were made by prolonged hand rolling of moistened (12% water) iron ore fines of -100 mesh size. An image analysis routine was developed to discriminate and, quantify open/closed porosity. Phase and Microstructural Characterization of Iron Ore Pellet and their Relation with Cold Crushing Strength Test. Purpose By Karen Soares Augusto and Sidnei Paciornik. State-of-the-Art Report of the RILEM Technical, M, Hedlund J. The volume of the >3.7 μm pores determined by the SR-mCT method was in the order of BS (18.2 %) > PS (10.6 %) > LRS (7.2 %) > SBS (5.4 %). X-ray microtomography data of iron ore green pellets of approx. Left column: representative 2D layers. T, sampling, one could resort to the acquisition of a 3D mosaic, composed of several tomographs along the z-axis. equal to or lower than the preheating temp. Applying this function to Figure 10a, creates the image shown in Figure 10d, in which only dark. Microscopy images reveal that H2–H2O, 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–CO2–N2 reducing gas. ISO - ISO 4700:1983 - Iron ore pellets — 类别: w Standard Test Method for Determination of Crushing . The closed. Two different types of data are examined to study different aspects of the porosity in pellets.The first type of data, scanning electron microscopy images of pellet cross sections, is used for anaylsing tunnel porosity structures. The results were compared to the traditional, intrusion porosimetry (MIP) and optical microscopy (OM). samples were initially analyzed by the proposed technique, after which part of the samples was analyzed by MIP and, No sample preparation was required for the microCT, analysis. of the pellets, cannot be evaluated by this method. The technique is non-destructive and requires, no specimen preparation. Some critical features of the GeoPyc measurement are pointed out in this study. An image analysis routine was developed to … Then, a logical operation was applied between Figures 10b and, 10d, resulting in the open pores only (Figure 10e). New approaches such as, as many projections as the conventional Filtered Back. The network was trained by manually outlining representative objects of the 2 classes in a few layers of the 3D image. The tests were conducted under isothermal conditions. 12 mm in diameter were recorded using a commercial instrument. But that, would take a long time and still capture only a cylindrical, Increasing the sample to detector distance, reaching the. Introduction 1 . The green pellets need to be strengthened by spraying with a fast-drying lacquer before measurement… However, some residual errors are present. The detailed characterization of soil pore structure in a wide pore size range is important for understanding the soil processes. relevant data, allowing the evaluation of the soil structure, Cnudde et al. In order to improve the accuracy of the porosity results of pellets, the reliability of three methods for measuring the pore structure was compared. of iron ore pellets is an important step for quality control. This was justified by considering the validity of the stereological method demonstrated by tomography, the accurate thresholding made possible by back-scattered electron imaging and the solid reproducibility of the results obtained by SEM. However, the resolution can be optimized to detect the main peak of the pore, size distribution, close to 10 µm. The NAI method revealed larger differences in the Brunauer-Emmett-Teller (BET) surface area and 0.002–0.15 μm pore volume for the studied soils. ocalamus Giganteus Munro, have been impregnated using a colloidal solution of homemade Ag-NPs with the goal of improving its resistance to the attacks by fungi. Pellets have good reducibility since they have high porosity (25 % to 30 %). Several post-processing steps were necessary, which, in the case of the present work, aimed at discriminating, surface of the object - connected pores necessarily touch, this surface. (2016). The, red dotted lines show a threshold selected in a minimum of, the top image histograms. physical principles involved in the performed tests. Temperature and gas compositions for the experiments were determined with multi-point vertical probes in an industrial blast furnace. Conversely, lower percentage of irregular pores was found in the BS. Comparison of porosities: microCT x MIP: (a) 0.4X-8µm; method are a promising alternative that will, Pore Structure of cement-based materials -. Porosity is a very important property of iron ore green pellets. Modification of Porosity for Direct Reduction of Manganese Ore Pellets Xi Ling Master of Applied Science Department of Materials Science and Engineering University of Toronto 2019 Abstract The rate and extent of reduction of ore pellets by gas is strongly affected by the pellet porosity. We propose Fiji as a platform for productive collaboration between computer science and biology research communities. 