Ore Fines Research Articles

Application of machine learning algorithms for prediction of sinter machine productivity

Sinter machine productivity is key techno-economic parameter of an integrated steel plant. It depends upon the composition of different constituents like iron ore fines, flux and coke breeze which are agglomerated to produce sinter for blast furnaces. It is difficult to assess the interdependence of these constituents and their effect on sinter productivity through physical experimentation. In this paper, machine learning and data analytics approach have been applied to predict the sinter machine productivity. Industrial data of sinter machine productivity from an integrated steel plant have been collected. Linear regression and artificial neural network (ANN) models were developed to predict sinter machine productivity with the composition of constituent materials of the agglomerate as model inputs. The ANN model, developed in the present work, agrees well with measured sinter machine productivity. Sensitivity analysis identified that, percentage of MgO in flux and CaO in sinter have a highly detrimental effect whereas total Fe content in iron ore fines and percentage of SiO 2 in sinter have the most favorable impact on sinter machine productivity.

Numerical simulation of the effect of priming methods on result of ore fragmentation in fan-patterned long hole blasting and its application

Fan-pattern long hole blasting is a common method which is widely applied in the sublevel or level mining methods in deposits in which the thickness of ore body is thick and the dip of ore body is steep and the country rocks are comparatively hard. The effect of priming methods on result of ore fragmentation is very important and numerically analyzing its mechanism has a theoretical and practical significance. In this paper, we investigated the damage and fragmentation grain size of ore body in according to the priming methods such as collar, middle and bottom priming by using Ansys Autodyn in detail. The simulation result showed that the producing rate of fine ore and boulder were 9.4% and 36.7% in the collar priming and 5.6%, 26.3% in the middle priming and 5.5% and 23.0 % in bottom priming respectively. This shows that the bottom priming method is more advantageous than the others. The practical design for field application of the fan-pattern long hole blasting was carried out by JKSimblast and the expected result has achieved.

Metallurgical Research and Its Contribution to Industrial Development

Metallurgical Research and Its Contribution to Industrial Development

Effect of TiO2 on the Sintering Behavior of Low-Grade Vanadiferous Titanomagnetite Ore.

Low-grade vanadiferous titanomagnetite ore (LVTM) is as an important mineral resource for sintering ore manufacturing. Furthermore, TiO2 has a significant effect on the sintering process of iron ore fines. The effects of TiO2 on the metallurgical properties, microstructure, and mineral composition of LVTM sinter were investigated by sintering pot tests, X-ray diffraction (XRD), scanning electron microscopy (SEM), and mineral phase microanalysis. The results were as follows: as the TiO2 content increased from 1.75% to 4.55%, the flame front speed and productivity decreased, while the reduction degradation index (RDI) and softening properties deteriorated. In addition, the tumbler index (TI) values reached a maximum at TiO2 = 1.75%. In addition, with increasing TiO2 content, an increase in the magnetite and perovskite phase, and a decrease in calcium ferrite and hematite were found with an increase in TiO2 content. Thus, the lower the TiO2 content, the better the quality of the sinter.

Reduction Kinetics of Fine Hematite Ore Particles in Suspension

Suspension reduction kinetics of hematite ore particles at 1710 K to 1785 K was described by the Johnson-Mehl-Avrami-Kolmogorov model with Avrami exponent of 1.405. The apparent activation energy is 105.5 kJ mol−1 with the rate determining step of nucleation and growth. The reduction degree of the hematite at the endpoint is a linear function of temperature and the logarithmic oxygen potential of the reacting gas. A peak function of reaction rate constant with particle size has been verified in this work, and the maximum value of the reaction rate is located at around 85 µm particle size. The influence of heat transfer on the reaction process has been evaluated. The results suggest that the heating-up process for large particles, 244 µm particles, for instance, cannot be ignored. It can retard the reaction rate compared to small particles. Normally, the reaction rate constant decreases linearly with the increase of ln[p(O2)] of the reacting gas mixture. However, 95 vol pct CO2 in the reacting gas can accelerate the reaction rate of thermal decomposition of hematite due to the emissivity of CO2 gas. It results in a higher reaction rate of 110 µm particles in 95 vol pct CO2-containing gas than that in other less CO2-containing gases.

