Search Results (43)

Iron-rich bauxite residue (red mud) is a hazardous alkaline solid waste produced during the production of alumina from high-iron bauxite, which poses severe environmental challenges due to its massive stockpiling and limited utilization. In this study, metallic iron was recovered from high-iron red mud using the smelting reduction process. Thermodynamic analysis results show that an increase in temperature and sodium oxide content, along with an appropriate mass ratio of Al₂O₃ to SiO₂ (A/S) and mass ratio of CaO to SiO₂ (C/S), contribute to the enhancement of the liquid phase mass fraction of the slag. During the smelting reduction process of high-iron red mud, iron recoveries for low-alkali high-iron red mud and high-alkali high-iron red mud under optimal conditions were 98.14% and 98.36%, respectively. The metal obtained through reduction meets the industrial standard for steel-making pig iron, which is also confirmed in the pilot-scale experiment. The smelting reduction process of high-iron red mud can be divided into two stages, where the reaction is predominantly governed by interfacial chemical reaction and diffusion control, respectively. The apparent activation energy of high-alkali high-iron red mud is lower than that observed for low-alkali high-iron red mud. The reduced slag can be used as a roadside stone material or cement clinker. This proposed method represents a sustainable process for the comprehensive utilization of high-iron red mud, which also promotes the minimization of red mud. Full article

The article presents issues related to the melting of cast iron with a limited or zero share of pig iron in the charge. The results of melts conducted in electric induction furnaces are presented. The elimination of pig iron and its replacement with steel or return scrap is highly significant in the context of sustainable production and product life cycle assessment (LCA). The paper presents the results of research carried out during melts conducted under both laboratory and industrial conditions. The chemical composition of the cast iron, its physicochemical properties obtained from the analysis of the cooling curve and its derivative, as well as the structure, were analyzed. It was found that cast iron produced using high-quality steel scrap contains fewer sulfur and phosphorus impurities. However, it was also observed that such cast iron exhibits reduced nucleation ability, which can be improved by applying an inoculation process. Full article

Red mud from bauxite processing is among the large-tonnage technogenic waste that poses a significant ecological threat. At the same time, red mud serves as a raw material source for expanding the resource base for obtaining iron, rare metals, and rare earth elements. Numerous studies on their utilization have shown that only through comprehensive processing, combining pyrometallurgical and hydrometallurgical methods, is it possible to maximize the extraction of all the useful components. This work addresses the first stage of a comprehensive technology for processing red mud through reduction smelting, separating iron in the form of pig iron, and producing slag. Studies were conducted on the reductive smelting of red mud using waste slurry from alumina production as the calcium-containing material, taken in proportions calculated to obtain a fluid slag with a hydraulic modulus of 0.55–0.8. The permissible mixing range of red mud with waste slurry was determined to be in the ratio of 0.56–1.2. In cases where the charge was prepared in violation of the required hydraulic modulus value, pig iron was not obtained during smelting. When the hydraulic modulus requirement was met, the temperature of the reductive smelting process was 1350–1400 °C. The total amount of recovered iron obtained as pig iron and fine fractions amounted to 99.5% of the original content. The low iron content (0.23–0.31%) in the non-magnetic slag fraction allows for the production of high-quality titanium oxide and rare earth element concentrates in the subsequent stages of the comprehensive hydrometallurgical processing of red mud, involving acid leaching. Based on the results of a phase analysis of the slag, pig iron, and melt, the reactions of the reductive smelting process were established, and their thermodynamic likelihood was determined. In fluid slags, the content of the sodium aluminosilicate phase is twice as high as that in slag with a higher hydraulic modulus. The reductive smelting of 100% red mud with the addition of calcium oxide, calculated to achieve a hydraulic module of 0.55 at a temperature of 1350–1400 °C, produced pig iron and slag with high alkali and iron contents. Full article

