Sintering Of Mixture Research Articles

Real-Time Control of Sintering Moisture Based on Temporal Fusion Transformers

The quality of sintered ore, which serves as the primary raw material for blast furnace ironmaking, is directly influenced by the moisture in the sintering mixture. In order to improve the precision of water addition in the sintering process, this paper proposes an intelligent model for predicting water-filling volume based on Temporal Fusion Transformer (TFT), whose symmetry enables it to effectively capture long-term dependencies in time series data. Utilizing historical sintering data to develop a prediction model for the amount of mixing and water addition, the results indicate that the TFT model can achieve the R squared of 0.9881, and the root mean square error (RMSE) of 3.5951. When compared to the transformer, long short-term memory (LSTM), and particle swarm optimization–long short-term memory (PSO-LSTM), it is evident that the TFT model outperforms the other models, improving the RMSE by 8.5403, 6.9852, and 0.453, respectively. As an application, the TFT model provides an effective interval reference for moisture control in normal sintering processes, which ensures that the error is within 1 t.

Improvement of the gas-dynamic and thermal modes of external heating of a sintering mixture layer

Improvement of the gas-dynamic and thermal modes of external heating of a sintering mixture layer

Modernization of equipment for preparing the barch for sintering in the sintering shop of JSC “Ural Steel”

The efficiency of pelletizing the sintering charge, in addition to its particle size distribution, moistening modes, and binding additives, is influenced by the characteristics of the equipment used for pelletizing ‒ design and operating mode. The normal course of the sintering process and the production of high-quality agglomerate are impossible if the charge is highly heterogeneous in size. Before sintering, the sintering mixture must be pelletised with pellet compaction after mixing. The equipment installed at JSC “Ural Steel” for preparing the charge for sintering does not provide a uniform granulometric composition of the pelletized sintering charge. In April 2023, one of the four sintering charge pelletizers Ø2.8×6 m operating at the enterprise was replaced with a drum pelletizer Ø2.8×8 m produced by LLC “Tsemek Minerals” (Magnitogorsk). The characteristics of the pelletized sintering charge and the quality indicators of the sinter produced at JSC “Ural Steel” are given. Measures are presented to modernize the equipment for preparing the charge for sintering, the implementation of which will allow the enterprise to obtain a sintering charge that is more uni-form in size, to increase the gas permeability of the sintered layer of the sintering charge on the pallets of the sintering machine, and also to improve the strength of the sintering material against impact and abrasion

Effect of moisture on the granulation and sintering characteristics of sinter materials with carbide slag as a flux

Carbide slag is a solid waste generated during acetylene production mostly not exceeding 200 μm, mainly composed of Ca(OH)2. Using carbide slag as a flux for iron ore sintering is a promising utilization method. The effect of moisture on the granulation and sintering process of sinter mixtures with carbide slag as a flux was studied in this study. The results indicate that carbide slag suppresses the deterioration of bed compressive strength with increasing moisture compared with our previous work. As the granulation moisture increases from 5.73% to 7.66%, the Sauter mean diameter of the granules increases from 1.48 mm to 3.35 mm, and the flame front speed increases from 20.55 mm/min to 34.09 mm/min. However, excessive moisture worsens the thermal pattern of the sintering bed, causing a decrease in the peak temperature from 1377 °C to 1340 °C. There is an optimal moisture content that maximizes the comprehensive index.

Optimized Prediction Model for the Granulation Effectiveness of Sintering Mixtures

The optimization model is proposed on the basis of the Litster's granulation model for the prediction of the granulation effectiveness of the sinter feed. Formulas are proposed to calculate parameters for the adhesive layer of the granules, including its mass‐averaged particle size and the water saturation. Based on small‐scale granulation and sieving experiments, a functional correlation is established that relates the granules properties to the distribution coefficient curve, confirming the validity of the model. The prediction of model is discussed with adhesive layer boundary conditions of −0.25, −0.5, and −1.0 mm, and when the boundary is −0.5 mm, the relative error is minimal. The optimization of the distribution coefficient curve based on the binomial interpolation method can make the model achieve a hit rate of 92.9%. Based on this model, the granulation effectiveness of the mixtures could be evaluated.

