Iron Ore Samples Research Articles

Gamma Spectrometric Analysis of Iron Ore Samples of Arak, Iran

Introduction Iron ore is one of the most important natural raw materials that is widely used for manufacturing iron and steel. This type of ore contains various amounts of radionuclides; thus, exposing workers handling their extraction, transportation, and processing to radiation. Materials and Methods In this study, 12 ore samples (each mass weighing about 2 kg) were collected from the iron ore mining areas of Arak region, Iran. The specific activities of 226Ra, 232Th, and 40K were determined usinggamma-ray spectrometry method employing high-purity germanium (HPGe) detector. Results The specific activities of 226Ra, 232Th, and 40K in samples were 9.39-271.70 Bq/kg, -3 Sv/y) suggested in International Commission of Radiological Protection (ICRP) Publication 82. Conclusion The gamma ray spectrometric analysis showed that the specific activities of natural radionuclides in samples, except for limonite ore, were within the worldwide range. The effective dose received by workers was much lower than the maximum acceptable value (1000 μSv/y); therefore, the level of radiations in this mine had no adverse consequences for public health.

English

Fifteen iron ore samples collected from Wadi Sawawin, Duba, Saudi Arabia were analysed using X-ray diffraction in order to determine mineral composition. Atomic absorption analysis was used to determine concentrations of Al, Ca, Fe, K, Mg, Bi, Pb, Th and U. Natural radioactivity concentrations were determined using gamma-ray spectrometry based on a hyper pure germanium (HPGe) detector; concentrations ranged from 1.89±0.39 to 4.50±0.53 Bq kg-1, 1.21±0.16 to 3.60±0.56 Bq kg-1 and detection level to 10.33±1.32 Bq kg-1 for 226Ra, 232Th and 40K, respectively. In order to assess the potential radiological risks to human health, the absorbed dose rate, radium equivalent activity, annual absorbed dose and external hazards were determined and compared to limits recommended by UNSCEAR. Results were within recommended safe ranges, meaning that the area under study is radiologically safe for habitation and that local iron ores are radiologically safe to be used as construction materials.   Key words: Atomic absorption spectrometer, natural radioactivity, radiological hazard, X-ray powder diffraction (XRD).

Water determination in iron oxyhydroxides and iron ores by Karl Fischer titration

Protohematite (Fe2−x/3(OH) x O3−x 1 ≤ x < 0.5) and hydrohematite (Fe2−x/3(OH) x O3−x 0.5 ≤ x < 0) are iron-defective phases containing hydroxyl groups in their structures. These species were described in prior studies mainly with the aid of X-ray diffraction and Infrared spectroscopy. The existence of these phases in soils might have influence in redox processes, and they were considered as a possible water reservoir in Martian soils. In this study, we have used for the first time the Karl Fischer titration method to determine the amount of water released after heating several synthetic samples of goethite, hematite and natural iron ores at 105, 400, 600 and 900 °C. It was found that heating at 105 °C did not remove all moisture from the samples, and higher temperatures were necessary to completely remove all the absorbed water. The water contents determined at 400, 600 and 900 °C were found to be the same within the experimental errors, suggesting the inexistence of both protohematite and hydrohematite in the investigated samples. Therefore, the above-mentioned effects of these phases in soils might have to be reevaluated.

Kinetics study on removal of LOI by thermal decomposition of hydrated minerals associated in hematite ore

In the present study, the kinetics of removal of loss on ignition (LOI) by thermal decomposition of hydrated minerals associated with natural hematite iron ore has been investigated in a fixed bed system using isothermal methods of kinetic analysis. Hydrated minerals in these hematite iron ores are kaolinite, gibbsite and goethite, which contribute to the LOI during thermal decomposition. Experiments in fixed bed have been carried out at variable bed depth (16, 32, 48 and 64 mm), temperature (400–1200 °C) and residence time (30, 45, 60 and 75 min) for iron ore sample. It is observed that beyond a certain bed depth (16 mm), 100 % removal of LOI is not found to be possible even at higher temperature and higher residence time. Most of the solid-state reactions of isothermal kinetic analysis have been used to analyze the reaction mechanism. The raw data are modified to yield fraction reacted ‘α’ versus time and used for developing various forms of ‘α’ functions. The study demonstrates that decomposition of hydrated minerals associated with hematite ore is controlled either by chemical kinetics or nucleation or both. The estimated apparent activation energy values in all the experimental situations are found to be of the order of 70 kJ mol−1, reinstating that the reactions are indeed controlled by chemical kinetics.

