly, an innovative few-shot segmentation network named Response Forgetting Attention-Hypercorrelation Squeeze Network (RFA-HSNet) is proposed for defect detection by employing a "Forgetting-Enhancing-Recalling" method. Extensive experiments have demonstrated that our method can achieve a precision rate of 93.3% and provide a satisfactory performance in the on-line grate bar defects monitoring system.

Research of the production of iron ore sinter from bauxite processing waste

This article presents the results of a study of the agglomeration of waste alumina ferrous sands and the use of sinter as a substitute for metal charge in steelmaking. At this time, in the process of processing bauxite, JSC "Aluminium of Kazakhstan" produces a large number of fines, which is of great interest to ferrous metallurgy. Wastes from alumina production include a variety of waste sludge, including red, gray sludge, and ferrous sands. According to the chemical composition, ferrous sands can be attributed to iron ore material with a high content of alumina. Most of these problems are eliminated by preliminary agglomeration of fines. In this work, agglomeration studies made it possible to establish the optimal parameters for sintering ferrous sands. When using 10% fuel, the best sintering performance is achieved. The optimal parameters for sintering ferrous sands mixed with other metallurgical wastes are such as productivity - 0.92 t / m2 h, mechanical strength - 80.0%, sintering speed - 19.3 mm/min, yield - 82.0%, the maximum temperature in the layer is 1340 °С. The results of laboratory melt carried out in an induction melting furnace indicate the possibility of using a sinter as a substitute for metal charge in iron and steel smelting. The conducted melting confirms the fundamental possibility of using a sinter, made from waste products of alumina production of ferrous sands, is a man-made charge material that is suitable for use as a 5% additive to the metal charge in the smelting of iron-carbon alloys similar in composition to cast irons.

Improvement of technology and technique for the production of sinter at the SP EVRAZ KGOK. Report 1. Loading and ignition of the mix.

A brief literature review of theoretical and applied works on charging and ignition of sinter mix has been made. The review considers experimental data on the influence of the distribution of the particle size of the mix and the fuel content over the height and width of the bed, and its bulk density on the consumption of solid fuel, height and gas permeability, on the productivity of sinter machines and sinter strength. The problems of sinter mix ignition, the influ-ence of throttling of the first vacuum chambers of sinter machines on the quality of sinter and gas consumption for ignition are discussed. The results of industrial studies of mix loading and ignition modes on EVRAZ KGOK sinter ma-chines are presented, which provide an increase in the bed height, an increase in the cold strength of the sinter, and a decrease in natural gas consumption for mix ignition. As a result of increasing the rotational speed of the drum feeder, the discrete descent of the mix from the mix flow stabilizer was eliminated. It has been established that due to the ex-pansion of the sinter pallets and the negative slope of their sides, there is no need to form a mix bed profile variable in height and width. The operation of sinter machines with and without separation of the loading chute from the bed has been studied. The presence of critical fluctuations of the grain size composition of the mix and the content of fuel car-bon in it along the width and height of the bed for both options of operation, due to the mode of operation of the shuttle mix distributor and fluctuations the height of the bed in the intermediate hopper, has been established. The important role of the design and mass of the mix smoother has been experimentally confirmed. The design of the throttling device of the vacuum chambers legs with manual change of the free section only as it wears out has been developed and implemented. The rational free section of the legs of the vacuum chambers is determined, which provides a minimum suction (1–2 Pa) in the chamber of the ignition hearth, and equal to 10–12%. As a result of the introduction of new technical solutions, an increase in the cold strength of the sinter by 1.09%, a decrease in natural gas consumption by 29%, and an increase in the height of the sintered charge layer up to 30 mm were achieved without reducing the productivity of sinter machines

IDENTIFICATION SOURCES OF EMISSION PERSISTENT ORGANIC POLLUTANTS IN UKRAINE AND WAYS TO REDUCE EMISSIONS FROM THE MOST PROBLEMATIC SOURCES

