Effect of silica-alumina molar ratio on iron ore tailings-based geopolymer eco-brick performance.

Experimental and numerical evaluation of convective heat transfer correlations in a packed bed of iron ore pellets

Efficient urea oxidation from strontium ferrite nanostructures synthesized using iron recovered from waste iron ore slime

A particle size control strategy for biochar in iron ore sintering enabled by fuel migration and granules combustion kinetics

This study investigates the impact of decanter solid and arbuscular mycorrhiza on the growth of oil palm seedlings in pre-nursery on ex-iron ore mining sites. The construction of pits during iron mining has resulted in soil degradation and abandonment. The addition of solid decanter and arbuscular mycorrhiza can improve the chemical characteristics of soil. The study sought to determine the interaction between solid decanter and arbuscular mycorrhiza, as well as the optimal dose of solid decanter and arbuscular mycorrhiza for oil palm seedling growth in the pre-nursery. This study employed a factorial Completely Randomized Design with two factors and four treatment levels. The first factor was solid decanter (0, 200, 300, and 450 g), whereas the second was arbuscular mycorrhiza (0, 5, 10, and 15 g/polybag). The parameter studied included initial soil analysis, solid decanter analysis, final soil analysis, seed height, stem diameter, number of leaves, leaf length, fresh and dry seedling weights. The study's findings revealed an interaction between solid decanters and arbuscular mycorrhiza on leaf length, fresh weight, and dry weight of seedlings. The treatment dose of 450 g solid decanter and 5 g/polybag arbuscular mycorrhizae resulted in the best growth in all variables. Keywords: arbuscular mycorrhizae, fertility, mycorrhiza, pre-nursery

Abstract Cokes are an essential material in the iron and steel industry, and widely used as a fuel and for reducing iron ore. The product properties of cokes are influenced by raw materials and process conditions, which in turn affect its performance. Because raw material components vary depending on the origin and production period, product properties can fluctuate even under the same process conditions, and thus, it is necessary to design appropriate process conditions for each raw material. The objective in this study is to construct machine learning models that predict product properties from raw materials and process conditions using data sets measured in needle and pitch coke production processes, and to design appropriate process conditions that achieve desired values of properties by inverse analysis of the constructed models. To select appropriate process conditions and their time delays for a data set, we propose a method called NSGA-II-VDS, combining elitist non-dominated sorting genetic algorithm (NSGA-II) and genetic algorithm-based process variable and dynamics selection (GAVDS), for multiple product properties, and confirmed that the proposed NSGA-II-VDS could construct models with higher prediction accuracy than the conventional GAVDS. Furthermore, we constructed models using a data set where time-series data was interpolated based on the maximum batch time for each process condition for a batch process data set. By inputting time-series data generated virtually into the constructed models for raw material information for a target product, we successfully designed process conditions predicted to achieve the desired product property values by selecting time-series data with promising predicted product quality values. Graphical abstract

Motor graders are widely used in mining operations, especially in open-pit mines, to move and level surfaces. These types of equipment have a blade that can be adjusted to different inclinations concerning the axis of travel and the horizontal plane, making them essential for earthmoving. Their main function is to level specific areas of the ground, ensuring the regularity of the terrain. However, these blades are subject to abrasive wear due to constant contact with the ground, which can impact their efficiency and useful life. In this work, a tribological study of the edges of motor graders at the end of their useful life was carried out, aiming to characterize the material and propose secondary applications. Several analysis techniques were used, including chemical analysis, stereoscopic images, Scanning Electron Microscopy (SEM), and hardness and abrasion tests. This work also presented a practical and sustainable proposal for the reuse of the material, promoting efficiency and reducing the environmental impact in the management of industrial waste. The results obtained provided a comprehensive understanding of the material properties of motor grader edges. It was also possible to formulate a detailed specification of the material, highlighting its physical and chemical characteristics. In addition, the study identified a potential application for the reuse of this material, suggesting its application as wear plate in buckets.

