Iron Ore Tailings Research Articles

Ex-post impact assessment on a large environmental disaster

Impact assessments following environmental disasters must be quick and in accessible language so that decision-makers and affected populations are aware of the main impacts and can target recovery measures. After the collapse of the Fundão dam (Minas Gerais, Brazil) in November 2015, an extensive monitoring program was implemented to understand the aquatic environmental situation and associated biodiversity status after the spill of the iron ore tailings in a large and highly populated watershed, that reached the Atlantic Ocean along the southeast Brazilian coast. A monitoring programme faced several challenges, including the large volume of data to be analysed, which difficult an objective environmental diagnosis and the communication between technical teams and decision makers. In this context, an impact matrix was proposed as a tool for assessing the environmental proxy results and summarizing the results obtained. The proposed Impact Matrix is an interaction matrix adaptation which consists of quantifying the impacts using pre-defined criteria and scores. Expert panels assessed the link between environmental measures and objectives by scoring the specific criteria. As an interaction matrix, the impact matrix is made up of two intersecting axes: the identified impact and the affected environmental compartments (whether abiotic or biotic). The final impact matrix is reached by summing up the score for the criteria on each of the identified intersections. The impact matrix is a supervised approach focused on provide relatively simple tool to apply and, when carried out periodically in parallel with a monitoring programme, it makes it possible to observe temporal trends in the evolution of the environment after the event causing the impact. The impact matrix can also serve as feedback to the monitoring programme itself, when used in an adaptive management approach.

Hydraulic Characteristics of Silt-Sized Iron Ore Tailings

Hydraulic Characteristics of Silt-Sized Iron Ore Tailings

Development of sacrificial anode from Al, Mg, and Ti from iron Ore tailings

ABSTRACT This investigation used aluminium, magnesium, iron ore tailings, and low-carbon steel. Iron ore tailings (5–30 wt% Mg and 50 μm in size) in an aluminium matrix formed the anode. In 0.5 M NaCl solution, the weight loss, corrosion rate, and electrochemical properties were measured. Samples A to E have corrosion rates of 0.43, 0.28, 0.36, 0.08, and 0.11 mm/yr, respectively. SEM/EDS examination revealed the presence of elemental Al, Mg, O, and Si in the anode. The XRD patterns indicate intermetallic compounds such as iron nitride (Fe3N), aluminium silver (Ag-Al), and manganese zirconium (Mn2Zr). In samples A, B, and C, Al and Mg formed a protective coating on the anode, while C and Si reduced passivation and released electrons to protect the steel. IOTs and Mg in the aluminium matrix improve the anodic corrosion resistance. The observed improvements in corrosion resistance highlight the potential of these sacrificial anodes for practical applications in corrosion protection systems.

Biomassa e demanda hídrica do capim mombaça em solo afetado pelo rompimento da Barragem do Fundão

ABSTRACT The collapse of the Fundão Dam in Mariana, MG, in 2015 introduced the challenge of using Technosol, a soil type formed by deposition of iron mining waste along the Doce River banks, for agricultural purposes. This study aimed to determine the optimal water depth for enhancing production of tropical forage, Megathyrsus maximus cv. Mombasa, when grown on iron ore tailings. Additionally, it sought to establish a crop coefficient applicable to the edaphoclimatic conditions of Viçosa, MG, Brazil. The experiment was conducted throughout the summer, fall, and winter of 2022, employing 21 drainage lysimeters. A completely randomized experimental design was adopted, featuring six treatment groups (plants in Technosol receiving water depths ranging from 20 to 120% of the crop’s evapotranspiration, as derived from the control treatment), along with a control group (plants in Latosol with a depth of 100%), each with three repetitions. Our findings showed that irrigation must replace 40% of the crop evapotranspiration. Moreover, cultivating in Technosol resulted in a reduction of productive capacity by 37.39% during the summer/fall and fall seasons. For Mombasa grass grown in Oxisol, crop coefficients of 1.2 during the summer and 1.5 during the fall and winter are advised.

