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Highlights The influence of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of industrial unsaturated polyester resin PN‐1 is investigated experimentally. The iron ore concentrate, electrostatic precipitator dust, high alumina cement grade HAC‐1, shavings made of cast iron, fine grade sand are used as fillers. To improve the strength characteristics of polyester resin composites the small amount (0.2–1.0 wt%) of organosilicon additives such as synthetic silicone rubber, tris(trimethylsiloxy) phenylsilane, octamethyl cyclotetrasiloxane are used. The heat release kinetics is studied for different ratios between accelerator (cobalt naphthenate) and initiator (cyclohexanone peroxide). The time to reach the maximum temperature of the heat release is significantly reduced when a large amount of iron ore concentrate is used as filler. The temperature of maximum heat release decreases and the time to reach it increases when adding electrostatic precipitator dust in small amount of 5 wt% to the high filled by iron ore concentrate (295 wt%) composite system. The optimum in strength indicators associated with the ratio of different fractions in systems consisting of two fillers of different properties and granulometric composition is found. The highest values of compressive strength in the cement–iron ore concentrate and sand–iron ore concentrate systems are observed. An increase in the strength characteristics of composites by 15%–20% with organosilicon additive introduction is observed. The addition of the silicone rubber increases the strength properties of samples the most among all additives considered. Effect of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of polyester resin is found. The time to reach the maximum temperature of the heat release is significantly reduced when the resin is filled by a large amount of iron ore concentrate. The temperature of maximum heat release decreases when the electrostatic precipitator dust in small amount is added to the high filled by iron ore concentrate. An increase in the strength characteristics of composites by 15–20% with introduction of organosilicon additives is observed. [ABSTRACT FROM AUTHOR]

The effects of two cokes with different reactivity on the lump ore's metallurgical properties and coke's solution loss are investigated under the high‐temperature load reduction. The work used an improved test device for softening‐melting and dropping characteristics of iron ores in both CO2 and CO2H2O atmospheres. The deterioration behavior of highly reactive cokes is expounded under hydrogen‐rich conditions. High‐reactivity cokes under hydrogen‐rich conditions are more favorable for enhancing the breathability of charge and the penetration of the coke layer. However, it increased the thickness of the softening zone. High‐reactivity cokes had obvious internal and external reaction gradients. The solution loss reaction mostly occurred on the surface, with selectivity. The longitudinal stacking height, layer number, and order degree in the carbon structure decreases after the reaction. The carbon‐structure difference weakens between the shell and core. The enhancement of coke's reactivity, however, results in the significant loss of coke powders on its surface. Unreduced FeO and refractory Fe2SiO4 are more likely to appear in the droplets, which is not conducive to the reduction of Fe and the generation of slag crust in the furnace. The difficulty in separating lump ores and cokes is aggravated, and more iron‐containing charge remain in the furnace. [ABSTRACT FROM AUTHOR]

Real-time Fe content monitoring in iron ore slurry is crucial for evaluating concentrate quality and enhancing mineral processing efficiency. Laser-induced breakdown spectroscopy (LIBS) is a promising technique for the online monitoring of elemental content at industrial sites. However, LIBS measurements are hampered by the matrix effect and the self-absorption effect, limiting the precision of linear analytical processes. To overcome this, we propose to introduce a nonlinear processing unit based on the S-transform to incorporate nonlinearity into the data analysis process. This approach integrates a feature selection unit based on the spectral distance variable selection method (SDVS), a nonlinear processing unit based on the S-transform (ST), and a partial least squares regression model (PLS). To demonstrate the improvement in accuracy achieved through nonlinear processing, a comparative analysis involving five models, Raw-PLS, SDVS-PLS, ST-PLS, SDVS-ANN, and SDVS-ST-PLS, is conducted. The results reveal a significant improvement in the performance of the SDVS-ST-PLS model, effectively facilitating the successful application of the LIBSlurry analyzer to the mineral flotation process. [ABSTRACT FROM AUTHOR]

Bacterial exopolysaccharides (EPS) have emerged as one of the key players in the field of heavy metal-contaminated environmental bioremediation. This study aimed to characterize and evaluate the metal biosorption potential of EPS produced by a novel Psychrobacillus strain, NEAU-3TGS, isolated from an iron ore deposit at Tamra iron mine, northern Tunisia. Genomic and pan-genomic analysis of NEAU-3TGS bacterium with nine validated published Psychrobacillus species was also performed. The results showed that the NEAU-3TGS genome (4.48 Mb) had a mean GC content of 36%, 4,243 coding sequences and 14 RNA genes. Phylogenomic analysis and calculation of nucleotide identity (ANI) values (less than 95% for new species with all strains) confirmed that NEAU-3TGS represents a potential new species. Pangenomic analysis revealed that Psychrobacillus genomic diversity represents an "open" pangenome model with 33,091 homologous genes, including 65 core, 3,738 shell, and 29,288 cloud genes. Structural EPS characterization by attenuated total reflectance-Fourier transform infrared (ATRFTIR) spectroscopy showed uronic acid and α-1,4-glycosidic bonds as dominant components of the EPS. X-ray diffraction (XRD) analysis revealed the presence of chitin, chitosan, and calcite CaCO3 and confirmed the amorphous nature of the EPS. Heavy metal bioabsorption assessment showed that iron and lead were more adsorbed than copper and cadmium. Notably, the optimum activity was observed at 37°C, pH=7 and after 3 h contact of EPS with each metal. Genomic insights on iron acquisition and metabolism in Psychrobacillus sp. NEAU-3TGS suggested that no genes involved in siderophore biosynthesis were found, and only the gene cluster FeuABCD and trilactone hydrolase genes involved in the uptake of siderophores, iron transporter and exporter are present. Molecular modelling and docking of FeuA (protein peptidoglycan siderophore-binding protein) and siderophores ferrienterobactine [Fe+3 (ENT)]-3 and ferribacillibactine [Fe+3 (BB)]-3 ligand revealed that [Fe+3 (ENT)]-3 binds to Phe122, Lys127, Ile100, Gln314, Arg215, Arg217, and Gln252. Almost the same for [Fe+3 (ENT)]-3knowledge, this is the first report on the characterization of EPS and the adsorption of heavy metals by Psychrobacillus species. The heavy metal removal capabilities may be advantageous for using these organisms in metal remediation. [ABSTRACT FROM AUTHOR]

OnabotulinumtoxinA (BTX-A) was first linked to beneficial effects in migraine 25 years ago and was approved by the FDA for preventive treatment of chronic migraine in 2010. The treatment has since had a major impact on the well-being of people with chronic migraine. The clinical development programme for BTX-A and research since its approval have provided insights into the neuromodulatory sensory effect of BTX-A, how it can control chronic migraine despite its peripheral action, and the underlying biology of migraine as a disease. In this Review, we consider the impact that BTX-A has had on the management of chronic migraine and on the research field. We discuss the insights provided by clinical research, encompassing the clinical trials and subsequent real-world evidence, and the mechanistic insights provided by preclinical and translational research. We also provide an overview of future directions of research in the field BTX-A in migraine and the clinical translation of this research. OnabotulinumtoxinA was first linked to beneficial effects in migraine 25 years ago and has since become a widely used treatment for chronic migraine. In this Review, Pozo-Rosich and colleagues consider the impact that onabotulinumtoxinA has had on the management of chronic migraine and on the research field. Key points: Since its approval for the treatment of chronic migraine, onabotulinumtoxinA (BTX-A) has positively affected the well-being of people with the disease. The clinical development programme for BTX-A led to an important change in the primary outcome measure used in migraine clinical trials, from frequency of attacks to number of headache days per month. Mechanistic research has provided insights into the neuromodulatory and anti-inflammatory effects of BTX-A, which are important in understanding its beneficial effects in migraine. BTX-A can prevent and reverse central sensitization, improve headache frequency and intensity of pain, and improve associated symptoms, such as anxiety and depression. Unilateral pain and a shorter disease duration are clinical predictors of good response to treatment with BTX-A. The presence of iron deposits in the red nucleus and periaqueductal grey matter is associated with poorer responses to BTX-A treatment. [ABSTRACT FROM AUTHOR]

