Sponge Iron Research Articles

A pilot-scale study of a novel two-stage denitrification filter

In this study, a pilot-scale two-stage denitrification filter (TSDNF) was developed to further remove the effluent nitrate from a cyclic activated sludge system. Sponge iron and volcanic rock were used as DNF-1 and DNF-2 filter beds, respectively. A single-stage DNF-3 filter with volcanic rock was used as the control. Most dissolved oxygen (DO) was consumed for iron oxidation in the DNF-1, and in turn denitrification rates increased in the DNF-2. In the DNF-1, 17.9 %±13.6 % of the NO3−-N was removed in the absence of organic carbons, resulting in a significant increase in the total NO3−-N removal in the TSDNF with a COD/NO3−-N ratio of about 2.6. Autotrophic denitrification should be finished by the dominant Fe(II)-oxidizing nitrate-reducing Gallionellaceae genus (21.38 %) in the DNF-1, while common denitrifying strains were dominant in both DNF-2 and DNF-3. Moreover, obvious chemical phosphorus removal (83.3 %) was found in the DNF-1. Therefore, simultaneous autotrophic denitrification and chemical P-removal can be achieved using iron ions released from sponge iron filters, which provides a new model to reshape the design of advanced removal of nitrogen and phosphorus in the secondary clarifier effluent.

Catalytic activity comparison of typical iron-bearing particle electrodes in heterogeneous electro-Fenton oxidation processes

Four kinds of iron-bearing materials including chalcopyrite, pyrite, sponge iron and iron–carbon composite were exploited as catalysts and 3D electrodes (particle electrode) for heterogeneous electro-Fenton oxidation processes. Their catalytic activities were compared according to decolorization (i.e. 1−C∕C 0) and COD removal efficacies, using Reactive Red X-3B as a model organic pollutant in dyeing wastewater. The iron–carbon composite was found to be the most effective catalyst, and 99.63 ± 1 % of decolorization and 79.86 ± 2 % of COD removal can be achieved. The addition of sodium chloride reduced catalytic efficacies of sponge iron and iron–carbon composite slightly, but promoted those of chalcopyrite and pyrite. Furthermore, the stability and reusability of catalysts were examined and insignificant reduction on catalytic activity was observed for 5 cycles of electro-Fenton processes.

A robust two layer green supply chain modelling under performance based fuzzy game theoretic approach

This article deals with a pollution sensitive production-transportation supply chain (SC) model with backorder under three-layer marketing executives’ performance based fuzzy strategic game approach. Each executive group follows a cycle time dependent performance function according to some rules. Considering a real case study, we develop a cost minimization centralized two-layer SC model under the effect of pollution. The amount of pollution is estimated by percentage via some pollution function studied for the emissions of carbon dioxide (CO2) during industrial production and road transportation. We split the original problem into equivalent game problem in which the producer (vendor) plays the role of player 1 in one side and the buyer (customer) plays the role of player 2 in the other side exclusively. The game problem is studied under different scenarios namely performance indices, game strategy and with and without pollution measures. Utilizing the data set of case study over sponge iron industry we perform some numerical computations with the help of LINGO software. Our findings reveal that, whenever the Gaussian probabilistic strategies with row interchanging performance matrix is employed on numerical illustrations then the centralized SC cost gets minimum with reduced pollution level. Finally, a comparative study, sensitivity analysis and graphical illustrations are done to justify the robustness of the proposed model.

Influencing factors for the Fenton-like of biological sponge iron system and its degradation mechanism of aniline

The application of zero-valent iron (ZVI) coupled with microorganisms, has gained considerable attention in recent years for eliminating recalcitrant organic matters from wastewater. Nevertheless, there are no general conclusions regarding the degradation mechanism and the operating variables. In this paper, sponge iron (SFe, a kind of ZVI) has been submerged to the activated sludge process to develop a biological sponge iron system (SFe-M). The treatment impact of SFe-M system on aniline (AN) wastewater under the optimal conditions was significantly better than that of the general activated sludge system. In the SFe-M system, the variation trends of hydroxyl radicals (•OH) production were consistent with those of Fe(II), and the hydrogen peroxide concentration was approximately twice as high as the sum of activated sludge system and the SFe system. Both SFe and microorganisms could induce Fenton-like reactions directly or indirectly. This contributed to the production of •OH that constantly attacked the benzene ring and the amino group. It resulted in some nitrogen in AN released in the form of ammonia ions. Moreover, microorganisms could also use the mass and electrons during the AN conversion process. The AN was eventually oxidized to carbon dioxide.