Evaluation of the effects of different hydroxamates and a sulfosuccinamate in the direct flotation of iron ore tailings

Evaluation of the effects of different hydroxamates and a sulfosuccinamate in the direct flotation of iron ore tailings

Effect of Iron Ore Tailings and High Magnesium Nickel Slag on Flyash - Ggbs Based Geopolymer Concrete (GPC)

Abstract: The cement industry is a major producer of carbon dioxide (CO2), a powerful greenhouse gas which contaminate the environment by emitting massive volumes of CO2. The building sector contributes both directly and indirectly to environmental degradation, natural resource depletion, and global warming. From a sustainability standpoint, it is critical that cement manufacturing be reduced. Geopolymer concrete (GPC) is a new material that does not require portland cement as a binder, instead, materials rich in Silicon (Si) and Aluminum (Al), such as Flyash (FA) and Ground granulated blast furnace slag (GGBS) are activated by alkaline liquids to produce the binder. The use of iron ore tailings (IOT) in place of traditional aggregates in concrete has been discovered to be feasible. Concrete made using IOT aggregate performed well with respect to strength and durable studies. GPC mix of 12M was prepared using FA, GGBS, aggregates, alkaline alkali activators such as Sodium hydroxide (NaOH) and Sodium silicate (Na2SiO3). A study on using iron ore tailings (IOT) in replacement of fine aggregates in percentages of 20, 30, 40 and 50 are studied in GPC. After achieving optimum strength in above mix then high magnesium nickel slag (HMNS) was replaced with varying percentages 5, 7.5, 10 and 12.5. As alkaline activators with 12M NaOH and Na2SiO3 solutions are used with a ratio of 2.5. Mechanical properties such as Compressive, Split tensile and Flexural strength are evaluated to determine the influence of IOT and HMNS replacement in GPC.

Hybrid Effect of Basalt and Polyacrylonitrile Fibers on Physico-Mechanical Properties of Tailing Mortar

In this study, 50% iron ore tailings (IOTs) were used to prepare the cemented mortar at low economic costs and with great environmental benefits. Basalt fiber (BF) and polyacrylonitrile fiber (PANF) were added to the tailing mortar to improve the comprehensive performance of tailing mortars, including BF (0~0.5%), PANF (0~0.05%) and the combination of them. The results show that the addition of BF and PANF can significantly improve the ultrasonic velocity, uniaxial compressive strength (UCS), split-tensile strength (STS), flexural strength (FS) and toughness of the tailing mortar. A novel finding is that the enhancement of hybrid fibers is much better than single fiber, and the best hybrid fiber combination is B0.25P0.05 (0.25 wt% BF and 0.05 wt% PANF), because this combination not only causes the most considerable increase in strength but also possesses great cost-effectiveness. Compared to the B0P0 group without fibers, the maximum increments of B0.25P0.05 in UCS, STS and FS are 45.74%, 52.33% and 15.65%, respectively. It is evidenced that the improvement in STS is the largest because the fibers have good cracking resistance and bridging effect in the tailing mortar. The scanning electron microscope (SEM) further confirms that too many hybrid fibers will agglomerate and produce more voids, which is harmful to the development of the internal structure. Beyond B0.25P0.05, the hydration products are also reduced due to the decrease in nucleation sites, observed by combining X-ray diffraction (XRD) tests. Therefore, it is suggested that the hybrid fibers containing 0.25% BF and 0.05% PANF should be used in this tailing mortar.

Novel insights into the effect of cone structure on the classification performance of dual-cone hydrocyclones

The classification process in hydrocyclones is affected by many factors, with the cone angle being recognized as a critical parameter determining the classification performance. In the context of recycling iron ore tailings, this paper primarily focuses on the influence of cone angles and their combination sequences on the classification performance of quartz particles within a dual-cone hydrocyclone through numerical simulations. The upper and lower cone angles were configured in 16 combinations to assess their respective impacts on classification. The results indicate that the upper cone angle primarily governs the pressure drop and tangential velocity, thereby controlling the centrifugal intensity and cut sharpness. Furthermore, the lower cone angle plays a pivotal role in determining axial velocity and particle enrichment ratio in the lower cone, thus influencing the cut size and grade efficiency. These findings should provide valuable guidance for the design and application of compound cone hydrocyclones, depending on specific requirements.