Stratification Studies with Sub Grade Iron Ore from Deposit No. 10 and 11A, Bacheli Complex, Bailadila, Chhattisgarh, India

Experiments were carried out with two different sizes of (−30 + 6 and −6 + 1 mm) sub grade iron ore sample from Deposit No. 10 and 11A, Bacheli Complex, Bailadila, India to study the stratification behaviour at optimised parameters in a under bed air pulsed jig at 1, 2, 5, 10, 15 and 20 minutes residence time. This paper deals with the rate at which stratification takes place and determines the optimum stratification time (residence time) for above two size fractions. Average apparent density along with Jig Stratification Index (JSI) of both the size fractions was calculated. It was observed that the stratification rate is high for fines (−6 + 1 mm) and stratification index was higher for lump (−30 + 6 mm) when compared with the other size fraction. The maximum JSI observed was 0.35 for lump (−30 + 6 mm) and 0.30 for fines (−6 + 1 mm).

Study of the effect of ultrasonic treatment on mineral materials of different morphologies

Coal, iron and manganese ore samples were exposed to different ultrasonic intensities of 250, 300 and 350 W/L for five minutes and to an ultrosonic intensity of 270 W/L for different time durations of 3, 5 and 7 minutes. The ultrasonically treated samples showed reductions in D80 particle diameters of 6 percent for the coal samples, 5.95 percent for the iron ore samples and 35.63 percent for the manganese ore samples during grinding. The ultrasonic treatment was also observed to assist in reducing ash content in the coal product by 8 percent and to reduce manganese losses in rejects by about 5 percent. Ultrasonic treatment was concluded to be capable of assisting in the comminution of friable ores more prominently than the hard and porous materials.

Bog iron ore as a resource for prehistoric iron production in Central Europe — A case study of the Widawa catchment area in eastern Silesia, Poland

Spreading from the Near East in the declining Bronze Age from the 2nd millennium BCE onwards, the technique of iron smelting reached Eastern Silesia, Poland, in approximately the 2nd century BCE (pre-Roman Iron Age). At this time the region of the Widawa catchment area was inhabited by the Przeworsk culture. While the older moraine landscape of the study area lacks ores from geological rock formations, bog iron ores were relatively widespread and, due to their comparatively easy accessibility, were commonly exploited for early iron production. This paper investigates the mineralogical and elemental composition of local bog iron ore deposits and iron slag finds, as a by-product of the smelting process, also taking into account the state of the art in research regarding the formation, distribution and utilization of bog iron ores and considering data from comparative studies.The crystalline mineralogical composition of local bog iron ores is dominated by quartz (SiO2) and goethite (α-FeO(OH)), in contrast to slag samples in which fayalite (Fe2SiO4), wüstite (FeO) and quartz, with traces of goethite, represent the main minerals. Ores and slags are both characterized by notable hematite (Fe2O3), magnetite (Fe3O4) and maghemite (γ-Fe2O3) contents. Analyzed bog iron ore samples show iron contents of up to 64.9mass% Fe2O3 (equivalent to 45.4mass% Fe), whereas the iron contents of bloomery slags vary between 48.7 and 72.0mass% FeO (equivalent to 37.9 and 56.0mass% Fe). A principal component analysis of the element contents, which were quantified by portable energy-dispersive X-ray fluorescence spectrometry, indicates local variations in the elemental composition. The results of this study show that bog iron ores are relatively widely distributed with spatially varying iron contents along the Widawa floodplain but present-day formation conditions, such as changed groundwater levels, are negatively affected by modern land-use practices, such as agriculture and melioration measures.

Bench-scale calcination and sintering of a goethite iron ore sample

This work presents the results of bench calcination and sintering studies conducted on an iron ore sample from Iron Quadrangle, Brazil with high goethite content. The natural samples and the products of calcination and sintering were characterised by inductively coupled plasma optical emission spectroscopy (OES/ICP), X-ray spectrometry and gravimetric methods. Optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) were used to identify the phases in the studied samples. Density, specific surface area, specific pore volume and pore diameter were determined through gas pycnometry. All of the natural sinter feed samples had a Fe grade >64% and a very high phosphorus grade (~0.17%). After calcination, a 3.1–3.4% increase was observed in the Fe grade compared to that of the natural sinter feed samples. The average Fe grade of the sintered samples was 59.1%. The identified phases with XRD in the raw materials were hematite and goethite. In the calcined samples, only hematite was identified because of the thermal decomposition of goethite. The density, specific surface area, specific pore volume and pore diameter of the calcined samples increased compared to those of the natural sinter feed samples. Hematite, brownmillerite, anorthite, and gehlenite were identified in the sintered samples. The sites for phosphorus occurrence were calcium silicates and apatite. The sintered samples exhibited specific surface areas lower than those of the calcined samples. This result was ascribed to the destruction of the pore structure by the sintering process. No relationship between the proportions of nucleate, intermediate and agglomerate particles used in mixture of sinter tests with the results of microtumbler was identified.