Steam Reforming of Methane on Sponge Iron: Influence of Gas Composition on Reaction Rate

Direct Reduction processes use gases (CO and H2) for iron reduction and production of sponge iron or direct reduced iron (DRI). The generation of this gas occurs through methane reforming, which can be done in a reformer or inside the reduction shaft with the sponge iron as a catalyst. The latter occurs in the auto-reforming processes. The kinetics of steam reforming of methane catalyzed by sponge iron was studied at temperatures between 875°C and 1050°C. Results showed that sponge iron acts as a catalyst and methane conversion is increased in higher temperatures and with higher H2/H2O ratio in the inlet gas. The inlet gas composition like one of the industrial auto-reforming processes led to intense carburization and hindered the catalytic reforming reaction.

Impact of Particulate Matter Emission Reduction with Respect to Sizing of Sponge Iron Kiln

Impact of Particulate Matter Emission Reduction with Respect to Sizing of Sponge Iron Kiln

Reaction Kinetics of Iron Oxides in Ok Tedi Magnetite Skarn Ore

Magnetic skarn ore (MSO) is one of the major copper bearing ore extracted by the Ok Tedi Copper Mine in Papua New Guinea (PNG). Copper minerals are recovered by flotation while the iron not associated with copper are discarded as tailings. The objective of this investigation was to determine the iron ore reduction kinetics for the Ok Tedi MSO and ascertain if it can be processed to produce sponge iron for a mini steel plant in Papua New Guinea. SEM-EDAX analyses of the Ok Tedi MSO indicated 10.1% C, 30% O, 0.6% Mg, 1.1% Si, 21.1% S, 0.8% Ca and 36.2 % Fe. Most of the iron is in sulfide form. Both naturally occurring and roasted sinters of Ok Tedi MSO samples of different particle sizes were reduced by charcoal carbon at three different temperatures and seven different reduction times. Analyses of the reduced products indicated a metallic iron content of more than 65 wt. % on average. Results showed that there was no significant difference in reduction between fluxed and control materials. Only a slight increase in kinetics with reduced particle size, hence the reaction rate constant (K) did not vary much within the temperatures investigated. Reaction kinetics increases with increasing reduction time at 900°C. Therefore, more iron reduction is observed with particles of 106 µm size. In addition, the results also confirmed that the reduction energy used was higher at 800°C and lower at 1000°C. In conclusion, iron reduction can be improved but close monitoring of temperature and reduction times are essential to determine the reaction kinetics of the Ok Tedi MSO.

An Analytical Way to Comparing the Affective Parameters on Iranian Pellet Strength

Iron ore pellets are the raw materials for direct reduction process of iron ore to sponge iron pellets and is an important step in the iron and steel production chain. Many of the defects in direct reduction and steel making processes could be identify in the iron ore processing stage. Therefore, the purpose of this study was to select the correct suppliers of iron ore pellets for direct reduction units based on criteria affecting the strength of cooked pellets, which played a key role in optimizing the production criteria of sponge iron and ultimately increasing production efficiency in the steelmaking stage which can be very effective. For this purpose, using the hierarchical analysis model, the parameters affecting the strength of pellets have been identified and studied by experts of several iron and steel production units, and finally, for example, several iron ore pellet production plants have been compared and ranked. According to AHP decision criteria, particle size is the most important parameter affecting the strength of cooked pellets.