Disturbance in iron homeostasis has been described in Parkinson's disease (PD), in which iron regulatory protein 2 (IRP2) plays a crucial role. IRP2 deletion resulted in the misregulation of iron metabolism and subsequent neurodegeneration. However, growing evidence showed that the levels of IRP2 were increased in the substantia nigra (SN) in MPTP-induced PD mice. To further clarify the role of increased IRP2 in PD, we developed IRP2-overexpressed mice by microinjecting AAV- Ireb2 in the SN. These mice showed decreased motor ability, abnormal gait and anxiety. Iron deposits induced by increased TFR1 and dopaminergic neuronal loss were observed in the SN. When these mice were treated with MPTP, exacerbated dyskinesia and dopaminergic neuronal loss were observed. In addition, TP53 was post-transcriptionally upregulated by IRP2 binding to the iron regulated element (IRE) in its 3′ untranslated region. This resulted in increased lipid peroxidation levels and induced ferroptosis through the SLC7A11-ALOX12 pathway, which was independent of GPX4. This study revealed that IRP2 homeostasis in the SN was critical for PD progression and clarified the molecular mechanism of ferroptosis caused by IRP2. [Display omitted] • IRP2 homeostasis in the SN is critical for PD progression. • IRP2 overexpression in the SN causes PD-like behavioral and pathological phenotypes in mice. • IRP2 overexpression causes the iron deposit and lipid peroxidation to induce ferroptosis. • TFR1-iron and p53-SLC7A11-ALOX12 pathway are involved in the neurotoxicity of IRP2 overexpression. [ABSTRACT FROM AUTHOR]

Dephosphorization is essential for utilizing high-phosphorus iron ore (HPIO), and this work prepared reduced iron powder via reductive roasting in a semi-industrial rotary kiln follower by magnetic separation. Under the conditions, reductive temperature of 1150°C, duration time of 60 min, mass ratio of briquettes to pea coal of 1:1, the reduced iron powder with an iron grade of 93.21% and phosphorus content of 0.13% was obtained, of which the corresponding iron recovery is 82.68% and dephosphorization ratio is 89.87%. The limestone reacted with gangue to form calcium aluminum silicate, preventing the reduction of phosphorate and in turn the formation of ferrophosphorus. [ABSTRACT FROM AUTHOR]

Predicting the liberation distribution of minerals in comminuted ore particles is one of the fundamental problems in mineral processing. However, there is still no widely accepted liberation model due to the complexity of the mineral fracture mechanism. In this study, the shape constants of the cumulative beta distribution were further optimized based on the investigation of the liberation distribution and fracture mechanism of iron oxide minerals in three types of iron ores with different grain sizes by locked-cycle grinding and batch grinding to model the liberation distribution of iron oxide minerals with different grinding methods. The results showed that the liberation distribution of iron oxide minerals in the three types of iron ores with locked-cycle grinding and batch grinding was related to intergranular fracture proportion and the closeness of ore particle size and mineral grain size. By relating the shape constants of cumulative beta distribution to ore particle size, mineral grain size, and the proportion of intergranular fracture, the developed liberation model well predicted the liberation distribution of iron oxide minerals with different grinding methods and its coefficient of determination (R2) was between 0.85–0.93. [ABSTRACT FROM AUTHOR]

A large amount of waste is generated during the processing of granite, resulting in negative impacts on the environment. As part of an environmental commitment, granite waste is currently recovered to obtain feldspar minerals, one of the main raw material for ceramic products. Nevertheless, the requirement of the ceramic industry for feldspar ore with low iron impurities complicates their recovery from granite waste. Various studies deal with the concentration of feldspar minerals, this literature review focuses on the different techniques used in the purification of feldspar minerals from its ferromagnetic impurities. The removal and liberation of iron-bearing minerals involves various mineral treatments, of which magnetic separation, leaching, and flotation are the main purification methods used. Several studies have been carried out on the application of these three techniques separately and combined, to obtain a feldspar concentrate with a low content of colored impurities that meets the requirements of the ceramic and glass industries. [ABSTRACT FROM AUTHOR]

This paper presents the results of a selective flocculation/magnetic separation study performed with a sample of iron ore slime from the desliming stage of the industrial flotation circuit of a mine in the southern region in the Quadrilátero Ferrífero-Brazil that was discarded in a tailings dam. Zeta potential measurements of pure minerals previously identified in the sample (goethite = 52.4%, hematite = 26.2%, quartz = 12.3%, kaolinite = 8.2%, and others = 0. 9%) were evaluated to assess the influence of the reagents used (sodium hexametaphosphate – SHMP (dispersant)) and flocculants (corn starch, nonionic polyacrylamide – P2500 and cationic polyacrylamide – P806)) on their surface properties and consequently on the stability of suspensions of the slime and of the pure minerals individually, aiming to establish conditions for selective separation between Fe-bearing minerals (goethite and hematite) and gangue minerals (quartz and kaolinite) in the subsequent magnetic separation step. At pH 10 and a 25 mg/L dosage of SHMP, a higher Fe recovery was verified with starch (2000 g/t) in relation to nonionic and cationic polyacrylamides, and similar Fe contents in all dosages tested of the flocculants. [ABSTRACT FROM AUTHOR]

Recently, geopolitical conflicts continue to intensify, with profound effects on global supply security of key mineral resources. Considering China's high dependence on foreign iron ore, once there is an import shortage, what impacts will it have on China's macro-economy and environment? Thus, using a computable general equilibrium model, this study introduced import supply disruption behaviour to assess the economy-wide and environmental effects of a large-scale iron ore import shortage on China. Furthermore, two supporting measures of enhancing upstream mining and cancelling steel import tariffs were constructed. The results demonstrated that an import shortage of iron ore will generate a negative effect on China's GDP and household welfare, wherein the higher the disruption degree, the greater the negative effect will be, and the maximum loss of GDP is 5.6 % in 2035. Secondly, total energy demand has reduced obviously, and the largest decline is 8.8 % in 2035. Particularly, the coal demand is most negatively affected by GDP loss, shrinking by up to 11.4 % by 2035. Meanwhile, the oil and gas demands have also dropped to some degree. Thirdly, the import disruption will help to reduce carbon emissions (by up to 9.9 % in 2035), but also have obvious environmental benefits. Finally, both measures will help alleviate the negative socio-economic impacts; however, the overall effects will be better if enhancing upstream mining is complemented by carbon pricing. [ABSTRACT FROM AUTHOR]