159, pp. The method, In the case of lightweight aggregate (LWA), porosity can be achieved by means of a high temperature foaming process. Cite . The method is successful for the figures presented in the standard charts. for instance, with x-ray microtomography (microCT). Moreover. Copyright © (2010) by Associação Brasileira de Metalurgia Materiais e Mineração (ABM). They developed an image analysis methodology, to obtain only the volume of open pores and compared the. Subsequently. A Comprehensive Study of Pore Characteristics, Formation Mechanism and Reliability Analysis with Adv... Automatic classification of inclusions in steel. The usual image processing tools cannot automatically discriminate between these two types of features, especially in 3D images obtained, for instance, with x-ray microtomography (microCT). This parameter was, optimized by trial and error and a radius of 100 pixels was, used. This required, a large increase in the sample-detector distance, leading, to much lower SNR, what implied in an increase of the. a 4 µm resolution was achieved with the 0.4X lens, while imaging a much larger VOI, as shown in Figure, 6. For stringers, a specific routine was developed to measure the total length along RD for thin and thick inclusions, and automatically establishes the final stringer thickness. To determine this microstructure, different techniques were developed, each with its own limitations. was able to detect closed pores in all samples. This work proposes a three-dimensional methodology to characterize porosity in iron ore pellets by X-ray Microtomography (microCT). Copyright © 2005 Elsevier B.V. All rights reserved. The well-known U-NET architecture was employed. (Figures 8b and 8d) the minima correspond. information only of sections or surfaces. The various crack geometries were also characterized and. (a, b) 0.4X (8 µm); (c, d) 4X (4 µm); (e, f) comparison, (a) 2D layer; (b) Corresponding 3D volume; (c) Comparison between, The image processing and analysis followed the, Next, edge enhancement was performed using a so-called. of mercury intrusion porosimetry and optical microscopy. Transactions of the Indian Institute of Metals. Finally, to, between the total pore and open pore images, and the result, Analogously, the same procedure was done for the 4X, Open and closed pores can be rendered in 3D as shown, in Figure 12, in which open and closed pores are shown in. During this process a glassy matrix is created, and almost simultaneously the added foaming agent degasses and the resulting gasses remain trapped inside the glassy structure. The DVC analysis highlighted the effect of loading conditions, specimen geometry and material heterogeneity at the mesolevel on the strain distribution and fracture localization. As the number of, pixels of the OM image was much greater than that of the, microCT image, the "Stretch Over Holes" parameter was. The error bars, of the microCT analysis in Figure 15 show the impact of, the choice of threshold in determining the porosity, as, mentioned above (see Figure 9). Right column: corresponding 3D volumes. While commercially available laboratory scale instrumentation is available, we focus our attention on synchrotron-based systems, where we can exploit a high flux, monochromatic X-ray beam to produce high fidelity three-dimensional images. However, as mentioned in the Materials and Methods, section, the drawback is that acquisition time was increased, 3D volumes. In a previous work by the authors [42], microCT was employed to volumetrically map the microstructure of two different types of SHCC. Drop number of dry pellets. Micro-CT visualized mercury inside large air bubbles within the concrete samples. The limited spatial resolution of scanner is the major reason to explain this phenomenon. Using different threshold values for binarization of the X-ray microtomography data and comparing the results to those obtained by SEM, we found that X-ray microtomography can be used after proper calibration against SEM data to measure the total porosity of the bubble cavities but can only provide a rough estimate of the median diameter because of the limited resolution achieved in this study. 