Non-Isothermal Reduction Kinetics of Iron Ore Fines with Carbon-Bearing Materials

This study investigates the non-isothermal reduction of iron ore fines with two different carbon-bearing materials using the thermogravimetric technique. The iron ore fines/carbon composites were heated from room temperature up to 1100 °C with different heating rates (5, 10, 15, and 20 °C/min) under an argon atmosphere. The effect of heating rates and carbon sources on the reduction rate was intensively investigated. Reflected light and scanning electron microscopes were used to examine the morphological structure of the reduced composite. The results showed that the heating rates affected the reduction extent and the reduction rate. Under the same heating rate, the rates of reduction were relatively higher by using charcoal than coal. The reduction behavior of iron ore-coal was proceeded step wisely as follows: Fe2O3 → Fe3O4 → FeO → Fe. The reduction of iron ore/charcoal was proceeded from Fe2O3 to FeO and finally from FeO to metallic iron. The reduction kinetics was deduced by applying two different methods (model-free and model-fitting). The calculated activation energies of Fe2O3/charcoal and of Fe2O3/coal are 40.50–190.12 kJ/mol and 55.02–220.12 kJ/mol, respectively. These indicated that the reduction is controlled by gas diffusion at the initial stages and by nucleation reaction at the final stages.

Modelling of Defluidization of ZrO<sub>2</sub>/Fe Particles in High Temperature Gas Fluidization: Influence of Fe Contents

The contents of Fe on the surface of iron ore fines had a great influence on the fluidization behavior during high temperature fluidized bed reduction, which would cause defluidization when exceeding a critical value. In this paper, simplistically, ZrO2/Fe particles with different Fe contents on the surface were used as raw materials. Through modification of previous models, a quantitative relationship was established to predict the defluidization temperature of ZrO2/Fe particles with different Fe contents, and the calculation results corresponded well with the experimental data obtained from the defluidization test. The model in this paper firstly explained the dependence of defluidization behavior on the contents of Fe in high temperature gas fluidization, and it could well predict the metallization degree of commercial iron ore fines when defluidization occurred during fluidized bed reduction. Therefore, the model could be used as a reference to select suitable operating conditions for treating fine iron oxide particles in high temperature gas fluidization processes, such as direction reduction and chemical looping.

Effect of BaSO4 on phase composition and sintering process of iron ore fines

Effect of BaSO4 on phase composition and sintering process of iron ore fines

Effect of K and Na on reduction swelling performance of oxidized roasted briquettes

Abstract The presence of potassium oxide (K2O) and sodium oxide (Na2O) causes high reduction swelling of pellets of Bayan Obo iron concentrate during reduction and thus affects the permeability of blast gases during blast furnace operations. The influencing mechanism of K2O and Na2O on the swelling behavior of reduction reactions (1) Fe2O3 → Fe3O4, (2) Fe3O4 → Fe x O, and (3) Fe x O → Fe was researched by adding (K2O + Na2O) to Australian fine ore briquettes. The mineral composition and structure of the briquettes, as well as the reduction swelling after the three reactions coupled with the morphology and lattice parameters of the reduced products, were studied. From the results, the swelling index with 0.6% (K2O + Na2O) added was 8.52%, 7.91%, and 33.81%, respectively, and without were 12.36%, 3.27%, and 12.61%, respectively, for the three reactions. The swelling index of the first reaction (Fe2O3 → Fe3O4) is reduced because alkali metal suppresses crystal cracking. The swelling mainly occurs at the third stage (Fe x O → Fe), because K2O and Na2O enhance the oriented growth of iron whiskers, as well as make them smaller. Crystal transformation does not occur at the second stage (Fe3O4 → Fe x O) and the reduction swelling is small, but the swelling index of the briquettes with added with K2O and Na2O increases (7.91% compared to 3.27%). The main reason is that the alkali metal reduces the melting point of the slag phase and promotes the cascade crystallization of FeO. Therefore, the abnormal swelling of briquettes caused by K and Na is mainly caused by the growth of iron whiskers at the third stage.

