Iron Ore Mixtures Research Articles

Frolov Yu. A., Chukin D. M., Aslamova Ya. Yu. Modern technical solutions for new and reconstructed sinter plants. Report 1. Averaging of iron ore raw materials and preparation of mix components for sintering.

The analysis of the level of technology and equipment of the complex for receiving and averaging iron ore raw materials of sinter plant No. 5 (SP-5) of Magnitogorsk Iron and Steel Works PJSC, commissioned in 2019, was performed. The complex is equipped with modern averaging equipment. Autonomous dosing of iron ore raw material components with lime before averaging, used for the first time at sinter plants in Russia, ensured high quality of mixture averaging with a chemical composition homogeneity of 90%. Due to the absence of a mixing drum in front of the closed warehouse, the specific productivity of SP-5 sinter machines was lower by 8.2% in the cold season than in the warm season. After installing the mixing drum, the homogeneity of iron ore raw materials with lime in chemical composition at the input to it was 82.5%, and at the output – 92.4%. The duration of lime aging in a stockpile for complete lime quenching in wet raw materials was determined to be 7 days. As a result, the productivity of the sinter machines does not depend now on the season. The design averaging of several types of coke breeze has not been implemented, which leads to increased variability of its moisture and ash content. In general, provided that the fuel is averaged, the modernized averaging complex meets modern requirements. The design solutions for SP-5 did not provide for additional crushing of lime of fraction 0–10 mm to 0–3 mm with its feed to the dosing department of the sinter plant. A hammer crusher is installed, the lime is crushed to a fraction of 0–3 mm and fed to the dosing department by pneumatic transport. A rational ratio has been established between the consumption of lime of fraction 0–10 mm entering to the averaging warehouse – 1.5% of the total 5% attributed to the lime content in the iron ore mixture, and the remaining 3.5% of lime of fraction 0–3 mm entering to the dosing department. The specific productivity of the sinter machines has increased by 5.2% compared to the design solution. The SP-5 solid fuel preparation complex, including screening of 0–3 mm fraction on a vibrating screen before crushing, preliminary crushing of the oversize product to 10 mm in a two-roll crusher and final crushing in a four-roll crusher, meets modern requirements. The same applies to typical limestone preparation equipment. The characteristics of the ore yard of the sinter plant of the Yenakiyevo Steel Plant are given for perspective construction of averaging warehouse with the use of modern technical solutions is given.

Effect of reduction behavior from Fe2O3 to FeO on the formation of metallic Fe in multi-stage reduction

The current study investigated the reduction behavior of iron ore using hydrogen in four-stage reduction processes. Reduction reactions from Fe2O3 to Fe3O4 and from Fe3O4 to FeO proceeded at the first and second stages, respectively. The third and fourth stages subsequently reduced FeO to metallic iron. Iron ore mixture of hematite and goethite achieved the final reduction degree to be 87% by multi-stage reduction processes. As the duration of reduction at the first stage was decreased, the final reduction degree was improved. The first reduction stage produced the most stable iron oxides as magnetite, while the second reduction stage corresponded to the reduction condition where wustite is the most stable. Decreasing the duration time of the first reduction stage resulted in the decrease of stable magnetite formation, consequently increasing the surface area of reduced iron ore. The omission of the first reduction stage resulted in the highest degree of final reduction of 95%. Kinetic analyses for each reduction reaction were performed to derive the optimal reduction conditions. The reduction of hematite to magnetite at the initial stage of iron oxide was controlled by diffusion, and the rate-controlling step of reduction was gradually shifted to chemical reaction in the reduction from FeO to metallic iron.