The reinforcement mechanism of basalt and polypropylene fibers on the strength, toughness and crack resistance of tailing mortar

The replacement of river sand in the mortar by using iron ore tailings (IOT) can not only turn waste tailings into wealth but also protect the environment. In order to further improve the physico-mechanical properties and cracking resistance of cement mortar with 50% IOT, a series of experiments were conducted by adding different contents of basalt fiber (BF) and polyacrylonitrile fiber (PANF). The consistency decreases significantly with increasing the BF and PANF contents. A proper content of fibers can be evenly distributed in the mortar and thus reduce the porosity. However, excessive fibers will aggregate and increase the porosity. In addition, it has been validated that fibers can significantly improve the strength and prevent the brittle cracking. With increasing fibers, the density, ultrasonic velocity, and mechanical strength of hardened fiber-reinforced mortar first increase and then decrease. The best adding contents of BF and PANF are 1.0% and 0.08%, respectively. The rigid BF (length=6 mm) can significantly increase the uniaxial compressive strength (UCS) by 32.57% due to its good shear-resistance ability, however, the flexible PANF with the length of 12 mm is better to improve the split-tensile strength (STS) and flexural strength (FS) by 22.63% and 17.43% due to the formation of three-dimensional network structure in the specimens. In addition, the scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests show that excessive fibers will agglomerate and produce a certain amount of air, while a proper adding content of fibers provides more attachment points for hydration products to promote the hydration reaction. It is suggested to adopt the best adding content and choose proper fiber types according to the loading form of construction structure with tailing cement mortar in the fields.

The Mechanical Properties and Microstructure of Tailing Recycled Aggregate Concrete.

The aim of this study was to develop sustainable concrete by recycling concrete aggregates from steel waste and construction waste (iron ore tailings (IOTs) and recycled coarse aggregates (RCAs)) to replace silica sand and natural coarse aggregates. In experimental testing, the compressive strength, peak strain, elastic modulus, energy dissipated under compression, and compressive stress-strain curve were analyzed. Microscopically, scanning electron microscopy and energy-dispersive spectrometry were employed to investigate the microstructural characteristics of the interfacial transition zone (ITZ), and the results were compared with the ITZs of natural aggregate concrete and recycled aggregate concrete (RAC). In addition, the pore structure of concrete was determined by nuclear magnetic resonance. The results revealed that an appropriate IOT content can improve the ITZ and compactness of RAC, as well as optimize the mechanical and deformation properties of RAC. However, due to the presence of a smaller number of microcracks on the surface of IOT particles, excessive IOTs could reduce the integrity of the matrix structure and weaken the strength of concrete. According to the research, replacing silica sand with 30% IOTs led to a reduction in the porosity and microcracking which resulted in a much denser microstructure.

A review on 3D printable cementitious material containing copper and iron ore tailings: material characterization, activation methods, engineering properties, durability, and microstructure behavior

A review on 3D printable cementitious material containing copper and iron ore tailings: material characterization, activation methods, engineering properties, durability, and microstructure behavior

Sustainable engineered geopolymer composites: A study on the potential of fly ash, BOF slag, and iron ore tailings

Industrial residues like Basic Oxygen Furnace (BOF) slag and Iron Ore Tailings (IOT) in the construction sector conserves natural resources by reducing carbon emissions and enhancing sustainability. However, it is crucial to establish significant research findings to build confidence among end users and stakeholders to facilitate the adoption of the same for practical applications. This study aims to investigate the feasibility of using BOF slag and Fly ash (FA) as primary precursors in the development of steel fibre (SF) reinforced Engineered Geopolymer Composites (EGC) with IOT replacing M-Sand as fine aggregate. Trial mixes (600 No.s) were conducted to synthesize EGC with BOF slag, FA, IOT, and SF. Compressive strength was measured and IOT was found to significantly improve the strength of EGC, following SF and BOF levels. Six optimized mixes were identified and subjected for water absorption, flexure, impact resistance and leaching toxicity of heavy metals. The mix comprising 40% BOF, 1.5% SF and 45% IOT showed the highest strength characteristics viz., 41.8 MPa, 5.78 MPa and 313.92 Nm correspondingly for compression, flexure and impact. The obtained results have implications for sustainable construction involving BOF slag and FA as viable precursors, alongside IOT as a partial substitute for fine aggregate.