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Comminution, particularly post-crushing, is a critical phase in mineral processing that reduces run-of-mine ore to an acceptable particle size before undergoing a downstream beneficiation process. Despite its importance, this stage has been under-investigated probably due to challenges of sampling and data collection and inadequate technical and financial support. This research presents a multi-method machine learning framework designed to simulate the power dynamics within an industrial-scale iron ore cone crusher circuit. The framework integrates advanced artificial intelligence techniques to evaluate energy consumption and estimate cone crushers output K80 accurately. The developed framework spans from different algorithms by data preprocessing techniques such as normalization and Principal Component Analysis (PCA) to standardize and reduce the dataset’s dimensionality, coupled with multiple machine learning algorithms, including Gradient Boosting Machines (CatBoost, LightGBM, XGBoost), Support Vector Regression (SVR), and Long Short-Term Memory (LSTM) networks. The study utilized real-time data collected over six months by considering the key operational parameters such as total tonnage, hopper filling levels, power draw, cone position, and crusher discharge settings. The modeling approach was assessed using Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Asymmetric Loss (AL), and the coefficient of determination (R2) as performance metrics. Results indicated that the LSTM model outperformed other methods by achieving the lowest MAE and RMSE and the highest R2 score of 0.92, thereby demonstrating superior precision in estimation. However, XGBoost showed optimal performance in managing asymmetric loss, highlighting its efficiency in error management across different scenarios. Model residual analysis, performance metrics box plots, and scatter plots comparing measured and estimated data across the models are also provided for further analysis. This study demonstrates the transformative potential of machine learning models in refining industrial process simulations, ultimately driving enhanced productivity and sustainability in the mining industry. [ABSTRACT FROM AUTHOR]

In this research, the reduction of iron ore sinter in a blast furnace (BF) simulator in CO–CO2–N2‐reducing gas, simulating conditions at the BF center and wall, is investigated. Measurements from an operating BF guide the study, ensuring realistic reduction parameters. Reduction rate and extent, along with physical properties, are assessed under a temperature range of 700–1100 °C. In isothermal reduction experiments, the BF center exhibits superior conditions, particularly at 900 °C, achieving an 83.78% reduction degree compared to 27.17% at the wall for the same temperature. In this study, it is highlighted that basic iron ore sinter demonstrates higher reduction efficiency compared to acid iron ore pellets under identical BF center reducing conditions. Specific surface area and porosity measurements unveil a contrasting trend in specific surface area and porosity evolution between the BF wall and center. Surface morphology analysis reveals that the reduction in specific surface area and porosity of sinter samples at the BF center conditions at 1000–1100 °C is attributed to the sintering of the formed metallic iron. Carbon analysis confirms no carbon deposition took place during reduction. Mineralogical and physical property analyses provide detailed insights into the evolving phase composition during sinter reduction. [ABSTRACT FROM AUTHOR]

Neuromelanin-pigmented neurons of the substantia nigra are selectively lost during the progression of Parkinson's disease. These neurons accumulate iron in the disease state, and iron-mediated neuron damage is implicated in cell death. Animal models of Parkinson's have evidenced iron loading inside the nucleoli of nigral neurons, however the nature of intranuclear iron deposition in the melanised neurons of the human substantia nigra is not understood. Here, scanning transmission x-ray microscopy (STXM) is used to probe iron foci in relation to the surrounding ultrastructure in melanised neurons of human substantia nigra from a confirmed Parkinson's case. In addition to the expected neuromelanin-bound iron, iron deposits are also associated with the edge of the cell nucleolus. Speciation analysis confirms these deposits to be ferric (Fe3+) iron. The function of intranuclear iron in these cells remains unresolved, although both damaging and protective mechanisms are considered. This finding shows that STXM is a powerful label-free tool for the in situ, nanoscale chemical characterisation of both organic and inorganic intracellular components. Future applications are likely to shed new light on incompletely understood biochemical mechanisms, such as metal dysregulation and morphological changes to cell nucleoli, that are important in understanding the pathogenesis of Parkinson's. Showcasing the application of scanning transmission x-ray microscopy to study the oxidation state of intranuclear iron in nigral neurons. Implications and potential future applications are discussed. [ABSTRACT FROM AUTHOR]

The thermal efficiency for the pelletizing process is intrinsically linked to the diameter and humidity of the iron ore pellets, so that the sensing of the granulometric range in the formation of the pellets becomes essential to the flow of the pelletizing process in the steel industry; this paper presents the assembly of a computer vision system for the detection and segmentation of pellets aiming at the automation of the granulometric measurement, following its formation in the pelletizing disk, using the instance segmentation method to verify whether the particle granulometric distribution (PSD) is adequate for "real-time" applications. The system calculates the normal distribution of the diameter in millimeters, evaluating the normal curve and the standard deviation of the segmented pellets, using a deep neural network based on the You Only Look At CoefficienTs (YOLACT) network, adding speed and precision in the granulometric analysis. In the sample sets, the need for adjustment factors inherent to the pelletizing process became evident. This led to the establishment of the computer vision system, termed the Volumetric Correction Factor (VCF) and Visual Overlay Factor (VOF). The VCF is utilized to estimate the volume of pellets within the pelletizing disk during operation, while the VOF adjusts the millimeter-per-pixel (mpp) ratio. The results of the measurement system proved to be efficient in real-time granulometric measurement. [ABSTRACT FROM AUTHOR]

This study proposed a strategy to prepare metalized pellets for direct steelmaking by hydrogen cooling reduction (HCR) of iron ore pellets with a focus on the effect of H2 flow rate on the process. It was demonstrated that increasing H2 flow rate could effectively enhance the reduction performance of iron ore pellets. However, due to the influence of the countercurrent diffusion resistance of gas molecules, too high H2 flow rate no longer promoted the reduction of the pellets when the maximum reduction rate was reached. The reduction swelling index (RSI) of the pellets initially increased and then decreased with increasing H2 flow rate. This change was associated with the decreased content of Fe2SiO4 in the metalized pellets and the changes in porosity and iron particle size. The compressive strength (CS) decreased continuously, showing a sharp decline when the H2 flow rate reached 0.6 L/min. It was attributed to the significant increases in porosity and average pore size of the metalized pellets, with the presence of surface cracks. When the H2 flow rate was 0.8 L/min, the metalized pellets had the optimal performance, namely, reduction degree of 91.45%, metallization degree of 84.07%, total iron content of 80.67 wt%, RSI of 4.66%, and CS of 1265 N/p. The findings demonstrated the importance of controlling the H2 flow rate in the preparation of metallized pellets by HCR. [ABSTRACT FROM AUTHOR]

The study of the cementitious material activity of industrial solid wastes is a key issue in the comprehensive utilization of its green building materials. In this study, mechanical activation was used to prepare cementitious materials from vanadium-titanium iron ore tailings (VTIOT) as the main raw materials, and the effects of grinding time, the key parameter, on the grinding characteristics of VTIOT, the mechanical properties of the VTIOT cementitious material, and the hydration mechanism were investigated by means of surface area analysis, particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), alkali leaching, mechanical testing, hydration heat analysis, and thermogravimetric analysis (TGA). The results show that: the grinding time and specific surface area of VTIOT exhibit a linear correlation. Prolonging the grinding time, the fractal dimension of the particles gradually increases. The activity of Si4+ and Al3+ elements increases rapidly, reaching a Si4+ and Al3+ content of 96 mg·L−1 at 90 min of grinding. With a VTIOT mixing amount of 30 %, a mortar paste ratio of 1:3, and a water cement ratio of 0.5, the 50 min ground VTIOT mortar demonstrates 7 d and 28 d compressive strengths of 29 MPa and 38.7 MPa, corresponding to the highest values of the activity index, measured at 71.4 % and 75.2 %, respectively. Under standard curing conditions, the hydration products of cementitious materials at 7 d are ettringite (AFt), calcium silicate hydrate (C-S-H), alumina, ferric oxide, monsulfate (AFm), calcium hydroxide (Ca(OH) 2), and calcium silica (CS). In the hydration process of 7 d, the exothermic peak and exothermic amount of the 50 min VTIOT cementitious materials are greater than those observed for other grinding times, but lower than those of pure reference cement. [ABSTRACT FROM AUTHOR]

