Sponge Iron Research Articles

Investigation of the effect of geometrical shape of sponge iron on the operating parameters of the induction furnace

ABSTRACT Today, smelting sponge iron in induction furnaces is one of the main processes in steel production. In this process, raw materials (sponge iron and scrap) are melted by inducing electromagnetic currents. Sponge iron has small cavities and is porous. One of the effective parameters on the performance of induction furnace in melting sponge iron is the geometric shape of sponge iron. Its usual state is spherical, which after charging into the furnace, the gap spaces between them remain. These chat spaces have a negative effect on the performance of the furnace. In this study, in addition to ordinary (spherical) sponge iron, other forms of sponge iron including crushed, conical and cylindrical were also made. After melting different samples with scrap, the device parameters of the induction furnace were studied. The results showed that the use of crushed sponge iron leads to a 28% reduction in melting time and a 26% reduction in energy consumption. By changing the geometric shape of the sponge iron as a result of improving the efficiency of the induction furnace, the profitability of steelmaking is significantly improved.

Use of sponge iron dosing in baffled subsurface-flow constructed wetlands for treatment of wastewater treatment plant effluents during autumn and winter

Sponge iron (SI) is widely used in water treatment. As effluents from wastewater treatment plant (WWTP) require advanced treatment methodology, three forms of constructed wetlands (CWs): wetlands with sponge iron (SI), copper sulfate modified sponge iron (Cu/SI), and sponge iron coupled with solid carbon sources (C/SI), have been investigated in this paper for the removal effects of organic matter and nutrients in WWTP effluents, and the corresponding mechanisms have been analyzed. The results showed the effect of baffled subsurface-flow constructed wetland (BSFCW) with SI dosing to purify the WWTP effluents after the stable operation. The water flow of this BSFCW is the repeated combination of upward flow and downward flow, which can provide a longer treatment pathway and microbial exposure time. The average removal rates of total inorganic nitrogen (TIN) were 27.80%, 30.17%, and 44.83%, and the average removal rates of chemical oxygen demand (COD) were 19.96%, 23.73%, and 18.38%. The average removal rates of total phosphorus (TP) were 85.94%, 82.14%, and 83.95%. Cu/SI improved the dissolution of iron, C/SI improved denitrification, and a winter indoor temperature retention measure was adopted to increase the effectiveness of wetland treatment during the winter months. After comprehensively analyzing X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and two-dimensional numerical simulation diagrams, a plausible conjecture that microbes use electrons from SI for autotrophic denitrification is presented. Moreover, the stress effect of wetlands dosed with SI on plants decreased stepwise along the course since C/SI used on wetlands had less impact on plant stress.

A systems dynamics simulation model of a steel supply chain-case study

Considering the complexity, interactions, and dynamics that permeate the Supply Chain (SC), computational modeling and simulation promote determining the system's behavior and decision-making. Among simulation techniques, system dynamics (SD) investigate on recognition of variables and their dynamic behavior trend throughout time in the SC. This paper presents a comprehensive SD model related to upstream steel SC management up to four echelons: concentrate, pellet, sponge iron, and steel. The model noticed Causal-Loops Diagrams (CLD) and Stock-Flow Diagrams (SFD) and provided a simulation framework. The robustness of the proposed model was evaluated by implementing the defined model in a multi-echelon steel complex in Iran. Various scenarios were analyzed applying stochastic simulation to include selected random variables. Iron ore grade and tonnage play the most critical role in the network’s performance. With an approximately 4% increase in the iron ore grade, steel production costs decreased 2.4%. The influence of the simultaneous uncertainty in iron ore grade and iron ore supply in the range of extreme levels of actual historical data resulted in an increase and decrease of +14% and −32% on the total steel production costs, respectively. Furthermore, removing energy subsidies and increasing five times in price results in a rise in total expenses up to 60% and a fall in the marginal profit up to 48%.

A study on pollution sensitive sponge iron based production transportation model under fuzzy environment

Over the last few years, sponge iron-based production transportation and pollution problems for major sponge iron producing countries are triggering a critical issue. The excess of marginal pollution from production industries and their disintegration takes drives towards the change of policymaking. The sustainable development of any country signifies the reduction of biohazards, which in turn improves the health index and livelihood status of people across the world. Keeping this in mind, a cost depreciation problem for the bi-layer integrated supply chain model has been built up. We consider the functional dependencies among all considerable decision variables like production rate, consumption rate which leads to the pollution rate of different countries exclusively. In this study, we have shown how production and rail freight transport relates to pollution. To draw several graphs and numerical computations we use MATLAB software and LINGO software via solution algorithm respectively. The comparative study has been presented using general fuzzy as well as cloudy fuzzy systems. Lastly, we have justified our proposed model using sensitivity analysis along with graphical interpretation.

