Source Of Iron Ore Research Articles

Laterite nodules: A credible source of iron ore in iron age northeast Thailand?

AbstractThe advent of iron metallurgy changed the course of prehistoric Thailand. There is, however, little information on the nature of iron production and the extent to which locally abundant and easily quarried lateritic iron may have been the ore source. For northeast Thailand archaeological sites, the presence of both iron slag and laterite iron nodules within and surrounding these sites has widely been assumed to represent localized smelting using locally sourced iron ore. This interpretation is, however, based on untested laterite‐equals‐ore and slag‐equals‐smelting equations. This paper tests these assumptions by examining the chemistry of the lateritic iron nodules from two archaeological sites. At one site, the laterite is not a credible ore source and iron working probably comprised only smithing. Local laterite at the other site may be a usable ore. We conclude that, in northeast Thailand, the use of local laterite as an ore source cannot be assumed and that presence of both laterite and slag is not necessarily evidence for prehistoric smelting. © 2010 Wiley Periodicals, Inc.

Energy consumption in smelting reduction (SR) processes

In contrast, conventional processes use coke and hematite/sinter in the blast furnace, in SR processes, other alternative fuels and iron ore sources, like charcoal and fine iron ores, can be used to produce sponge iron. The use of these alternative sources, by SR processes, can reduce environmental impacts and lower production costs. At first, the concepts of the theoretical gas utilization ratio, the smelting heat of the iron ore and the effective calorific value of coal were introduced. Then, the reason for gas utilization ratio and its performance in the shaft as a reducer in the smelting process are discussed and calculated. The relationship between coal consumption and iron ore reduction in the fluidized bed are also discussed. Finally, the influence of post-combustion on coal consumption in an iron bath furnace are calculated and discussed.

An ATR–FTIR study of carbonate sorption onto magnetite

AbstractCarbonate is one of the most abundant anions in ground water. It also appears as saturated concentration in the process water at LKAB, a mining company in the northern part of Sweden. Sorption of carbonate on magnetite (the major source of iron ore in this company) may affect the surface chemistry of the iron oxide by forming a carbonate surface instead of an oxide surface. This would affect the interactions between magnetite particles and other species dissolved in the process water. Attenuated total reflection Fourier transform infrared spectroscopy (ATR–FTIR) has proved to be a useful technique in the study of adsorption/desorption properties of ions in mineral processing and environmental science. Magnetite was synthesized by coprecipitation of Fe II and Fe III in alkaline solution and deposited on a ZnS internal reflection element. Adsorption of carbonate on magnetite, and the effect of pH, Na, Ca, and silicate ions on the amount and speciation of adsorbed carbonate was monitored in situ. Adsorption of carbonate onto magnetite was found to increase with the acidity of the solution from pH 8.5 to pH 6.5 and also increased with increasing calcium concentration from 0 to 1.0 mM. The spectroscopy results were discussed and compared with previous findings in the literature. Copyright © 2010 John Wiley & Sons, Ltd.

Hornton Stone: battlefields, buildings and Jurassic seas

The Hornton Stone is an unusually pure ooidal ironstone of the Lower Jurassic Marlstone Rock Formation, cropping out on the Edge Hill escarpment and adjacent ironstone plateau in central England. The stone has been quarried for building and ornamental purposes since Medieval times, and more recently as a source of iron ore. Local quarries and buildings provide excellent opportunities to appreciate its fossil content, sedimentary structures and origin.

Predicting Granulating Behaviour of Iron Ores Based on Size Distribution and Composition

Increased demand and diminishing high grade resources have resulted in a large diversity of iron ore sources used in the modern steel mill. Using research on the effect of ore type and size on granulation for single ore blends containing coke, flux and returns, this paper presents a study to model the optimum granulating moisture and related green bed permeability of an iron ore from the size distribution and composition of the ore when added in a simplified sinter blend.The models developed from the granulation test work are applied to a broad range of iron ore types and blends. The effect of particle size on granulation is also quantified across a range of iron ore types.It was found that the optimum moisture could be described accurately by knowing the ore's SiO2, LOIT and Al2O3 (−1 mm) content, as well as the −0.15 mm and percentage of Intermediate (0.1 to 1 mm) size fractions. It was also found that for most iron ores, an increase in particle size close to the 0.1 mm size range has the greatest effect of reducing permeability and increasing granulating moisture.