Abstract The blast furnace (BF) has been the predominant technology for producing molten iron since its invention and widespread adoption. Challenges of decarbonisation and production of direct reduced iron (DRI) from low-grade iron ore have raised the potential for incorporating electric smelting furnaces (ESFs) into the direct reduced iron-basic oxygen furnace (DRI-BOF) pathway to produce molten iron. Developed smelting technologies, such as the Submerged Arc Furnace (SAF) has been widely used in ferro-alloy production for more than 100 years. Though three ESFs are currently in operation worldwide for molten iron operation (Craig et al. in Global Low-Carbon Metallurgy Innovation Forum 2022 and the 8th Baosteel biennial academic conference, 2022; Garlick et al. in J Sustain Metall, 2025) they are not at the scale required to replace the BF operation. Open Slag Bath Furnace (OSBF), which uses “open arc” or “brush arc”, shows promise in processing low-grade DRI. It is claimed (Steinberg in Development of a control strategy for the open slag bath furnaces, Highveld Steel and Vanadium Corporation Ltd., University of Pretoria, Pretoria, 2008) that an OSBF can operate at a higher resistance (2 to 4 mΩ) compared to a SAF (1 mΩ or even below). It has also been reported ( Steinberg WS (2008) Development of a control strategy for the open slag bath furnaces at Highveld Steel and Vanadium Corporation Ltd. University of Pretoria (South Africa)) that the OSBF furnace can work in higher power level (100 MW at 3 mΩ) compared to a SAF (70 MW at 1 mΩ). Critical analysis of the literature indicates that there is a lack of independent research on OSBF furnaces. One potential major drawback of employing an open arc in OSBFs is the increased heat loss through radiation from the furnace roof, which can accelerate the wear of roof refractories and lower overall energy efficiency. This paper critically reviews the current understanding of ESF technology for ironmaking, identifies the key knowledge gaps, and proposes directions for future research. Graphical Abstract

Peroxymonosulfate-based advanced oxidation technologies (PMS-AOTs) are an effective sludge treatment strategy for sludge volume reduction and treatment cost saving, but rely on high external energy and/or material input. We achieved in situ PMS activation driven by intrinsic iron (Fe) minerals in sludge rather than exogenous catalysts. Sufficient PMS doses (i.e., 100 mg g-1 total solids (TS)-1) reactivated intrinsic Fe minerals by acidifying the sludge matrix and partially dissolving passivated Fe phases, effectively converting inert Fe into active and mobile species. This action triggered a self-reinforcing cycle, where abundant Fe(II) in high-Fe sludge (>30 mg Fe g-1 TS-1) donated electrons for homolytic PMS activation, generating a radical-dominated pathway. Continuous Fe(III) reduction via PMS intermediates and sludge sulfur-based groups reinforced the Fe(III)/Fe(II) redox cycle, enabling persistent Fenton-like radical generation. Conversely, low-Fe sludge exhibited a limited Fe supply and fewer reactive Fe sites, shifting the PMS reaction toward a less efficient nonradical pathway. Accordingly, high-Fe sludge achieved markedly superior performance, evidenced by a 41.0% lower water content of sludge cake and a 1.2-fold higher sulfamethoxazole (SMX) removal compared with low-Fe sludge. A pilot-scale experiment confirmed stable sludge dewatering and SMX removal. Collectively, the autonomous activation of PMS by sludge-intrinsic Fe minerals presents a new direction for sustainable sludge treatment, notable for its simplicity, stability, and economic effectiveness.