Enhanced nitrate removal and nitrogen-selective conversion mechanism of a combined sponge iron/biochar/manganese sand system

To find a method for efficient removal and conversion of inorganic nitrogen compounds in three reduction systems, which are the sponge iron (s-Fe0)，the sponge iron + biochar (s-Fe0/BC) micro-electrolysis system and the sponge iron + biochar + manganese sand (s-Fe0/BC/MS)-enhanced micro-electrolysis system, the studies have been completed on the conditions of different material ratios and initial pH. When the initial pH is 7, the nitrate removals reached to 7.6%, 61.5% and 80.3%, the nitrogen ratio of products reached to 5.8%, 22.4% and 38.3% respectively in s-Fe0, s-Fe0/BC (3:1) and s-Fe0/BC/MS (6:2:1) systems. The s-Fe0/BC/MS system was the best at nitrate removal over a wide pH range (2−12). At the same time, the nitrogen selectivity in the s-Fe0/BC/MS system was always better than that in other two systems. The X-ray photoelectron spectroscopy (XPS) results showed that the addition of manganese sand could enhance the ratio of Fe3O4 in the sponge iron surface oxide, reduce the passivation of the sponge iron surface and accelerate the electron transfer rate. As a catalyst for the corrosion of sponge iron, manganese sand can increase the corrosion of sponge iron and enhance the micro-electrolysis role between iron and carbon.

Kinetics Analysis of Steam Reforming of Methane on Sponge Iron

The kinetics of steam reforming of methane catalyzed by sponge iron was studied at temperatures between 875°C and 1050°C. Results shows that sponge iron acts as a catalyst and methane conversion is increased in higher temperatures and with a higher H2/H2O ratio in the inlet gas. A kinetic model based on chemical reaction control fits well the experimental data up to methane conversion of 0.5 with an apparent activation energy of 258 kJ/mol. Pore diffusion limits the reaction rate more intensely at higher conversions of methane, higher temperatures, and larger particle size (from 9 to 17 mm). Two types of industrial pellets were compared showing that microstructural properties such as porosity, pore size, and grain size impact reduction rate with hydrogen and the catalytic property of the obtained sponge iron.

Applications of Sponge Iron and Effects of Organic Carbon Source on Sulfate-Reducing Ammonium Oxidation Process.

The typical characteristics of wastewater produced from seafood, chemical, textile, and paper industries are that it contains ammonia, sulfate, and a certain amount of chemical oxygen demand (COD). The sulfate-reducing ammonium oxidation process is a biochemical reaction that allows both ammonia and sulfate removal, but its low growth rate and harsh reaction conditions limit its practical application. Due to the adsorption properties of the iron sponge and its robust structure, it provides a suitable living environment for microorganisms. To reduce the negative impact on the environment, we employed 4.8 kg of sponge iron in a 2.0 dm3 anaerobic sequencing batch reactor (ASBR). We investigated the effects of the type and concentration of carbon sources on the performance of the sulfate-reducing ammonium oxidation (SRAO) process. The results demonstrated that during a start-up period of 90 days, the average ammonium removal efficiency and the sulfate conversion efficiency of the reactor containing the sponge iron were 4.42% and 8.37% higher than those of the reactor without the sponge iron. The addition of the sponge iron shortens the start-up time of this greenhouse gas-free denitrification process and reduces future costs in practical applications. The removal of total nitrogen (TN) significantly increased after adding organic carbon sources and then declined sharply, while the most considerable reduction of ammonium removal efficiency from 98.4% to 30.5% was observed with adding phenol. The performance of the group employing glucose as the carbon source was recovered on the 28th day, with the average ammonium removal efficiency increasing from 49.03% to 83.5%. The results of this simulation study will help the rapid start-up of SRAO in the water treatment industry and can precisely guide the application of the SRAO process for wastewater containing different organic carbon sources.

