Rheological study of Indian iron ore tailings and correlated to its mineralogical characteristics

This chapter deals with the characterization and assessment of iron ore tailings (IOT) as raw materials for the construction industry. This chapter specifies the production process of iron ore and generation of waste material followed by listing the nature and prospective issues of IOT. Methods of IOT characterization are explained through five elements, which are chemical composition, leaching behavior, thermal stability, mineralogical characterization, and morphology. The experimental program and research results of this study are explained in six subtitles, namely chemical composition, leaching behaviour, thermal stability, x-ray diffraction pattern, Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM/EDX). Results revealed that the IOT materials are suitable for use in construction and building industries due to their substantial silica and alumina contents and could possibly be used to fabricate paving blocks, sand-crete blocks, mud blocks, geopolymer bricks, and ceramic floor tiles.

In order to study the feasibility and sand substitution mechanism of cement mortar mixed with iron ore tailings (IOT), iron ore tailings cement mortars (referred to as IOTC) with IOT content of 0%, 25%, and 50% were made and tested. First, the basic properties of IOT used were measured to verify the theoretical feasibility. Second, the uniaxial compressive and tensile strengths, as well as the crack resistance performance of IOTC under different curing ages and different sand substitution rates were tested. Third, the techniques of inductively coupled plasma atomic emission spectrometry (ICP-OES), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS) were used to study the influence of curing age and different sand substitution rates on the chemical, mineralogical, and microstructural characteristics of IOTC. The sand substitution mechanism of IOT was then discussed. The research results proved the feasibility of using IOT to substitute standard sand in cement mortar. Within substitution rate of 0–50%, the mechanical properties increased with the increase of substitution rate. Though limited chemical effects were found by adding IOT, in comparison with standard sand mortar, more hydration products were found and the pore size distribution was changed for IOTC, which corresponds to its mechanical improvement.

The strength of the filling body is largely affected by the properties of the binder, mineral composition, fineness, and slurry concentration of tailing. In this paper, the rheological test was conducted to determine the slurry concentration of iron ore tailing containing gypsum. Then, the samples made from slurry and three binders, Portland cement, filling plant binder, and Huazhong binder, were tested, respectively. The effects of curing time, binder‐tailing ratio by mass (b/t), and slurry concentration on compression strength were investigated. The sample made from Huazhong binder and iron ore tailing presented the largest compression strength.

Effect of iron ore tailings industrial by-product as eco-friendly aggregate on mechanical properties, pore structure, and sulfate attack and dry-wet cycles resistance of concrete

An alternative to conventional methods for mine tailings disposal is stabilization with alkali-activated binders (AABs), developed from agro-industrial waste. Despite increasing interest in this topic, there is still a lack of studies focusing on the stabilization of iron ore tailings (IOTs) using AABs, particularly those that combine the characterization of cementitious gels with an evaluation of leaching behavior. This study assessed the strength, mineralogy, and leaching performance of IOTs stabilized with AABs formulated from rice husk ash (RHA) and hydrated eggshell lime (HEL), using sodium hydroxide as the alkaline activator. Tests included unconfined compressive strength (UCS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and metal leaching analyses. The IOT–AAB mixture with the highest AAB content and dry unit weight achieved an average UCS of 2.14 MPa after 28 days of curing. UCS increased with AAB content, followed by dry unit weight and curing time, the latter showing a non-linear influence. The formation of C–S–H gel was confirmed after 28 days, while N–A–S–H gel was detected as early as 7 days of curing. The cemented IOT–AAB mixtures showed no metal toxicity and effectively encapsulated barium originating from the RHA.