While increasing hydrogen share in the reducing gas represents an attractive path for reducing CO 2 ; emissions in blast furnace ironmaking, its effects on burden permeability remain poorly understood. This study systematically examines how hydrogen-enriched atmospheres affect the permeability of iron ore sinter and pellets across the lumpy zone temperature range (300–1100 °C). To isolate intrinsic hydrogen effects and establish performance boundaries, samples were reduced at three representative temperatures (500, 800, and 1000 °C) under pure gas compositions (100% CO, 60% CO-40% H 2 , and 100% H 2 ), followed by degradation and quantitative permeability analysis. Results show material-specific responses: Hydrogen improves sinter permeability by over an order of magnitude at 500 °C by suppressing carbon deposition, while pellets achieve optimal performance at 800 °C but deteriorate severely at 1000 °C under hydrogen-rich conditions. The middle lumpy zone (600–900 °C) emerges as the most favourable region for hydrogen injection, where both materials maintain adequate permeability while enabling CO 2 emission reductions. The study provides quantitative permeability parameters ( K , β) for computational modelling and strategic guidance for burden-specific hydrogen injection optimization, though alternative materials may exhibit different behaviours.

ABSTRACT High-Pressure Grinding Rolls (HPGR) are widely recognised for their superior energy efficiency and throughput compared to conventional grinding technologies; however, industrial-scale performance data remain limited. This study evaluates the influence of key operating parameters, including operating pressure (145–185 bar), roll speed (0.6–1 m/s), feed rate (1000, 1400 t/h), feed fines content (30%, 42%), feed moisture (1.8–4%), and roll wear (new rolls, worn rolls), on the performance of an industrial HPGR operating in the primary grinding circuit of an iron ore beneficiation plant. The results demonstrate that operating pressure and roll speed are the dominant factors governing product size reduction, energy consumption, and throughput, while feed characteristics and moisture content exert secondary but measurable effects. Increased pressure and roll wear improve size reduction but reduce throughput and increase energy demand, whereas higher roll speeds enhance throughput with moderate energy penalties. Progressive stud wear significantly degrades grinding efficiency and necessitates higher operating pressures to maintain product quality. Overall, the findings provide practical insights into the operational trade-offs affecting HPGR performance and offer guidance for improving energy efficiency, throughput, and equipment utilisation in industrial iron ore grinding circuits.

Long-term exposure to high concentrations of radon has been identified as an important risk factor for lung cancer. The risk of radon exposure in nonuranium mines has been ignored for a long time because of insufficient protective measures and weak health awareness among practitioners. To understand the effects of radon exposure on human health in the microenvironments of underground nonuranium mines and to explore the effects of cumulative radon exposure on the health of miners. The National Occupational Radiation Sickness Surveillance Workbook (Survey of Miners with High Radon Exposure) and an expert consensus on low-dose spiral CT screening for lung cancer were used. A total of 62 miners were selected from underground nonuranium mines. Chromosome aberrations in peripheral blood lymphocytes, micronuclei in lymphocytes, and low-dose CT screening of lung cancer were used as observation indices. There are significant differences in the detection rates of Nodular shadows and Patches and cable strip shadows in miners between an iron ore mines, gold mines and miners in deep nonuranium mines.Combined with monitoring data from nonuranium mines in iron and gold mines, this study reveals that the occupational health status of workers in underground nonuranium mines is at risk of lung cancer caused by radon exposure, and improving mining technology to reduce the deposition of radon and its progeny is the key.

The sintering process is undergoing a transformation to meet future challenges, so a more profound understanding of the potential influence of the individual recirculation gas constituents, in particular O 2 , CO, and H 2 O, is essential. Within this paper, miniaturized lab‐scale sintering experiments are presented using an industrylike raw mixture, to study the effects of variations in the individual O 2 , CO, and H 2 O supply on the sintering process and the sinter quality. As the O 2 content (up to 30 vol%) in the suction gas increases, both sintering yield and strength increase, resulting in lower return rates, with more or less constant amounts of CO in the off‐gas. Productivity and sintering strength increase with increasing CO concentration, while the NO concentration in the off‐gas tends to be lower. With increasing H 2 O content, productivity and sintering strength increase with a significantly lower CO concentration in the off‐gas, due to the water‐gas shift reaction taking place in the flame front. The results demonstrate the potential of adjusting the raw mixture recipe by selectively modifying the recirculation gas, particularly towards a lower coke breeze content. This would enable reductions in the specific emissions of CO, CO 2 , SO 2 , and NO per ton of product sinter.