On iron reduction from magnetite by gaseous reducing agents

The chemical process of iron reduction from magnetite by gaseous reducing agents is the basis of MIDREX technology implemented at the Oskol Electrometallurgical Plant (OEMK). In the paper, this process was modeled using the TERRA software package developed at the Bauman Moscow State Technical University. During the simulation, thermodynamic system Fe‒С‒О‒Н was analyzed at constant temperature (900 °C) and gas pressure (0.2026 MPa). Mixtures of carbon monoxide and hydrogen in different ratios, as well as individual components of natural hydrocarbon gases, were used as reducing agents. The chemical compositions of reducing agents were estimated by the gross formula СрОrHq , where p, r and q are stoichiometric coefficients. The results of the calculations were the expenses of the reducing gas m, necessary for the complete iron reduction from magnetite, which corresponded to the degree of iron metallization φ = 1. In the future, the values m were used to evaluate the reducing abilities of various gas mixtures, and the values of φm – to determine the required expenses of these mixtures for iron reduction. Subsequent analysis showed that the machine calculation of the value m can be approximated with a small error (up to 0.001) by the formula where mC and mH are the partial costs of carbon and hydrogen for iron reduction, respectively, and mO is the partial oxygen consumption for iron oxidation. It was also established that the parameters of mC and mH depend on the process temperature and are interrelated in accordance with the equation where K is the chemical equilibrium constant of the “water gas reaction” CO + H2 O = CO2 + H2 , simultaneously occurring in the gas phase. The mO parameter is actually a constant independent of temperature and numerically equal to the value of (–4/3) moles per 1 mole of iron. The arguments of partial costs can also be characteristic molecular compounds accompanied with appropriate stoichiometric coefficients. In the practice of OEMK, natural gas consumption V is taken into account, measured in cubic meters per ton of sponge iron. The forecast of this value can be performed using the formula: In general, the proposed calculation algorithm of the chemical process can be correctly applied in the temperature range of 800 – 900 °C. Possible variations in the gas working pressure will not require significant adjustments in the calculation results.

Removal of microcystin (MC-LR) in constructed wetlands integrated with microbial fuel cells: Efficiency, bioelectricity generation and microbial response

Microcystins (MCs) pollution caused by cyanobacteria harmful blooms (CHBs) has posed short- and long-term risks to aquatic ecosystems and public health. Constructed wetlands (CWs) have been verified as an effective technology for eutrophication but the removal performance for MCs did not achieve an acceptable level. CWs integrated with microbial fuel cell (MFC-CWs) were developed to intensify the nutrient and Microcystin-LR (MC-LR) removal efficiencies in this study. The results indicated that closed-circuit MFC-CWs (T1) exhibited a better NO3−-N, NH4+-N, TP and MC-LR removal efficiency compared to that of open-circuit MFC-CWs (CK, i.e., traditional CWs). Therein, a MC-LR removal efficiency of greater than 95% was observed in both trials in T1. The addition of sponge iron to the anode layer of MFC-CWs (T2) improved only the NO3−-N removal and efficiency bioelectricity generation performance compared to T1, and the average effluent MC-LR concentration of T2 (1.14 μg/L) was still higher than the provisional limit concentration (1.0 μg/L). The microbial community diversity of T1 and T2 was simplified compared to CK. The relative abundance of Sphingomonadaceae possessing the degradation capability for MCs increased in T1, which contributed to the higher MC-LR removal efficiency compared to CK and T2. While the relative abundance of electrochemically active bacteria (EAB) (i.e., Desulfuromonadaceae and Desulfomicrobiaceae) in the anode of T2 was promoted by the addition of sponge iron. Overall, this study suggests that integrating MFC into CWs provides a feasible intensification strategy for eutrophication and MCs pollution control.

Understanding the co-relationships of variables and improving product quality and productivity of DRI in rotary kiln

Sponge Iron manufacturing process is an alternative process to manufacturing of Steel through blast furnace route. Sponge Iron is also widely known as Direct Reduced Iron (DRI). As the name suggests direct reduced iron plant utilizes the method of solid-state reduction of Iron Ore to Iron. The reduction process is based on both exothermic and endothermic reaction concerning generation of enormous heat by the use of Coal as the source of Energy input to the process. The main raw materials for the process are Iron Ore, Coal and dolomite. Dolomite is mostly used as a de-sulphurization agent. These industries face many challenges with respect to quality & productivity because of frequent variation in raw material quality (both physical and chemical) of Iron Ore, Coal and dolomite. This variation in the raw materials affect the chemical reactions inside the rotary kiln and which in turn impact the quality and thereby productivity. This process is also associated with generation of solid wastes, which always creates opportunity for improving the efficiency in operation. So also, understanding the co-relationships of input parameters plays an important role in process optimization to reduce losses and thereby improve productivity.

