Iron Ore Grade Research Articles

A Study and Implications on the Potential of Satellite Image Spectral to Assess the Iron Ore Grades of Noamundi Iron Deposits Area

Jharkhand is well known for the largest iron deposits in India. Noamundi is the main deposit, which is associated with shale, keolinite. The rock succession exposed in the southern Singbhum and Keonjhar and lying unconformably over the older metamorphics are known as Iron Ore Series (Ravindrakumar, 1986). This paper relates the assessment of grades of iron ore of the area. The study involves with pre-processing, FLAASH (Fast Line-of-Sight Atmospheric Analysis of Spectral Hypercubes) Atmospheric correction algorithms of EO-1 Hyperion data and evaluating the spectral characteristic by using ENVI 4.7 software package. The position of peak reflectance and absorption trough, continuums removal and absorption band depth are considered for assessment the spectral characters. The strong absorption observed is between the 860 to 900nm wavelength region and peak reflectance is observed in the 750 to 780nm wavelength region of the image spectra. The position of the NIR absorption trough shift to the direction of the longer wavelengths is due to decrease of iron content. Higher values of band depth indicate a better possibility of the iron occurrence. As a result, this spectral study enables the possibility to differentiate the grades of iron ores from hyperspectral satellite images.

Geological Controls on High-Grade Iron Ores from Kiriburu-Meghahatuburu Iron Ore Deposit, Singhbhum-Orissa Craton, Eastern India

Numerous iron ore deposits are hosted within the Meso to Neo-Archean banded iron formations (BIFs) extending across the Singhbhum-Orissa Craton, eastern India. Despite the widespread distribution of BIFs, which forms part of the iron ore group (IOG), heterogeneity in their grade and mineral composition is occasionally observed even within a single ore deposit. Kiriburu-Meghahatuburu iron ore deposit (KMIOD), west Singhbhum district, Jharkhand, eastern India is characterized by a dominant hematite (often martitized) occurrence with a total resource of >150 million tonnes (MT) at 62.85 wt % Fe. Very high-grade blue dust ore (friable and powdery hematitewith~67% Fe), high-grade massive, hard laminated hematitic ores (~66% Fe) and medium to low grade goethitic/lateritic ores (50%–60% Fe) are the common iron-ore lithologies in KMIOD. These ores can be distinguished in the field from their physical appearance, meso-scale texture and spatial occurrences with the host rocks along with the variation in chemical composition. The high-grade ores are characterized by high Fe (>62 wt %), low Al2O3 (1.5–2.5 wt %), low SiO2 (2.0–4.5 wt %) and low P (<0.06 wt %). Detailed field studies and laboratory investigations on the ore mineral assemblages suggest that the mineralization of high-grade iron ores at KMIOD is controlled by three major parameters, i.e., lithological, paleoclimatic and structural controls. High-grade iron ores such as blue dust seem to be formed during leaching processes through inter-bedded ferruginous shale and banded hematite jasper (BHJ) occurring within BIFs. Structural elements such as folds, joint network, fracture arrays, local faults and steeply dipping bedding planes are surmised as strong controls for the evolution of different iron ore types from the BHJ. Most of the high-grade ores are concentrated at the hinge portions of second generation folds (F2) owing to the easy access for circulation of meteoric solution along the fractures developed due to release of stresses at the hinge portions aided by supergene ore enrichment processes. The BHJ and interbedded ferruginous shale seem to have been given a significant contribution for the formation of different grades of iron ores over the area. Lithologically, the BIFs are governed by rheological features providing channel ways in the ore enrichment process. The variation in the iron ore mineralogy is caused by the variation in depositional and paleoclimatic environment, structural setting and lithological attributes. Hence, these parameters could be used for future exploration and grade recovery of iron ore resources in the region and in the adjoining areas.

Phase Transition and Metalization of DRI According to the Quality of Iron Oxide

Direct reduced iron was made using an electric furnace. The reduction ratio of direct reduced iron varied depending on the grade of iron ore. Coal played an important role as a reducing agent in making the direct reduced iron. The coal must contain a suitable amount of volatile components having high calorie values and low impurity content. In this study, oxidized pellets were directly reduced using anthracite as a reductant in an electric furnace. Direct reduction behaviors of hematite and magnetite pellets were confirmed in a coal-based experiment. Reduction behaviors were demonstrated by analyzing the chemical compositions, measuring the reducibility, and observing the phase changes and microstructure. The superior reducibility of hematite pellets can be ascribed to their high effective diffusivity, which is due to their high porosity. The quickly after reducing for 40min and achieves a high value at the end of the reduction.