Recently, interest in developing functional foods that promote health has grown significantly. This study aimed to evaluate the feasibility of microencapsulating guinea pig blood erythrocytes by vacuum drying and incorporating them into gummies fortified with tumbo juice. Physicochemical analysis (proximate analysis, iron content, color, pH, soluble solids, and particle size) and functional group analysis by Fourier transform infrared spectrophotometry were performed on three formulations of gummy candy with added encapsulated erythrocytes from guinea pig blood (EEGPB): F1 (4% EEGPB), F2 (5% EEGPB), and F3 (6% EEGPB). The results showed a significant decrease in the moisture content (52.02% in F1 to 43.27% in F3) and increases in protein (11.44% in F3) and iron (2.63 mg Fe/g in F3) contents when higher EEGPB levels were used. Sensory evaluation revealed that F3 was the most acceptable formulation in terms of taste, aroma, and texture, with no significant differences in color. FTIR analysis confirmed physical incorporation with no chemical interactions between ingredients. These results demonstrate that the encapsulation of erythrocytes by vacuum drying not only preserves the bioactive compounds but also improves the organoleptic properties of the gummies, making them an attractive product for consumers. In conclusion, this technique is effective for fortifying functional foods and has potential application in other food products. This approach represents a significant advance in the development of innovative functional foods. Full article

There is a growing interest in the preservation of indigenous pig breeds, as they serve as a valuable genetic reserve. Pork meat products are widely consumed due to their desirable flavor, which is largely influenced by their chemical composition and the production processes employed. The aim of this study was to characterize and compare the nutritional composition, mineral content, and fatty acid profile of meat products derived from indigenous Croatian pig breeds. Three types of meat products, including bacon, dry-cured ham, and dry-fermented sausages, originating from the Turopolje pig, Black Slavonian pig, and Banijska šara, were collected and analyzed for proximate composition, fatty acid profile, and mineral content. Concerning the proximate analysis, statistically significant differences were found in the water and fat content in bacon and dry-fermented sausages, while the mineral analysis revealed differences in iron content. The fatty acid profile of the tested products was found to be in accordance with previously reported data. The results indicated similarities in chemical composition, mineral content, and fatty acid profile between meat products from different pig breeds; however, performing PCA analysis revealed that the major influence on product and breed characterization could be attributed to differences in fatty acid composition. Full article

Biochar-based additives can enhance the ability to produce methane during anaerobic digestion (AD), and biogas residues (BRs) are solid waste that can cause environmental pollution. Therefore, in this work, BRs were used as raw material to prepare biochar, and Fe³⁺ was used to modify biochar for use in the AD process, generating pig manure water (PMW). The results showed that biogas residue biochar (BRB) showed good pore size and had a “honeycomb structure” on its surface. The commercially available iron–carbon composite material (Fe-C) showed the greatest cumulative methane production (CMP), the greatest removal rates of chemical oxygen demand (COD), and the greatest degradation rate of volatile fatty acids (VFAs), with the order of Fe-C > Fe³⁺-modified biogas residue biochar (FBRB) > BRB > control group. Fe³⁺ and Fe⁰ showed similar effects, where both could enhance the methanogenesis performance of anaerobic digestion by promoting direct interspecific electron transfer, and Fe⁰ was slightly more effective than Fe³⁺. Bacteroidotas and Firmicutes were the predominant phyla, and Clostridium_sensu_stricto_1 was the predominant genus. The addition of biochar and Fe³⁺ promoted the transformation of microorganisms from the conventional metabolic mode into an efficient metabolic mode. Extracellular electron transfer played a crucial role in this. Full article

Steel slag is a significant environmental liability generated by pyrometallurgical processes. Residue generation, such as granulated blast furnace slag and basic oxygen slag (BOF), is intrinsic in steel production. Blast furnace slag, generated in the carbothermal reduction of iron ore, is almost entirely used as a supplementary cement material in Portland cement. BOF slag, produced in the conversion of pig iron into steel in a basic oxygen converter, is still not consolidated or valued for reuse. This research proposes the reuse and valorization of BOF slag combined with blast furnace slag in clinker-free cement production. Cement formulations were produced with different slag and gypsum contents, ranging from 80 to 90% blast furnace slag, 10 to 20% gypsum, and 10 to 15% BOF slag. All formulations were evaluated for compressive strength at ages of 3, 7, 14, 28, 91, and 180 days of curing. At the initial ages, the cement formulations exhibited high resistance. On the 3rd day, the cement formulations reached up to 10 MPa, and on the 7th day, 40 MPa. At late ages, the best-performing formulation, ECO2, showed, after 28 days of hydration, a compressive strength greater than 50 MPa, and at 180 days, a compressive strength greater than 80 MPa. It was possible to understand that BOF slag acts in cement alkaline activation with pH increase, more or less actively due to the presence of lime, portlandite, and calcite. Full article