Persistent organic pollutants (POPs) belong to a group of toxicants, which, due to their extremely dangerous impact on human health, is regulated by a special international agreement — the Stockholm Convention on POPs. Each Party to the Convention must develop and consistently update the National Implementation Plan for the requirements of this Convention. Ukraine developed a National Implementation Plan in 2007. Today, the plan needs to be revised and supplemented, taking into account the changes that have occurred in the structure of sources and volumes of POP emissions. During the time that has passed since the development of the first edition of the National Plan, new approaches have appeared to prevent the emission of POPs. The article contains the results of an expert analysis of changes in the volume and structure of POP emission sources in the world and in Ukraine. Calculations of POPs emissions, made according to the UNEP methodology, showed that the largest sources of POPs emissions in Ukraine are: sintering production and electric arc smelting of steel in ferrous metallurgy; production of thermal and electrical energy from biomass in the energy industry; incineration of solid household and hazardous waste. For the most problematic sources of POP emissions, the most promising methods and practices for preventing the formation and removal of POPs from the products of technological process have been determined. Bibl. 25, Fig. 4, Tab. 3.

Study of Polymer Inorganic Composites for Electromagnetic Radiation Absorption Using Potassium Titanates

The article aims to investigate polymer inorganic composites for electromagnetic radiation absorption using potassium titanates. The selected polyamide 6 (durethane brand) and sodium polytitanate materials contain TiО2, K2СО3, and KCl received by charge sintering. Results showed that modification of polyamide 6 with sintering products in the form of a fine powder of potassium polytitanate with particle size 1-5 microns that contain the primary phase K2O × 2TiO2 with an admixture of a phase K2O × 4TiO2, which increased their strength properties. The optimal content of potassium polytitanate was over 10 % by mass. To fully ensure the reinforcing effect due to the filling of potassium polytitanate polyamide 6, it is necessary to use whiskers K2O × 6TiO2, which can be collected by the additional crystallization of the amorphous charge sintering product.

Optimization of Spark Plasma Sintering Technology by Taguchi Method in the Production of a Wide Range of Materials: Review.

This paper reviews the production of sinters using the spark plasma sintering method. SPS (spark plasma sintering) technology has been used for several decades, mainly in laboratories, to consolidate a huge number of both new and traditional materials. However, it is now more often introduced into practical industrial use, with equipment as early as the fifth generation capable of producing larger-size components at competitive costs. Although the mechanism of sintering with the use of this method is not yet understood, the effectiveness of the SPS process for the rapid and efficient consolidation of a wide range of materials with novel micro-structures remains indisputable. With a relatively wide variation in chemical composition, the structure allows the selection of appropriate consolidation parameters for these materials. The influence on the values of apparent density and mechanical properties depends on the parameters of the spark plasma sintering process. In order to achieve a density close to the theoretical density of sinters, optimization of the sintering parameters, i.e., sintering temperature, heating rate, sintering time, pressing pressure and protective atmosphere, should be carried out. In this paper, the optimization of spark plasma sintering of Si3N4-Al2O3-ZrO2 composite was carried out using the Taguchi method. The effects of four sintering factors, namely heating rate, sintering time, sintering temperature and sintering pressure, on the final density were investigated. Optimal sintering conditions were proposed and a confirmation experiment was conducted. The optimal combination of sintering conditions for spark plasma sintering (SPS) of Si3N4-Al2O3-ZrO2 composite for high apparent density was determined as A3-B3-C3-D2. Based on ANOVA analysis, it was found that the apparent density of sintering was significantly influenced by sintering temperature, followed by pressing pressure, sintering time and heating rate. Validation of the developed mathematical model predicting the apparent density of sinters showed close agreement between the predicted response results and experimental results.