Recycling Blast Furnace Dust as Raw Material in Iron-Making

A large amount of dust is formed as one of the primary by-products during the blast furnace ironmaking process. Iron and carbon are mainly compositions in the dust. Blast furnace dust (BFD) is cycled to protect the environment and recover valuable components. In this study, BFD is used pelletization process with iron ore concentration for raw materials charging to the iron-making furnace. The mixture of BFD and iron ore (30; 40; 50 by mass %) with 2 % bentonite as a binder was used for making pellets. The produced pellets were tested drop strength and fired at 1200 °C for 30 minutes in the atmosphere environment. Fired pellets were examined compressive strength and reduced at 900; 1000; 1100 °C in 30 minutes. Mechanical, porosity and reduction degree properties of reduced pellets were analysed. The results show that green strength and compressive strength are acceptable values. Good porosity is observed when using a high amount of BFD so that it gives a high degree of reduction. XRD, SEM were used for characterization. Iron whiskers were observed in the sample, which was reduced at 1000 °C. It is clearly shown that the pellets using BFD are appropriated for charging to blast furnace as raw materials.

The Origin of Mineral Waste from Constanta Port and the Necessity to Introduce it into the Circular Economy

Abstract Constanta Port is the largest port on the Black Sea. Only here are operated the largest ships that have access through the Bosporus and Dardanelles straits. Of these, the largest tonnage is operated in berths 80 – 84 belonging to COMVEX SA. In the port there are also terminals for operating bulk cargo belonging to SOCEP and Minmetal. During the operation of ships, transport and storage of bulk cargo, basic activities of the terminal, losses of bulk materials occur, which periodically collected are waste because they no longer meet the original characteristics of the goods. According to GD 111/2002, these quantities of materials are called technological losses and are a mixture of iron ore, bauxite, coke and coal. The mineral components of this waste, defined as mineral waste, are from the handled materials, and which are of the highest quality. This quantity cannot be shipped to customers and therefore the respective quantities of goods represent operating and storage losses. Periodically, this mixture must be removed so that the land surfaces on which the stacks of materials are formed remain clean. The production of mineral waste is closely linked to the activity of the Ore Terminal. The mineral mixture from cleaning operations is stored in temporary storage dumps. In addition to the fact that these quantities of goods represent losses, they also represent an impact on the environment. The storage of this waste involves occupying important, available, adjacent areas and sometimes production areas. This also has implications for the operator's handling capacity as it requires additional operations involving energy consumption, labour consumption, vehicle use, etc. In conclusion, this scenario negatively affects the economic and social development of the company operating with bulk materials. Due to the specificity of the bulk cargo handling terminal, between 1991 and until now, significant quantities of mineral waste valued at approx. 650.000 t. Similar wastes are a characteristic of large ports, which transit such bulk goods, such as: Rotterdam – EMO operator – Netherlands, Dunkirk and Sollac sur Mer – France, Tianjin – China.

Effects of process parameters on the growth behavior and granule size distribution of iron ore mixtures in a novel high-shear granulator

Effects of process parameters on the growth behavior and granule size distribution of iron ore mixtures in a novel high-shear granulator

Reduction Reactivity of Low Grade Iron Ore-Biomass Pellets for a Sustainable Ironmaking Process

Currently, fossil fuels are still the primary fuel source and reducing agent in the steel industries. The utilization of fossil fuels is strongly associated with CO2 emissions. Therefore, an alternative solution for green steel production is highly recommended, with the use of biomass as a source of fuel and a reducing agent. Biomass’s growth consumes carbon dioxide from the atmosphere, which may be stored for variable amounts of time (carbon dioxide removal, or CDR). The pellets used in this study were prepared from a mixture of low-grade iron ore and palm kernel shells (PKS). The reducing reactivity of the pellets was investigated by combining thermogravimetric analysis (TGA) and laboratory experiments. In the TGA, the heating changes stably from room temperature to 950 °C with 5–15 °C/min heating rate. The laboratory experiments’ temperature and heating rate variations were 600–900 °C and 10–20 °C/min, respectively. Additionally, the reduction mechanism was observed based on the X-ray diffraction analysis of the pellets and the composition of the reduced gas. The study results show that increasing the heating rate will enhance the reduction reactivity comprehensively and shorten the reduction time. The phase change of Fe2O3 → Fe3O4 → FeO → Fe increases sharply starting at 800 °C. The XRD intensities of Fe compounds at a heating rate of 20 °C/min are higher than at 10 °C/min. Analysis of the reduced gas exhibits that carbon gasification begins to enlarge at a temperature of 800 °C, thereby increasing the rate of iron ore reduction. The combination of several analyses carried out shows that the reduction reaction of the mixture iron ore-PKS pellets runs optimally at a heating rate of 20 °C/min. In this heating rate, the reduced gas contains much higher CO than at the heating rate of 10 °C/min at temperatures above 800 °C, which encourages a more significant reduction rate. In addition, the same reduction degree can be achieved in a shorter time and at a lower temperature for a heating rate of 20 °C/min compared to 10 °C/min.