The Efficient Improvement of Original Magnetite in Iron Ore Reduction Reaction in Magnetization Roasting Process and Mechanism Analysis by In Situ and Continuous Image Capture

Magnetization roasting followed by magnetic separation is considered an effective method for recovering iron minerals. As hematite and magnetite are the main concomitant constituents in iron ores, the separation index after the magnetization roasting will be more optimized than with only hematite. In this research, the mechanism of the original magnetite improving iron ore reduction during the magnetization roasting process was explored using ore fines and lump ore samples. Under optimum roasting conditions, the iron grade increased from 62.17% to 65.22%, and iron recovery increased from 84.02% to 92.02% after separation, when Fe in the original magnetite content increased from 0.31% to 8.09%, although the Fe masses in each sample were equal. For lump ores with magnetite and hematite intergrowth, the method of in situ and continuous image capture for microcrack generation and the evolution of the magnetization roasting process was innovatively examined with a laser scanning confocal microscope (LSCM) with confocal technology and 3D morphologic technology for the first time. The naturally uneven areas, protogenetic pore edges, and magnetite and hematite edges provided active sites for reduction reactions. The microcracks gradually evolved from the lump ore surface and the edges of magnetite and hematite, which had a direct connection with the efficient improvement in ore reduction.

Briquetting of porous alumina-containing materials with organic binders

Waste from corundum production in the form of porous alumina sludge is a promising material for providing ferrous metallurgy with cheap alumina-containing slag-formers. However, the direct feeding of the pulverized materials to the steelmaking furnace generally results in a significant carryover of such materials with waste gases. This paper considers the possibility of making briquettes from porous sludge of corundum production by cold briquetting using various common binders (molasses, cement, powder based on polyacrylamide, emulsion based on polyvinyl acetate). A comparison of the features of cold briquetting of powdered porous materials (slimes from the production of electrocorundum) and dispersed crystalline materials (fines of chrome ore) was made. Experiments were carried out to determine the impact strength of briquettes on different binder (“cold” strength) and tests to determine the “hot” strength (by the “thermal shock” test method). The authors have determined the consumption of the binder required to obtain satisfactory characteristics of briquettes from corundum slimes and from chrome ore fines. A technique has been developed and a mechanism for the binding of particles of loose and crystalline materials has been determined during briquetting using polyacrylamide powder. The destruction of a briquette of loose materials occurs mainly along the grains of the most porous material, and briquettes of crystalline materials are destroyed along the boundaries of the grains glued with a binder. For porous materials, the binder consumption increases more than twice as compared to briquetting on the same binder crystalline bodies of a fine fraction, and the binder must necessarily impregnate the entire volume of the porous material.

Полнота использования ресурсов недр и здоровье населения горнодобывающего региона

The study of the biochemical status of the population revealed a decrease in the antiradical activity and inhibition of the oxidase activity. The dynamics of glutathione reductase activity was established, which is a consequence of metal-induced intoxication. Indicators of the health status of the population of mining areas correlate with the number of pollutants entering the environment and the size of the contaminated area. The advances development of metal-induced oxidative stress was established, which reduces the quality and duration of human life. The health of the inhabitants of the mining region and the loss of metals during the extraction of ores depend on the share of dust and fine ore fractions, which, during enrichment end up in waste and are carried by water and wind. It is shown that the minimization of chemical pollution of the environment with metals is possible with the use of technologies that limit the contact of ores with the environmental ecosystems. At the same time, aggressive small fractions do not enter the habitat, and the extraction efficiency increases due to the recovery of the previously lost metals. The technology of leaching metals in the underground blocks was industrially used for more than half a century ensuring in some cases a large share of the production capacity of the enterprises. Leaching in the disintegrators passed the stage of laboratory research on the Sadon polymetallic ores and ferruginous quartzites of the Lebedinskoye deposit. The results of study of the quality of mined ores use, including the effect of dust and fine ore fractions on the health of the population are consistent with the conclusions of the researchers. It is concluded that there is a correlation between the health of residents of residential areas and the quality of mined ores use. Therefore, expanding the scope of metal leaching technologies is the key in solving the problems of rational use of subsoil resources and ensuring the safety of workers.