Mechanical Properties and Corrosion Resistance of Borosintered Distaloy Steels

Distaloy SA is a sponge iron powder (nominal composition: Fe-1.75Ni-1.5Cu-0.5Mo) widely used in the production of powder metallurgy (P/M) parts in the automotive industry. In this study, Distaloy SA powders were sintered in two different atmospheres, one consisting of pure Ar gas (traditional sintering) and the other consisting of a mixture of 90 wt.% B4C and 10 wt.% NaBF4 powders (borosintering). To investigate the effects of the different sintering atmospheres, the P/M samples were characterized using density measurements, surface roughness tests, scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, microhardness measurements, nanoindentation experiments, wear tests and corrosion tests. On the surface of the borosintered samples, a 160-325 µm thick double-phase FeB + Fe2B boride layer was formed. The hardness (1405-1688 HV) and elastic modulus (122.21-162.42 GPa) of the surface were significantly improved with the borosintering treatment compared to conventional sintering (215-250 HV, 63.28-94.86 GPa). Borosintering also provided low friction coefficient values and an increased wear resistance compared to conventional sintering. A significant increase in corrosion resistance was also observed with the borosintering treatment in three different solutions. The corrosion rates of both sintered and borosintered samples were ranked as NaCl < HCl < H2SO4. The borosintered samples displayed superior corrosion resistance compared to the sintered samples, especially in the acid solutions. The results of this study show that significant cost savings can be achieved by combining the boriding and sintering treatments in a single borosintering process.

Assessment of heavy metal pollution in groundwater of an industrial area: a case study from Ramgarh, Jharkhand, India

ABSTRACT In the present study, pollution evaluation indices were carried out to assess the intensity of pollution in Marar industrial area of Ramgarh in Jharkhand. Fifteen groundwater samples were collected from the study area in May 2016. The physicochemical parameters (pH and EC,, HCO3 −, Cl−, SO4 2-, NO3 −, F−, Ca2+, Mg2+, Na+, K+) and heavy metals (Fe, Mn, As, Zn, Cu, Cr, Ni, Se, Al, Ba, Pb and Cd) were analysed. Measured concentration of heavy metals in the study area in decreasing order is as follows: Fe> Zn> Mn > Al> Ba > Ni> Cu > Pb> Cr > Se> As > Cd. Fe concentration was found beyond desirable limit in each sample. In the study area 73%, 60% and 21% water samples surpass desirable limit of Al, Mn and Ni respectively as per BIS,10,500 (2012). Concentration of As, Cu, Cr, Se, Pb, Ba and Cd was within the desirable limit in each sample. The analysed data was then applied for the calculation of Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI) and Degree of Contamination (Cd). HPI values have not surpassed the critical value of 100 in any of the sample despite of various industrial activities. Fe is the prominent contributor for all the three pollution indices followed by Ni, Cr, Pb, Cu and Mn. According to multiple of mean value approach 100%, 93% and 80% of the samples belong to low and medium classes of HEI, HPI, and Cd respectively. Cluster analysis results advocate that heavy metal concentration in groundwater resources are contributed by both lithogenic as well as anthropogenic inputs such as large number of ferro alloys, non-ferrous alloys, sponge iron, foundry, instrument manufacturing and welding industries in the study area.

Influence of Charge Quality on Physical, Mechanical and Operational Properties of Low-Alloy Steel 30KHGSA