Investigation into Biomass Tar-Based Carbon Deposits as Reduction Agents on Iron Ore Using the Tar Impregnation Method

Increasing carbon deposits in iron ore to upgrade the reduction rate can be performed by impregnating iron ore in tar. Carbon containing iron ore was prepared from low-grade iron ore and biomass tar, which was generated from palm kernel shell (PKS) pyrolysis using the impregnation method. The optimum condition of the method was investigated by varying the tar-iron ore ratio (1 and 1.5) and impregnation time (0 and 24 h). After the carbonization of the tar–iron ore mixture in a flow-type quartz tubular fixed-bed reactor at 500 °C for an hour, the carbon deposits adhered well to surfaces of all iron ore samples. The carbon deposits increased when the ratio of tar-iron ore was enhanced. The effect of impregnation time on the formed carbon deposit only applied to the tar-iron ore ratio of 1, but it had a weak effect on the ratio of 1.5. The highest carbon content was obtained from the impregnation of a biomass tar–iron ore mixture with the ratio of 1.5 which was directly carbonized. In addition, the high water content of biomass tar affected the reformation of FeOOH at the impregnation within 24 h. Furthermore, the reduction reactivity of the obtained carbonized ore, which was observed using thermogravimetric analysis, was perceptible. The carbon deposits on iron ore were able to demote total weight loss up to 23%, compared to 8% of the dehydrated ore, during the heating process to 950 °C. The carbon content obtained from iron ore impregnation with biomass tar can act as reduction agents, thereby enhancing the reduction reactivity.

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.

Semi-variograms and kriging techniques in iron ore reserve categorization: application at Jebel Wenza deposit

Iron ore is a fundamental raw material for the world steel industry. For the success of mining projects, the average rate of the iron ore content ought to be acceptable to produce steel and cast iron. With irregular useful mineral contents, iron deposits address a problem for Algeria steel industry performance and it makes the operating cost very expensive. In this research, we used the geostatistical interpolation to evaluate the iron ore mixtures in Wenza open cast mine, northeast Algeria. We applied semi-variograms and kriging techniques to interpolate the needed values for mineral resource estimation. Then, we have integrated a mathematical approach to calculate and compare the grade of the sites in operation, with the orders grade. The results showed a significant variability of the iron content in the study area. The variogram revealed a nugget effect of 0.16, a range of 95.05 (m), and 17,329 kriged blocks of 5 × 5 × 7.5 m. We have used the output values of the geostatistical model as input data of the analytical model to set an operating mode of mining activities. Our study proposes to install out a homogenizing stock to correct the iron rate in Wenza deposit and to guarantee the quantity and quality required by the customer.

Effect of Coal Blended on the Physical Properties of Iron Ore Briquette for Direct Reduction Iron

Iron production by using the direct method has been promoted in order to produce iron effectively, low cost, and environmentally safe. The method was optimal requirements with respect to the feed materials especially iron ore, coal as well as a binder. In this study, the experiments were conducted on physical properties of iron ore briquette from Aceh (Indonesia) to analyze its suitability to meet the feed requirements for iron production. The term iron ore briquette refers to the materials compressed under high pressure formed by variable mixtures of iron ore, coal and binders. In the experiments, the physical properties such as the tumbler index (TI), abrasion index (AI) and shatter indices of the iron ore briquette were carried out. The experimental results show that the iron ore briquette blended with coal and using asphalt as a binder has a high tumbler index (TI) or not easily breakable compared to the iron ore briquette using dammar powder as a binder. On the other hand, the blended coal in iron ore briquette with dammar powder as the binder significantly increases the shelter index or easily breakage.