Effect of CaO Component on Strength of Pre-granulated Pellets in Composite Sinter Products

Effect of CaO Component on Strength of Pre-granulated Pellets in Composite Sinter Products

Thermodynamic Analysis of a Composite Obtained Using a Mixture of Copper and Molybdenum Oxides and Sulphides

The purpose of the study is selecting the optimal composition of antifriction composites alloyed with refractory metal sulfides in copper-based systems and developing the design of a laboratory plant for the production of sinter by pyrolysis of coke chemistry production resins. The object of the study is antifriction composites based on rare metal sulfides and coke chemistry production resins. The methodology of the work is determined by the use of modern physical and chemical research methods and modern software systems. As a result of the studies, the probable chemical reactions between compounds of copper and rare metals: molybdenum, tungsten with and without the participation of carbon, have been compiled. The optimal compositions of antifriction composites based on copper and rare metal sulfides have been determined, and a laboratory plant has been designed for the production of sinter by pyrolysis of coke chemistry production resin. The scope of the results is materials science and technology of new materials. Based on the thermodynamic analysis of various reactions that are likely to occur during the preparation of the cladding carbon lubricant composition based on powdered copper and carbon with the addition of rare metal sulfides (MoS2), the most appropriate component composition of the charge has been selected. In this case, a reducing agent is used: soot obtained from resins of coke production that has an amorphous structure and does not have solid impurities. The main choice was made on the formation of metallic copper and disulfides of rare metals in the presence of active carbon. The most probable reaction is the formation of metallic copper and molybdenum disulfide in the presence of carbon. Carbon and copper are macro-components of the lubricant, and rare metal sulfides are additives that improve its plasticity. It is also important that carbon does not contain abrasive impurities and has certain hardness and fineness. These qualities are ensured in the production of black carbon using coke chemistry resins. To obtain black carbon, a laboratory plant has been designed that will be used for the pyrolysis of resin from the coke chemistry production.

Migration and Reaction Mechanism of Barium in BaSO4–CaCO3–Fe2O3 System during Sintering

With the increasingly strict requirements of blast furnaces on the sinter quality, analyzing the phase transition process and reaction mechanism of special elements in the sintering process plays an important role in understanding the sintering process and improving the sinter quality. Herein, the decomposition process of barite during sintering and the influence mechanism on the bonding phase of calcium ferrite are studied by laboratory experiments and thermodynamic calculations. The results show that calcium ferrite and ferric oxide can promote the decomposition of barite and reduce the decomposition temperature in the sintering process. The generated barium enters the calcium ferrite phase and affects the strength and melting point of calcium ferrite. With the increase of barium content, the strength of calcium ferrite sample increases from 1.62 to 2.00 kPa, and the initial melting temperature of calcium ferrite sample stays at 1473 K. However, with the further increase of barium, the sample strength and melting temperature both show a worsening trend. Finally, based on the research results, some suggestions for sintering production are put forward, and the optimal barite content is determined. Results help to better understand the reaction process and action mechanism of barium in the sintering process.

Influence of low temperatures and the limited consumption of lime on the operation of sinter machines at the SP-5 of PJSC MMK in winter conditions

Lime is the only additive that has shown high efficiency in the sinter production due to the double effect on the sintering process: improving the granulation of the mix and its heating. At the sinter plant No. 5 of PJSC “MMK”, a rational ratio was established between the lime consumption of 0‒10 mm fraction supplied to the closed blending storage of mono-mix, and a fraction of 0‒3 mm, supplied to the charge room after its additional blending arrangement. During the previous research period (November 2022), the air temperature in blending storage did not fall below 6 °С, and the moisture of iron ore raw materials was maintained at the level of 3.5‒4.0%. It was recommended in winter conditions to supply lime with a fraction of 0‒3 mm to the mix department in the amount of 3% in relation to the concentrate, and the rest of the lime with a fraction of 0‒10 mm to the blending storage. In December of 2022 after the previous experiments the air temperature dropped to ‒25 °С. It was necessary to additionally estimate the minimum content of lime fraction 0‒10 mm in iron one concentrate in the storage, preventing its freezing. In this study, it was found that a decrease in air temperature over several days to ‒25 °С with a lime fraction of 0‒10 mm in the blending storage in relation to the concentrate of only 1.5% did not cause problems with flow ability and intake of iron ore con-centrate. In addition, after the start-up of sinter plant No. 5, the lime content in relation to the concentrate consumption was maintained about 5%, and the effect of its consumption on the productivity of sinter machines was not determined. As installed the decrease in productivity of sinter machines, as a result of a break due to frost in the supply of the rest of the lime by pneumatic transport to the mix department, was 12%. The influence of the basicity of iron ore on the degree of removal of sulfate sulfur in the sintering of charge was also clarified