Purpose of reseach is to study the influence of the quality of the original charge on the complex of physical, mechanical and operational properties of structural low-alloy steel 30HGSA.Methods. As an object of research, a typical representative of low-alloy structural steels has been chosen - steel 30HGSA, smelted using metallized sponge iron pellets, ordinary scrap metal and billets obtained by the method of a boiling slag layer. In accordance with the set objectives of the study, steel 30HGSA of various melts, obtained with different charge, had the same conditions for melting, evacuation, deoxidation, casting and crystallization. The casting temperature was 1600...1620 оC and the post-vacuum treatment temperature was 1530...1560 °C. Duration of evacuation - 5 minutes. Casting of melts was carried out into cast iron molds with a siphon for 4 ... 5 minutes. Deoxidation was carried out in a ladle with aluminum in the amount of 4 ... 4.5 kg / melt. After solidification, the ingots were cooled in special wells. The ingots were cut into 3 parts: head, middle and bottom (600 × 600 mm). The middle part was then hot forged and rolled to a Ø30 mm bar. The length of the rod was 2 ... 3.4 m. After hot deformation, the rods were cooled in air.Results. Mechanical tests have been carried out. Statistical processing of experimental results has been performed. Regularities of changes in the characteristics of mechanical properties have been revealed: tensile strength, creep strength, relative narrowing of the cross-sectional area of the sample, relative elongation of the initial working length, impact strength (σВ, σ0.2, ψ, δ, aН).Conclusion. It has been found that with an increase in temperature, the mechanical properties of steel 30HGSA, smelted on various charges, decrease. It has been established that the cold brittleness threshold of 30HGSA steel is lower for purer melts on spongy iron and intermediate product KShS, the value of impact toughness at low temperatures is higher than in melting on a conventional metallized charge. Noticeable softening begins at a tempering temperature of 300 °C The temperature of the maximum tempering brittleness for steel 30HGSA, melted on a conventional metallized charge, is 550 °C It is shown that steel 30HGSA smelted with a pure original charge (spongy iron) has a lower tendency to temper brittleness than steel smelted with a conventional charge. The value of the impact toughness of the steel of this melt is higher than that of the steel of conventional melting over the entire tempering temperature range.

Toward a Fossil Free Future with HYBRIT: Development of Iron and Steelmaking Technology in Sweden and Finland

The Swedish and Finnish steel industry has a world-leading position in terms of efficient blast furnace operations with low CO2 emissions. This is a result of a successful development work carried out in the 1980s at LKAB (Luossavaara-Kiirunavaara Aktiebolag, mining company) and SSAB (steel company) followed by the closing of sinter plants and transition to 100% pellet operation at all of SSAB’s five blast furnaces. However, to further reduce CO2 emission in iron production, a new breakthrough technology is necessary. In 2016, SSAB teamed up with LKAB and Vattenfall AB (energy company) and launched a project aimed at investigating the feasibility of a hydrogen-based sponge iron production process with fossil-free electricity as the primary energy source: HYBRIT (Hydrogen Breakthrough Ironmaking Technology). A prefeasibility study was carried out in 2017, which concluded that the proposed process route is technically feasible and economically attractive for conditions in northern Sweden/Finland. A decision was made in February 2018 to build a pilot plant, and construction started in June 2018, with completion of the plant planned in summer 2020 followed by experimental campaigns the following years. Parallel with the pilot plant activities, a four-year research program was launched from the autumn of 2016 involving several research institutes and universities in Sweden to build knowledge and competence in several subject areas.

Pelletization of synthesized magnetite concentrate obtained by magnetization roasting of Indian low-grade BHQ iron ore

In India, the use of iron ore pellets in the blast furnace, electric arc furnace, or sponge iron production is continuously optimized, considering different aspects of the production chain from the run of mining (ROM) to metallic iron depending upon the industrial need and ore availability (recent aggressive iron ore mining auction 2020 in India). The scarcity of high-grade iron ore resource and availability of the considerable quantity of low-grade iron ore fines, banded hematite quartzite (BHQ) ore in mines (mostly in Bihar, Odisha, Madhya Pradesh, and Karnataka), has to lead the way to beneficiate and utilize the concentrate as pellet feed for the steelmaking process. Banded iron ore such as BHQ is one of the potential resources of iron having a total iron content, i.e., Fe (T) of 35–48 wt%, which is lying unutilized in most of the Indian iron ore mines. The challenge before the policymakers and researchers is to think of a sustainable process technology to utilize these iron ore resources wisely. The conventional beneficiation of this type of siliceous BHQ iron ore resource having low iron content is not advisable. Therefore, pelletization of synthesized magnetite concentrate obtained from the magnetization roasting of BHQ emerged as an alternative energy-saving and ore conserving process that may be scaled up and commercialized for low-grade banded iron ores. The pelletization of magnetite concentrate is an independent heat hardening process; thereby requirement of anthracite coal fines as a fossil fuel additive to maintain the temperature gradient from core to the periphery of the pellet can be avoided. Physical properties such as cold crushing strength (CCS) and porosity of the pellets were optimized to study their suitability in the steelmaking process. In this regard, characterization studies of the pellets were performed using X-ray diffraction (XRD), scanning electron microscope (SEM), optical microscope, and X-ray micro-computed tomography to understand the microstructural properties of the pellets. The CCS of 255.8 kg/pellet and porosity of 25.42% were achieved at the optimized induration temperature and residence time of 1250 °C (50 °C to 80 °C less than conventional hematite pellet induration) and 10 min, respectively. The properties studied are encouraging and comparable with the pellet prepared from the natural magnetite/hematite ore.