Development and study of protective properties of the composite materials for shielding the electromagnetic fields of a wide frequency range

Composites were shown to be the most promising materials for protection against electromagnetic fields. A technology of magnetic treatment of textile material with magnetic fluid and technology of ultrasonic treatment of a mixture of latex and iron ore concentrate has been developed. This has increased saturation of fibers of the textile material with magnetic fluid nanoparticles, dispersity of the iron ore concentrate, and isotropy of the liquid metal-polymer material. As a result of the use of this technology, the consumption of magnetic fluid for the treatment of the textile material decreased from 45‒50 g/m2 to 35 g/m2 with an improvement of shielding properties. It has been experimentally established that one layer of metal-textile material reduces the magnetic field of industrial frequency by 6 times and the electric field of industrial frequency by 1.5 times. Corresponding figures for the metal-polymer material were 3 and 2. It was found that an electromagnetic field with a frequency of 2.45 GHz is reduced 3.6 times by the single-layer metal-textile material and 5.7 times by the metal-polymer material. It was shown that the metal-textile material with such properties is suitable for the manufacture of personal protective means for personnel operating electrical and radio transmission equipment. Metal-polymeric material is suitable for the manufacture of collective protective means. A calculated evaluation of the effectiveness of protective materials was proposed. It is based on determining the shielding factors of structures of standard shapes. This enables the determination of electrophysical and magnetic properties of the material and their use in the development of protective materials with required shielding factors. The necessity of optimization of shielding factors under conditions of simultaneous influence of electromagnetic fields of heterogeneous sources was substantiated

Slag Formation during Reduction of Iron Oxide Using Hydrogen Plasma Smelting Reduction.

Replacing carbon by hydrogen is a huge step towards reducing CO2 emissions in the iron- and steel-making industry. The reduction of iron oxides using hydrogen plasma smelting reduction as an alternative to conventional steel-making routes has been studied at Montanuniversitaet Leoben, Austria. The aim of this work was to study the slag formation during the reduction process and the reduction behaviour of iron oxides. Furthermore the reduction behaviour of iron ore during continuous feeding was assessed. Mixtures of iron ore and calcined lime with a basicity of 0, 0.8, 1.6, 2.3, and 2.9 were melted and reduced by hydrogen. The off-gas composition was measured during the operations to calculate the process parameters. The reduction parameters, namely the degree of reduction, degree of hydrogen utilisation, produced iron, and slag, are presented. The results of the batch-charged experiments showed that at the beginning of the reduction process, the degree of hydrogen utilisation was high, and then, it decreased over the operation time. In contrast, during the continuous-feeding experiment, the degree of hydrogen utilisation could be kept approximately constant. The highest degrees of reduction and hydrogen utilisation were obtained upon the application of a slag with a basicity of 2.3. The experiment showed that upon the continuous feeding of iron ore, the best conditions for the reduction process using hydrogen could be applied.

Analysis of Cylindrical Briquette Dimension on Total Iron Content and the Degree of Metallization in Direct Reduction Process of Iron Ore and Iron Sand Mixture

