Characterization Of Iron Ore Research Articles

Characterization of Iron Ore Tailings as Fine Aggregate

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Automatic characterization of iron ore by digital microscopy and image analysis

This paper presents an automatic system for mineralogical and textural characterization of iron ores based on digital microscopy and image analysis. It employs a motorized and computer-controlled reflected light microscope in a correlative approach that combines bright field and circular polarization modes. Mosaic images covering large areas of polished sections are acquired to image thousands of particles. Different classifiers discriminate compact and non-compact hematite, polycrystalline and monocrystalline particles, and identify particles as granular, lamellar, and lobular. The entire process is automatic and produces a full pdf report containing typical images and the quantification of mineral and textural phases.

Characterization of iron ore with Al2O3 as oxygen carrier in Chemical Looping Combustion (CLC)

Chemical looping combustion (CLC) is one of the carbon capturing technologies, in which oxygen from oxygen carrier reacts with fuel inside fuel reactor to produce CO2 and H2O. Fe-based oxygen carrier is widely used in CLC due to the low cost and less susceptible to carbon formation. This research focuses on synthesizing and characterizing iron ore with alumina in order to analyse the suitability of Malaysia iron ore as an oxygen carrier for CLC application. Iron ore with alumina was prepared using ball milling at various milling time which are 1 hour, 6 hours, 8 hours and 10 hours. The phase transformation, morphology and elemental composition of obtained samples were characterized using X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Energy Dispersive X-Ray (XRD), respectively. In CLC application, high reactivity of CLC can be obtained with the small particle size of oxygen carrier. This research succeeded in producing Fe2O3/Al2O3 using ball milling with particle size that less than 10μm with crystallite size 17nm at 10 hours, which favourable to be used as oxygen carrier.

Spectroscopic characterization of iron ores formed in different geological environments using FTIR, XPS, Mössbauer spectroscopy and thermoanalyses

Application of thermoanalyses, FTIR, XPS and Mössbauer spectroscopic methods can differentiate between iron ores formed in different geological environments. Two types of iron ore are formed in shallow marine environments in the Bahariya Depression, Egypt, yellowish brown ooidal ironstones (type 1) and black mud and fossiliferous ironstones (type 2). Both types were subjected to subaerial weathering, producing a dark brown lateritic (pedogenic) iron ore (type 3). Microscopic investigation indicates goethite is the main mineral in types 1 and 3, while hematite is the main mineral in type 2 and also occurs in type 3. Thermoanalyses indicated the dehydroxylation endothermic peak of goethite of type 1 occurs between 329 and 345°C, while in type 3 occurs between 284 and 330°C. This variation can be attributed to the nanocrystalline nature of the pedogenic goethite. The presence of an exothermic peak at 754°C in type 3 is probably attributed to goethite-hematite phase transformation. FTIR spectroscopy indicated that goethite of type 1 is characterized by the presence of the δ-OH band between 799 and 802cm−1, the γ-OH between 898 and 904cm−1 and the bulk hydroxyl stretch between 3124 and 3133cm−1. Goethite of type 3 is characterized by the absence of the bulk hydroxyl stretch band and the δ-OH and γ-OH are shifted to higher Wavenumbers that can attributed to a relative Al-for Fe-substitution. Hematite is identified by two IR bands; the first is between 464 and 475cm−1 and at the second is between 540 and 557cm−1. Quartz is identified in all iron ore types, nitrates are identified in types 1 and 2, but absent in type 3 and Kaolinite is identified in type 2. The Mössbauer spectrum of type 1 is fitted with one magnetic sextet corresponding to goethite with an isomer shift (IS)=0.374mms−1, a quadruple splitting (QS)=−0.27mms−1 and a hyperfine magnetic field (BHF)=∼37. The Mössbauer spectrum of type 2 is fitted with one magnetic sextet corresponding to hematite with IS=0.363mms−1, QS=−0.23mms−1 and BHF=∼50. The Mössbauer spectrum of type 3 is best fitted with a single doublet corresponding to ferrihydrite and one sextet corresponding to hematite. The XPS survey scans and the high resolution of the Fe 2p3/2 can differentiate between the yellowish-brown and green ooidal laminae of type 1. The XPS survey scans indicate the presence of Fe, O, C, N, Na, Cl, Ca and Si in all laminae, while S, Zn, Ti and P are only restricted to the green laminae. The high resolution of the Fe 2p3/2 indicates that Fe is linked to OH− ligand in the yellowish-brown laminae that correspond to goethite, while Fe is linked to SO42− ligand in the green laminae. The XPS survey scans of types 2 and 3 indicate that Fe is linked to O2− ligand that corresponds to hematite.

Methodology for selection of samples from borehole probe for technological characterization of iron ore

The risks in the evaluation of mining projects are directly related to the probability of errors in the estimates, and, as the estimates are based on sampling results, this activity must be performed in a careful and planned way, to prevent surprises at the beginning of operation. To validate the representativeness of the borehole samples selected for the mineral processing studies, the geological resources evaluation team proposed a methodology based on the utilization of statistical analyses that, beyond considering the spatial distribution of the samples in the deposit, also assessed if they are representative of the populations under investigation. With this data, the geologist is able to make a fast analysis of the sampling's representativeness.