Effect of Silica Content on Iron Ore Sintering

During the iron ore sintering process, its SiO2 content considerably affects the sinter quality. In this study, the effect of SiO2 content on iron ore sintering indexes was studied, with mineral composition and microstructure analyses. It was shown that the strength and reducibility of sintering products improved when SiO2 content increased. The sinter yield and tumbler index increased from 69.57% and 58.67% to 74.02% and 62.32%, respectively, with SiO2 content increasing from 3.92% to 5.12%. Moreover, the reduction disintegration index (RDI+3.15) increased from 66.50% to 68.28%. There was a quadratic function relationship between SiO2 content (x) and RDI+3.15 (y): y = −0.4841x2 + 5.8932x + 50.8189. Maintaining the SiO2 content in the range of 4.52% to 5.12% would promote the formation of compound calcium ferrite (SFCA) and silicate as the main binding phase which determined the quality of sintering products.

Mineral Phase Reconstruction and Separation Behavior of Zinc and Iron from Zinc-Containing Dust.

Zinc-containing dust can be found in ironmaking and steelmaking, and it is an important secondary resource of zinc. Zinc-containing dust from an electric furnace was used as a raw material to study the phase transformation behavior of the dust using a calcification roasting process and the zinc-iron separation behavior by using ammonia leaching. The zinc-bearing dust was mixed with CaO and roasted to transform the zinc ferrite into zinc oxide. The results showed that increasing the calcium oxide to dust ratio could promote the conversion of zinc ferrite to zinc oxide. When the calcium oxide ratio reached 60%, the peak of zinc ferrite in the calcined-roasted product in the zinc-containing dust basically disappeared. As the temperature increased, the zinc oxide grains increased but were still smaller than 10 µm. The calcined-roasted product was crushed and ground, and the zinc was leached by ammonia. A zinc-iron recovery rate of 86.12% was achieved by the ammonia leaching. The leachate could be used for zinc extraction by electrolysis. The leaching residue was mainly calcium ferrate, which could be used in sintering production. The proposed process may achieve on-site recovery of zinc-containing dust in steel-making plants.

Iron Ore Granulation for Sinter Production: Developments, Progress, and Challenges

Iron ore granulation is an indispensable process in the production of sinter that can influence and regulate the yield, efficiency and quality. Although a great deal of research has been done on the granulation process over the past decades, we still need to think about the current and future development of this process, as sinter is still an essential raw material for ironmaking blast furnace today. This paper begins with a review of particle agglomeration theory development for sintering granulation, followed by a summary of existing granulation evaluation methods and indexes. The roles of iron ore, fuel, fluxes, and moisture in sintering granulation are also analyzed, and finally advanced granulation equipment and processes for industrial production, as well as their applications, are summarized. Correspondingly, the challenges in sintering granulation field are proposed to include: (1) Development of iron ore sintering industry; (2) Ore blending optimization based on synergistic coupling of granulation and sintering; (3) Optimization of granulation process and equipment; (4) Methods and tools for granulation scientific research. These issues will be tackled and overcome in the future by both steel enterprises and academic researchers, generating suggestions for future development in the field of sintering granulation.

Life cycle assessment of blast furnace ironmaking processes: A comparison of fossil fuels and biomass hydrochar applications

The impact of the iron and steel production process on the ecological environment cannot be ignored. This study aims to assess the impact of life cycle assessment on the traditional fossil fuel blast furnace ironmaking process and the biomass hydrochar blast furnace ironmaking process. The Simapro v9.0 software is used to comprehensively evaluate the life cycle impacts of biomass hydrochar in the blast furnace ironmaking process. The results show that the life cycle impact categories of the blast furnace ironmaking process mainly include global warming, non-renewable energy and respiratory inorganics. The global warming impact of the ironmaking process using hydrochar is 2054.00 kg CO2 eq, which is 420.61 kg CO2 eq less than that of traditional blast furnace ironmaking process. The global warming impact is mainly reflected in the emission of CO2 gas, and the main source is the generation of blast furnace gas and the use of sinter. The respiratory inorganics impact is mainly manifested in the emission of nitrogen oxides, sulfur oxides and particulates, which mainly comes from the mining of iron ore and the production of sinter. The non-renewable energy impact mainly comes from the coal resources, and the use of other renewable energy such as biomass energy is an important way to reduce the impact. Therefore, biomass hydrochar used in the metallurgical process is more suitable for sustainable development of the ecological environment.