Recovery of Valuable Materials with the RecoDust Process

The RecoDust process is a pyrometallurgical process for treating steel mill dusts that cannot be recycled internally due to their zinc content, providing numerous benefits compared to conventional processes. State-of-the-art processes often face the problem of recycling only zinc, but not iron, which is frequently landfilled and withdrawn from a closed loop. Furthermore, these processes are also often limited to a specific zinc content in the feedstock. Within the described RecoDust smelting campaigns, basic oxygen converter dust with about 15 wt.% zinc was taken as feedstock. After high-temperature treatment of the input material, the RecoDust slag (RDS) has a zinc content of 0.4 wt.% and the crude zinc oxide (CZO) has a ZnO content of up to 80 wt.%. The RDS is suitable for use in the sinter plant as a secondary raw material. To investigate the influence of adding RDS to a common sintering mixture, sintering pot tests followed by RDI (reduction disintegration indices) tests were carried out. The influence of the admixture of RDS on the RDI values is not detectable. The CZO was fed into a soda extraction system for halogen removal. The halogen removal of this two-stage leaching was highly efficient with over 90% for chlorine.

Effect of municipal sludge addition on the sinter process and sinter quality

ABSTRACT In order to analyse the feasibility of sintering for municipal sludge treatment, a sintering pot was used for the experiment. The results showed that the main effects of sludge addition on the sintering process and sinter quality come from the changes in the heat addition and moisture content of the granulated sinter. The addition of sludge could improve the granulation efficiency of the sinter mixture and the particle size composition of the sinter. When the proportion of sludge was 7%, the addition of sludge completely replaced the water required for mixing, and the overall sintering index was the best. In this case, after reducing fuel consumption by 10%, except for the content of P, the sinter quality and the sintering index could met the requirements of steel production. Finally, the use of fuel and raw materials with high P content needed to be reduced with the addition of sludge.

On-Line Analysis of Sinter Mixture Composition and Correction of Moisture Influence Based on Laser-Induced Breakdown Spectroscopy

On-Line Analysis of Sinter Mixture Composition and Correction of Moisture Influence Based on Laser-Induced Breakdown Spectroscopy

Soft Sensors Using Heterogeneous Image Features for Moisture Detection of Sintering Mixture in the Sintering Process

Soft Sensors Using Heterogeneous Image Features for Moisture Detection of Sintering Mixture in the Sintering Process

Neural Network Prediction Model for Sinter Mixture Water Content Based on KPCA-GA Optimization

The design and optimization of a sinter mixture moisture controlling system usually require complex process mechanisms and time-consuming field experimental simulations. Based on BP neural networks, a new KPCA-GA optimization method is proposed to predict the mixture moisture content sequential values with time more accurately so as to derive the optimal water addition to meet industrial requirements. Firstly, the normalized input variables affecting the output were dimensionalized using kernel principal component analysis (KPCA), and the contribution rates of the factors affecting the water content were analyzed. Then, a BP neural network model was established. In order to get rid of the randomness of the initial threshold and weights on the prediction accuracy of the model, a genetic algorithm is proposed to preferentially find the optimal initial threshold and weights for the model. Then, statistical indicators, such as the root mean square error, were used to evaluate the fit and prediction accuracy of the training and test data sets, respectively. The available experimental data show that the KPCA-GA model has high fitting and prediction accuracy, and the method has significant advantages over traditional neural network modeling methods when dealing with data sets with complex nonlinear characteristics, such as those from the sintering process.