Rock quality designation (RQD) is a parameter that describes rock mass quality in terms of percentage recovery of core pieces greater than 10 cm. The RQD represents a basic element of several classification systems. This paper studies scale effects for RQD measurements using synthetic rock masses generated using discrete fracture network (DFN) models. RQD measurements are performed for rock masses with varying fracture intensities and by changing the orientation of the simulated boreholes to account for orientation bias. The objective is to demonstrate the existence of a representative elementary length (REL, 1D analogue of a 3D representative elementary volume, or REV) above which RQD measurements would represent an average indicator of rock mass quality. For the synthetic rock masses, RQD measurements were calculated using the relationship proposed by Priest and Hudson and compared to the simulated RQD measurements along the boreholes. DFN models generated for a room-and-pillar mine using mapped field data were then used as an initial validation, and the conclusion of the study was further validated using the RQD calculation results directly obtained from the depth data collected at an iron cap deposit. The relationship between rock mass scale and assumed threshold length used to calculate RQD is also studied. [ABSTRACT FROM AUTHOR]

Potentially harmful element (PHE) bioavailability is important to environmental contamination and must be checked under several soil conditions. This study aimed to assess Fe, Mn, and PHE uptake by rice (Oryza sativa) grown on flooded and non-flooded Fe tailings collected from the Doce River basin after its collapse in Brazil. After 65 days of sowing, shoots and roots were harvested to determine PHE concentrations. The mean concentrations of Mn in shoots and Fe in the roots of rice grown on the flooded tailings were 2140 mg kg−1 and 15,219 mg kg−1, respectively. Mn was extensively translocated from roots to shoots (translocation factor (TF) = 2). Conversely, Fe accumulated in roots (TF = 0.015) and caused morphological damage to this rice organ. The application of macro and micronutrients lessened Fe toxicity in the roots of rice cultivated on the flooded tailings. The flooding of tailings influenced more Fe accumulation than Mn accumulation by rice plants. The PHE Ag, As, Cd, Ni, Hg, Pb, and Sb exhibited low total concentrations (maximum of 9 mg kg−1 for Ni and a minimum of 0.2 mg kg−1 for Cd, Hg, and Sb), and it was not observed an increase in their availability under tailings flooding conditions. [ABSTRACT FROM AUTHOR]

Electroplating sludge (ES), the inevitable by‐product of electroplating wastewater treatment processes, has been conventionally managed via solidification landfilling or thermal processing; these methods may engender secondary environmental pollutants. This study proposes an innovative approach using iron ore sintering for effective ES treatment. The study reveals that incorporating 1.0% ES reduces the yield quality of the sintered ore, yet it remains within acceptable thresholds. It is noteworthy that when the addition of ES is 0.5%, it not only increases the sinter yield from 68.57% to 69.23% but also enhances the productivity from 1.19 to 1.32 t (m2 h)−1. Furthermore, the consumption of solid fuel decreases to 48.01 kg t−1. Additionally, the treatment method significantly reduced the emissions of CO and NOx in the sintering flue gas, with the average concentrations decreasing from 12681.32 to 9744.51 ppm for CO and from 244.81 to 161.11 ppm for NOx. This study investigates the migration and transformation mechanisms of nickel and chlorine elements in ES by conducting inductively coupled plasma analysis on the sintered raw materials and their products, as well as scanning electron microscopy with energy dispersive X‐ray spectroscopy analysis on the sinter ash. [ABSTRACT FROM AUTHOR]

Cobalt is a critical and strategic metal mainly found as associated element in several types of deposits, of which skarn‐type deposits are the major sources. Han‐Xing type skarn iron deposit, having high grade iron ore and associated cobalt, is a typical skarn‐type iron ore in China. But the complete recovery and exploitation of cobalt are restricted because of the lower grade of related cobalt and the dearth of prior research on its occurrence condition and enrichment mechanism. In this paper, pyrite from five typical ore deposits in the Han‐Xing area was studied by using electron probe microanalysis (EPMA) and laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA–ICP–MS) techniques to decipher the occurrence state and enrichment mechanism of associated cobalt in skarn‐type iron deposits. The results show that Co2+ replaces Fe2+ in pyrite through isomorphism. The distribution of cobalt in pyrite from different deposits varies greatly, that is, in the Xishimen iron deposit, the cobalt content is comparatively enriched in the pyrite's core. In contrast, in other deposits, the cobalt content is concentrated in the pyrite's rims, where it can be up to 1000 times higher than in the core. The cobalt mineralization in Han‐Xing area can be divided into several stages. The sulphur element of sulphide is mainly derived from evaporite, while cobalt mineralization occurred in the early stage with pyrite formation or in the late stage by metasomatism/cementation of Co‐rich ore‐forming fluid. The magma assimilated with the Ordovician evaporite not only promoted iron mineralization, but also became the main controlling factor for cobalt enrichment. [ABSTRACT FROM AUTHOR]

High-iron Bayer red mud, containing over 30% of iron, is considered low-grade iron ore. Due to the global iron deficiency in recent decades, the effective utilization of the iron contained in high-iron red mud has received increasing attention. In this work, a technological scheme was developed for the extraction of iron into cast iron from red mud by smelting reduction, followed by rapid cooling to separate the metal from the slag. The influence of various experimental parameters, including temperature, basicity, and reduction time, on the recovery of iron from red mud was studied in detail. The results demonstrated that the separation of metal from slag was complete. The maximum extraction of iron into cast iron was obtained at a temperature of 1450 °C, with approximately 88.5% achieved in the absence of sodium carbonate and 91.5% with sodium carbonate. The optimal experimental result is of great importance for the large-scale and highly efficient recycling of red mud. [ABSTRACT FROM AUTHOR]

This paper gives an overview of findings, connected with metallurgical activity, at the Pržanj archeological site near Ljubljana, Slovenia. More than 230 kg of slag and other remains connected with early medieval (from the 5th to the 12th century AD) metallurgical activities was found at the excavation site. The remains were grouped into four categories, i.e., furnace remains, ore, slag and a ferrous product, and analyzed in detail to obtain their chemical composition, microstructural characteristics, and mineral phase composition. The furnace wall remains, identified by their morphology and chemical composition, revealed an intensive iron processing activity at the site. The iron ore at the site was identified as goethite (FeO(OH)), a surprising find in Slovenia where limonite is typically used, and its presence suggests the potential exploitation of local bog iron ore, given the site's geological context. Abundant slag remains at the site, identified by their shape, molten microstructure, and mineral components like wuestite, fayalite, and hercynite, indicated sophisticated smelting practices, including the use of CaO-rich materials to lower the melting temperature, a technique likely preserved from antiquity. Findings of ferrous products at ancient metallurgical sites are rare due to their value, but the discovery of a corroded iron bloom conglomerate at this site, initially mistaken for furnace remains, highlights the challenges in identifying small, corroded ferrous fragments that are often misidentified as ore. The results indicate extensive metallurgical activity at the excavation site, marking it as the first documented early medieval iron smelting production site in Slovenia. [ABSTRACT FROM AUTHOR]