Investigation of sintered iron ore fines as an oxygen carrier in chemical looping combustion

Sintered iron ore fines were selected as oxygen carriers in chemical looping combustion. The reactivity of the sintered iron ore was investigated in redox cycles using thermogravimetric methods under isothermal or non-isothermal conditions. The used sintered iron ore samples from the redox cycles in isothermal tests, which were chosen to evaluate their structural changes, were characterized using the N2 adsorption–desorption, SEM–EDS, XRD and Raman spectroscopy. Results revealed that multiple redox cycle was an activation process of the selected sintered iron ore to promote its redox kinetics, as well as formations of the new crystalline phase. This was attributed to variations of the sintered iron ore in both their physical and chemical structural changes during redox cycles. The N2 adsorption–desorption analysis indicated an increase of its surface areas of sintered iron ore during redox cycles. The SEM–EDS results revealed the appearance of tiny cracks on the tested ore sample surfaces. Both XRD and Raman results presented appearance of a new crystalline phase, such as the lepidocrocite (γ-FeOOH), which was apparently generated in the reduction reaction of chemical looping cycles. The formation of the new lepidocrocite phase seemed correlated with the decrease of the oxygen transport capacity of the sintered iron ore. The sintered iron ore performed properly in the carbon-laden atmospheres, and there was no carbon deposition on its surface.

MINERALOGIE ŽELEZNÝCH RUD Z LOŽISKA ŘÍDEČ V JIŽNÍ ČÁSTI ŠTERNBERSKO-HORNOBENEŠOVSKÉHO PRUHU (MORAVSKOSLEZSKÁ JEDNOTKA ČESKÉHO MASIVU)

The Řídeč iron ore deposit of the Lahn-Dill type is located in the southernmost part of the Šternberk-Horní Benešov belt. The Jiří-Hugo Mine near Řídeč was in operation to 1947. Basic volcanites form the immediate footwall of an iron ore horizon which is covered with clastic sediments. All iron ore samples found on a heap at the Jiří-Hugo Mine represent one variety of ore: stilpnomelane ore with variable amounts of magnetite and calcite. The ore exhibits a banded structure – it consists of repeated, thin bands composed of black stilpnomelane scales and fine-grained magnetite, alternating with thin bands of calcite. Chamosite, siderite and ankerite are present in small amounts in some samples. Sulphides (pyrite, less abundant chalcopyrite, sporadically sphalerite) occur as disseminations in the ore. Chromite inclusions were found in magnetite. Hydrothermal veins are composed mainly of quartz, calcite, chamosite and stilpnomelane penetrate iron ore.High-grade stilpnomelane-magnetite ores poor in calcite contain 51–56 wt. % of iron. Therefore, they are one of the richest iron-ore varieties mined at deposits of the Lahn-Dill type in the Šternberk-Horní Benešov belt and in the Vrbno Group.

A single-step trans-vertical epoxy preparation method for maximising throughput of iron-ore samples via SEM-MLA analysis

A novel approach to creating a trans-vertical grain mount embedded in epoxy has been demonstrated through the creation of a new mounting mould, as well as a polisher adapter and sample holder for the Quanta 400 SEM. These rectangular moulds result in a sample that is 30 mm long × 10 mm high × 17 mm wide, thus leading to the ability to polish 10 samples at once. Up to 14 samples may fit in the SEM holder for analysis. This represents an increase in efficiency of over 50%, and with a slow-speed polishing method, the consumables used are reduced by at least a factor of 4. This has the potential to lead to significant financial savings. A comparison of mounting techniques using a −100+200 mesh size fraction of an iron-ore sample from Labrador demonstrates that this new mounting system removes any bias in analysis resulting from density stratification during the sample preparation. These moulds yield similar modal mineralogy abundances and standard deviation as the two-step trans-vertical method, but they are less labour-intensive to make and more efficient to analyse.