The objective of the present report is the dissemination of information acquired during the application of ISO 6579-1:2017 for the isolation of Salmonella spp. from swine samples. ISO 6579-1:2017 is the protocol officially recommended by the EU for the isolation of Salmonella spp., aiming for the harmonization of effective control of Salmonella infection in food-producing animals. Successful control of animal salmonellosis is highly dependent on the sensitivity and reliability of the biochemical methods used to detect the presence of the pathogen in various stages of food production. Application of ISO 6579-1:2017 resulted in the isolation of twelve Salmonella spp. and eighteen other members of the family of Enterobacteriaceae biochemically and other bacteria antigenically resembling salmonellae. An evaluation of the culture media was conducted, including xylose-lysine-desoxycholate agar (XLD), Salmonella–Shigella Agar (SS), Brilliant Green Agar (BGA), Salmonella Chromogenic Agar (SCA), Triple Sugar Iron (TSI), and modified semi-solid Rappaport–Vassiliadis (MSRV) agar. The evaluation showed that these culture-selective media differed significantly in their performance for the isolation of Salmonella from swine samples. It was concluded that the presence of atypical Salmonella strains negatively affects the prevalence of Salmonella, thus affecting the identification of carrier pigs and eventually affecting the efficiency of control programs. Thus, doubtful results require additional biochemical testing to confirm the accuracy of such universally recommended isolation methods. Full article

The miniature pig is a suitable animal model for investigating human cardiovascular diseases. Nevertheless, the alterations in lipid metabolism within atherosclerotic plaques of miniature pigs, along with the underlying mechanisms, remain to be comprehensively elucidated. In this study, we aim to examine the alterations in lipid composition and associated pathways in the abdominal aorta of atherosclerotic pigs induced by a high-fat, high-cholesterol, and high-fructose (HFCF) diet using lipidomics and RNA-Seq methods. The results showed that the content and composition of aortic lipid species, particularly ceramide, hexosyl ceramide, lysophosphatidylcholine, and triglyceride, were significantly altered in HFCF-fed pigs. Meanwhile, the genes governing sphingolipid metabolism, iron ion homeostasis, apoptosis, and the inflammatory response were significantly regulated by the HFCF diet. Furthermore, C16 ceramide could promote iron deposition in RAW264.7 cells, leading to increased intracellular reactive oxygen species (ROS) production, apoptosis, and activation of the toll-like receptor 4 (TLR4)/nuclear Factor-kappa B (NF-қB) inflammatory pathway, which could be mitigated by deferoxamine. Our study demonstrated that dysregulated ceramide metabolism could increase ROS production, apoptosis, and inflammatory pathway activation in macrophages by inducing iron overload, thus playing a vital role in the pathogenesis of atherosclerosis. This discovery could potentially provide a new target for pharmacological therapy of cardiovascular diseases such as atherosclerosis. Full article