Bulk geochemistry, Sr, Nd, and O–H isotope systematics are reported for the first time on banded iron formation (BIF)-hosted high-grade iron ore at the north-western segment of Congo Craton (CC). Located in Mbalam iron ore district, Southern Cameroon, Metzimevin iron ore deposit is a hematite-magnetite BIF system, dominated by SiO2 + Fe2O3 (97.1 to 99.84 wt%), with low concentrations of clastic elements e.g., Al2O3, TiO2, and HFSE, depicting a nearly pure chemical precipitate. The REE + Y signature of the iron deposit displays strong positive Eu anomaly, strong negative Ce anomaly, and chondritic to superchondritic Y/Ho ratios, suggestive of formation by mixed seawater-high temperature hydrothermal fluids in oxidising environment. The 87Sr/86Sr ratios of the BIF are higher than the maximum 87Sr/86Sr evolution curves for all Archean reservoirs (bulk silicate earth, Archean crust and Archean seawater), indicating involvement of continentally-derived components during BIF formation and alteration. The ƐNd(t) (+ 2.26 to + 3.77) and Nd model age indicate that chemical constituents for the BIF were derived from undifferentiated crustal source, between 3.002 and 2.88 Ga. The variable and diverse O and H isotope data (− 1.9‰ to 17.3‰ and − 57‰ to 136‰ respectively) indicate that the Metzimevin iron ore formed initially from magmatic plumes and later enriched by magmatic-metamorphic-modified meteoric fluids. Mass balance calculations indicate mineralisation by combined leaching and precipitation, with an average iron enrichment factor of > 2.67 and SiO2 depletion factor of > 0.99. This is associated with an overall volume reduction of 28.27%, reflecting net leaching and volume collapse of the BIF protholith. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increase in environmental catastrophes involving mining dam failures. This study assessed the potential risks of iron ore tailings in riparian soils to human health after the worst dam collapses recorded in Brazil: from Córrego do Feijão Mine-CFM and Fundão. Chemical monitoring data from the three-year time interval since the collapses were used to estimate human risk indexes for trace elements such as arsenic, cadmium, chromium, mercury, nickel, lead, and zinc. In both case studies, the adult group indicated a propensity for the development of non-carcinogenic diseases through ingestion, inhalation and dermal pathways for all contaminated areas. Overall, children showed an exacerbated sensitivity to possible cancerous and non-cancerous effects, especially in the areas surrounding the dams and in Barra Longa, São José do Goiabal, Córrego Novo, Veneza, Periquito, Governador Valadares, Tumiritinga, Conselheiro Pena, Honório Fraga and Linhares (from the Fundão dam) and in all study areas from the CFM dam. These assessments demonstrate that in regions with mining activities, the cumulative effects of trace elements over time are harmful and expected. Therefore, there is a need for greater supervision by competent government bodies of conservation practices that enable environmental recovery or mitigation of their impacts, ensuring appropriate health and well-being conditions for local residents and workers. [ABSTRACT FROM AUTHOR]

The Wutonggou iron deposit is located in the well-known iron metallogenic belt in the eastern Tianshan, NW China, and has been regarded as a sedimentary iron deposit. Although hydrothermal overprinting could play indispensable roles in the formation of high-grade iron ores in sedimentary iron deposits, previous studies mainly focused on sedimentary-related iron mineralization, while the nature and contribution of hydrothermal fluids are poorly constrained. Accordingly, an integrated study of ore geology, H-O-C isotopes and 40Ar-39Ar dating, is conducted on the Wutonggou deposit, in order to reveal the features, source, and timing of hydrothermal mineralization. The studied deposit includes two mining sections namely the Jianshan and Wutonggou. The δ18O values of early magnetite from the Jianshan section range from +3.0‰ to +5.8‰ that nearly consistent with classic magmatic magnetite, while increase to 6.3‰–8.0‰ in the late stage. Quartz from the two sections shows comparable H-O isotopic compositions and identical fractionation trends, and is plotted in or periphery to the primary magmatic water area. Calcites from the two sections are broadly similar in carbon and oxygen isotopic compositions, and siderite from the Wutonggou section is plotted in the same region. Thus, comparable stable isotopic compositions and evolution trends indicate similar magmatic fluids contributed hydrothermal iron mineralization in the two mining sections. Moreover, water-rock interactions of varying degrees generated distinct mineralization styles in the Jianshan and Wutonggou sections, and caused the isotopic fractionation in late stages. Biotite extracted from a hydrothermal siderite ore yielded a 40Ar-39Ar plateau age of 299.5 ± 2.0 Ma, indicates the timing of hydrothermal iron mineralization is corresponding to the emplacement of vicinity granitoids. Taken together, the hydrothermal mineralization in the Wutonggou iron deposit was the product of remobilization and upgrading of early sedimentary iron ores, and ore-forming fluids were most probably originated from regional granitic magmatism. [ABSTRACT FROM AUTHOR]

In this research, we propose an environmentally friendly method for producing hematite nanoparticles (H‐NPs) from natural hematite ore, focusing on their application as efficient contrast agents in x‐ray and computed tomography (CT) imaging for medical purposes. The process involves the reduction of iron oxide within the ore to attain the desired hematite phase, crucial for synthesizing H‐NPs. To ensure sustainability, we adopted a Green Chemistry approach, utilizing a combination of carbon soot and limestone for the purification process, thereby achieving eco‐conscious production. The produced H‐NPs were thoroughly characterized using various analytical techniques, such as x‐ray fluorescence (XRF), x‐ray diffraction (XRD), Fourier transmission infrared spectroscopy (FT‐IR), and FESEM‐EDX (field emission scanning electron microscopy‐energy‐dispersive x‐ray spectroscopy). XRD analysis confirmed the crystalline rhombohedral hexagonal lattice structure, while FT‐IR spectra indicated the presence of characteristic Fe–O stretching modes in line with the expected molecular composition. FESEM‐EDX imaging unveiled agglomerated particles, ranging in size from 54.6 to 149.9 nm for iron ore and 22 nm for H‐NPs. These particles were primarily composed of iron (Fe) and oxygen (O). The magnetic properties of the H‐NPs were investigated through vibrating sample magnetometer (VSM) studies, highlighting their distinct ferromagnetic behavior. Of particular significance, the H‐NPs demonstrated exceptional performance as contrast agents in both x‐ray and CT imaging. Even at minimal concentrations, they exhibited remarkable x‐ray absorption capabilities. CT scans further validated their exceptional absorptive capacity. These findings emphasize the potential of H‐NPs as valuable assets in medical imaging, serving as sustainable tools for enhanced diagnostic applications. The study showcases an eco‐conscious approach to harnessing natural resources, paving the way for a greener and more effective utilization of H‐NPs in the medical imaging landscape. [ABSTRACT FROM AUTHOR]

Lately, dry stacking of filtered tailings has emerged as a safer alternative to traditional slurry disposal in ponds as it comprehends the compaction of the unsaturated cake to form piles. A cementing agent can be added to the mixture to improve the mechanical properties of the compacted tailings; however, it is essential to understand its response under different conditions. The present study examines the mechanical behavior of compacted iron ore tailings (IOT)-binder blends for dry stacking purposes, highlighting the effect of the cement type on the behavior of the tailings: two commercially available types of binders, portland pozzolan cement (PPC) and high early-strength portland cement type III (PC III); and one green alkali-activated cement (AAC). A full factorial design approach was used to study the influence of the following parameters on the strength and stiffness of the studied mixtures: dry unit weight (γd), cement content (C), type of cement (TC), and curing period (CP). To do so, a set of unconfined compression, ultrasonic pulse velocity, and consolidated drained triaxial tests were carried out. To compare the microstructural and compositional characteristics of the three different cement types, secondary scanning electron microscopy (SSEM) and backscattered scanning electron microscopy (BSEM)/energy dispersive spectrometry (EDS) analyses were performed. The stiffness and strength results have been successfully correlated to the porosity/cement index (η/Civ) and the statistical analysis has unveiled the great effects attributed to the cement content, type, and CP. Additionally, microstructural and macrostructural observations revealed that after seven days of curing, the IOT mixtures stabilized with PC III exhibited more robust microstructures and superior mechanical performance: around five times greater strength and stiffness than AAC-containing samples and two times higher considering the PPC-containing specimens. With extended CPs (90 days), the performances of PC III and PPC samples are equivalent, whereas the strength is around three times greater than that of the AAC samples. That is, there was a notable enhancement in the cementitious matrix for IOTs stabilized with PPC and AAC for a more extended CP. [ABSTRACT FROM AUTHOR]

