•This work revealed the law of gas sulfides release during the reduction process of blast furnace raw materials.•The precipitation of sulfur during the reaction of coke and sinter in reducing ...atmosphere was divided into two stages.•Low temperatures favored the generation of H2S, while high temperatures promoted the generation of COS.
Understanding the transformation behavior of sulfides in the blast furnace raw materials during the ironmaking process is crucial for controlling the form and emission of gaseous sulfides in the blast furnace top gas. This study investigates the reactions of coke and sinter at different reducing atmosphere ranging from 200 °C to 1000 °C by using of thermogravimetry and mass spectrometry (TG-MS). Additionally, thermodynamic theoretical calculations were performed to enhance the understanding of the reaction behavior. The results showed that the mixed sinter and coke started to generate H2S at 100 °C under the mixed H2-CO atmosphere and reached the peak between 350 and 400 °C. With the increase of H2 concentration, the peak temperature of H2S generation initially decreased and then increased, with the lowest peak temperature observed under a 50% H2-50% CO atmosphere. Furthermore, COS generation started around 300 °C and reached its peak at approximately 800 °C. The peak content of COS generation increased as the CO concentration. Low temperatures favored the generation of H2S from the mixed sinter and coke, while high temperatures were conducive to the generation of COS.
As for ferrous burden, the softening and melting (SM) behaviors greatly affect the cohesive zone thickness, position and shape. Ironmaking researchers have found that it’s not appropriate to evaluate ...the blast furnace burdens only based on the SM behavior of single iron-bearing materials because the sinter will interact with acid materials at high temperatures. In present study, a new visual method has been given to research the SM behavior of five single iron ores and four types of mixed burdens. The results show that the SM properties of all iron ores in the cohesive zone (CZ) are enhanced through interactions at high temperature. Due to intense interaction at high temperature, SM behavior of the mixture burden A (containing lump ore L-A and sinter) is better than the mixture burden B (containing lump L-B and sinter), despite the lump ore L-A SM behavior is remarkably reduced compared with the lump ore L-B. Additionally, experimental results for melting and dropping of integrated burdens also prove that high temperature interaction is important for enhancing the performance of SM in ferrous materials and improving the permeability of the blast furnace.
The inverse calculation of burden distribution matrix (BDM) is one of the most important challenges in the blast furnace operation in iron-making processes. In general, blast furnace consumes 65% of ...the total energy for the whole steel-making. Focusing on this practical challenge, this article proposes a new burden distribution spatial model in calculating burden charging process, and develops a B-spline approximation-based probability density function (PDF) control algorithm to assign the expected thickness distribution of burden layer and, thus, develops a new method for the required inverse calculation of BDM. First, a novel method for the thickness distribution of burden layer is given using B-spline model to produce an expected distribution shape subjected to a desired tracking within a specific spatial constraint. Then, according to the coexistence of continuous and bounded discrete variables in BDM, a novel hybrid optimization control method by combining integer programming and PDF tracking is further established for the effective inverse calculation of BDM. Finally, the proposed PDF-based iterative inverse calculation of BDM using B-spline models are tested using various data from industrial examples. The simulation results show that the proposed method is well suited to solve the BDM inverse calculation problem in practice.
The iron ore consumption doubled several times due to the rapid development of ironmaking industry in China, resulting in the worse quality of iron ores in the past decade. Therefore, the efficient ...utilisation of poor quality iron ore resources is of great importance for the sustainable development of ironmaking industry. In this work, a new method for optimisation of blast furnace burdens was studied based on the primary slag formation behaviour because it has significant influence on the formation of the cohesive zone. The results showed that there was obvious interaction between sinter and acid iron ores at high temperature, and the primary slag formation behaviour was clearly improved by the high temperature interaction. The poor quality lump ore could be utilised together with high basicity sinter and self-fluxed pellet to enhance the high temperature interaction. Besides, increasing CaO and MgO content in blast furnace burdens would further improve their primary slag formation behaviour and the performance of cohesive zone.
This paper presents the methodological basis for creating a model system for selecting the optimum composition of blast furnace burden, providing the required technical and economic performance and ...the melting of pig iron of the required composition. The system implements a new systematic approach to modeling the processes of directed formation of blast-furnace melts. Description of composition and properties of metallurgical systems in different states is based on an original concept of directional chemical bonding using integral parameters of interatomic interaction of components in the system. The developed complex of mathematical and physical-chemical models and criteria provides a solution to the direct problem of predicting the composition of pig iron and properties of blast furnace slag, depending on burden and technological conditions. Determination of the optimal burden composition is carried out using vector optimization methods with mandatory verification of compliance with the technological requirements of high-temperature properties of the burden. The results of testing the model system on actual industrial data of blast furnace operation are illustrated, which made it possible to formulate recommendations on the composition of the loaded feed, taking into account the available raw material and energy resources.