Biomass Reduction Roasting-Magnetic Separation of Low Grade Goethite

The average grade of iron ores in China is around 32%, about 10% lower than the world’s average level. In order to alleviate the demand of iron ore for steelmaking industries, it is urgent to develop a highly efficient, energy-saving, low-carbon and environment-friendly technology. The goethite ore from Northern Hainan Island was studied via reduction magnetization by pine, rice chaff, and corn straw biomass fuels. The magnetic properties and magnetic separation were discussed by optimizing the parameters of roasting temperature, roasting time, and the ratio of biomass fuels. The results show that we could obtain concentrated iron ore grade of pine roasting and magnetic separation grade of iron concentrate 61.64% with the recovery of 79.75% via pine fuel roasting, 61.75% with the recovery 80.16% via rice chaff, and 61.47% with the recovery of 81.28% via corn straw roasting. Thereby, we could deduce that biomass fuels for reduction roasting of low goethite ore is promising to substitute the traditional coal and coke fossil fuels.

Eliminating Accelerated Flow Technique Based on Grading and Continuous Transportation

The characteristics of different grade of iron ore concentrate slurry are different, which causes confusion in pulp conveying process. Therefore, aiming at the problem of accelerated flow wear the pipeline, further propose the accelerated flow elimination technique to reduce the pipeline wear caused by accelerated flow, and ensure the safe operation of iron concentrate pipeline. The production practice shows that the technique can effectively inhibit the accelerated flow phenomena and ensure the different grade of iron concentrate without mixing in conveying, at the same time minimize the pipe wear.

Hyperion image analysis and linear spectral unmixing to evaluate the grades of iron ores in parts of Noamundi, Eastern India

This paper reports the results of a study to differentiate iron ores in terms of their grades, using the hyperspectral (EO-1 Hyperion) image data, covering a mineralized belt in the Noamundi area, eastern India. The study involves hyperspectral data collection, pre-processing (reduction of atmospheric and solar flux effects), generation of spectral curves from the image for the iron ore deposits, extraction of key spectral parameters and linear spectral unmixing for mapping iron ore abundance. Spectral curves for iron ore deposits extracted from the Hyperion image pixels exhibit strong absorption at 850–900nm and 2150–2250nm wavelengths, which is typical of iron ores. The strength of the absorption features in the continuum removed spectra varies spatially in the image around the mining areas, indicating differences in composition/grade of the iron ores. Spectral parameters such as the depth, width, area and wavelength position of the absorption features, derived from image spectra in the 850–900nm and 2150–2250nm regions, correlate well with the concentration of iron-oxide and alumina (gangue) in the ore samples obtained from the mine face. Well defined correlations are evident between the concentration of iron oxide and (i) the depth of NIR absorption feature (R2=0.883); (ii) the width of NIR absorption feature (R2=0.912); and (iii) the area of the NIR absorption feature and (R2=0.882). Further, the linear spectral unmixing resulted in an iron ore abundance map which, in conjunction with the image- and laboratory-spectra, helped in assessing the grades of iron ores in the study area. Thus, this study demonstrates the feasibility of discriminating grades of iron ores based on spectral information derived from spaceborne hyperspectral imagery.

A Study on the Potential of Satellite Image-derived Hyperspectral Signatures to Assess the Grades of Iron ore Deposits

Abstract This paper present the results of a study made to assess the grades of iron ore deposits in parts of Noamundi area using the hyperspectral image data (EO-1 Hyperion). The study involves hyperspectral image data, preprocessing (removal of atmospheric effects), spectral curve generation from the image, extraction of certain spectral parameters and spectral data analysis. Atmospheric correction was carried out by using algorithms involving atmospheric analysis of spectral hyper-cubes and Quick Atmospheric Correction modules. Spectral curves generated for the pixels that contain iron ores resemble the spectral signature of iron ores, i.e., very strong absorption at 850-900nm region is observed. The strength of the absorption varies spatially at different pixels. Hence, spectral parameters such as radius of curvature of NIR absorption trough (750-1000nm), position of NIR absorption trough and distance from a reference(100% reflectance) line have been derived for all the image-derived spectra and were compared with the concentration of iron in the ore samples of mines. Empirical models were generated by relating the image-derived spectral parameters of iron ore locations and geochemistry of the samples collected from the same location which shows a reasonable match. Strong negative correlation is seen between the radius of curvature of the NIR absorption trough and concentration of iron with a R2 value of 0.809. The position of the NIR absorption trough is seen to shift towards longer wavelengths with decreasing iron content and the distance from the reference line increases with increasing iron content. Thus, this study indicates that it is feasible to discriminate the grades of iron ores from the spectral parameters derived from Hyperspectral satellite images.