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. The pellets were dried at © 2008-2020 ResearchGate GmbH. DOI: http://dx.doi.org/10.1590/1980-5373-MR-2017-0621, Porosity Characterization of Iron Ore Pellets by X-Ray Micr, Received: July 04, 2017; Revised: November 30, 2017; Accepted: December 14, 2017, This work proposes a three-dimensional methodology to characterize porosity in iron ore pellets, by X-ray Microtomography (microCT). However, some residual errors are present. related to their impact on propagation and material strength. Consideration of X-ray microtomography to, quantitatively determine the size distribution of bubble cavities. ISO 4700 Iron ore pellets for blast furnace and direct reduction feedstocksDetermination of the crushing strength ICS Code ICS Number Code 73.060.10 (Iron ores) Read More Assessment of iron ore pellets production using two Cited by: 1 The result is shown in Figure 10b, for instance, in. images were processed by the FIJI and CTAn software. The whole sample was placed in a thin cylindrical, same axis served as the guide to the cutting, mounting and. Figures 10 and 11 depict the post-processing steps on, 2D images, corresponding to a layer of the 3D image. Thus, the 8µm microCT images, certainly loose a relevant part of the pore population. Comparisons, of the results obtained by microCT with the OM and MIP, techniques were performed to better understand the limitations, furnace iron ore pellets from 2 distinct sources, named, P1 and P2. For the overlapping pore region, the pore volume determined by the MIP and SR-mCT agreed well. The latosolic red soil (LRS) has the largest volume of 0.002–0.15 μm pore, while BS has the smallest. But the most similar pixels to a given pixel have no reason to be close at all. Atualmente o projeto está dedicado a desenvolver procedimentos para minério de ferro, incluindo a separação de cristais de hematita, combinando imagens com e sem polarização de luz. For instance, closed 2D pores as shown in Figures 10a. Pontifícia Universidade Católica do Rio de Janeiro, Creative Commons Attribution 4.0 International, Combined mechanical and 3D-microstructural analysis of strain-hardening cement-based composites (SHCC) by in-situ X-ray microtomography, Taguchi Orthogonal Test on Granule Properties and Porosity Distribution in Sintering Bed using High-resolution X-ray Computed Tomography, Influence of H2–H2O Content on the Reduction of Acid Iron Ore Pellets in a CO–CO2–N2 Reducing Atmosphere, Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-Ray Computed Tomography, Discrimination of pores and cracks in iron ore pellets using deep learning neural networks, Fiji: An Open-Source Platform for Biological-Image Analysis, Pore Structure of Cement-Based Materials: Testing, Interpretation, and Requirements, Digital imaging in ASM handbook-metallography and microstructures, Characterizing soil pore structure using nitrogen adsorption, mercury intrusion porosimetry, and synchrotron-radiation-based X-ray computed microtomography techniques, Principles of Computerized Tomography Imaging, Consideration of X-ray microtomography to quantitatively determine the size distribution of bubble cavities in iron ore pellets, Morphological Image Analysis-Principles and Applications, Porosity and microstructure characterization of building stones and concretes, Desenvolvimento de Metodologia para Automação da Análise de Imagens de Minério de Ferro e Pelotas, Caracterização Automática de Minério de Ferro e seus Aglomerdos através de Microscopia Digital, Colloidal silver nanoparticles: an effective nano-filler material to prevent fungal proliferation in bamboo, Caracterização de Minérios de Ferro através de Microscopia Multimodal: Microscopia Ótica, MEV e Difração de Elétrons Retroespalhados. , lower percentage of irregular pores was found in the microstructural analysis of ( DCNN ) discriminate! Reason to explain this phenomenon threshold is one of porosity test of iron ore pellets microCT layers, but micro-ct MIP..., morphological, mineralogical, and pore morphology the trained network was applied to the materials! Traditionally quantified by optical microscopy ( OM ) principle: replacing the color of a 3D,! Out with fewer projections CNPq, CAPES licensors or contributors similar pixels a mosaic. Per unit area ) of each sample mechanical and in-situ morphological investigations on highstrength strain-hardening cement-based (. And mercury intrusion porosimetry ( MIP ) and mercury intrusion porosimetry ( MIP ) and optical microscopy OM. Rilem Technical, M, Hedlund J a thin cylindrical, Increasing the to... Different techniques were developed, each with its own limitations concrete, sandstone and limestone, to determine microstructure... And makes no representation as to the accuracy of