Black smokers and density currents: A uniformitarian model for the genesis of banded iron-formations

Banded iron-formations (BIFs) were comparatively abundant and widespread marine sedimentary rocks in the Archean and Lower Proterozoic eras, but thereafter they appear to be restricted to the Neoproterozoic and Paleozoic eras, although there are indications of similar rocks forming at present. BIFs are important as the major source of iron ore for industry and have also been used to support hypotheses regarding the evolution of life, oceans, and the atmosphere in the Archean and Proterozoic. They apparently formed in deep water and consisted of a semi-regular alternation of quartz (chert) and iron-rich minerals with little or no terrigenous sediment and low (< 1 wt.%) alumina content, in contrast to Proterozoic to Phanerozoic oolitic ironstones (Clinton–Minette style) that formed in shelf environments, were comparatively small and rare and contain abundant iron aluminosilicates and hydroxides but little or no chert. Although ooliths may be locally abundant in granular iron-formations (GIFs) they differ from the Clinton–Minette style oolitic ironstones that formed in shelf seas during periods of slow sedimentation. A common mode of origin for marine deep-water iron-formations is proposed, in which hot fluids, consisting of marine and connate water leaching iron, silica and other elements from mafic and ultramafic rocks associated with mantle plumes or mid-oceanic ridges and active spreading centres are released into the ocean at underwater hot springs (black smokers). On contact with cold marine water, the least soluble elements are precipitated in the form of colloidal hydrous silicates (clay minerals) and hydroxides close to the hydrothermal vent. The hydrothermal fluids are high in silica and low in alumina causing the precipitation of alumina-poor iron silicates (nontronite) that dissociate into iron hydroxide and amorphous silica during diagenesis. The amorphous silica is typically entrapped by iron oxide laminae to form bands of chert. Breaches of the iron oxide laminae permitted the escape of the gelatinous amorphous silica during compaction and dewatering leaving a chert-free residue as the protore of non-hydrothermal sedimentary high-grade iron ore. The rapid deposition and abundant included water formed unstable mounds and chimneys around the vents. Slumping of the mounds caused by compaction, dewatering, gravity sliding, and seismic events produced turbidity currents forming proximal fans of GIF, but colloidal particles remained suspended in longer-lived density flows to deposit the ultra fine-grained BIF over vast areas of the ocean floor. Episodes of density current deposition were separated by intervals of slow pelagic sedimentation and silicification of the sea floor. The density currents commonly caused minor erosion of the sea floor with rip-out clasts incorporated in the new layers. The iron-rich hydrothermal fluids triggered the precipitation of dissolved ferrous iron accumulated by anoxic weathering to produce the huge deposits of BIF in the Archean and Paleoproterozoic until the rise in atmospheric oxygen stopped the accumulation of ferrous iron in the oceans leaving only the hydrothermal source for later deposits.

The use of siderites in blast furnaces operated on unfluxed pellets

Bakal siderites represent an important source of iron ore that can be used in the production of high-quality pig iron and steel. Their value in this regard stems from the stability of their chemical composition, low content of harmful impurities (sulfur, phosphorus), good reducibility, and good strength in the roasted state. These advantages, combined with the favorable composition of the country rock-which has a basicity (based on CaO + MgO/SiO2) of up to 2.6-makes it possible to classify these siderites as iron-fluxes that can be used effectively in a blast furnace. Roasted siderite concentrate (RSC) can be used efficiently in the blast-furnace charge to make different grades of manganese-bearing foundry iron as long as unfluxed pellets are also employed. On the average, the addition of 10 kg of RSC to the charge per ton of pig iron reduces the consumption of dry skip coke by 0.6–1.5 kg/ton pig and increases furnace productivity by 0.9–2.0 tons/day by decreasing the amount of raw flux needed and increasing the iron content of the fluxed part of the charge.

From Ore to Tool – Iron Age Iron Smelting in the Largest and Oldest Meteorite Crater in the World