Coastal marine ecosystems are key components of biodiversity and ecosystem functioning but have been increasingly degraded by human activities. One of the most severe environmental disasters in Brazil occurred in November 2015, when the Fundão tailings dam collapsed in Mariana (Minas Gerais), releasing approximately 40 million m3 of iron ore waste into the Rio Doce basin and adjacent coastal environments. To evaluate the long-term biological consequences of this event, we analyzed the taxonomic composition and diversity of marine communities using environmental DNA (eDNA) metabarcoding from sediment cores collected in 2018 across three coastal sectors-Front (mouth of the Doce River), North, and South. A total of 761,517 reads generated 11,061 unique amplicon sequence variants (ASVs) assigned to 148 taxa revealing significant spatial variation in taxonomic (species-level) composition and diversity indices (PERMANOVA, pseudo-F = 16.55; p = 0.047). The South region exhibited the highest species richness (q₀ = 103 taxa), followed by the North (97) and Front (70). Cluster and SIMPER analyses indicated two distinct biological assemblages: (1) the Front region, dominated by diatoms (Mediophyceae, Bacillariophyceae) and protists tolerant to metal enrichment, and (2) the North-South regions, characterized by higher evenness and presence of benthic invertebrates such as Holothuroidea and nematodes (Desmodorida). Species abundance distribution (SAD) models differed among areas, reflecting ecological gradients associated with the dispersal and chronic accumulation of mining residues. These results demonstrate a persistent imbalance in marine communities near the Doce River mouth, suggesting that the legacy of historical contamination and the Fundão dam failure continues to shape benthic biodiversity patterns more than three years after the disaster.

Sunlight-activated semiconducting iron minerals in anammox granules: Stimulating metabolic cooperation, suppressing nitrate accumulation, and mitigating oxidative stress.

Dephosphorization is essential to purify iron ore before converting it into valuable products like steel. This is carried out using the flotation process, where selectively hydrophobized phosphorus compounds like apatite impurities are recovered and a higher grade iron ore is achieved in the form of magnetite and haematite. The REFLUX TM Flotation Cell (RFC TM ) has displayed tremendous potential in coal applications and mineral processing at the lab scale. The cell has broken the operating boundaries of the conventional flotation processes, which have not been achieved before, and enabled very high upgrades and recoveries. This study applies the RFC TM for the first time for the reverse flotation of apatite from magnetite-rich iron ore. The study focuses on improving the hydrodynamic parameters without focusing on the reagents optimization. The experiments are divided into pre-experiments at lower solid concentrations, and the observations are used to formulate a Design of Experiments for solid concentrations up to 50 % (w/w), as used at the mine site. Additionally, for the first time, the Wire mesh sensor, operating in electrical resistivity mode, is fixed in the cell cross-section to determine the gas–liquid phase distribution. The mineralogical results are correlated to the observations and the measured phase distributions. • RFC TM reverse flotation removing apatite from magnetite up to 20% (w/w) solids. • Sensitivity analysis of hydrodynamic flux effects on cell performance. • Bubbly-zone liquid interface loss to underflow is the main cause of poor performance. • In-situ phase distribution via high-resolution conductivity Wire-mesh sensor.

Photo-transformation of dissolved organic matter coupled with iron minerals upon hydrological particulate resuspension-settlement

Generation of environmentally persistent free radicals in paddy soil and their impact on arsenic speciation and bioavailability: A review.

A synthesis on the spread of the tailing plumes resulting from the Fundão dam collapse along the Brazilian coast: Integrating evidence from multiple sources.

Prediction of iron ore inventory at ports: A decomposition-integration hybrid approach incorporating key influencing factors