The preparation of high-quality inorganic fibers by centrifugation from modified melting-separated red mud, which is the product of the efficient recovery of pig iron from red mud, is a new approach to achieve large-scale production of high value-added materials from red mud. This method has a wide range of application prospects and could contribute substantially to the comprehensive utilization of bulk industrial solid waste and the development of a circular economy. In this study, melting-separated red mud was modified with water-quenched blast furnace slag, quartz sand, and quicklime. The effect of the CaO/Na₂O mass ratio on the viscosity, fluidity, and crystallization performance of the melting-separated red mud was investigated; slag wool was prepared by centrifugation under laboratory conditions; and the effect of the CaO/Na₂O mass ratio on the morphology and properties of the slag wool was investigated. The viscosity of modified melting-separated red mud with different CaO/Na₂O mass ratios shows a decreasing trend with increasing temperature, and the fluidity increases with increasing temperature, indicating that the melt fluidity is improved. The suitable fiber-forming temperature of the melting-separated red mud shows a trend of increasing–decreasing–increasing with an increasing CaO/Na₂O mass ratio, and at a CaO/Na₂O ratio of 3.0, the maximum suitable fiber-forming temperature is 81 °C. Considering the feasibility of slag wool preparation from modified melting-separated red mud, the CaO/Na₂O of the modified raw material system should not be higher than 3.0. The crystallization temperature of modified melting-separated red mud with different CaO/Na₂O mass ratios first increases and then decreases, with a peak of 1450 °C at a CaO/Na₂O ratio of 4.0. Slag wool prepared from modified melting-separated red mud with different CaO/Na₂O mass ratios exhibits good properties, with a diameter of 5.47–6.67 µm and a slag ball content of 2.7–8.4%. Full article

Incorporating blast furnace slag into the composition of paving concrete can be one of the cost-effective ways to completely eliminate by-products from the pig iron production process (approximately 70% granulated slag and 30% air-cooled slag). The possibility to reintroduce blast furnace slag back into the life cycle will provide significant support to current environmental concerns and the clearance of tailings landfills. Especially in recent years, granulated and ground blast furnace slag (GGBS) as a substitute for cement and air-cooled blast furnace slag (ACBFS) aggregates as a substitute for natural aggregates in the composition of concretes have been studied by many researchers. But concrete compositions with large amounts of incorporated blast furnace slag affect the mechanical and durability properties through the interaction between the slag, cement and water depending on the curing times. This study focuses on identifying the optimal proportions of GGBS as a supplementary cementitious material (SCM) and ACBFS aggregates as a substitute to natural sand such that the performance at 90 days of curing the concrete is similar to that of the control concrete. In addition, to minimize the costs associated with grinding GGBS, the hydration activity index (HAI) of the GGBS, the surface morphology, and the mineral components were analyzed via X-ray diffraction, scanning electron microscopy (SEM), energy dispersive spectrometry (EDX), and nuclear magnetic resonance relaxometry (NMR). The flexural strength, the basic mechanical property of road concretes, increased from 28 to 90 days by 20.72% and 20.26% for the slag concrete but by 18.58% for the reference concrete. The composite with 15% GGBS and 25% ACBFS achieved results similar to the reference concrete at 90 days; therefore, they are considered optimal percentages to replace cement and natural sand in ecological pavement concretes. The HAI of the slag powder with a specific surface area equivalent to that of Portland cement fell into strength class 80 at the age of 28 days, but at the age of 90 days, the strength class was 100. The results of this research present three important benefits: the first is the protection of the environment through the recycling of two steel industry wastes that complies with European circular economy regulations, and the second is linked to the consequent savings in the disposal costs associated with wastefully occupied warehouses and the savings in slag grinding. Full article

The purpose of the foundry is to provide the consumer with blanks for general machine-building (special) purposes which are as close as possible to the size of the future part in full compliance with the requirements. The competitiveness of these products is primarily dependent on the use of efficient and reliable smelting equipment which meets the necessary cost. The replacement of high-value ironworks and ironworks iron with steel scrap using induction melting furnaces (ICFs) reduces the cost of producing synthetic cast iron. However, this results in temperatures greater than 1500 °C, reduced lining stability and increased downtime of the smelter. As a result of the research carried out, a technology for the use of quartzite is proposed. Thereby, the purpose of this work is to establish temperature regimes for the smelting of synthetic pig iron, allowing the use in metal filling up to 70–90% of steel scrap; this leads to a reduction in the cost of purchasing bulk materials (depending on the brand of cast iron) up to 50% and, thus, increases the efficiency of synthetic cast iron smelting and castings production in general. After removal of the original moisture and the subsequent sintering of the manufactured lining, it provides the possibility of melting using the melting temperatures 1550–1600 °C. It increases the efficiency of the operation of the melting furnaces and eliminates the consumption of the ironworks and the melting of the cast iron in the blast furnace, as well as the cost of the lost alloy. As a result, metallurgical production will be able to reduce the volume of production and supply of cast iron for ironworks, which will improve their environmental situation during the production and processing of necessary raw materials. Full article

