Porosity Characterization of Iron Ore Pellets by X-Ray Microtomography

Augusto, Karen Soares; Paciornik, Sidnei

doi:10.1590/1980-5373-mr-2017-0621

Cited by 24 publications

(10 citation statements)

References 10 publications

(4 reference statements)

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“…As we have seen in the preceding sections and as has been reported in the literature, X-ray computed tomography is a method with great potential and is being increasingly used for non-destructive materials evaluation, in particular for characterising porosity [23][24][25]. However, one of the limitations to a more wide-spread use of XCT is the relative complexity of the data processing.…”

Section: Discussionmentioning

confidence: 87%

Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

et al. 2020

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The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.

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Section: Discussionmentioning

confidence: 87%

Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

et al. 2020

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“…For systems designed to transport fluids, as is the case of hydrogels, open pores are desirable because they have communication channels with the exterior of the solid, improving absorption. On the other hand, closed pores, which are inaccessible to the external fluid, influence other characteristics, such as, mechanical strength and elasticity 38 …”

Section: Resultsmentioning

confidence: 99%

Hydrogels of starch/carboxymethyl cellulose crosslinked with sodium trimetaphosphate via reactive extrusion

Cagnin

Simões

Yamashita

et al. 2020

J of Applied Polymer Sci

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Hydrogels are materials with advantages in specific applications, such as, retention of food active compounds. This work aims to develop starch (S)/carboxymethyl cellulose (CMC) hydrogels with porous structure, using reactive extrusion to promote crosslinking with sodium trimetaphosphate (STMP). The expansion, porosity, degree of substitution, gel fraction, swelling properties, and FTIR are studied, comparing S, S/CMC, S/STMP, and S/CMC/STMP formulations. Samples containing STMP present the same degree of substitution (0.050 ± 0.001). Higher porosity and percentage of open pores are observed in the mixed hydrogel (S/CMC/STMP). Crosslinking increase the swelling capacity at pH 7, and this property, just like the gel fraction, are sensitive to pH variations. The hydrogel S/CMC present the highest swelling rate compared with the other samples, suggesting strong interaction between components. The reactive extrusion process is efficient to produce starch and starch/CMC hydrogels crosslinked with STMP and the overall results demonstrate the advantages of the mixed hydrogel.

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“…The porosity of iron ore pellets has, traditionally, been determined using optical microscopy (OM) and mercury intrusion porosimetry (MIP). 20) However, MIP was not used because an apparatus was unavailable. OM imaging was not used to determine porosity since it only quantifies porosity in two-dimensional sections, and the preparation steps may affect the results, leading to overestimating porosity.…”

Section: Density and Porositymentioning

confidence: 99%

Influence of H2–H2O Content on the Reduction of Acid Iron Ore Pellets in a CO–CO2–N2 Reducing Atmosphere

et al. 2020

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Using hydrogen as a reducing agent for iron production has been the focus of several studies due to its environmental potential. The aim of this work is to study the influence of H 2-H 2 O content in the gas phase on the reduction of acid iron ore pellets under simulated blast furnace conditions. Temperature and gas compositions for the experiments were determined with multi-point vertical probes in an industrial blast furnace. The results of the reduction tests show that higher temperatures and H 2 content increase the rate and extent of reduction. For all the gas and temperature combinations, morphological, mineralogical, and microstructure changes were observed using different characterization techniques. Microscopy images reveal that H 2-H 2 O, in the gas phase, has a positive influence on reduction, with metallic iron forming at the pellet's periphery and core at lower temperatures compared to CO-CO 2-N 2 reducing gas. Porosity and surface area changes were determined using a gas pycnometer and the BET method. The results indicate that increasing the reduction temperatures and H 2 content results in greater porosity and a larger surface area. Moreover, carbon deposition did not take place, even at lower temperatures. A rate minimum was detected for pellets reduced at 800°C, probably due to metallic iron formation, hindering the diffusion of reducing gases through the product iron layer.

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Porosity Characterization of Iron Ore Pellets by X-Ray Microtomography

Cited by 24 publications

References 10 publications

Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography

Hydrogels of starch/carboxymethyl cellulose crosslinked with sodium trimetaphosphate via reactive extrusion

Influence of H<sub>2</sub>–H<sub>2</sub>O Content on the Reduction of Acid Iron Ore Pellets in a CO–CO<sub>2</sub>–N<sub>2</sub> Reducing Atmosphere

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