Use of Sponge Iron as an Indirect Electron Donor to Provide Ferrous Iron for Nitrate-Dependent Ferrous Oxidation Processes: Denitrification Performance and Mechanism

Use of Sponge Iron as an Indirect Electron Donor to Provide Ferrous Iron for Nitrate-Dependent Ferrous Oxidation Processes: Denitrification Performance and Mechanism

Characterization of Iron Powder Produced by Reduction of Hot-Rolled Mill Scale In Hydrogen Gas

Rolled mill scale is one of the most valuable industrial waste. The produced mill-scale briquettes are reduced by hydrogen at varying temperatures. The reduction is carried out at 800°C, 900°C, and 1000 °C and lasts for 120 minutes. The reduced samples are studied by X-ray diffraction and scanning electron microscopy. The reduction of mill scale allows the new use and development of this material to obtain sponge iron that can be reused to produce iron-based powder metallurgy components. From the SEM, EDS, and XRD analysis, it is clear that as the reduction temperature increases from 800°C to 1000°C, the amount of produced iron powder also increases at constant holding time, where the amount of iron powder produced at 800oC is 94.55%, but it is 98.22% at the reduction temperature of 1000°C. The proposed reduction process allows obtaining a sponge iron powder of an irregular morphology with different crystallite sizes as measured by the Scherrer equation, where the crystallite size increased with the reduction temperature. The minimum crystallite size value is 44.45nm at the reduction temperature of 800°C, but it equals 60.1nm at 1000°C.

Mining in a Sacred Landscape: Adivasis, Deities and Alliances in a Former Princely State in Odisha/India

The papers explores ideas of a sacred landscape inhabited by indigenous people as well as other communities, deities as well as other beings manifested in localities and ‘objects’ forming various relationships, alliances and a thick web of relationality in a former kingdom in central-eastern India. It introduces these historically evolved ties through the foundational narratives as well as contemporary rituals, while the area is undergoing major transformations after Indian independence and even more so in a phase of accelerated industrialisation, especially tied to a mining boom and sponge iron factories. The latter not only threatens to uproot an existing, though changing sacrificial polity around local deities, but it also has massive ecological consequences and leads to partially successful protests.

Synergistic Degradation of Chloramphenicol by an Ultrasound-Enhanced Fenton-like Sponge Iron System

In this study, an ultrasound Fenton-like sponge iron system was used to enhance the degradation efficiency for chloramphenicol (CAP). Three single-factor experiments of reaction pH, hydrogen peroxide (H2O2) concentration, and sponge iron (Fe) concentration were used to explore the impact on CAP degradation efficiency. The response surface method revealed the interactions between various factors. The degradation efficiency for CAP was as high as 99.97% at pH = 3, 3.19 mmol/L H2O2, and a sponge iron concentration of 2.26 g/L. The degradation rate for CAP was significantly reduced upon the addition of some inorganic salts, mainly due to the quenching of OH radicals. Gram-negative (G(−)) Escherichia coli and Gram-positive (G(+)) Staphylococcus aureus were used to evaluate the changes in the antibacterial activity of CAP. Finally, gas chromatography/mass spectrometry (GC-MS) was used to identify the degradation products and the degradation path for the products was proposed based on the detected products.

Utilization of Iron Ore Slag in The Manufacture of Calcium Silicate Boards

This study aims to determine the iron ore slag effect as an additive in particleboard based on the SNI 7705:2011 standard. Iron ore slag comes from the waste processing of iron ore into sponge iron. The iron ore slag is reduced to a size of 200 mesh. Particleboard made with the composition of slag and silica is 0:40, 8:32, 16:24, 20:20, 24:16, 32:8, and 40:0 wt%. Meanwhile, other materials were made permanent, namely PCC cement and lime 16 wt%, coconut fiber 3wt%, and water 3 wt%. They are pressed with 3 tons of pressure for 1 hour using a hydraulic press. Drying at room temperature for one day, under the hot sun for two days, then in an oven at 110 oC for 8 hrs. Analysis of the chemical composition of X-ray fluorescence and X-ray diffraction crystalline phase, SEM-EDS micro-photographs, physical tests including density and porosity, and mechanical compressive strength tests. The dominant composition of SiO2 and CaO affects the formation of silicon dioxide (SiO2), calcium silicate (CaSiO3), and dicalcium silicate (Ca2SiO4) phases. Silica has a positive effect on the compressive strength of particleboard but is different from Ca, which has an impact on reducing the compressive strength. The sem morphology shows that coconut fiber cannot withstand heating at 190 oC and results in agglomeration. The addition of 20% ore slag and silica has met the calcium silicate board SNI 7705-2011. These results can be used to develop slag waste from iron ore processing into much more useful objects.