Several frequently used cross-linked fracturing fluids, hereafter referred to as gels, have been evaluated as to the effects that shear and that 20/40 mesh sand proppant have on their rheological properties. A closed-loop pipe viscometer was used to evaluate the shear resistance and post-shear recovery of various gels as a function of pH, cross-linker type, polymer concentration, shear intensity (shear stress and shear rate), and shear duration. The aqueous-base gels that were tested included those made with guar, hydroxypropyl guar (HPG), and carboxymethyl hydroxyethyl cellulose (CMHEC) polymers. Selected aqueous-base gels were also evaluated as to the effect on slurry viscosity of varying concentrations of 20/40 mesh sand proppant. Test results indicate that when cross-linked with borate ions, guar and HPG gels have the greatest resistance to shear. Yet when cross-linked with various titanates, HPG gels showed significantly lower resistance to induced shear. Tests on CMHEC gels which were cross-linked with trivalent aluminum (Al+++) indicate a shear resistance between that of the HPG-borate gels and that of the HPG-titanate gels. Also tested was post-shear recovery or the percentage of viscosity increase following high shear exposure as correlated to field tubular pumping conditions. The HPG-borate gels and the CMHEC-Al+++ gels demonstrated considerably higher post-shear recoveries than those attained with HPG-titanate gels. In addition, the effect of 20/40 mesh sand on the viscosity of gels is a larger increase in slurry viscosity in the fracture than that predicted from Newtonian slurry mathematical models. Finally, laboratory study indicates that the actual slurry viscosity, accounting for shear and proppant effects within the fracture, is apparently moderately to extensively lower than that predicted by conventional rheological methods.

Effect of slurry composition on the microstructure and mechanical properties of SS316L open-cell foam

The search for alternatives that minimize the generation of tailings and enable their reuse, leads to characterization studies with the objective of a better understanding of the physical, chemical and mineralogical properties of iron ore tailings. The increase in demand for high-quality ore overlapping ore extraction with increasingly lower iron concentration levels, is part of the challenge of mineral exploitation. In view of the aforementioned needs, a more detailed characterization of the tailings contributes to the improvement of the mineral processing stage and the reuse of the generated tailings. To this end, an analysis of the characteristics of the tailings was carried out through physical, chemical and mineralogical characterization, with emphasis on quantitative electron microscopy - QEM. The tests revealed that the predominant phases are hematite and quartz and, to a lesser extent, goethite, gibbsite and kaolinite. As for the degree of release, hematite/magnetite has 88.13% of its particles totally free, 0.53% associated with quartz and 6.77% associated with goethite. The chemical composition is 32.29% Fe, 47.92% SiO2, 2.76% Al2O3, and 2.14% PPI. In this scenario, mineralogical characterization, as a main component of geometallurgy, makes it possible to propose alternatives that improve the ore beneficiation process and the reuse of tailings.

The mechanics of filtered compacted normally consolidated (NC) and overconsolidated (OC) iron ore tailings (IOTs) was studied by performing triaxial testing at high pressures of up to 120 MPa. The OC specimens were obtained by isotropically compressing compacted IOT to 120 MPa, unloading it to distinct confining pressures, and shearing at constant radial stress. Particle size distribution analyses were used to examine the effect of compression and shear stresses on particle breakage. Additionally, the triaxial test results illustrate the stress history influence on the deviatoric stress–axial strain–volumetric strain curves, as well as on the IOT peak strength. Furthermore, these results also show that the amount of breakage during the shearing stage plays an essential role in the geomaterial’s response, marking the existence of curved critical state locus in both v–ln p′ and q– p′ planes, which is unique in the studied confined stress range (4–120 MPa) for the compacted NC and OC (considering OC ratio up to 30) IOTs.

Rheological characterization and performance of flocculants in iron ore tailings management

Minas Gerais stands out asone of the main iron ore extraction regions in Brazil, the world's second largest producer. During this extraction, large amounts of waste are generated. In the Civil Engineering and Architecture sector, there is the challenge of presenting construction solutions with less environmental impact. Rammed earth emerges as a sustainable construction technique due to its low embodied energy compared to conventional techniques. Therefore, this paper proposes to analyze the possibility of using iron ore tailings (RMF) as a physical stabilizer for rammed earth soils. No research on this use specifically was found. However, it was found that RMF can be viable for grain size correction of rammed earth soils or as a substitute for base materials due to its suitable physical, chemical and mineralogical characteristics, especially when requiring percentages of sand, fine sand or silt.