Effect of the Carbon Mixing Ratio on Mineral Evolution and Gasification Dephosphorization during the Pre-reduction Sintering Process of Bayan Obo Iron Ore Concentrate

The pre-reduction sintering process is an effective measure to fundamentally solve the detrimental circulating accumulation of phosphorus in iron- and steel-making procedures. The effect of the carbon mixing ratio on the mineral evolution, gasification dephosphorization and pre-reduction degree of sintering products was primarily investigated based on the phosphorus occurrence status in Bayan Obo iron ore concentrate. The obtained results indicated that iron oxide was dominantly transformed from magnetite into wüstite, and metallic iron was basically not detected. Regarding silicate slag, the precipitated dendritic phase accounted for a higher content of FeO and MgO and a lower content of Na2O + K2O and SiO2 over the vitreous matrix phase. Moreover, as the carbon mixing ratio was increased from 5 to 25 wt%, the gasification dephosphorization and pre-reduction degree first increased from 11.3% and 30.7%, respectively, to 70.0% and 67.4%, respectively, due to the enhanced reducing atmosphere and then decreased to 45.0% and 59.0%, respectively, led by the increased content of liquid slag and the reduced permeability of the burden layer. Both maximum values were obtained at a 20 wt% carbon mixing ratio. Furthermore, the pre-reduction sintering products as raw materials for blast furnaces could not only largely reduce the phosphorus content in hot metal but could also dramatically decrease coke usage and carbon dioxide emissions, which could be highly beneficial to realize carbon peaking and carbon neutrality.

Research on Multi-Decision Sinter Composition Optimization Based on OLS Algorithm

The adjustment of sintering raw materials has a decisive influence on the composition of blast furnace slag and the properties of sinter. In order to smelt high-quality molten iron in the blast furnace, the composition of the sinter must be properly adjusted so that the composition of the blast furnace slag and the metallurgical properties of the sinter are optimal for the quality of the iron and are conducive to the smooth operation of the blast furnace. In view of the huge difference in the quality and price of sintering raw materials, this paper proposes an automatic sintering ore blending model to quickly configure sintering raw materials according to the requirements of the production line. This method is based on the calculation process of blast furnace charge, combined with the constraints of process composition and cost performance, to establish a multi-decision sintering ore blending model based on the OLS(Ordinary least squares) algorithm to automatically screen from available raw materials and give the sinter that meets the requirements of the furnace. The plan finally makes TFe, CaO, MgO, SiO2, TiO2, Al2O3, P, Mn, Na2O, K2O, Zn, and other components meet the requirements of the production line, and meet the cost performance requirements of the enterprise for sinter. The model can complete the screening and proportioning of 43 kinds of raw materials within 10 s, and its performance can meet the requirements of the production of variable materials. Combined with an example, a comparative analysis experiment is carried out on the accuracy and practicability of the designed sintering and ore blending model. The experimental results show that the accuracy and efficiency of the method proposed in this paper are higher than those of the current ore blending scheme designed by enterprise engineers. This method can provide an effective reference for the stable operation of the sintering production line.