Direct Reduction Experiment on Iron-Bearing Waste Slag

A lot of iron-bearing slags were produced, and whose grade is much more than that of industrial iron ore grade. Chemical analysis and phase identification shows that the iron-bearing slag is amorphous, has fayalite main phase, iron grade is 36. 10%, and is difficult to recover iron from the slag. Thermodynamic calculation indicates that CO cannot reduce fayalite at high temperature and carbon direct reduction can be effective. Moreover, the reaction begins at 770 °C and the temperature can be reduced down to 500 °C when CaO is added. On this basis, a method is put forward to making direct enrichment of iron by taking carbon contained pellets to realize the rapid reduction of fayalite, and the direct reduction process were studied in this paper. Experiments show that Xc/xo should be less than 1. 5 for the need of reduction and carburization, and CaO and A12O3 can spur the reduction of fayalite. On conditions that xc/xo is 1. 2, metallization rate can be 77% when temperature is 1 250 °C and only carbon is added, and metallization rate can be 74% when temperature is 1200 °C and only CaO is added. Moreover the addition of A12O3 can get a higher metallization rate (10% or so) than usual as R is between 0. 4 and 1. 0. Under the optimized condition of R equals to 0. 6, temperature of 1 250 °C, slag melting point of 1 320 °C, and time of 30 min, the metallization rate can reach 88. 43%.

Beneficiation Test Research on High Grade Hematite-Limonite Ore

The run of mine ore grade of Gan Shang Yan is 47.83%, iron ore grade is higher, but harmful element sulfur and impurity silica content is relatively high. This experiment using a simple process low intensity magnetic separation-high gradient magnetic separation, for the ultimate index for comprehensive grade of iron concentrate is 58.41%, at a total recovery of 80.85%, and obtain good experiment index, the harmful elements and impurity content can meet the standard.

Mechanism Study on the High-Phosphorus Hematite Carbothermal Reduction in Microwave Field

In the paper, the research on raising the grade of iron ore and dephosphorization for high-phosphorus oolitic hematite by coal-based carbothermal reduction in microwave field was carried out. The microwave action mechanism was analyzed by the aspects of ionic crystal lattice energy and thermodynamics and dynamics[1]. The possibility of the application of microwave in raising the grade of iron ore and dephosphorization for high-phosphorus hematite was discussed. The research indicated that the primary structure of the high-phosphorus hematite was changed by the high-phosphorus hematite carbothermal reduction in microwave field, meantime the carbothermal reduction reaction activation energy was decreased and the reduction rate was speeded up[2-4].

Hyperspectral Radiometry to Quantify the Grades of Iron Ores of Noamundi and Joda Mines, Eastern India

This paper present the results of a preliminary study to assess the potential of the visible, NIR and SWIR energy of the EMR in differentiating iron ores of different grades in a rapid manner using hyperspectral radiometry. Using different iron ore samples from Noamundi and Joda mines, Jharkhand and Orissa, states of India, certain spectro-radiometric measurements and geochemical analysis were carried out and the results have been presented. It was observed that the primary spectral characteristics of these iron ores lie in the 850 to 900 nm and 650–750 nm regions. The spectral parameters for each curve used for studying the iron ores are: (i) the slopes of the spectral curve in 685–725 nm region; (ii) position of the peak with respect to wavelength in 730–750 nm region and (iii) radius of curvature of the absorption trough in the 850–900 nm region. Comparison of these spectral parameters and the geochemistry of the samples indicates that the position of the peak of the curve in 730–750 nm region shifts towards longer wavelength with increasing iron oxide content, while the slope of the curvature in the 685–725 nm region has a strong negative correlation with the iron oxide content of the samples. Similarly, a strong negative correlation is observed between the radius of curvature of the 850–900 nm absorption trough and the iron oxide content. Such strong correlations indicate that hyperspectral radiometry in the visible and NIR regions can give a better estimate and quantification of the grades of iron ores. This study has demonstrated that generation of empirical models using hyperspectral radiometric techniques is helpful to quantify the grade of iron ores with limited geochemical analysis.