Soil mechanics traditionally have focused on studying pure clays and clean sands. However, natural soils and other geomaterials usually do not fall into these two classes. Most geomaterials are a complex matrix of fines and coarser particles, with distinct shapes and mineralogy interacting. This paper studied iron ore tailings over a broad range of pressures and stress histories to investigate the mechanical behavior of this nontextbook geomaterial. A thorough experimental program was conducted, and aspects of the stress–strain response, yielding, hardening, and critical state were evaluated. The state boundary surface of iron ore tailings also was investigated. The results demonstrated that the stress history of tailings affects the tailings' behavior only at elevated stress levels. The existence of particles with distinct mineralogy in the iron ore tailings (mainly iron oxide and quartz) could have induced different breakage patterns, with an evolving particle morphology being the dominant mechanism up to the pressures achieved. [ABSTRACT FROM AUTHOR]

The Washan iron deposits in Ningwu district contain different magma-related genetic natures, including magmatic, magmatic–hydrothermal and hydrothermal types, and their ore-forming processes remain a subject of debate. To elucidate the ore-forming processes of iron ores from Washan, we present textural, major element analytical, and thermal data of magnetites from various ore bodies in Washan, probing the crystallization conditions and subsequent formation sequence of magnetites. SEM analysis with back-scattered electron (BSE) imaging reveals diverse magnetite textures, including mineral inclusions, exsolution lamellae, and recrystallization features, reflecting the transitional environment from magmatic to hydrothermal. Based on Ti, V, and Cr compositions of magnetite from different ore bodies, two distinct evolution trends of genetic processes are identified, including evolution paths from porphyry-type to IOA- and IOCG-type magnetite. High-resolution WDS mapping highlights the intensifying alterations during this process. Calculated magnetite crystallization temperatures among different types of magnetite range from 597 °C to 378 °C, suggesting a cooling trend from porphyry-type magnetite (~558 °C) to IOA-type magnetite (~515–439 °C) and IOCG-type magnetite (~378 °C). These results underscore the significant role of magma-derived hydrosaline liquids and vapors in the formation of iron ores from Washan, where variations in the salinity of ore-forming fluids lead to different evolutionary paths for subsequent generations of magnetite. The metallogenic model of the Washan iron deposit suggests that highly saline, iron-rich fluids connect the varying geneses of magnetite, transitioning from deeply formed porphyry-type magnetite to IOA- or IOCG-type magnetite generated in the subaerial zone. [ABSTRACT FROM AUTHOR]

Depending on the ore quality, a washing process can be conducted with the bauxite, which basically consists of scrubbing the ore and screening in order to increase the available alumina grade, i.e., the alumina extractable using the Bayer Process, and reduce the impurity content. Tailings are usually disposed of in a tailings dam in the form of a slurry, which is a mixture of solid particles and liquid, consisting mainly of ultra-fine kaolinite, making the dewatering operation challenging. To reduce the environmental impact, mining companies are studying alternative methods to dewater the tailings, and different dewatering methods are available worldwide. The use of new technologies to dewater the tailings has contributed to facing the challenges of achieving sustainable development with their disposal. The decanter centrifuges are already an option for operations for the Canadian oil sands, gold ore in Peru, and nickel in New Caledonia; they are also being tested for iron ore in Brazil. In the present work, bauxite dewatering using the decanter centrifuge was evaluated to understand more about the behavior of these materials and to investigate the effects of various process parameters on the solid recovery and solid content of the flows, using three different kinds of equipment. The results indicated that decanter centrifuges can be used to achieve a high concentration of solids in the cake, with values ranging from 60% to 80% solids per weight and a great clarification in the liquid phase (centrate) from 0 to 6% solids per weight, values which mean the solid phase is suitable for reutilization in the processing circuit. Additionally, the present work provides a better understanding of how different solid contents feed can affect the behavior of the equipment. [ABSTRACT FROM AUTHOR]

The beneficiation of low-grade iron ores is a key research and development topic in the mineral processing industry. The gradual exhaustion of high-grade iron ore reserves, and rising consumer iron and steel demand globally necessitate efficient low-quality iron ore beneficiation to meet steelmaking quality requirements. This comprehensive review explores various beneficiation techniques for low-quality iron ore, focusing on conventional methods including comminution, froth flotation and gravity separation. This article discusses the principles, processes, and equipment used in these techniques and highlights recent advancements and research efforts in the field. This review also emphasizes the importance of effective beneficiation processes in enhancing economic viability, sustainable resource management, and environmental conservation. Furthermore, it presents a case study of iron ore deposits in Botswana, highlighting the potential economic growth and sustainable development that can be achieved by maximizing resource utilization through reductive roasting, followed by magnetic separation of iron ore using semi-bituminous coal as a reductant. Overall, this review provides valuable insights into low-grade iron ore beneficiation techniques and their significance in meeting the growing demand for high-quality iron and steel products. [ABSTRACT FROM AUTHOR]

An enrichment in nickel (Ni) or platinum group elements (PGE) is seldom observed in ores of the iron oxide–copper–gold (IOCG) type. This phenomenon is, however, known from a few deposits and prospects in the Carajás Mineral Province, Brazil. The Ni-PGE enrichment is explained, in part, by the spatial association of the IOCG-type ores with altered mafic-ultramafic lithologies, as well as by reworking and remobilization of pre-existing Ni and PGE during multiple mineralization and tectonothermal events across the Archean-Proterozoic. One such example of this mineralization is the Jatobá deposit in the southern copper belt of the Carajás Domain. This is the first detailed study of the Ni and PGE mineralization at Jatobá, with implications for understanding ore genesis. Petrographic and compositional study of sulfides shows that pyrite is the main Ni carrier, followed by pyrrhotite and exsolved pentlandite. Measurable concentrations of palladium (Pd) and platinum (Pt), albeit never more than a few ppm, are noted in pyrite. More importantly, however, the trace mineral signature of the Jatobá deposit features several platinum group minerals (PGM), including merenskyite, naldrettite, sudburyite, kotulskite, sperrylite, and borovskite. These PGM occur as sub-10 µm-sized grains that are largely restricted to fractures and grain boundaries in pyrite. All Pd minerals reported contain mobile elements such as Te, Bi, and Sb and are associated with rare earth- and U-minerals. This conspicuous mineralogy, differences in sulfide chemistry between the magnetite-hosted ore and stringer mineralization without magnetite, and microstructural control point to a genetic model for the sulfide mineralization at Jatobá and its relative enrichment in Ni and PGE. Observations support two alternative scenarios for ore genesis. In the first, an initial precipitation of disseminated or semi-massive Ni-PGE-bearing sulfides took place within the mafic rock pile, possibly in a VHMS-like setting. Later partial dissolution and remobilization of this pre-existing mineralization by mineralizing fluids of IOCG-type, possibly during the retrograde stage of a syn-deformational metamorphic event, led to their re-concentration within magnetite along structural conduits. The superposition of IOCG-style mineralization onto a pre-existing assemblage resulted in the observed replacement and overprinting in which PGE combined with components of the IOCG fluids like Sb, Bi, and Te. An alternative model involves leaching, by the IOCG-type fluids, of Ni and PGE from komatiites within the sequence or from ultramafic rocks in the basement. The discovery of PGM in Jatobá emphasizes the potential for additional discoveries of Ni-PGE-enriched ores elsewhere in the Carajás Domain and in analogous settings elsewhere. [ABSTRACT FROM AUTHOR]

