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

Unleash the potential of mechanically activated Iron ore tailings in cement mortar containing silica fume and fly ash

Iron ore tailing (IOT) chemical composition and content impact on the physical, mechanical, and durability properties of blended cement

The present work aims to investigate the influence of the replacement of sand fractions by iron ore tailings (IOT) on concrete. The reactivity of tailings in the presence of cement, the variation of porosity and workability, and the filler effect of the material were studied. For this purpose, a series of chemical, physical, mechanical and thermal tests were conducted. The IOT was characterized by its chemical composition, particle size and specific weight. It is found that the material is formed by silica and hematite and has a specific weight similar to that of sand, although its grains are ten times smaller. To evaluate the reactivity of the IOT, the results of several experiments were compared. Axial compression tests were performed on cement pastes with replacement of 10%, 20% and 30% cement by IOT at different ages. The IOT was chemically tested by the modified Chapelle test and the pozzolanic activity index was determined. In addition, IOT concrete fragments at 28 and 90 days were tested by thermogravimetry and the hydration products were compared to the reference sample. The degree of crystallinity of the IOT was determined by X-ray diffraction. All evidence indicates that the material is inert. The effect of IOT on the workability of concrete and cement paste was tested by slump test and flow table, respectively, and an increase in workability was detected by increasing the IOT fraction. Porosity was evaluated by the water immersion test on concretes with different IOT fractions, and by computed tomography, which determined the pore distribution. In general, a tendency to reduce porosity was observed as IOT fraction increased. The mechanical strength of the concrete was evaluated for 10%, 20% and 30% sand replacements by IOT and the results were compared to the replacement of the same sand fractions by inert material, in the IOT granulometry. The filler effect caused an increase in resistance, with the best result being the 20% IOT fraction. It was also evaluated the flexural behavior in prismatic concrete specimens with addition of steel fibers in the fraction of 30 kg/m and 20% of sand substitution by IOT. The results of PUC-Rio -Certificao Digital N 1712759/CA maximum loads, residual stresses and toughness were on average very similar in the IOT and reference samples.

Goa’s iron ore mining industry has generated over 7.7 million tonnes of iron ore tailings (IOTs) in the past two decades. These IOTs pose a significant environmental threat due to heavy metal contamination, dust generation, and acid mine drainage. While some IOTs are used for backfilling, the majority are stored in tailings storage facilities (TSFs), posing long-term risks to surrounding water resources, ecosystems, and land use. Large-scale utilization technologies are crucial for sustainable IOT management. This study investigates the feasibility of incorporating IOTs in construction block production, aiming for high-volume waste consumption and improved resource efficiency. This approach offers a potential pathway to remediate the environmental impact of IOTs. The proposed method replaces 85% of the cement content with a cementitious material comprising 65% Ground Granulated Blast Furnace Slag (GGBS), 10% Fly Ash, and 10% Lime. It also utilizes IOTs entirely as a substitute for sand, with ceramic waste partially replacing coarse aggregates. While partial substitution of coarse aggregates with ceramic waste was attempted, it decreased workability. The optimal mix design, achieving the highest compressive strength, utilizes 15% cement, 65% GGBS, 10% Fly Ash and Lime, and 100% IOTs as fine aggregate with 100% basaltic aggregates. This formulation successfully demonstrates the potential use of IOTs in manufacturing construction blocks that reach compressive strengths of 10.91 N.mm-² and 15.92 N.mm-² at 7 and 28 days, respectively, satisfying the IS 2185-Part 1 (2005) code requirement. The block density was 2.20 g.cm-³. This research demonstrates the potential to convert a significant environmental challenge into a sustainable solution. By utilizing IOTs in construction block production, we can effectively achieve waste remediation; and create resource-efficient and eco-friendly building materials, offering substantial dual benefits for Goa’s environment and construction sector.