Relevance of geological aspects and ore mineralogy in selecting beneficiation methods for processing of eastern Indian iron ores

Geological aspects, particularly mineralogy and ore genesis of different iron ores have important roles to play in understanding their behaviour during processing and decide suitable beneficiation method for particular type of ore so to produce desired quality end products. The implications of different geological aspects and mineralogical characteristics specific to ore types in mineral beneficiation have been outlined in this paper. Experiments indicated that iron ores, such as massive hard ores, laminated hard ores, fine powdery ore and blue dust ore, do not require complicated processing, however at the other end; sub grade ores, such as flaky, friable, shaly, ochrous, powdery, lateritic and goethitic ores having low iron and high alumina content, require specific beneficiation treatments before their use as direct or as agglomerates in the blast furnace feed. While processing, different ore types need treatment differently for their up gradation. Hence, in addition to the conventional methods of processing such as crushing, screening and washing, advanced beneficiation techniques using concepts of gravity and magnetic separation have found their specific applications for beneficiation of different types of ores, based upon their physicochemical and mineralogical characteristics. Geological setup of the deposits and mode of occurrences of different ore types, physical, chemical and mineralogical characterisation and extensive beneficiation experiments conducted on Indian iron ores have established that quality of lumps can substantially be up graded through simple processing and log washing. On the other hand, for fines ores, Jigging has been found to be the best suitable method. Slime beneficiation requires combination of processes and treatment through hydrocyclones, multigravity separation, magnetic separation and sink float methods, etc. These applications would help not only to recover more values from the inferior grades of iron ores but also to conserve and preserve the natural resources too.

Exploring the Potentials of Tailings of Bukuru Cassiterite Deposit for the Production of Iron Ore Pellets

Cassiterite ore was sourced from Dogo-Na-Hawa, in Bukuru, Jos South Local Government of Plateau State, Nigeria. The ore was analyzed as mined and its various constituents noted. Previous study has shown considerable iron ore composition of the deposit. The present study entails the separation and analysis of magnetic mineral (mostly iron ore) from the ore. The beneficiated iron ore was pelletized using the facilities of the Nigerian Metallurgical Development Centre (NMDC), Jos. The pellets so produced were subjected to various tests such as drop resistance, green compressive strength, dry compressive strength at 900℃, tumbler resistance, micro porosity and indurations compressive strength at 1100℃. The results indicated Bukuru cassiterite contains sufficiently high grade of iron ore that could be beneficiated for iron production. The pellets produced are of good quality and could be utilized for iron and steel making.

Prospects for China's iron ore imports

Although China has a large volume of iron ore deposits the grade of iron ore is very low. This has led to unfavourable conditions for developing China's iron and steel industry. In particular the big steel plants in East China have faced severe shortages of iron ore. China is a large developing country and the demand for finished steel is increasing rapidly. Consumption growth of finished steel cannot depend entirely on increased imports of steel. China will therefore develop its local iron and steel industry vigorously. In the coming ten years China's resource policy for iron ore is for the greater part to depend on domestic mining, but there will also be a step by step expansion of imports. As a result China's share of world trade in iron ore is expected to rise.

Production of an iron ore concentrate from the iron-rich fraction of power plant fly ash

Removal of gangue materials, principally silica and alumina, from a magnetically-separated, iron-rich fraction of bituminous coal fly ash shows promise of yielding an iron ore grade concentrate. As separated, the iron-rich fraction contains 65 to 75 wt. % iron oxides or about 50 % of the iron originally in the ash. A hydrothermal caustic extraction followed by a mild acid wash has been found to give a residue containing as high as 95 % iron oxides, a concentration that compares favorably with that found in taconite and other concentrate pellets used as feed to blast and electric reduction furnaces. The controlling step in the process is the caustic extraction which dissolves the highly insoluble silica and allumina from the fly ash matrix. As the extraction proceeds, aluminate and silicate compounds precipitate onto the surface of the iron-rich particles and must be removed by a subsequent acid wash. The precipitate does not interfere significantly with the dissolution of silica and alumina by the caustic solution. During the caustic extraction, the solution rapidly becomes saturated, and, if it were not for the precipitation, dissolution of the gangue from the ash would cease. The simultaneous dissolution-precipitation allows use of high solid to liquid ratios and reuse of the caustic as the extraction proceeds. A typical extraction residue contains, on a weight basis, about 65% Fe, 4% Al 20 3 and 2% SiO 2. Pelleting and sintering should give an iron oxide produce suitable for use in the manufacture of iron and steel.