The role of iron and nickel smelters for the Indonesian steel industries

The iron and steel industries play a crucial role in supporting national development. The high dependence on imported raw materials causes Indonesia to suffer US $ 2.11 billion steel trade deficit per year. This study identifies the role of iron and nickel smelters in supporting the development of steel industries. The methodology used is descriptive statistics and regression models. Ferronickel and nickel pig iron as the primary raw materials for stainless steel have been produced in Indonesia, but only 23.05% and 47.77% are sold domestically. According to the linear regression models, it is expected that steel production and consumption will grow. Indonesia will become an independent steel producer and even export it by 2050. However, the supply chain is weak and poorly integrated as the local raw materials do not meet the domestic steel industry’s specifications. By 2050, 44 million tonnes of scrap, 19 million tonnes of sponge iron, 16 million tonnes of nickel, and 10 million tonnes of other raw materials will be needed annually. Hence, to reduce the national steel trade deficit, Indonesia must increase the smelters capacity and optimize local iron resources by increasing Fe content to meet the specifications of the national steel industry.

A Study on the smelting process of low carbon steel scrap and sponge iron in medium frequency induction furnace for production of front bumper beams

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

Assessing the feasibility of fabrication and welding of nickel-alloyed ductile iron through the evaluation of tensile properties and mechanical characterization

Fabrication of metallic components using welding processes is of great importance in the engineering world. Alloying element added material is a necessary to fabricate industry-ready components, especially after the invention of fabrication methods using welding processes. In the present work, raw materials including iron scraps, sponge iron, and forged steel scraps are melted in a medium frequency furnace. Casting samples are cast produced as per the ASTM standards using nickel alloyed ductile iron and inspected for porosity and other defects. Tungsten inert gas welding is exercised to check for the suitability of produced alloy for the welding process. Mechanical characterization and tensile property of as-welded components were performed. Both cases were carefully examined and found with satisfactory results. Tungsten inert gas-welded samples were noticed without any weld defects; this opens the advantage to employ welding processes for the fabrication. This will certainly enhance the feasibility of welding process for various component fabrications.

Technoeconomical investigation of energy harvesting from MIDREX® process waste heat using Kalina cycle in direct reduction iron process

Iron and steel industry is one of the main energy and water consumer globally which produces high amount of waste heat and air pollution. Numerous regulations, agreements and commitments ask the industry to reduce its energy and water consumption further to its environment fingerprints. MIDREX process is one of the leading technology for direct reduction of iron oxide to sponge iron which is dominant in Iran industry with annual capacity of more than 21 million metric tons. So, recovery of waste heat is essential for this industry. In this regard, using Kalina cycle as an efficient method is investigated in terms of thermodynamic study and economically. The results for analysis of a conventional MIDREX plant in Iran with capacity of annual 1.38 Mt of sponge iron shows that more than 2 MW electricity is extractable via Kalina cycle with mixture of ammonia and water. It also reveals that the heat exchanger and condenser are the main causes of exergy destruction of the proposed system with amount of 70%. The sensitivity analysis demonstrates that concentration and pressure at evaporator affect the energy and exergy efficiencies of the system. Changing the flue gas temperature also can be controlled by changing the concentration of the mixture to keep the stability of the net power. The economic investigations represent the long term for payback period for more than 17 years based on the present feed-in-tariff prices for waste heat recovery. For making the proposed system more profitable, technical and policy modifications are considered simultaneously which is associated with payback period of less than 9 years.

Enhanced refractory organics removal by sponge iron-coupled microbe technology: performance and underlying mechanism analysis.

Sponge iron (SFe) is a zero-valent iron (Fe0) composite with a high-purity and porous structure. In this study, SFe was coupled with microorganisms that were gradually domesticated to form a Fe0/iron-oxidizing bacteria system (Fe0-FeOB system). The enhancement effect of the Fe0-FeOB system on refractory organics was verified, the mechanism of its strengthening action was investigated, and the relationship and influencing factors between the Fe0 and microorganisms were revealed. The average removal rates of the Fe0-FeOB system were 8.98%, 5.69%, and 40.67% higher than those of the SBR system for AF, AN, and NB wastewater treatment, respectively. With the addition of SFe, the microbial community structure was gradually enhanced with a large number of FeOB were detected. Moreover, the bacteria with strong iron corrosion and Fe(II) oxidation abilities plays a critical role in improving the Fenton-like effect. Interestingly, the variation trend of ⋅OH was fairly consistent with that of Fe(II). Thus, the main drivers of the Fenton-like effect are biological corrosion and metabolism. Consequently, microbial degradation and Fenton-like effect contributed to the degradation performance of the Fe0-FeOB system. Among them, the microbial degradation accounted for 96.09%, of which the biogenic Fenton effect accounted for 8.9%, and the microbial metabolic activity accounted for 87.19%. However, the augmentation of the Fe0-FeOB system was strongly dependent on SFe for the strengthening effect of microorganisms disappeared after leaving the SFe 35days.