Improving the quality of sintering fuel preparation. Reconstruction of the solid fuel preparation unit at sinter plant No. 3

JSK “Severstal” is working to reduce the load on the environment. Considering that more than 70% of emissions of harmful substances into the atmosphere fall on the share of sintering production, special attention is paid to the introduction of rational technological schemes for preparing the charge for sintering. The results of laboratory studies to determine the optimal granulometric composition of coke breeze for various charge conditions are presented. The analytical model of predicting the quality of crushing was developed to analyze and optimize the operation of the fuel preparation section. The model describes the main dependences of the separation of fuel by size on the screen, in the separator and the dependence of the fractional yield ‒0.5 mm and +3.15 mm on roller crushers. The use of the model is supposed to compile regime maps of the operation parameters of four-roll crushers and a classifier, depending on the quality of the incoming fuel, the proportion of sinter ore in the iron ore part of the sinter charge, and the productivity of the complex as a whole. The diagrams are presented for the flow diagrams for preparation of coke breeze in Sinter Plant No. 3 before and after reconstruction. It is shown that the transition to the technology of fuel preparation in four-roll crushers makes it possible to reduce its consumption for agglomeration and reduce emissions of pollutants into the atmosphere. The total potential for reducing of CO emissions due to this activity is about 6 thousand tons per year. It is noted that the refinement of equipment and technology for the classification of coke breeze has additional potential to reduce the consumption of coke breeze for the sintering of iron ore raw materials and improve the quality of the sinter.

Research on Sinter Quality Prediction System Based on Granger Causality Analysis and Stacking Integration Algorithm

Sinter ore quality directly affects the stability of blast furnace production. In terms of both physical and chemical properties, the main indicators of sinter quality are the TFe content, alkalinity, and drum index. By analyzing the massive historical data on the sinter production of a steel company, this study proposes a sinter quality prediction system based on Granger causality analysis and a stacking integration algorithm. First, based on real historical data of sintering production in steel enterprises (including coal gas pressure, ignition temperature, combustion air pressure, etc.), data preprocessing of raw data was carried out using a combination of feature engineering and the sintering process. Second, Pearson correlation analysis, Spearman correlation analysis, and Granger causality analysis were used to screen out the characteristic parameters with a strong influence on the target variable of sinter quality (drum Index, TFe, alkalinity). Third, a prediction model for sinter quality parameters was developed using a stacking integration algorithm pair for training. Finally, a program development tool was used to realize the establishment and online operation of a sinter ore quality prediction system. The test results showed that the predicted goodness of fit of the model for the TFe content, alkalinity (R), and drum index were 0.942, 0.958, and 0.987, respectively, and the model calculation time met the actual production requirements. By establishing a suitable model and running the program online, the real-time prediction of the main indicators of sinter quality was realized to guide production promptly.

Research and application of the sintering whole process intelligent manufacturing system

ABSTRACT Stable production processes, high efficiency and good product quality are the main objectives of the sintering industry. Taking the whole sintering production process as the research object, cutting-edge intelligent algorithms and classical sintering theories are applied to establish a sintering batch optimization model, a sinter layer permeability prediction model, a sintering end point optimization control model and a sinter quality prediction and evaluation model respectively, supported by a large amount of historical data, so that the model has reasonably accurate results as well as strong practicality. At the same time, a sintering whole process intelligent manufacturing system based on the above four models is constructed using Java and Python programming languages. The system realizes the functions of real-time analysis of key parameters, intelligent early warning, decision optimization and fault tracing, which provides reasonable line optimization suggestions for field operators, and significantly improves the intelligence and production efficiency of sintering process.

Red mud recycling by Fe and Al recovery through the hydrometallurgy method: a collaborative strategy for aluminum and iron industry.

In this work, a collaborative strategy for the aluminum and iron industry based on red mud recycling through the hydrometallurgy method was proposed. In this method, Fe3+ and Al3+ were firstly separated from the red mud by using H2SO4 as a leaching agent, which was by-produced from the sintering process of an iron and steel industry. Multiple influence factors on the leaching process were investigated, with the H2SO4 addition amount showing the strongest influence on the leaching rates of Al and Fe. The main components of the filter residue were CaSO4, TiO2, and SiO2, which could be reused as additives in the building materials. Subsequently, the final Fe recovery product was obtained through the co-precipitation, Fe/Al separation, and Fe(OH)3 calcination. In the final product, the content of Fe2O3 reached 82.87%, and the iron grade was 58.01%, meeting the requirement being raw materials for sinter production.