Influence of Sinter Parameters on CO Emission in Iron Ore Sintering Process

Carbon monoxide is the major hazardous component in flue gas exhausting from the iron ore sintering. This study aims to reduce the CO emission by changing the sinter parameters by sintering pot tests; specifically, the sinter quality, CO concentration, and total emission in sintering flue gas were analyzed in detail. The sinter strength properties, including the shatter index and the tumble index, are analyzed by the sintering pot test and the sintering flue gas discussion. The results show that the CO emission can be suppressed by modifying the sinter parameters, such as carbon content, coke breeze and coal breeze ratio, water addition, and sintering negative pressure. The good sinter parameters with the lower CO emission are 2.8% carbon content and 7.5% water in the sintering mixture. A higher coke breeze to coal breeze ratio, or only coke breeze fuel in the sinter mixture, is beneficial for the lower CO emission with a negative fan pressure of −12 kPa.

Effects of the Layered Distribution Pattern on the Gas Flow Resistance through the Bed with the Multisize Irregular Particle for the Waste Heat Recovery

The application of the sinter vertical cooling technology in the iron and steel industry is conducive to the realization of the double carbon in China. To reduce the energy consumption and improve the economy of the new process, the gas flow resistance in the sinter bed under the layered distribution pattern was experimentally studied. The gas flow resistance of most of the layered distribution modes is lower than that of the random distribution mode. Among all layered arrangement modes, the layered mode with the particle size increasing from the bottom-up has the lowest resistance, followed by the layered mode with the particle size decreasing from the bottom-up. These two modes ensure the feasibility of the application of the layered distribution pattern in the continuous production of the moving bed. Besides, increasing the number of layers benefits the reduction of the gas flow resistance, which has a more significant effect on the layered mode with the particle size increasing from the bottom-up. For the sinter mixture with the equivalent particle diameter of 11.45 mm, the gas resistance of the modes with the particle size increasing and decreasing from the bottom-up decreases by 11.71% and 8.26% with the layer number increasing from three to five, respectively. Also, the effect of the layered distribution pattern on the gas flow resistance progressively weakens with increasing the equivalent particle diameter. For the five-layer distribution mode with the particle size increasing from the bottom-up, the gas resistance decreases by 2.72% with the equivalent particle diameter increasing from 11.45 mm to 15.45 mm, while that decreases by 4.61% with the equivalent particle diameter increasing from 15.45 mm to 19.45 mm. What's more, the change of the equivalent particle diameter has a more significant influence on the layered mode with the particle size decreasing from the bottom-up. With the equivalent particle diameter increasing from 15.45 mm to 19.45 mm under the five-layer distribution pattern, the gas resistance of the layered mode with the particle size increasing from the bottom-up reduces by 4.61%, while that of the mode with the particle size decreasing from the bottom-up reduces by 7.38%.

Assessment of using shungite rock technological feasibility in the production of manganese agglomerate

Industrial experience in the production of manganese sinter shows that the known technological proposals do not provide an increase in the productivity of sintering machines and the necessary strength properties of fluxed manganese sinter. Known methods of sintering fluxed manganese agglomerate, characterized by increased mechanical strength and high moisture resistance. The disadvantage of these measures is a significant complication of the technological line of sinter production and an increase in energy costs. In this regard, one of the main directions is the development of charge compositions and parameters of the sintering process of manganese raw materials. The purpose of the study is the analysis of physical and chemical processes, experimental research and the development of innovative technological solutions and recommendations for attracting shungite rock to the metallurgical production to expand the raw material base of the mining and metallurgical complex. Calculations of the thermodynamic equilibrium of oxide systems adequate to sinter systems have been performed, and the chemical composition of the phase components of manganese agglomerate microstructures has been studied. The rational content of shungite in the sinter charge has been established, which ensures the production of agglomerate with specified characteristics (strength, usable yield, manganese content) is 12...13% of the mass of the initial charge. A further increase in its particles in the sinter mixture leads to a decrease in strength and the release of suitable heat. Increasing the degree of dispersion of shungite to 0-2 mm allows increasing the level of use of shungite carbon as a fuel without increasing the amount of traditional fuel - coke - for the process.