Evaluation of industrial byproduct iron ore tailings and carbon fiber cement-based materials under sulfate freeze-thaw cycles: Durability, piezoresistivity, and microscopic mechanism

This study investigated the feasibility of utilizing industrial byproduct iron ore tailings and carbon fiber cement-based materials (ICCM) in sulfate freeze-thaw (F-T) environments. The effects of carbon fiber (CF) and iron ore tailing (IOT) on the sulfate F-T resistance, piezoresistivity, and pore distribution were tested. The results revealed that CF (0.6 vol%) and IOT (30%) significantly improved the compressive strength (51.6 MPa) and resistance to sulfate F-T of ICCM. The stress sensitivity was obviously enhanced to 1.389 %·MPa−1. Furthermore, the stress sensitivity is closely related to the sulfate F-T environment. After the sulfate F-T cycles, the fractional change in resistivity (FCR) and compressive stress agreed with a first-order exponential decay relationship. Replacement with IOT compensated for the degradation in piezoresistivity by formation of balanced pore distribution over 200 F-T cycles. The combination of IOT and CF in cement material yields excellent performance in terms of stress sensing, cost, and environmental impact (EI). This approach is expected to be developed for self-sensing in extreme environments with a recycled conductive filler.

Triaxial testing response of compacted iron ore tailings considering a broad spectrum of confining pressures

The filtered tailings disposal (dry stacking) up to 300 m high is an alternative to overcome the drawbacks related to the slurry tailings storage in large impoundments as it is safer and demands smaller portions of the existing landform. Even so, the understanding of the denser and dewatered material response over a broad range of confining pressures is essential to safely design tall dry stacking tailings facilities. Accordingly, the present research assesses the mechanical behavior of compacted iron ore tailings through triaxial tests. A series of compression and extension drained and undrained triaxial tests were conducted over a wide spectrum of confinements (σ́3 ranging from 75 to 8,000 kPa) to check possible particle breakage occurrence and effects. The influence of the initial density due to compaction was, as well, evaluated since the tests were performed using specimens molded at distinct dry unit weight values. The results were analyzed in the light of the critical state soil mechanics and have indicated the existence of a curvilinear critical state line in the ν: log ṕ plane. Small particle breakage has occurred and can be associated with reduction in surface roughness, breakage of asperities, and reduction in particle angularity. Moreover, a tendency for static liquefaction was observed amongst the loosest specimens sheared under the lowest confining levels.

Sustainable assessment and synergism of ceramic powder and steel slag in iron ore tailings-based concrete.

Solid waste management is a critical issue worldwide. Effectively utilizing these solid waste resources presents a viable solution. This study focuses on Iron ore tailings (IOTs), a solid waste generated during iron ore processing, which can be used as supplementary cementitious materials (SCMs) but have low reactivity, hindering their large-scale application in concrete production. To address this, ternary SCMs were prepared using ceramic powder (CP) and steel slag (SS) to enhance the performance of concrete incorporating IOTs. The study found that the synergistic effect of CP and SS significantly improved the compressive strength of concrete, with a notable increase of up to 21% compared to concrete with IOTs alone. Mercury intrusion porosimetry (MIP) and backscattering electron (BSE) analyses revealed that the ternary SCMs significantly optimized the characteristics of the interfacial transition zone (ITZ), which in turn enhanced the compressive properties of the concrete. This contributed to maintaining the structural integrity of the concrete, even amidst variations in the pore structure. Importantly, the incorporation of ternary SCMs led to a 23% reduction in carbon emissions, from 400.01kg CO2/m3 to 307.48kg CO2/m3, and elevated eco-strength efficiency from 0.1 to 0.14. The study highlights the role of multi-material synergy in developing composite SCMs systems, fostering the sustainable advancement of green building materials.