The study of iron crusts containing iron-coated grains from different sections of the Prebetic (SE Iberia) and the overlying marine sedimentary rocks also containing iron-coated grains in the Prebetic and the Iberian Range (NE Iberia) allowed us to determine the palaeoclimatic and palaeoenvironmental conditions under which they originated. The iron crusts are mainly composed of clay minerals (kaolinite and illitic phases) and/or goethite and hematite. The kaolinite texture indicates that it is authigenic, whereas the illitic phases are probably detrital. The mineralogy and texture of the iron crusts allow us to classify them as plinthitic palaeosols. The iron-coated grains consisting of a nucleus and a cortex, both composed of a mixture of kaolinite, goethite, and hematite, originated in situ during the plinthite development. Reworking processes caused the fragmentation and incorporation of the iron-coated grains into the overlying ferruginous oolithic limestones and terrigenous-carbonated breccia. New marine iron-coated grains formed later in the ferruginous oolithic limestones. The high Chemical Index of Alteration and Chemical Index of Weathering values and the geochemical ratios (Ba/Sr, Rb/Sr, Sr/Cu, Ga/Rb) from iron deposits reflect intense weathering under warm and humid conditions in the South Iberian Palaeomargin during the Callovian–Oxfordian, which may also take place in the East Iberian Palaeomargin (Iberian Range). [ABSTRACT FROM AUTHOR]

Understanding the liberation properties of minerals in ores with different grinding degrees is very important for establishing liberation models. However, a detailed study of the effect of grinding degree on the liberation properties of minerals in ores is still highly desirable. In this study, three types of iron ores with different mineral grain sizes were ground to different particle size distributions by locked-cycle grinding and batch grinding. The liberation properties of iron oxide minerals and quartz in each grinding method and the size fraction product were analyzed using Mineral Liberation Analyzer (MLA). Statistical methods were used to quantify the extent of the difference in liberation properties between the two grinding methods. Furthermore, the fracture mechanisms of iron oxide minerals and quartz were investigated. It was found that the liberation degrees of the products were higher in locked-cycle grinding with a lower grinding degree. For fine-grained iron oxide minerals, the iron oxide minerals distribution of 80–100% composition class differed by 22% at −75 + 53 μm size fraction with the two grinding methods, and its corresponding standardized mean differences (SMD) was 20.5, indicating that the difference was statistically significant. The significant change in the percentage of intergranular fracture with different grinding degrees is the reason for the obvious difference in the liberation properties of the products. [ABSTRACT FROM AUTHOR]

The mining sector plays a significant role in the economic development of countries by contributing to their gross domestic product. Once the demand for commercialized ore grows, the mining industry looks for new technologies to boost exploration and manage residue disposal. One promising technique to dispose of these residues is dry stacking. This research investigates the behavior of cemented iron ore tailings (IOTs) that use unconfined compression strength (UCS) and triaxial testing. The UCS tests investigated different dosages of cement–tailings compacted blends. In addition, nine triaxial tests were carried out, where six were cured under atmospheric pressure, and three were cured under 300 kPa. Samples were sheared under mean effective stresses of 300 and 3,000 kPa. Both curing conditions were subjected to drained axial loading, constant mean effective stress (p′), and lateral unloading stress paths. The results indicate that the porosity/cement index (η/Civ) could control the mixtures' UCS. The triaxial tests revealed the effective strength parameters stress dependence. Samples that were consolidated under high stress might experience bond breakage, which leads to a decrease in the friction angle and a tendency toward critical state conditions. No meaningful variation was observed between samples that were cured under stress and atmospheric pressure. [ABSTRACT FROM AUTHOR]

The collapse of the Fundão dam was responsible for generating numerous environmental impacts. The Gualaxo do Norte River basin was one of the areas most affected by the tragedy, where the deposition of iron ore waste caused a worsening of the erosion processes, especially during rainy periods when water erosion mechanisms intensify. This article aims to analyze the erodibility of tailings through a geotechnical approach that has been little explored in works on rupture, analyzing how physical, chemical and geomechanical properties relate to surface erosion processes. The results of the physical characterization confirmed the high susceptibility to erosion of the tailings, presenting high levels of silt (48%) and fine sand (32%), in addition to a high specific weight of particles (29.5 KN/m3) and low plasticity. The water retention curve showed that the material tends to lose suction quickly when moisture levels rise. Mineralogical analyzes indicated the predominance of quartz, iron and aluminum oxides and hydroxides. Oedometer tests identified low compressibility and collapsible behavior for tensions of 25, 50 and 100 kPa. The loss of shear strength due to flooding was high, reducing the cohesion value by approximately 15 times when compared to the dry condition. The results obtained demonstrated that the tailings from the rupture are highly prone to water erosion, thus contributing significantly to erosion processes and favoring environmental degradation in the basin. [ABSTRACT FROM AUTHOR]

The technological push for hydrogen-based steel production has become a flagship project of the Swedish state for advancing its global environmental leadership and becoming the world's first fossil free welfare state. The new production process has the potential to drastically cut emissions in a heavy polluting industry. The plans also entail a drastic upscale in steel production, energy and iron ore consumption and risk increasing existing pressures on Indigenous Sami land, local communities, and biodiversity. This article sets out to investigate the frontier-making function of green steel imaginaries to contribute to debates on sacrificed spaces of extraction for green commodity demand. The article speaks to a call for a critical turn in sustainability transitions literature by introducing the concept of hype to scrutinise the material consequences of growth-based green transition imaginaries. This article builds on a narrative analysis of government, industry, and company actors' visions of a green steel future. The analysis illustrates how sociotechnical imaginaries are constructed to enable particular industrial futures over other green transition pathways. We show that the sociotechnical imaginary of green steel, fuelled through hype, serves to advance the new commodity and growth of the industry while effectively cancelling out democratic nuance and non-extractive alternatives. The findings illustrate the importance of pluralising green imaginaries to ensure inclusive transition pathways and to nuance and discursively dismantle the hype of green transitions that fail to break with the growth paradigm. [ABSTRACT FROM AUTHOR]

During the pellet cooling process, cooling air velocity is crucial for optimizing the cooling rate, evaluating the utilization rate of cooling heat energy, and improving pellet performance. As the simulated cooling air velocity increased, the gas temperature at the cooling endpoint decreased from 87 °C to 51 °C, and the solid temperature decreased from 149 °C to 103 °C. The total enthalpy of the recovered gas initially reduced and then increased while the heat recovery rate gradually increased. During the experiment, the inhomogeneity of pellet quality gradually increased with the rise in cooling air velocity. The effect of cooling air velocity on pellet properties is primarily reflected in the formation of cracks and low-melting liquid phases (FeO and fayalite). As the cooling air velocity increases, the softening onset temperature of the pellet decreases significantly. The melting zone decreases from 193 °C to 105 °C, and the permeability of the adhesive zone increases. [ABSTRACT FROM AUTHOR]

The recovery of iron contained in mill scale rather than iron ore can be considered a promising valorization pathway for this waste, especially if carried out through reduction using biogenic carbon sources. Nevertheless, the physicochemical properties of the latter may hinder the industrial transferability of such a pathway. In this work, the mechanical and metallurgical behavior of self-reduced briquettes composed of mill scale and four biogenic carbons (with increasing ratios of fixed carbon to volatile matter and ash) was studied. Each sample achieved mechanical performance above the benchmarks established for their application in metallurgical furnaces, although the presence of alkali compounds in the ash negatively affected the water resistance of the briquettes. In terms of metallurgical performance, although agglomeration successfully exploited the reduction by volatiles from 750 °C, full iron recovery and slag separation required an amount of fixed carbon higher than 6.93% and a heat treatment temperature of 1400 °C. Finally, the presence of Ca-, Al-, and Si- compounds in the ash was essential for the creation of a slag compatible with steelmaking processes and capable of retaining both phosphorus and sulfur, hence protecting the recovered iron. [ABSTRACT FROM AUTHOR]