A forecast model of the sinter tumble strength in iron ore fines sintering process

Tumble Strength (TS) of iron ore sinter, affected by numerous factors, is considered as a vital performance to assess sinter quality for blast furnace (BF) iron-making. For the sake of providing a credible manipulative strategy of TS in sinter production, we built a mathematical model using artificial neural network, the so-called ANN technology, to predict the sinter TS. In building process of this model, the principal component analysis method (PCA) and the genetic algorithm method (GA) were introduced to optimize the ANN model so that we could obtain an accuracy model. Moreover, the sensitivity of possible influence factors was analyzed to pick up their detailed influence on TS. The calculating data demonstrate that the forecast precision of the model here is 95.1%, signifying that this model is available to describe the sinter TS basing on the initial values of numerous influence factors.

Reduction Mechanism of Fine Hematite Ore Particles in Suspension

In order to understand the pre-reduction behaviour of fine hematite particles in the HIsarna process, change of morphology, phase and crystallography during the reduction were investigated in the high temperature drop tube furnace. Polycrystalline magnetite shell formed within 200 ms during the reduction. The grain size of the magnetite is in the order of magnitude of 10 µm. Lath magnetite was observed in the partly reduced samples. The grain boundary of magnetite was reduced to molten FeO firstly, and then the particle turned to be a droplet. The Johnson-Mehl-Avrami-Kolmogorov model is proposed to describe the kinetics of the reduction process. Both bulk and surface nucleation occurred during the reduction, which leads to the effect of size on the reduction rate in the nucleation and growth process. As a result, the reduction rate constant of hematite particles increases with the increasing particle size until 85 µm. It then decreases with a reciprocal relationship of the particle size above 85 µm.

Influence of the Application of a Sound Field on the Flow State Reduction of Newman Fine Iron Ore

To improve the fluidization of the fluidized bed in ironmaking, the particle loss and bonding during the fluidized bed are largely removed by changing the properties of the particle surface or by adding an external field. Currently, the vibration, magnetic, sound, and electric fields have been commonly applied to provide external energy to the fluidization bed systems. In this work, experiments are conducted for Newman ore particles under the application of an external sound field at a reduction temperature of 1023 K, linear velocity of 0.6 m/s, duration of 60 min, pressure of 0.2 MPa, and typical mineral powder particle size of 80–100 mesh, with H2 used as the reducing gas. The power and frequency of the ultrasonic field are varied, and the effects of sound field are evaluated by the comparative analysis of the effects of the sound field with different powers of sound fields and application times on the metallization rate and binder ratio of the samples. The acoustic pressure and frequency were varied to determine the critical speed and influence on the bed and to study the interactions of the iron ore powder particles in the sound field and the bonding mechanism of the particles. The results of this paper reproduce the actual particle fluidization process and analysis of the interactions of the particles in the sound field well. The influence of the external sound field on the gas-solid flow was studied from the perspective of macroscopic motion and force analysis.

Synergistic utilization of diverse industrial wastes for reutilization in steel production and their geopolymerization potential

Recycling wastes back into a manufacturing process, or into a separate product, is an important challenge. The primary aim of this work was to combine wastes from the steel industry, the galvanizing industry and the pulp and paper industry to form two new useful products. The steel industry generates the wastes red dust, mill scale, blast oxygen furnace slag and iron ore fines. Galvanizing industrial facilities dispose of sulfuric acid contaminated with iron. The pulp and paper industry produces the byproduct black liquor, which is high in lignin. Inserting these wastes as resources into the steel industry, or as stand-alone products, could reduce the need for virgin materials. The main methodology of the work was three-fold. First, spent sulfuric acid was used to precipitate the lignin from black liquor. Second, this lignin was combined with steel industry wastes and geopolymeric materials to make briquettes, a sustainable reducing material for steelmaking furnaces. Briquettes contained red dust, mill scale, blast oxygen furnace slag, iron ore fines and lignin precipitated from black liquor with spent sulfuric acid. Key research findings of compressive strength and weight loss testing showed the briquettes to be feasible for steel-making furnace use. Third, these steel industry wastes were investigated as a partial fly ash replacement in geopolymers. Main research findings were that compared to the control geopolymer, these geopolymer samples improved compressive strength and gave similar workability. Thus, the investigated wastes have the potential to both increase recycling in the steel industry and to improve geopolymeric products.