Automatic recognition of hematite grains under polarized reflected light microscopy through image analysis

The recognition of hematite grains is an intermediate task that aids the texture characterization of iron ores. Hematite is a strongly anisotropic mineral. Thus, the combined use of a polarizer and an analyzer in reflected light microscopy (RLM) can be used to obtain images that present sufficient contrast to differentiate grains. The present work proposes a methodology for recognizing hematite grains in images obtained with RLM. Three images per field are acquired in different conditions: without polarization in common bright field arrangement; and with polarization under two symmetrical polarizer/analyzer angles. These images are automatically registered. Then, the hematite grains are recognized through a modified region growing segmentation method based on reflectance and textural information. An optimal value for the polarization angle was determined. The results are promising. The vast majority of grains was correctly recognized. The automatically segmented images were compared to edited versions in which all crystals were correctly discriminated. A statistical comparison of crystal size and shape showed no statistical differences, to within 99% confidence, between automatic and edited segmentation results.

Characterization of Iron Ore via Combining Optical and EBSD Technic

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Beneficiation of Synthetic Iron Ore Kaolinite Mixture Using Selective Flocculation

High demand of steel necessitates the use of low and lean grade iron ores by beneficiating them. However the fines, slimes and tailings generated in the process of beneficiating these low grade iron ores contains good amount of iron values. These iron values can be recovered by further beneficiating the fines, slimes and tailing by selective flocculation, which is defined as the selective agglomeration of iron ore particles using flocculant. In the present study an attempt has been taken to study the applicability of selective flocculation to Indian iron ore using corn starch as flocculant. A detail mineralogical and chemical characterization of iron ore and kaolinite were performed; in addition to this the flocculant was characterized by FTIR which gives an idea about the functional groups present in the flocculant. Different experiments were performed to optimize the operating parameters of the selective flocculation process. It was observed that product grade and recovery was strongly affected by pH of slurry and solid concentration compared to the flocculant dose. It was also found that the iron value can be upgraded to 63-66.9 % from the feed iron value of 37.65-55.33 % with the recovery of 63-90 %.

The use of diffuse reflectance spectroscopy for the characterization of iron ores

The aim of this work was to develop a diffuse reflectance methodology for quantifying minerals in powdered iron ores, which is a key quality control requirement for these materials. Selected samples ranging widely in their concentrations of hematite (as specularite and martite), goethite, magnetite, and quartz were collected in mines from the Iron Quadrangle, Minas Gerais State, and also in the Carajás region, Pará State, Brazil. A chemometric analysis based on the concentrations of the different minerals as determined with a combination of conventional methods (chemical analysis, X-ray diffraction, Mössbauer spectroscopy, light-reflected microscopy, and magnetic susceptibility) and the principal components derived from the diffuse reflectance spectra in the visible range was performed. Principal component regression analysis provided successful calibration for the concentrations of goethite ( r 2 = 0.94; standard error of validation (SEv) = 4.2%) and hematite ( r 2 = 0.89; SEv = 7.4%), in addition to good estimates for quartz ( r 2 = 0.83; SEv = 7.4%), specularite ( r 2 = 0.80; SEv = 11.6%), and martite ( r 2 = 0.78; SEv = 10.6%). Our results suggest that diffuse reflectance spectroscopy is a promising tool for the simultaneous determination of minerals in iron ores within a few minutes only.

CARACTERIZAÇÃO TEXTURAL COMO AUXÍLIO NA TIPOLOGIA DOS MINÉRIOS DE FERRO DA MINA DE CONCEIÇÃO, ITABIRA - MINAS GERAIS, BRASIL

Textural characterization of iron ores using lattice-preferred orientation (LPO),is a powerful tool for revealing microstructures and petrographic features. Furthermore, this technique yields insights regarding the geologic evolution of the material, in that it can be used to establish parameters which help in controling typologic c1assification of such ores. In this article,itabirites (ores with 20 to 50%Fe) and hematites (ores with more than 60%Fe) from the Conceição Mine,Itabira-MG, were analyzed. In this area,tectono-metamorphic processes, probably associated with the Brasiliano orogeny, were responsible for the recrystallization of the main mineral phases present in these rocks (hematite and quartz) and, consequently, for the development of their textures and microstructures. Later,intense supergenic processes were responsible for the leaching of silica from the ores, there by increasing their iron content. This leaching process, however, did not significantly affect the primary tectono-metamorphic textures. The results of the textural characterization and microstructural and petrograph analyses done on iron ores of the Conceição Mine, helps to establish a better understanding of the variations in ore quality throughout the mine. Hence,this work has important implications for improving the extraction and processing of ore in this region.

Mössbauer effect characterization of some Brazilian iron ores

Characterization of iron ores from different Brazilian locations is illustrated here with the application of Mössbauer spectroscopy to ganga, criptomelane, hematite and chalcosine ores.

Rapid characterization of iron ore by Fourier transform infrared spectrometry

Rapid characterization of iron ore by Fourier transform infrared spectrometry