The mineralogical characterization studies search for the best processing route, with the lowest environmental impact, aiming to improve the use of mineral resources. The electronic quantitative mineralogy (EQM) provides quickly and accurately great information about the characteristics of these materials. This work aims to characterize iron ore tailings by EQM as the main tool. It has selected seven samples of itabirite ores flotation tailings from the main mining regions of the Quadrilatero Ferrifero, Brazil. All samples were mostly composed by quartz and iron minerals, with a low presence of mixture particles of these minerals - less than 20% of the sample mass. Due to the difference between the size of particles of quartz and iron minerals, it has observed an opportunity to reprocess the fractions -37µm + 5µm of the studied tailings, with a potential recovery of 12% of the total sample mass generated for AM4, AM6 and AM7 and more than 5% for samples AM1, AM2, AM3 and AM5.

India is well enriched with abundant resources of magnetite and hematite iron ore. Mining activities are tremendously increasing to cater the demand of market, which in turn is responsible for huge generation of mining waste. Mine tailings impoundments produced during beneficiation and extraction of iron ores create environmental threat and are disposed at high monetary and ecological cost. There is a need to find a sustainable and economical solution to handle large quantity of generated waste. Depleting natural resources like granular soil as backfill material needs a substitution in many application-like pavements, mechanically stabilized wall, embankments, etc. This paper presents a critical review on literatures highlighting on use and reuse potential of iron ore tailings as a backfill material in structural application such as MSE wall, embankments, pavements. Characterization and engineering behaviour of the tailings are the central necessity for estimating its effectiveness as its properties vary from ore structure. Mineralogical characterization, shear strength, permeability, workability, and compressive strength are the properties discussed in this paper. Results show that iron ore tailings have properties which can be considered as an effective substitute in structural applications. Adopting it as backfill material can be considered an environmentally friendly method of stabilization. It protects the surface structures and abate subsidence in abandoned underground mines. It has its potential in handling large volume of tailings and significantly reduces the quantity of waste generated in the state.

Objective: By evaluating operational filtration conditions, chemical, mineralogical, and particle size properties of the tailings, the study aimed to identify critical variables affecting porosity and provide predictive models for optimizing dewatering operations. Theoretical Framework: This research builds upon existing theories of solid-liquid separation and dewatering processes in mineral processing. Key references include classical works on filtration dynamics, particle size distribution, and cake porosity characterization. The study addresses gaps in literature regarding the relationship between tailings composition and filtration results. Method: The Leaf Test method was employed on 33 fresh slurry samples from the Brucutu plant to simulate industrial filtration conditions. Filtration cycle parameters such as cake formation and drying times were standardized. Porosity was calculated using Grace's equation and correlated with characterization data, including mineralogical composition, true density, and particle size. Statistical methods such as clustering, regression, and Random Forest modeling identified key predictors of porosity. Results and Discussion: The results indicated that porosity correlates strongly with silica content and certain mineralogical attributes, such as the presence of martitic hematite and quartz. Cluster analysis revealed two sample groups with distinct filtration characteristics. While operational parameters showed limited impact on porosity, the statistical models highlighted the significance of ore composition. Research Implications: This research provides a foundation for optimizing iron ore tailings filtration by identifying the key variables influencing porosity. The findings support more efficient dewatering techniques, contributing to sustainable tailings management. Further, the development of predictive models aids industrial operations in minimizing risks associated with tailings disposal. Originality/Value: This study is among the first to integrate statistical modeling and mineralogical characterization in exploring filter cake porosity. The results offer novel insights into the optimization of solid-liquid separation processes in the mining industry.

The apparent viscosity of coal slurry prepared with hydrogenated anthracene oil was measured at temperatures between 323 and 473K, and the mechanism of viscosity change with heating was investigated. Depending on the coal rank, the slurry viscosity increased with increasing temperature, time and coal concentration at temperatures above 423K. The slurry viscosity of Miike coal, a bituminous coal, increased much more than that of Wandoan coal, a sub-bituminous coal, with heating time at 453K, although Taiheiyo coal, a lower rank coal, and Beatrice coal, a semi-anthracite, showed no remarkable changes in slurry viscosity. The effect of coal dissolution on the increase in slurry viscosity was relatively small, and the viscosity increase of coal slurry was found to be caused mainly by solvent absorption into the coal particles.