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The issue of ring formation in rotary kilns poses a significant obstacle to the efficient and cost-effective production of oxide pellets. This study focuses on sampling and analyzing deposit formation at various points along the longitudinal axis of a 40-m-long, high-silica, pellet coal-fired rotary kiln. The primary factors influencing deposit formation in the kiln are fines generation and liquid phase formation. Through laboratory experiments and utilization of the "FactSage" calculation system, measures to reduce fines generation and inhibit liquid phase formation are analyzed, thereby establishing a foundation for mitigating deposit-forming speed in rotary kilns and increasing pellet production. [ABSTRACT FROM AUTHOR]

The impurity sulfur in lead–zinc-bearing hematite–limonite ore mainly exists in the form of galena, sphalerite, pyrite, and natural sulfur, and deep reduction roasting–low intensity magnetic separation does not effectively remove sulfur in a low valence state, which affects the quality of iron ore concentrate. Thereby, the desulfurization mechanism of the oxidative roasting process was investigated via XRD, TG, microscopy, thermodynamics, electron probe micro-analysis–energy-dispersive spectroscopy (EPMA-EDS) analyses. It is noted that hematite–limonite ore contains the valuable components of Fe2O3 (59.72 wt.%), SiO2 (15.43 wt.%), which are 46.32% of total of Fe, with a numerous number of impurities such as S (3.34 wt.%), Pb (1.50% wt.%), Zn (1.25% wt.%), etc. Microscopic identification revealed a complex relationship between hematite, pyrite, galena, sphalerite, and silica inclusions. Therefore, optimal roasting conditions were 60 min and 1050°C, respectively, where the total desulfurization rate was 92.33%, with the desulfurization rate of low valent sulfur reaching 98.64%. Meanwhile, thermodynamic and XRD analyses showed that pyrite was oxidized to ferrous oxide, magnetite, and hematite, etc., sphalerite was oxidized to zinc oxide, while galena was oxidized to lead oxide, and the difficulty of removing products such as PbO·PbSO4, and PbSO4 is noted [ABSTRACT FROM AUTHOR]

Globally, bentonite is being used as a binder in iron ore pelletizing due to its high swelling index, thermal resilience, and water absorption capacity. However, the conventional use of bentonite contributes to increased gangue content (Al2O3 and SiO2) in pellets, subsequently affecting blast furnace operations in terms of high solid fuel consumption, low productivity, and high slag rates. In this work, sodium hydroxide has been used with bentonite to reduce its consumption without affecting the pellet properties. Pellets are prepared by varying the NaOH addition from 0 to 0.1 pct at an interval of 0.02 pct. Green and fired pellets were tested for green compressive strength (GCS), dry compressive strength (DCS), drop number, cold compressive strength (CCS), Hoogoven simulations (HOSIM), softening-melting, and swelling index (SI). The interaction between hematite and bentonite was studied using molecular modeling simulations (ReaxFF MD). Microstructural studies (optical and SEM-EDS) of pellets were carried out for phase quantification and to assess the chemical composition of slag phases. Besides, FactSage simulations were performed to validate the slag phase formation. It is inferred that a 50 pct reduction in bentonite consumption is possible at 0.04 pct NaOH with a 12 pct improvement in CCS. Laboratory results were validated for a seven-million-tonne pellet plant with 0.02 and 0.04 pct NaOH dosage. Plant trial shows that there is an 18 and 39 pct reduction in bentonite consumption with the addition of 0.02 and 0.04 pct NaOH dosages, respectively. [ABSTRACT FROM AUTHOR]

Ca2Fe2−xAlxO5 solid solution is an intermediate product for reduction of complex calcium ferrites, which is a restrictive step for efficient metallurgy of high-aluminum iron ore for ironmaking. In this work, three Ca2Fe2−xAlxO5 (x = 0.00, 0.21, 0.41) solid solutions were synthesized to investigate the reduction mechanism of Ca2Fe2−xAlxO5 solid solution. Combined with the Rietveld refinement method, it was confirmed Ca2Fe2−xAlxO5 is a substitutional solid solution, where the Al3+ could replace the position of Fe3+ to lower the cell size with orthorhombic crystal. The reduction result of Ca2Fe2−xAlxO5 shows that the solid solution of Al3+ in Ca2Fe2−xAlxO5 increased the structure stability, in which the reduction-beginning temperature increased from 820 °C to 1020 °C when x increased to 0.41, which was also verified by first principle calculation. It was found the reduction products of Ca2Fe2−xAlxO5 were iron, CaO, and Ca3Al2O6, where the CaO belongs to a solid solution with the lower melting-temperature, resulting in decrease of the reduction rate at the higher temperature. Furthermore, it was revealed that the Al3+ has been gradually dissolved into Ca2Fe2−xAlxO5 remained with the reduction in progress at the earlier stage, but the Al3+ separates from Ca2Fe2−xAlxO5 and reacts with CaO to generate Ca3Al2O6 at the later stage of reduction due to the Al3+ amount exceeding the solid solution limit (x = 0.63 at 1050 °C). [ABSTRACT FROM AUTHOR]

Visible and near-infrared (Vis–NIR) spectroscopy technology can better meet the needs of identification of mineral differences in iron ores by using a large amount of chemical bond vibration information contained in the spectra. In this paper, the original Vis–NIR spectra data of six kinds of iron ore are dimensionally reduced by the principal component analysis (PCA) algorithm, and the influence of sample noise and outliers is eliminated at the same time. After processing, the sum of the contribution rates of the first three principal components of the reflectance spectra reaches 99.27 pct, and the eigenvalue inclusion rate of the principal component analysis data is high, which has a good data processing effect. Then, based on the random forest (RF) algorithm, the spectra data after PCA are classified and predicted. After multiple authentications, the identification accuracy of the algorithm can reach more than 95 pct on average. Finally, the receiver operating characteristic (ROC) curve is used to characterize the prediction success rate of the recognition model and its accuracy for the recognition of single iron ore. [ABSTRACT FROM AUTHOR]

Copper slag is a residue from the copper smelting process that not only takes up large amounts of space, but also contains harmful elements that can cause environmental pollution. In this paper, zinc in copper slag is sulfide-roasted using pyrite as a vulcanizing agent and anthracite and K2CO3 as additives, thus leaving zinc in the slag mainly in the form of ZnS. After sulfurization roasting, the slag can be stripped of Zn by flotation, and the remaining iron can be further applied in the blast furnace ironmaking process. The effects of temperature, holding time, pyrite addition, and K2CO3 addition on the Zn sulfation rate were investigated. The results showed that when pyrite, anthracite, and K2CO3 were added to the slag in amounts of 35, 2, and 10 pct of the slag's original mass, respectively, the total Zn in the slag was 3.16 pct, and its sulfuration rate was 83.5 pct. When pyrite was used to sulfide and dezincify copper bottom-blown smelting slag, the ZnO content in the slag was effectively reduced in preparation for subsequent ironmaking after flotation. This approach not only solves the problem of large piles of copper slag that cannot be fully utilized, but also alleviates the current shortage of iron ore in China. [ABSTRACT FROM AUTHOR]