Significant influence of self-possessed moisture of limonitic nickel laterite on sintering performance and its action mechanism

In consideration of the abundant moisture of limonitic nickel laterite mined, it is essential to determine whether the self-possessed moisture of limonitic nickel laterite after pre-dried is appropriate for sintering. Thus, based on the characterization of limonitic nickel laterite, the influence of its self-possessed moisture on sintering performance was expounded by sinter pot tests and the relevant mechanism was revealed by the systematical analyses of the granulation properties of sinter mixture, thermodynamic conditions during sintering and mineralogy of product sinter. The results indicate that the self-possessed moisture of limonitic nickel laterite indeed has significant influence on its sintering performance. At the optimum self-possessed moisture of 21 mass%, sinter indices are relatively better with tumble index, productivity and solid fuel rate of 48.87%, 1.04 t m−2 h−1 and 136.52 kg t−1, respectively, due to the superior granulation properties of sinter mixture and thermodynamic conditions during sintering, relatively large amount of silico-ferrite of calcium and alumina and tighter sinter microstructure. However, sintering performance of limonitic nickel laterite is still much poorer than that of ordinary iron ores. It is feasible to strengthen limonitic nickel laterite sintering by inhibiting the over-fast sintering speed and improving the thermodynamic conditions during sintering.

Study of iron content in iron ore concentrate increasing effect on sintering process indices and on metallurgical properties of sinter

Effectiveness of blast furnaces operation in many respects depends on metallurgical properties of agglomerate, in particular, iron content in the sinter and its basicity. At the same time, it is accepted that usage of iron ore concentrates with iron content more than 66–67% for sinter production results in decreasing of its strength. As a result of the planned modernization of the technological sections of the concentration plant JSC “Stoilensky GOK”, iron content in the concentrate will be increased to 68–70%. It makes it actual to accomplish comprehensive studies of metallurgical properties of the sinter while increasing iron content in the raw material. Results of the study of sinter properties presented, the sinter being obtained with utilization of iron concentrate with iron content 66.6 % (base), 68.0 and 69.2 % (exp. 1 and exp. 2 correspondently). The iron ore mixture for all the stages was the same and consisted of iron ore concentrate – 78.3%, sintering ore – 8.0%, lime – 5.5% and sintering additives (sludge, dust, scale) – 8.2%. The sintering mixtures composition for all the study stages differed only by fluxes and iron ore mixture consumption. 18 test sintering operations at three values of basicity 1.6, 1.8 and 2.0 units were accomplished. It was established that increase of iron content in the concentrate and basicity of the sinter results in improving of the sintering process indices, increase of the vertical sintering rate, sintering machines productivity, recovery and the sinter cold strength. Increase of the sinter basicity and its production with increased content of iron results in improving RDI indices at low temperature reducing. Results of the study of porosity indices and metallurgical properties of the sinter presented, in particular the collapsibility during reducing and temperature interval softening-melting presented. The advisability of concentrate with increased iron content utilization in the iron ore mixture shown.

Experimental study on the permeability and resistance characteristics in the packed bed with the multi-size irregular particle applied in the sinter vertical waste heat recovery technology

The gas flow resistance in the packed bed of multi-size irregular particles applied in the sinter vertical cooling process is measured experimentally to analyze the effect of the equivalent particle diameter (dp,m) and the particle size distribution on the permeability and resistance characteristics. Results show that the flow resistance per unit bed height (ΔP/L) decreases with the reduction of dp,m. However, the decrement of ΔP/L ascends first and then descends due to the comprehensive influence of the bed voidage and the particle size distribution, which is quite different from that in the mono-size sinter bed. Compared to the mono-size sinter packed bed, the bed permeability of the multi-size sinter mixture is lower under the same equivalent particle diameter. The particle size distribution of the multi-size sinter mixture has a great impact on the gas flow regime, especially at the low gas velocity. This makes the gas flow resistance in the packed bed of the multi-size sinter bigger. Since the mean error of the previous resistance correlations is greater than 44.79%, the resistance correlation applicable for the multi-size sinter is obtained by modifying the Ergun equation with the mean error less than 10%.