This study is aimed at developing a technology for processing electric arc furnace dust (EAFD) into granulated cast iron and a zinc-containing product. The study object was the dust from the EAF of PJSC Magnitogorsk Iron and Steel Works (Magnitogorsk, Chelyabinsk region). It has been established that the dust contains valuable components in the form of ZnFe₂O₄ and ZnO. The processing of EAFD involves the reduction of Fe and Zn in a charge from their oxygen-containing forms with C and CO. The content of the charge components was calculated in % as follows: EAFD—17.44; scale—51.33; hard coal—20.61; quartz sand—4.71; lime—5.91. The experiments in the high-temperature LHT 08/17 furnace (Germany) allowed for defining the optimal temperature regime for reduction melting. As a result of laboratory tests, granulated pig iron samples were obtained, containing in wt%: Fe—95.27; C—4.4; S—0.07, and others. Captured zinc-containing product after calcination (to remove halogens) contained 90.21 wt% ZnO. The resulting granulated pig iron is recommended as one of the charge components in electrometallurgical steel production. The zinc-containing product is recommended as a raw material for Zn production and others. Full article

A numerical simulation procedure is proposed for analyzing the partial replacement of pulverized coal injection by hydrogen, oxygen, and blast furnace gas (BFG) injections mixed with pulverized coal (PCI) within the tuyeres of large blast furnaces. The massive use of hydrogen-rich gas is extremely interesting for ironmaking blast furnaces in the context of net-zero carbon hot metal production. Likewise, this new approach allows for increasing productivity and for reducing the specific emissions of carbon dioxide toward a net-zero carbon ironmaking technology. Nevertheless, the mixture of pulverized coal injection and gas injection is a complex technology. In addition to the impact on chemical reactions and energy exchange, the internal temperature and gas flow patterns can also change drastically. With a view to assessing the state of the furnace in this complex operation, a comprehensive mathematical model utilizing multiphase theory was developed. The model simultaneously handles bulk solids (sinter, pellets, small coke, granular coke, and also iron ore), gas, liquid metal and slag, and coal powder phases. The associated conservation equations take into account momentum, mass, chemical species, and energy while being discretized and solved using finite volume techniques. The numerical model was validated against the reference operating conditions using 220 kg per ton of pig iron (kg/t_HM) of pulverized coal. Therefore, the combined injection of different concentrations of fuel hydrogen, blast furnace gas, and oxygen was simulated for replacing 40, 60, and 80 kg/t_HM of coal injection. Theoretical analysis showed that the best scenario with stable operation conditions could be achieved with a productivity increase of 20% corresponding to a CO₂ reduction of 15% and 60 kg/t_HM of PCI replacement. Full article

The objective of this study was to evaluate the possible changes of zinc (Zn), copper (Cu), iron (Fe) and ferritin during the entire productive cycle in fattening pigs and at different diurnal sampling times. Moreover, the possible effects of the presence of pen contaminants and storage stability at different temperature conditions were assessed. The analytes changed along the different phases of the fattening productive cycle, showing, in general, higher values at the initial phases. In addition, statistically significant variations were found in Zn and Cu measurements at different sampling times of the day. In the spectrophotometric assays, the values of all analytes significantly increased after adding high concentrations of feces or feed. However, when low concentrations of feces or feed were added, only Cu showed a significant increase. Overall, the salivary levels of Zn, Cu, Fe and ferritin in pigs can change during different fattening phases and the different hours of the day. These analytes were more stable at −80 °C and, if saliva is contaminated with feces or feed, it can lead to an increase in these analytes. Full article