Soil Contamination in the Industrial Vicinity of Bemetara and Raipur District of Chhattisgarh, India

Soil samples (≤ 50) samples were collected around the different industries located in Chhattisgarh. Soil samples were collected from the 15 c.m. depth during post monsoon 2018 from the different industries of Bemetara and Raipur District (C.G., India). Chemical analysis of these samples indicates that due to industrial pollutants the adverse effect shown in crop growing fields. Around rice mill Fe concentration observed 19.36 - 19.23 mg/kg, Cu concentration observed 1.23-1.65 mg/kg, Mn concentration observed 26.44 – 25.51 mg/kg and Zn is observed 0.96 -0.49 mg/kg from 50 m – 4500 m distance. Around Sponge iron industry the concentration of Fe is observed 16.41 – 16.88 mg/kg, Cu is observed 1.79 – 1.94 mg/kg, Mn is observed 16.43 – 16.51 mg/kg, and Zn is observed 0.64 – 0.65 mg/kg from 50 m – 4500 m distance. Same as around the power plant industry the concentration of Fe is observed 11.35-11.39 mg/kg, Cu is observed 2.36-2.58 mg/kg, Mn is observed 29.41 – 29.39 mg/kg and Zn is observed 0.85 – 0.84 mg/kg from 50 m to 4500 m distance.

Advanced Packed-Bed Ca-Cu Looping Process for the CO2 Capture From Steel Mill Off-Gases

A novel configuration of the Ca-Cu looping process based on dynamically operated packed-bed reactors is proposed to convert blast furnace gas (BFG) into H2/N2 and highly concentrated CO2, accompanied by a large amount of high-temperature heat. Preliminary energy and mass balances of the process reveal that around 30% of the BFG can be upgraded via calcium assisted WGS if only BFG is used as reducing gas in the reduction/calcination stage. A higher amount of H2/N2 can be produced by using other steel mill of gases (e.g. COG, BOFG) or natural gas in the regeneration of the CO2 sorbent. This decarbonized fuel gas could be used for onsite power generation or to obtain sponge iron by a DRI process, increasing the overall capacity of the steel plant. Energy efficiencies higher than 75% have been calculated, reaching maximum values around 88% in case of using natural as fuel gas for the sorbent regeneration stage. Low values for the specific energy consumption of around 1.5 MJLHV/kgCO2 and CO2 capture efficiencies higher than 95% support the further development of the proposed Ca-Cu looping process.

Chemoadsorption for Separation of Hydrogen Sulfide from Biogas with Iron Hydroxide and Sulfur Recovery

AbstractHydrogen sulfide (H2S) removal from biogas is essential to allow biogas storage in the natural gas grid. Several established methods exist, most of them making use of non‐reusable substrates such as iron sponge or active carbon. Coated metallic foams provide a reusable sustainable alternative. Several iron oxides and hydroxides were tested to validate the H2S adsorption properties before and after thermal regeneration, i.e., sulfur removal. Amorphous iron hydroxide proved to efficiently clean biogas after maximum four sulfur removal cycles and showed an almost ten times larger capacity for sulfur adsorption than crystalline hematite Fe2O3. Very low H2S contents could be realized until breakthrough.

A Graphdiyne Oxide-Based Iron Sponge with Photothermally Enhanced Tumor-Specific Fenton Chemistry.