Comparative analysis of some DNA extraction kits used for Molecular analysis of Iron Ore samples

Comparative analysis of some DNA extraction kits used for Molecular analysis of Iron Ore samples

Iron ore textural information is the key for prediction of downstream process performance

Textural information or information about the presence of porosity, different material or mineral types and their structural arrangement in iron ore is crucial for understanding, predicting and optimising downstream processing performance. Ores with the same chemical and mineral composition may behave very differently during downstream processing due to differences in textural components.To produce a textural description of iron ore, it is preferable to use an automated system to avoid subjectivity and to collect additional information about mineral abundance, liberation and association. CSIRO created a unique dedicated optical image analysis software package for automated textural classification and characterisation of different minerals, sinters and coke. This software, called Mineral4/Recognition4, has been used extensively to collect data for this article.Four case studies of CSIRO research are presented to demonstrate the importance of textural information.•The first example shows that iron ore samples with different texture but similar mineralogy undergo different degrees of assimilation in compact sintering.•The second example shows that empirical modelling of sinter properties was improved considerably after introducing textural information.•The third example demonstrates the application of classification by ore texture to model and optimise hydrocyclone performance.•The last example is an experimental study of ultrasonic treatment of hematitic–goethitic iron ore fines. It demonstrates how the resulting breakdown or deagglomeration of different particles, and the mineral deportment, can be better understood when textural information is also considered.In all cases, the availability of textural information was critical, providing a better prediction of process performance or a deeper understanding of the unit process.

Study on Bioleaching of Sulfur in Iron Ore by Mixed Culture

Iron ore is the raw material for steel production, in addition to iron and slag major component, still contains sulfur and phosphorus compounds and other harmful elements, is the potential adverse effects of factors constitute the steel product quality and environment. Sulfur in iron ores into the steel products will not only produce "heat brittle" phenomenon, but also in the sintering process by roasting produce sulfur dioxide into the air, causing damage to the atmosphere and ecological environment. A typical of the high sulfur iron ore from Inner Mongolia, China, iron grade of 53.06% and sulfur content is 2.76%, the main metal mineral in the ore is magnetite, followed by magnetic pyrite, pyrite and siderite, otherwise a small amount of copper mineral chalcopyrite, bornite. In this work, a mixed culture composed by Sulfobacillus thermotolerans, Leptospirillum ferriphilum and Ferroplasma acidiphilum was used to leach the sulfur in iron ore samples, we investigated the leaching rate of sulfur under different initial pH, temperature and pulp density conditions. The results showed that under the condition of the initial pH of 1.8, the temperature was 33 °C, and pulp density 15%, after 7 days of oxidation, we got a yield of 80.16% product in which iron grade of 62.31% and sulfur content is 0.17%. Compared with original sample, sulfur content decreased 95.06%, iron grade increased by 9.25%, and iron recovery was 94.13%. From the results it can be concluded that this microbial process for high sulfur iron ore lead to a significant effect of sulfur reduction and substantial increase in iron grade.

Improvement of phosphorus removal from iron ore using combined microwave pretreatment and ultrasonic treatment

Abstract Most of the past studies examined the effects of ultrasonic treatment on the removal of phosphorus, silica and alumina minerals from iron ores. In the present work, the effect of combined microwave pretreatment and ultrasonic treatment on the efficiency of disintegration and removal of phosphorus and other gangue minerals associated with iron ores has been studied. Three different iron ore samples have varying total iron concentration (TFe) and P2O5 content and mineralogical textures were studied. Microwave pretreatment generated intergranular fractures between the gangues (fluorapatite and chamosite) and oolitic hematite. These intergranular fractures improved liberation of iron ore, and accelerated ultrasonic disintegration and removal of phosphorus and gangue minerals from oolitic hematite. The results indicated that microwave pretreatment increases the efficiency of ultrasonic disintegration and removal of particles by about 20% compared to untreated sample. The results of ultrasonic treatment are quite promising. Significant increase in iron grade and reduction in phosphorus and alumina content of enriched product can be obtained. Depending on the sample texture and phosphorus distribution, about 59% phosphorus removal can be obtained.

XPS and FTIR spectroscopic study on microwave treated high phosphorus iron ore

A growing interest in microwave heating has emerged recently. Several potential microwave applications regarding minerals’ processing have been investigated. This paper investigates the effect of microwave radiation on Egyptian high phosphorus iron ore. Three different iron ore samples have varying Fe2O3 and P2O5 contents and mineralogical textures were studied. A comparative study has been carried out between untreated and microwave treated iron ore. XRD and FTIR analyses showed that after microwave radiation the crystallinity of iron bearing minerals (hematite) increased, while the functional chemical groups of phosphorus bearing minerals (fluorapatite) and other gangues dissociated. High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). This means that after microwave radiation iron oxide (hematite, Fe3+) transformed into more magnetic phase. The results indicated that microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases.