River Sand is one of the basic ingredients used in the production of concrete. Consequently, continuous consumption of sand in construction industry contributes significantly to depletion of natural resources. To achieve more sustainable construction materials, this paper reports the use of iron ore tailings (IOT) as replacement for river sand in concrete production. IOT is a waste product generated from the production of iron ore and disposed to land fill without any economic value. Concrete mixtures containing different amount of IOT were designed for grade C30 with water to cement ratio of 0.60. The percentage ratios of the river sand replacements by IOT were 25%, 50%, 75% and 100%. Concrete microstructure test namely, XRD and Field Emission Scanned Electron Microscopic/Energy dispersive X-ray Spectroscopy (FESEM/EDX) were conducted for control and IOT concretes in order to determine the interaction and performance of the concrete containing IOT. Test results indicated that the slump values of 130 mm and 80 to 110 mm were recorded for the control and IOT concretes respectively. The concrete sample of 50% IOT recorded the highest compressive strength of 37.7 MPa at 28 days, and the highest flexural strength of 5.5 MPa compared to 4.7 MPa for reference concrete. The texture of the IOT is rough and angular which was able to improve the strength of the concrete.

Study of mechanical, durability and microstructural properties of cementitious composite with addition of different iron ore tailings from Brazil

Purpose – This paper aims to produce iron ore tailings reinforced polypropylene composites (ITR-PPCs) from conventional compo-casting (CC) and a proposed compo-indirect squeeze casting (C-ISC) processes. It intends to quantify the compressive behaviour of ITR-PPC with respect to production process, iron ore tailings volume and particle size inclusion in polypropylene (PP) through controlled material and compressive testing. The study aims to provide useful information on possibility of the use of ITR-PP for compressive applications which will culminate to judicious use of iron ore tailings that is been piled up as waste material at the iron ore beneficiation sites. Design/methodology/approach – ITR-PPC compression specimens were produced using C-ISC and CC processes. Prior to production, the iron ore tailings was dried at room temperature according to ASTM 618, ASTM 171 and ASTM E 41. The different particle sizes were generated using standard laboratory sieves. Uniaxial compressive test procedure according to ASTM D 695 was carried out on ITR-PPC compression specimens with length/diameter ratio equal to 2.0 under standard laboratory atmosphere on an Instrom 3,369 machine. Findings – It was discovered that pure PP produced using the C-ISC process exhibited better compressive strength and Young’s modulus of about 12 and 4.5 per cent, respectively, while a reduction of 9.2 per cent in yield strength was recorded. ITR-PPCs with 150-μm fillers produced from C-ISC process have lower yield stress, compressive strength and Young’s modulus at volume contents above 10 per cent. It also exhibited lower strain at fracture at volume content above 15 per cent, while composites filled with 212- and 300-μm particle size iron ore tailings using the C-ISC process had better strain at fracture. Research limitations/implications – The present work cannot ascertain the compressive behaviour of ITR-PPC produced from other production processes, hence the need for further work in this area. Practical implications – The paper provides an avenue to address the pollutant effect of iron ore tailings by putting it to judicious use through addition as fillers in plastics. It also removes the need for expensive and repeated experimentation to determine the compressive behaviour of ITR-PPCs. Originality/value – This paper has brought to fore the need to study iron ore tailings as filler in plastics and other material matrices.

The study evaluated the effect of elapsed time after mixing on the strength properties of lime and iron ore tailings (IOT) treated black cotton soil (BCS) (an expansive tropical black clay) as road construction material. BCS was treated with 0, 2, 4, 6, and 8% lime and 0, 2, 4, 6, 8, and 10% IOT content by dry weight of soil. Tests carried out include Atterberg limits, compaction, unconfined compressive strength (UCS), California bearing ratio (CBR) (unsoaked condition), and microstructure of specimens. Statistical analysis was done using MINI-TAB software. Results show that the liquid limit (LL) of BCS–lime–IOT mixtures decreased with increase in lime and IOT content. The LL values of all the treated BCS increased between 0 and 1 h elapsed time after mixing. On the other hand, the plastic limit (PL) of BCS decreased with increase in lime and IOT content while the plasticity index (PI) decreased from 27.7 to 22.9% for 0% lime/0% IOT content and from 30.6 to 26.6% for 0% lime/10% IOT content. Maximum dry density (MDD) of BCS increased while optimum moisture content (OMC) decreased with higher IOT content. The natural BCS recorded OMC value of 25.6% decreased to 15.2% for 8% lime/10% IOT treatment. The strength (i.e., UCS and CBR values) increased with increase in lime/IOT contents between 0 and 2 h elapsed time after mixing. Peak values were recorded for 8% lime/8% IOT treatment for all lime content considered. Regression analysis shows a strong relationship between the strength properties and the soil parameters. An optimal 8% lime/8% IOT treatment of BCS for elapsed time after mixing not exceeding 2 h was established and is recommended as sub-base material for low-trafficked roads.