Indonesia has abundant resources or raw materials, especially the iron sand raw materials. But, the iron sand processing in Indonesia is still low. Even though, the steel demand in Indonesia is still high. So, the iron sand processing product as raw materials in steelmaking is the solution of it. In this research, the study was conducted by using the variation of briquette dimension of mixture of iron sand and iron ore in Direct Reduction process. The aim of this research is to study the effect of briquette dimension on Fe content and degree of metallization of the Direct Reduced Iron (DRI). First, the iron sand and iron ore were crushed and shieved until pass the 50 mesh standar size. Then, iron sand and iron ore were mixed and briquetted based on the variation of dimension. There are three variations of briquette dimension. Then, the briquettes was reduced at 1250°C for 12 hours. The reduced briquettes then were analyzed using XRD, XRF and degree metallization calculation. The result showed that the dimension of briquette affect the Fe content and the degree metallization of DRI. The dimension of briquette will affect the reductor gas flow in the crucible, so the rate and direction of reduction process of iron oxide will be affected too. The best briquette is Briquette B (7.9 cm for inside diameter, 15.1 cm for outer diameter and 19.5 cm for the height), with 75.02% for Fe total content and 66.52% for degree of metallization. This was due to The briquette B has the most evenly diffused dimension either vertically and horizontally.

Mechanism of improved magnetizing roasting of siderite–hematite iron ore using a synergistic CO–H2 mixture

A fluidized-bed magnetizing roasting–magnetic separation process was selected to treat this type of material. Phase transformations and microstructural changes in the product resulting from magnetizing roasting under different reducing gases (CO, H2, CO + H2) were clarified by vibrating sample magnetometry, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results indicated that the conversion ratio and saturation magnetization of samples roasted in a mixed gas of CO and H2 were higher than those of samples produced under CO or H2 alone. This indicated that synergy of the combined CO and H2 gas had a positive effect on the fluidized-bed magnetizing roasting process. The mechanism and kinetics of the improved magnetizing roasting of a siderite–hematite iron ore mixture under this synergistic CO–H2 system were investigated under isothermal conditions. The results indicated that the apparent activation energies of the reactions of the iron oxides decreased from 37.7 and 17.9 to 15.9 kJ/mol when the roasting atmosphere was changed from pure H2 or CO to a gas mixture of CO and H2, respectively. The mixed CO–H2 gas promoted the conversion ratio of hematite and siderite to magnetite, thereby improving the conversion ratio in the fluidized-bed magnetizing roasting process.

Influence of Agitating Conditions on Agglomeration and Collapse of Iron Ore Mixture

Influence of Agitating Conditions on Agglomeration and Collapse of Iron Ore Mixture

Simulation of the pressure drop across granulated mixtures using a coupled DEM – CFD model

The sinter process converts mixtures of iron ore, iron ore fines and fluxes into a fused aggregate (sinter) that is used as burden material in the blast furnace. The rate of this process is predicted by measuring the pressure drop across the green granulated mixture before ignition. A lower pressure drop corresponds with a higher permeability resulting in a higher sinter rate. The addition of fine material, such as concentrate or concentrate agglomerated into micropellets, to the sinter mixture affects the pressure drop. This study numerically predicts the pressure drop over several granulated mixtures in order to reduce the number of experimental measurements. The pressure drop was studied both experimentally using a pot grate and by coupled DEM (Discrete Element Method) – CFD (Computational Fluid Dynamics) simulations. The validation of the model was performed by comparing the measured and numerical values of the pressure drop across glass beads 3 and 6 mm in diameter respectively. The simulation of the pressure drop was extended to granulated mixtures that contain 0–40% concentrate or micropellets. DEM was also used to numerically simulate iron ore granules and relate their mechanical behaviour to particle size distribution, shape, friction coefficient, Young’s modulus and adhesion force.

Iron Metallurgy via Concentrated Solar Energy

Environmental protection is deeply rooted in current societies. In this context, searching for new environmentally friendly energy sources is one of the objectives of industrial policies in general, and of the metallurgical industries in particular. One of these energy sources is solar energy, which offers a great potential in high temperature applications, such as those required in metallurgy processes, when properly concentrated. In this paper, we propose the utilization of concentrated solar energy in ironmaking. We have studied the utilization of concentrated solar thermal in the agglomeration of iron ore mixtures and in the obtaining of iron via reduction with carbon (and coke breeze). The results from the experiments show the typical phases of the iron ore sinters and the presence of iron through smelting reduction.