Design modification of iron ore bearing transfer chute using discrete element method

Purpose The dryer feed chute of the pellet plant plays an important role in the pelletizing process. The chute discharges sticky and moist iron ore fines (<1 mm) to the inline rotary dryer for further processing. Since the inception of the installation of the dryer feed chute, the poor flowability of the feed materials has caused severe problems such as blockages and excessive wear of chute liners. This leads to high maintenance costs and reduced lifetime of the liner materials. Constant housekeeping is needed for maintaining the chute and reliable operation. The purpose of this study is to redesign the dryer feed chute to overcome the above challenges. Design/methodology/approach The discrete element method (DEM) has been used to model the flow of cohesive materials through the transfer chute. Physical experiments have been performed to understand the most severe flow conditions. A DEM material model is also developed for replicating the worst-case material condition. After identifying the key problem areas, concept designs were proposed and simulated to assess the design improvements to increase the reliability of chute operation. Findings Flow simulations correlated well with the existing flow behavior of the iron ore fines inside the chute. The location of the problematic areas has been validated with that of the previously installed chute. Subsequently, design modifications have been proposed. This includes modification of deflector plate and change in slope and cross-section of the chute. DEM simulations and analysis were conducted after incorporating these design changes. A comparison in the average velocity of particle and force on chute wall shows a significant improvement using the proposed design. Originality/value Method to calibrate DEM material model was found to provide accurate prediction and modeling of the flow behavior of bulk material through the real transfer chute. DEM provided greater insight into the performance of the chute especially modeling cohesive materials. DEM is a valuable design tool to assist chute designers troubleshoot and verify chute designs. DEM provides a greater ability to model and assess chute wear. This technique can help in achieving a scientific understanding of the flow properties of bulk solids through transfer chute, hence eliminate challenges, ensuring reliable, uninterrupted and profitable plant operation. This paper strongly advocates the use of calibrated DEM methodology in designing bulk material handling equipment.

Low-carbon production of iron and steel: Technology options, economic assessment, and policy

Summary Given increased urgency to transition the global economy to net-zero CO2 emission, governments and industry have increased focus on decarbonizing hard-to-abate sectors, including steel making, which contributes roughly 6% of global CO2 emission and 8% of energy-related emission (including power consumption emission). This paper reviews current global iron and steel production and assesses available decarbonization technologies, including hydrogen injection, solid biomass substitution, zero-C electricity substitution, carbon capture and storage (CCS) retrofit, and combinations of these decarbonization approaches. Blast furnace-basic oxygen furnace (BF-BOF) dominates production (71%) and is particularly stubborn to any decarbonization technology. Direct reduced iron to electric arc furnace (DRI-EAF) production is 5% and growing, it appears to have better decarbonization potential to move toward net-zero. Secondary steel production using mainly steel scrap in electric arc furnace (EAF-scrap) is 24% of global production and has both the lowest energy consumption and is technically simplest to decarbonize through electrification but is limited in market share to recycled steel capacity. Of the options assessed, blue hydrogen, carbon neutral biomass, and CCS appear to have the lowest cost and highest technical maturity. However, no single approach today can deliver deep decarbonization to the iron and steel industry and all approaches lead to substantial production cost increase. No uniform ideal solution exists, and different geographies, infrastructure, and economies will determine the local optimum solution with viability and cost. Policy measures will be required to provide financial incentives for decarbonization and to avoid unwelcome outcomes such as emissions leakage or job loss.

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.

Quality and productivity enhancement of sintering process using correlation-based online permeability by infrared-based flow measurement technique

ABSTRACT Sinter is the most preferred metallic burden for modern-day blast furnaces. It is produced by agglomeration of iron ore fines in sinter machine. Sintering process depends on airflow through the sinter bed under high suction. The airflow through the sinter bed is measured by sinter bed permeability and has direct correlation with sinter productivity. Permeability can be determined by different ways. Among these methods, permeability detection by measuring the airflow through granular sinter bed by placing the instrument in the static wind box is very well known. But there is a challenge due to multiphase and turbulent conditions in the wind box.Infrared-based flow measurement technique has been used to measure flow. Therefore, this flow has been used to get permeability in the form of JPU (Japanese Permeability Unit). Productivity increases by 4% in spite of decrease in mean particle size of iron ore by 3.4% for a fixed time duration.