In order to improve blast furnace efficiency, reduce CO
2
emission and accelerate energy utilisation, a new preparation process of iron coke hot briquette (ICHB) based on the raw materials conditions ...in China, a new type blast furnace ironmaking burden, was experimentally investigated in this paper. The new preparation process was researched and optimised through single factor experiment and orthogonal experiment. Meanwhile, the reactivity and the post-reaction strength of ICHB prepared under the optimised conditions were tested and the effect of ICHB on the thermal performance of conventional coke was researched. In addition, softening and dripping properties of mixed burden with optimised ICHB charging was simultaneously investigated. The results showed that the optimised preparation parameters of ICHB include 15% iron ore, 65% bituminous coal, 350°C hot briquetting temperature, 1100°C carbonisation temperature and 4 hours carbonisation time. The reactivity and the post-reaction strength of ICHB prepared under the optimisation conditions are 62.4 and 10.6%, respectively. ICHB has protective effect on conventional coke and the protective effect is more obvious with 10% ICHB adding. With the increase of ICHB charging ratio, softening interval T
40
-T
4
of mixed burden is widened while melting interval T
D
-T
S
(namely cohesive zone) is narrowed. Additionally, the permeability of mixed burden becomes better and dripping ratio is first increased then decreased. The suitable charging ratio of ICHB in mixed burden is about 30%.
With the depletion of high-grade iron ores, iron and steel companies all over the world are expected to use refractory iron ore resources in the sintering process. Composite agglomeration process ...(CAP) was utilised to improve the sintering performances of high-SiO
2
-content iron concentrates in this study. Theoretical calculation indicates that CAP is more effective for the agglomeration of high-SiO
2
-content iron concentrates compared with traditional sintering process (TSP). The sintering pot tests results showed that the sintering yield of 74.15 wt-%, tumbler index of 72.75 wt-% and productivity of 1.54 t·(m
2
·h)
−1
were achieved, which is 9.12 wt-%, 10.70 wt-% and 0.45 t·(m
2
·h)
−1
higher than that by TSP, respectively. Moreover, CAP decreased the solid fuel consumption by 11.77 kgfuel/tproduct. Researches of metallurgical performances showed the CAP product can be used as high-quality blast furnace burdens. This investigation provides an effective route to utilise the inferior high-SiO
2
-content iron concentrates.
An approach to selecting the optimal composition of multicomponent blast-furnace burden based on a set of mathematical models for predicting change-of-state transformations of iron-ore raw materials, ...as well as for calculating chemical composition and properties of primary and final products of smelting, is presented. The results of predictive-analytical studies of the change in the indices of high-temperature properties of iron-ore materials and formed primary molten slags with respect to the distribution features of burden components along the radius of the throat for burden conditions of one of the blast furnaces are considered. The performed evaluation of the calculated indices of primary melts and their comparison to the technological requirements to iron-ore raw materials is a constituent part of designing an algorithm for solving an optimization problem of selecting the composition of a blast-furnace burden in the expert system under development.
Burden distribution at the furnace throat plays an important role in blast furnace (BF) iron-making, which influences the furnace efficiency and stable operation. Burden distribution matrix (BDM) is ...a key operating variable to adjust a reasonable burden distribution. However, due to complex iron-making mechanism, it is difficult for operators to formulate BDM to achieve a reasonable burden distribution in practice. Focus on this challenge, this paper studies the burden distribution model and proposes a decision method of adjusting BDM based on Dandelion Optimizer (DO). Finally, simulation results demonstrate that the decision model based on DO has better reliability and generalization performance, comparing with other models which are based on the Particle Swarm Optimization (PSO) and Simulated Annealing (SA).
Blast furnace gas utilization rate is one of the indicators for measuring the smooth operation of the blast furnace. The prediction model of the blast furnace gas utilization rate based on the ...extreme learning machine algorithm (ELM) is firstly established. The burden surface characteristics and the indexes of the blast furnace condition are the input parameters, and the blast furnace gas utilization rate is the output parameter. In most cases, the regular item factor is introduced for ELM to ensure satisfactory output. In this paper, the same prediction model based on PCA-ELM algorithm which is based on the principal component analysis method (PCA) and ELM is established secondly. Real production data of the blast furnace is used to verify the prediction model. By comparing with the results of two models, the model based on the PCA-ELM algorithm has better accuracy than that based on ELM.
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