Investigation of Balling Characteristics of Mixture of Iron Oxide Bearing Wastes and Iron Ore Concentrates

Iron oxide bearing wastes in form of dust and sludges are hard to handle because of their micron size particles and moisture content in case of sludge. More often they are stockpiled in large quantities that can occupy large area of real and agricultural estates and cause pollution. Balling or palettization, an agglomeration process was used to process the wastes in order to address the problem of micron size particles and to make them fit for recycling back into metallic iron production route like blast furnace. Balling or green pelletization is the process of forming nearly spherical shaped granules by tumbling moistened particulates with or without binders in balling drums or discs disc. For a pellet to be effective either for being transported or for being recycled in blast furnace to produce metallic iron without disintegrating to dust its balling characteristics should measure up to required standard. Most outstanding of those balling characteristics include Drop Number, Green or Wet Compression Strength, Dry Compression Strength, Abrasion and Tumbler Indices. In this work iron oxide bearing wastes was mixed with iron ore concentrates in various proportions. These mixes were taken through balling or wet pelletization process using Radicon Balling Disc. The balls formed balls were taken through Drop number tests adopting the Free Fall method, where balls are made to fall freely from a height of 50 mm on steel surface, Green compression and Dry compression tests using a 5 kN Universal Testing Machine (INSTRON Corp., model 1011 UK) System while Abrasion and Tumbler indices tests were conducted using Tumbler Index cylinder or drum and adopting ASTM method. It was found that Drop number as high as 7.8 times, Green compression strength and Dry compression strength up to 11.7 N/pellet and 25.99 N/pellet respectively were attained by some of the pellets. The Tumbler and Abrasion indices recorded were up to above 95% and 5% respectively. These values are higher than the minimum recommended.

Simplified Core-Shell Model of Biochar - Iron Ore Mixture for Calculation of Effective Permittivity and Permeability

The simplified model of biochar-bearing iron ore with binder was studied. It was considered a mixture of two types of core-shell particles, ‘iron ore – binder’ particles and ‘biochar – binder’ particles. The expressions to calculate complex effective permittivity and permeability was derived by effective medium approximation (EMA). The corresponding dependencies on volume fraction of iron ore in the mixture are provided.

Research on the Post-reaction Strength of Iron Coke Hot Briquette Under Different Conditions

The utilization of iron coke hot briquette (ICHB) prepared by carbonizing iron ore–coal composite agglomerate made from hot-pressing the mixture of iron ore and blended coal has been considered to be an effective countermeasure to improve blast furnace ironmaking reaction efficiency and to reduce carbon emissions. The strength of ICHB after gasification reaction is overestimated by the Chinese National Standard (GB/T 4000/2008, equivalent to the Nippon Steel Corporation method) and should be evaluated by different methods. In this study, the post-reaction strength of ICHB with the addition of different ratios of iron ore under various conditions was experimentally investigated to illuminate the degradation mechanism of ICHB reacted with CO2. The results showed that, with increasing the iron ore addition ratio from 0% to 20%, the reactivity of ICHB reacted with CO2 at 1100°C for 2 h is remarkably increased, due to the catalytic effect of metallic iron in ICHB, while the post-reaction strength is distinctly decreased. Furthermore, stopping at the weight loss ratio of 20%, the strengths of ICHB after reaction at 1100°C under a CO2 atmosphere and a CO2/CO=1/1 atmosphere are clearly reduced, from 89.74% to 75.93% and from 85.24% to 73.65%, respectively. Meanwhile, the post-reaction strength of ICHB under CO2 is greater than that obtained under CO2/CO=1/1 atmosphere, since there is more time for the reaction gas to diffuse from the exterior to the interior of the ICHB under the latter condition. Additionally, the post-reaction strength of ICHB decreases with increasing weight loss ratio regardless of the reaction gas composition; however, it can be maintained at a high level.