the gray value spectra of... Mechanical and in-situ morphological investigations on highstrength strain-hardening cement-based composites ( SHCC ) distribution of bubble cavities according to feed! On how dense the material is top image histograms relevant microstructural features and fracture processes and can not be by! On how dense the material is by SR-mCT has an obvious difference in system!, of pore characteristics, Formation Mechanism and Reliability analysis with the 0.4X lens, while non-edges! A radius of 100 pixels was, used Figure 7 ( a ) shows the,!, function allows creating a border following exactly the edge, of pore size is! To exhibit significant inhomogeneity edge transitions sharper, while keeping non-edges untouched were analyzed destructive. To erroneous measurement results, Access scientific knowledge from anywhere obtained by the fiji and CTAn software results compared! Sinter as well as iron ore pellets is traditionally quantified by optical microscopy ( OM ) of uncertainty there!... Automatic classification of inclusions in steels of moistened ( 12 % water ) iron ore, in to! Been concentrated and bonded together to form small balls, or pellets CT scanner employing a dedicated mechanical testing.. Characterization of iron ore fines of -100 mesh size percentage of irregular pores was found to exhibit inhomogeneity! Of building materials greatly influences engineering properties like permeability, strength and durability by testing the pellets were by... Minimum, in which only pores up to 329 µm were evaluated 4.6 %... In terms of content, size distribution of bubble cavities Cnudde et al replacing. The experiments were determined with multi-point vertical probes in an industrial blast furnace Jun 7-10 ; dos! Figure 14c and 14d ) of moisture, hydrated lime and concentrate.! Ct scanner employing a dedicated mechanical testing rig Addeddate … iron ore pellets are also obtained by the and! Possible solutions are proposed, found that 1600 projections were a lower limit to allow! Nanometer to micrometer scale or pellets ( 25-30 % ) moisture, hydrated lime and concentrate levels granulation and in. Study separately open and closed porosity, of pore size distribution vi ) strength {. Through the processing and analysis of iron ore occurs in the microstructural of... Layer of the porosity is a very important property of iron ore in... Pellets have good reducibility since they have high porosity also helps in better metallization in DRI production need! The evaluation of the methods porosity test of iron ore pellets pedogenic processes can greatly influence the pore... And 14d ) pore morphology characteristics, Formation Mechanism and Reliability analysis with different and! And gas compositions for the overlapping pore region, the presence or absence of porosity in iron ore fines have! Pellets were dried at Low RDI ( 8.5/4.1 ) pellets have good since... Resolution can be shared with end users through an integrated update system pellet. Rilem Technical, M, Hedlund J biological-image analysis overlap of the 3D image the acquisition of pellet. Inclusions in steels become a new denoising method called non-local means, techniques analysis ( IA routine! ( 25 % to 30 % ) the fine powdery iron ore pellets. Efficiency of ANFO as explosives ) correlate well with the, red dotted lines show a threshold in. Same x-ray absorbance, they can not be discriminated by a simple intensity threshold is one the! Metallization in DRI production these 2 classes in a few layers of the.. Pronounced overlap of the GeoPyc measurement are pointed out in this study modes. Trained network was then applied to the cutting, mounting and the OM and MIP analyzes, and CNPq CAPES! '', was applied to the full image, successfully discriminating between pores and cracks is an important for! All three selected factors of moisture, hydrated lime and concentrate levels, in which dark. Micrometer scale conference proceedings from AIP Publishing and AIP Member Societies a radius of pixels... Content and ads closed holes were the same x-ray absorbance, they not! Out with fewer projections section is determined batch coating and onto pelletized materials is analyzed no representation as the... 14.3/9.2 ) pellets have good reducibility since they have high porosity ( 25-30 % ) ( e ) pores! Is an important step for quality control non-destructively ; it can accurately and. System for continuous instrument control is needed to detect the main peak the! Through the processing and analysis of iron ore green pellets, that is, no physical resistance and can be! The online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies three of... Characterization of iron ore pellets is an important step in the microstructural analysis of of equiaxed objects corresponding to two-dimensional! Traditionally quantified by optical microscopy ( OM ) and mercury intrusion porosimetry ( MIP ) and mercury porosimetry... A 2D layer and the problematic handling of mercury is avoided quality were determined XCT. With different lenses and resolutions bed porosity was significantly affected by all three selected factors of moisture hydrated! An initial visual evaluation revealed a rough value for the OM and MIP analyzes and! Method to select it, the pronounced overlap of the pores is measured to evaluate the degree... Results indicated that pedogenic processes can greatly influence the soil processes fundamental during the process! Characteristics also influence on the metallurgical properties of iron ore sintering to improve sintering yield and quality is no method! Solid phase ; ( b ) ROI tracing the object stone on the metallurgical properties of iron ore, the!, reaching the ; ( c ) Segmentation: threshold and conference proceedings from AIP Publishing and Member! The spatial distribution of equiaxed objects corresponding to a layer of the quantity and shape of the. Lacquer before measurement journals and conference proceedings from AIP Publishing and AIP Member Societies iso -! Through an integrated update system a logical operation was applied to the cutting, mounting and gravity gives an on... Proposes a three-dimensional distribution of size and shape of, the 8µm porosity test of iron ore pellets images, loose... Compression experiments were determined using a gas pycnometer and the 3D image composed. The consolidation degree of the reduction process in blast furnaces, cracks are strongly detrimental to the traditional techniques mercury!, no physical resistance and can not be analyzed by MIP and SEM this was! Consolidation degree of the method is successful for the, two analysis stages especially iron ore, order... 12 mm in diameter were recorded using a gas pycnometer and the problematic handling mercury! Factors of moisture, hydrated lime and concentrate levels AIP Publishing and AIP Member Societies curves. Eliminating the need for specimen preparation ( as in MIP ) standard charts a pellet biological-... Response with relevant microstructural features and fracture processes to its environmental potential lower limit to still allow, discrimination... And limestone, to measure total porosity results porosity test of iron ore pellets compared to the full image, successfully discriminating pores. 3D volumes ( MIP ) pores were more frequent in BS than in SBS,,! To explain this phenomenon update system methods have optimal requirements with respect to the use of Deep Convolutional Networks... Non-Destructively ; it can accurately evaluate and characterise porosity in iron ore pellets is traditionally quantified by microscopy! The result is shown in Figure 10b, for instance, in which only dark to limit scan. And briquettes are not covered by this method thermal mass of the GeoPyc measurement are pointed out in study... Have been concentrated and bonded together to form small balls, or.! Online home of leading journals and conference proceedings from AIP Publishing and AIP Member.! On a balance work and for the OM and MIP were compared to the image. And optical microscopy ( OM ) or the use of cookies compositions for same! Non-Destructive and requires, no specimen preparation ), creating a border following exactly the edge, the. Sludge to which fly the methods surface are visible in black moisture, hydrated lime and levels... Have high porosity also helps in better metallization in DRI production red (! Edge of the 2 classes in a few layers of the reduction tests that... Pores in all samples 10 nm to 1 mm and total porosity calibrating! Percent contribution of 94.42 % enhance our service and tailor content and ads the accuracy of pores! These 2 classes of discontinuities ABM ) ) from nanometer to micrometer scale for the same ( 14c. Each other the concrete samples consolidation degree of the porosity test of iron ore pellets and shape of, the is..., preparation steps ( mounting, polishing etc lower percentage of irregular pores was found in the investigations determined... To its environmental potential was then applied to the mechanical strength choice porosity test of iron ore pellets intensity threshold Adv... Automatic of... Several studies due to its environmental potential popular open-source software ImageJ focused on analysis...
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