Evaluation of Iron Ore Concentrate and Micropellets as Potential Feed for Sinter Production

ABSTRACT The use of iron ore concentrate and micropellets as sinter feed was evaluated. Five mixtures containing different proportions of concentrate and micropellets, together with iron ore fines, were granulated and sintered in a pilot scale sinter plant. It was found that the addition of iron ore concentrate and/or micropellets to the sinter feed resulted in a significant increase in permeability of the granulated bed, but a large drop in sinter production rates. Although the introduction of iron ore concentrate and/or micropellets to the sinter mixture did not significantly impact sinter strength or reducibility (as measured through tumble – (TI) and reducibility indices (RI)), it severely impacted on their strengths during reduction (as measured through RDI−3.5 mm and RDI−0.5 mm). The introduction of iron ore concentrate and micropellets resulted in a general increase in the amount of fines that form during reduction, exceeding the maximum acceptable levels (RDI−0.5mm maximum 5%) set by industry. Sinters containing high amounts of micropellets experienced a more severe degradation than the concentrate-rich sinters. It is therefore more viable to use iron ore concentrate in the sinter feed as higher production costs are associated with the production of micropellets. Sinters produced through concentrate addition also generate less fines on reduction.

Optimization of PGNAA device and algorithm for testing basicity index of sinter mixture

Sinter is the main raw material in the blast furnace iron-making process, and basicity (CaO/SiO2) is an important quality index of sinter. Prompt gamma neutron activation analysis is a multi-elemental online detection technology that has been successfully applied in cement, coal, etc. Compared with cement as a raw material, sinter exhibits poor moderation ability and a large neutron absorption cross section. Therefore, cement detection devices are not suitable for sinter mixture detection. In this study, a prompt gamma neutron activation analysis equipment used for testing cement was re-optimized to render it suitable for measuring a sinter mixture. Using Monte Carlo simulation, the comprehensive detection efficiency of the detection device improved by 71.52%. Because of the gamma-ray self-shielding effect of the sinter mixture, the detection errors of CaO and SiO2 are significant. By applying the gamma-ray self-shielding correction algorithm, the detection accuracies improved, and their linear correlation coefficients R2 exceeded 0.99. Furthermore, by applying an improved analyzer to a sintering plant, the first-grade product rate of the factory increased by 4.64%.

Bulk Raw Materials Handling and Blending Techniques of Sinter Plant: A Case Study of Ajaokuta Steel Company Limited, Kogi State, Nigeria

Bulk raw materials handling plant and sintering plant preparatory plants are established to receive, blend, stockpile, prepare and supply specified grades of raw materials for smooth operations of iron making plant (Blast furnace), steel making plant (Basic oxygen converter) and lime Plant(calcinations plant). The study discusses bulk raw materials handling and some general problem of scientific analysis and documentation of basic equipment details, stockyard facilities, bulk materials transport systems and sinter processes, for the general knowledge and operational procedures of these plant for effective and efficient operational processes for optical results. Iron ore concentrate supplied from the mines to some extent fluctuate in their chemical composition as a result of the nature of the deposit with various factors controlling beneficiation processes and addition of metal-bearing materials collected as a waste product from the Rolling Mills, Blast Furnace and Sinter Plant which must be recycled through Iron ore concentrate stockyard. The part of the sinter mixture is melted at a temperature about 1300-1480 ° C and a sequence of reactions shaping the sinter cake to be loaded into the blast furnace to produce iron from a pig.

Granulation Behavior of an Iron Ore Sintering Mixture Containing High Grade Pellet Feed with Different Specific Surface

Granulation Behavior of an Iron Ore Sintering Mixture Containing High Grade Pellet Feed with Different Specific Surface