Flocculation/flotation of hematite fines with anionic temperature-responsive polymer acting as a selective flocculant and collector

A novel approach to the recovery of valuable fines is the use of temperature-responsive polymers such as poly (N-isopropyl acrylamide) (PNIPAM). These polymers act as dual-function flocculants and collectors to form hydrophobic aggregates improving particle–bubble collision and attachment. The aim of this study is to investigate the flotation performance of anionic PNIPAM for an iron ore sample containing fines compared to sodium oleate, an industrial collector for hematite. PNIPAM conditioned at room temperature (25°C, below the lower critical solution temperature (LCST)) and floated at 50°C (above the LCST) was found to provide improved hematite grade and recoveries for particles above 20μm, compared to sodium oleate. This was attributed to the increased selectivity and hydrophobicity of PNIPAM. Turbidity testing confirmed the flocculation of fines with PNIPAM, which deslimes the surface of the coarser particles. Below 20μm, the hematite fines were almost completely recovered with PNIPAM. However, this recovery was not selective, attributed to the entrapment of gangue in the hydrophobic aggregates. Furthermore, conditioning of the polymer above the LCST resulted in significant losses in grade and selectivity, as the polymer self-aggregates hydrophobically and precipitates unselectively onto the closest surface.

Mineralogy of Iron Ores of Different Alumina Levels from Singhbhum Belt and Their Implication on Sintering Process

To increase the life of the mines, ores of lower quality are blended with the higher quality ores. In general, the blending of ores at mines site is controlled by the chemical composition of the ores by controlling the Al2O3 and SiO2 levels on the lowest side possible. However, if there is a change in mineralogy, like an increase in hydrous phase the composition may still be the same, but this difference may affect the sinterability and sinter quality. The mineralogical investigation of iron ores and their chemistry are required to avoid the increase in deleterious elements during sintering. By the know-how of the behavior of individual iron ores in terms of their sinterability, in advance, the quality of the iron ores blend can be optimized to produce quality sinter and productivity. Characterisation studies conducted on iron ores of Singhbhum Orissa belt revealed that hematite, goethite, clay, gibbsite and quartz occur in all the iron ore samples but in variable proportions. Traces of alumina, present as solid solution in the iron oxide minerals, has also contributed Al2O3 to the ores.

Avaliação da rota de redução do teor do elemento fósforo contido no minério de ferro através da técnica de aquecimento por energia de micro‐ondas seguida de lixiviação ácida

Iron ore when found containing high levels of phosphorus element becomes detrimental to the manufacture of steel due to the increase of its hardness making it brittle and fractures. In this sense the process of acid leaching of iron ore is seen in the literature as favorable, providing its desfosforização. However, depending on the way the element phosphorus is present in the iron ore application structure becomes additional power required for its release. Thus this work, the acid leaching process with the aim of reducing the phosphorus content in iron ore as well as the application of heating the particles of iron ore by using microwave energy. By using Termocalc® software to parse the different structures formed having different levels of phosphorus element. By scanning electron microscopy technique (SEM) was possible to observe the structure of the iron ore particles after treatment with microwave energy. Through the use of statistical design factor with central and axial points was possible to determine the optimal conditions used in the acid leaching process, the following values are found: 19.25g mass ore, leaching time 20min, leaching temperature of 65°C, agitation speed of 620rpm, average grain size of 28mm size, having a 3‐minute contact time with the microwave energy. Under these conditions the reduction of phosphorus content in iron ore sample reached a value of 52.47% was possible to demonstrate the positive effect of the sample heating process of iron ore and may therefore be regarded as increasing the acid leaching technique to reduction of the phosphorus content.

Estimation of Bulk Density, Recovery Tests and Mineralogical Analysis of Iron Ore Mine at Obulapuram Village, Anantapur District, Andhra Pradesh

The iron ore formation belongs to Precambrian, Dharwarian age. The lithological formations consists of Sedimentary and metamorphic rocks represented by Quartzite, shale, slate and phylites and iron ore occurring in from the mainly massive and fairable brown color hematite type presented. Source rock belongs to Banded hematite quartzite (BHQ) formation. The main Iron ore had been initially worked as open pit method of mining. The Hematite ore concentration mainly along the ferruginous shale and at some places pyrites are encountered. The recovery percentage of iron ore samples varied from 58.50%, 63% and 61%, the average being the float ore recovery is around 43%.The float ore occurs to a limited thickness of 1m and the workings are being carried out forming single bench to a maximum height of 3m from the surface. The results of the bulk density determined in the field for iron ore shown are 2.98 to 3.03. The average bulk density for float ore can be taken as 2.51. In the case of Iron ore the average works out to be 2.88.