Evaluation of mechanical and thermal properties of PP/iron ore tailing composites

The revegetation of areas degraded by iron ore mining is a difficult challenge mainly due to water availability and impoverished metal-rich substrates. We sought to understand the photosynthetic responses to drought of native tropical grasses Paspalum densum (Poir.) and Setaria parviflora (Poir.) grown in iron ore tailing. The grass P. densum presented better photosynthetic adjustments when grown in the iron ore tailing and S. paviflora in response to water stress. Both species accumulated iron above the phytotoxic threshold when grown in an iron ore tailing. The net photosynthesis, stomatal conductance, transpiration, and water use efficiency decreased followed by a reduction in leaf relative water content in response to water stress for both species. The photochemical efficiency of photosystem II only decreased at the point of maximum drought. At this point, the water-stressed grass grown in the iron ore tailing presented higher H2O2 concentrations, particularly S. parviflora. After rehydration, full recovery of photosynthetic variables was achieved with decreased malondialdehyde concentrations, increased catalase activity, and, consequently, decreased H2O2 concentrations in leaves for both species. The fast recovery of the native grasses P. densum and S. parviflora to drought in the iron ore tailing substrate is indicative of their resistance and potential use in the revegetation of impoverished mined areas with high iron content and seasonal water deficit.

Unlocking the potential of iron ore tailings in controlled low-strength material: Feasibility, performance, and evaluation

Use of iron ore tailings as partial replacement for cement on cementitious composites production with vegetable fibers

Synthesis of magnetite powder from iron ore tailings

The workability of any soil, when used as a construction material, is greatly affected by its plasticity and compaction characteristics. This research investigates the effect of iron ore tailings (IOT) on the plasticity and compaction properties of lateritic soil (LTS) and black cotton soil (BCS). Atterberg limit and compaction test using three energies, British standard Light, BSL, British standard Heavy, BSH, and West Africa standard, WAS were carried out. These tests were conducted on mixed ratios of 0, 2, 4, 6, 8, and 10 % of IOT mixed each with LTS and BCS separately. A Statistical conceptual model was developed using Minitab R15 to predict the values of the maximum dry density (MDD) and optimum moisture content (OMC) from the computed laboratory results. Analysis was then carried out on the predicted results using origin pro version 8 to test the efficacy of results obtained. The result of specific gravity test shows increase with IOT concentration. An improvement on the plasticity of the modified soil was noted. The liquid limit for both LTS and BCS decreased with increasing IOT concentration. Values drop from 43.4 to 42.7% for LTS and 56 to 52.6% for BCS at 0 and 10% of IOT content, respectively. Plastic limit increased with increasing IOT concentration for LTS and decreased for BCS. In the case of the Plasticity index, values decreased for LTS and marginally increased for BCS treated with IOT. MDD values increased and thereafter drop for LTS treated with IOT while for BCS values increased from natural up to 10% IOT content. OMC values increased for LTS treated with IOT and decreased for BCS treated with IOT. The effectiveness of the developed model was validated using the values of the correlation coefficient obtained from the statistical analysis, which showed a solid relationship between predicted and measured values. Plasticity index values obtained for IOT stabilized BCS did not meet up to the standard requirement when used as a sub-base and base course material respectively. However, the treatment of LTS and BCS with 8-10% IOT improved the soil properties and can be used for pedestrian walkways.

Effect of incorporation of rice husk ash and iron ore tailings on properties of concrete