Reuse of Iron Ore Tailings by Magnetic Separation Using Functionalized Magnetic Particles

ABSTRACT This study aimed at the investigation of the effect of colloidal magnetic particles on the magnetic separation of iron ore tailings (IOT). For this, the synthesis and characterization of bare iron, iron-dextran, and iron-oleate magnetic particles is reported. FTIR spectra confirmed that the synthesized particles were composed by magnetite. In general, the iron recovery was superior when magnetic particles were introduced, regardless of the addition of bare magnetic or functionalized iron particles. When iron-crosslinked-dextran particles were added into the pulp at the dosages of 0.5 and 1.0 g/t, an increase in recovery of about 7% took place at 0.34 T, but with a loss in grade of about 5%. Further cleaning stages are necessary to reduce the silica content. This work is aligned with the sustainability needs of mining operations, constituting an alternative technology for the reuse of iron ore tailings.

Sustainable approach towards alternatives for the use of iron ore tailings in the construction sector using Data Envelopment Analysis methodology.

Iron ore tailings (IOTs) need to be properly managed to mitigate the environmental, social, and economic impacts of mining activities. To cope with this issue, we use data envelopment analysis (DEA) to evaluate alternatives for using IOT in the construction sector. The classical and weight restriction output-oriented DEA models were used in this analysis. The results show that the ranking of alternatives depends on the aspect being evaluated. Concrete block is the most environmentally friendly alternative when analysing both models. For both social and economic aspects, ceramics produced better results in the classical model, whereas Portland cement showed better outcomes in the weight restriction model. In this sense, the results suggest great potential for the use of IOT in the construction sector, enabling the reduction of risks and social and environmental impacts of tailings dams.

Evaluation of the Calibration Curve of Water Content Sensors in Iron Ore Tailings

Evaluation of the Calibration Curve of Water Content Sensors in Iron Ore Tailings

Iron ore tailings stabilization with alternative alkali-activated cement for dry stacking: mechanical and microstructural insights

Upstream tailings dams are high-risk structures that have experienced several failures worldwide, particularly with iron ore tailings (IOT). In this study, new disposal methods/techniques, such as cement-stabilized dry stacking, are discussed that provide enhanced mechanical behavior while reducing failure risks. Alkali-activated materials are used as cementing agents due to their mechanical and environmental advantages compared to ordinary Portland cement. This study evaluates the mechanical and microstructural behavior of IOT stabilized with an alkali-activated cement (AAC) composed of two by-products from the IOT beneficiation process, metakaolin and sodium silicate, tested under plane strain conditions. Simple shear tests and microstructural analysis were performed. Mixtures of IOT were produced with 0%, 1%, 3%, and 5% AAC to examine the influence of such variables on strength and deformability parameters under undrained conditions. The mixtures with 3% and 5% AAC showed the greatest impact on the strength; however, the addition of 1% AAC was able to reduce positive pore-pressure generation. Cementitious bounds were evidenced by forming a sodium aluminosilicate hydrate gel. The studied AAC was effective in stabilizing IOT, even at small contents.

Characterization and Analysis of Iron Ore Tailings Sediments and Their Possible Applications in Earthen Construction

Mineral extraction is of ultimate importance for the economies of different countries, and Brazil is one of the world’s leading producers of iron ores. Unfortunately, dams are still the main problem, mainly in Minas Gerais, especially after the Fundão Dam rupture in 2015. Additionally, there is still a massive presence of buildings built on earth throughout the Minas Gerais mining region, built from the 18th century to today. Investigating the potential of iron ore tailings (IOT) to be incorporated into traditional earthen construction techniques in regions affected by dam ruptures presents a relevant and innovative research approach. In addition, the local reuse of these sediments should be the priority. Thus, the main objective of this work was to collect, characterize, and analyze the possibilities of the application of these tailings to produce rammed earth (RE). A complete characterization analysis was performed on the samples collected at three points. To analyze the soil-IOT compatibility, representative mixtures of RE were produced, and the specific mass, compaction, and compressive strength were performed. It was observed that the IOT samples have a high silica content and that the mixtures of IOT–soil, even without cement, reached the compressive strength values of the international standards, or even above them.