Fenton reaction-mediated oncotherapy is an emerging strategy which uses iron ions to catalytically convert endogenous hydrogen peroxide into hydroxyl radicals, the most reactive oxygen species found in biology, for efficient cancer therapy. However, Fenton reaction efficiency in tumor tissue is typically limited due to restrictive conditions. One strategy to overcome this obstacle is to increase the temperature specifically at the tumor site. Herein, a tumor-targeting iron sponge (TTIS) nanocomposite based on graphdiyne oxide, which has a high affinity for iron is described. TTIS can accumulate in tumor tissue by decoration with a tumor-targeting polymer to enable tumor photoacoustic and magnetic resonance imaging. With its excellent photothermal conversion efficiency (37.5%), TTIS is an efficient photothermal therapy (PTT) agent. Moreover, the heat produced in the process of PTT can accelerate the release of iron ions from TTIS and simultaneously enhance the efficiency of the Fenton reaction, thus achieving a combined PTT and Fenton reaction-mediated cancer therapy. This work introduces a graphdiyne oxide-based iron sponge that exerts an enhanced antitumor effect through PTT and Fenton chemistry.

Combustion behavior of pulverized sponge iron as a recyclable electrofuel

In this work, the combustion behavior of pulverized sponge iron (PSI), a practical-grade iron product that was proposed as a potential candidate in the metal fuel cycle, was observed directly using high-magnification shadowgraphy and other optical diagnostics techniques. The PSI was combusted in a laboratory-scale, McKenna flat-flame burner. Results suggest that, in agreement with theoretical models, PSI combusted heterogeneously, with most of the particle mass converting to an intact, solid oxide. However, in contrast with previous hypotheses, the formation of a microflame of combusting aerosol that was attached to the particle surface was observed. Results from quantitative shadowgraphy indicated near-instantaneous melting and complex behavior—we attempted to explain these based on the FeO phase diagram. The analysis of micron- and nano-sized combustion products confirmed that the PSI combusted heterogeneously and a gaseous sub-oxide was formed. Combustion under high excess oxygen was hypothesized to reduce the formation of these oxides.

Flame analysis for prediction of thermocouple temperature and quality of sponge iron at TATA steel long products limited

The temperature profiles of the gas and charge in a coal-fired rotary sponge iron kiln affect both the iron ore reduction process and accretion formation. The temperature profile of charge is estimated from the eleven thermocouples (TC1-TC11) placed along the 80 m length of the kiln. The quality prediction models are heavily dependent upon the accuracy of the measurement of TC10. However, slowly, as the kiln’s campaign life increases TC10, and other thermocouples too, get corrupted due to deposition of material (accretions) on the thermocouples. At the beginning of the campaign, however, there is no accretion on TC10. In the present work, an attempt is made to directly correlate flame characteristics with TC10 and with quality of iron produced so that when TC10 is corrupted due to accretion or breakdown, we can still survive by using flame characteristics as a guide to control quality. The flame inside the rotary kiln has been analysed by using image analysis procedures for the first time in a sponge iron plant. The flame’s estimated average temperature and pixel intensity information are correlated with (a) the temperature measured by the thermocouple TC10 (which is installed at a distance of 20 m from the rotary kiln outlet hood) and (b) with quality of iron produced. It is found that use of average flame temperature for quality prediction has several advantages in terms of increased accuracy of prediction and quicker response time of flame to short-time changes in coal quality (particle size, moisture, ash content, etc) whereas TC10 thermocouple takes much longer to reflect these changes due to slow process of heat transfer to charge. In addition, the adverse effect of accretion formation on TC10 for quality prediction has been overcome.

Dynamic quality prediction and control in rotary sponge iron kilns

The quality of sponge iron produced in the coal-fired rotary kilns at TATA Steel Long Products Limited (TSLPL) is permitted to vary in a small window of 80-83% Fe. In order to adhere to this window, the expected quality in the next hour is predicted, and appropriate actions are taken if changes or rates of change that take place are not in the right direction. Airflow rate through the primary air blower is controlled constantly. For quality prediction and control purposes, the One Step Ahead Adaptive Control and Prediction Algorithm (OSAA) and Grey (1,1) prediction algorithm have been tailored and tuned. The working principle of OSAA and Grey(1,1) are described, and their accuracy is compared. The results show that OSAA performs better than the Grey(1,1). The OSAA is therefore used to predict the changes required in volume of air blown through the primary air blower and also the amount of injection coal. An expert control system has been developed based on allowable windows of control variables.