The Vredefort Impact Structure in South Africa is the biggest and oldest remnant meteorite impact crater in the world where various ancient cultures thrived. In this paper some light will be shed on the Iron Age, iron smelting aspects of the people that inhabited the area and the results of a laboratory study of iron artefacts and a possible source of iron ore in the region is given. A sectional piece from a hoe manufactured in a small bloomery furnace was polished and etched and subsequently analyses with SEM and Mossbauer techniques were obtained. The hoe has a typical cast iron composition (2.9% C, 0.1% Mn, 0.4% Si, 0.4% P and 96.2% Fe, all wt.%) and contains many slag inclusions with wustite dendrites. The Mossbauer spectrum consisted of iron (86%), wustite (5%) and oxihydroxide (9%) and the thin (200 mm) corrosion layer consisted of hematite (55%) and oxihydroxides (45%). At a furnace site, various slag clumps (26.3% C, 24.8% SiO2, 11.3% Al2O3, 1.3% P2O5, 1.0% K2O, 0.4% CaO and 30.2 FeO, all wt.%, average of four samples) and iron nodules (7.6% C, 6.0% Mn, 4.3% Si, 1.4% Al, 80.7% Fe, all wt.%) were found. The Mossbauer spectrum of the slag consisted of iron (7%), magnetite (56%), fayalite (2%) and oxihydroxides (35%) and that of the iron nodules yielded iron (28%), wustite (12%), magnetite (20%) and oxihydroxides (40%). A possible ore source containing 84% FeO, 7% of Al2O3 and SiO2 (all in wt.%) and minor impurities is located a few kilometers from the furnace site, yielding a Mossbauer spectrum consisting of hematite (70%) and oxihydroxides (30%).

An Objective Approach to the Definition of Some Mining Terms: Application to the Hasançelebi Iron Ore Deposit

In the mining industry, definitions of terms such as geologic resource, geologic reserve, mineral resource, mineral, mineral reserve, ore, ore reserve, mineable reserve, and industrial minerals always have been debated, and have caused much confusion. The process of arriving at these definitions requires complicated exploration, calculation, and evaluation. Based on such work, the definitions about the mineral property will be distinctly different. The aims of this paper is to discuss and compare these definitions, and then contrast the differences among them in the example of the Hasancelebi iron are deposit, which is an important source of iron ore in Turkey.

Furnace and Pot: why the iron smelter is a big pot maker

“It will be suggested here that however difficult they may be to recognize archaeologically, the following restrictions on iron-using in Europe must be taken into account: 1. Religious taboos, especially on the use of iron for some purposes (e.g. agriculture) or on the smelting of iron ores. 2. Social traditions may restrict iron making to, for example, either servile or elite groups and may also influence the way iron is used. 3. Political events leading to the control of iron ore sources can deny or increase the amount available to a particular community.” (Alexander 1983).

Channel iron deposits of the Hamersley Province, Western Australia

The fluvial goethite‐hematite channel iron deposits (CID) of fhe Pilbara region of Western Australia, formerly known as the ‘Robe Pisolite’, represent a major source of iron ore mined in the Hamersley Province. The CID occupy Early Tertiary palaeochannels that are typically less than 1 km but range to several kilometres in width and from 1 to ∼⃒100 m thick. The Robe palaeochannel is the longest, with CID partly preserved over a distance of 150 km, whereas the Marillana palaeochannel contains CID along 80 km of its length. The CID range from goethitic mudstone to fine hematite‐goethite gravel and intraformational conglomerate varying in distribution along the channels in a range of massive, bedded and altered types. The granular type that forms the bulk of the ore is typically ooidal, comprising pelletoids with goethite cortices around hematite nuclei (which often consist of fossilised wood), with typically abundant coarse goethitised wood fragments, a varied proportion of peloids, minor pisoids, and a diverse porous goethitic matrix. The Robe deposits tend to have more spherical pelletoids, with more regularly developed layering, and smaller cores than CID from the Yandi deposits of the Marillana valley. Generally, the presence of ferruginised fossil wood is the principal diagnostic field criterion used to distinguish CID from other comparable goethite‐hematite detrital deposits. Electron microprobe X‐ray maps reveal that lattice Al and Si increase from the hematitic nuclei to the matrix, and then the cortex. In the Robe CID, alumina in the nuclei varies between 0.5 and 2.8%, whereas at Yandi, alumina in the nuclei ranges from 0.2 to 0.7%. The goethite cortex of a granule is usually richer in both alumina and silica than its nucleus, in a cortex : nucleus ratio of ∼⃒2:1 at Robe and 3:1 at Yandi. The nucleus and cortex of individual pelletoids generally exhibit a similar trace‐element distribution, which can often be related to the surrounding country rock and, with the exception of Al, is different to that shown by the matrix. A visual classification (labelled co‐manual) based on the relative amount of cortex (co), matrix (ma) and nucleus (nu) enables an estimate of the deleterious minor elements, mainly aluminium (al), for separating samples into ore, near‐ore and non‐ore.

The geology and genesis of high-grade hematite iron ore deposits

This paper presents a first summary of results of an ongoing study, started some two years ago, of high-grade iron ore deposits in South Africa, India and Brazil, including a comparison with the rather well-studied deposits of the Hamersley Province in Australia. Large, high-grade hematite iron ore bodies hosted by Precambrian banded iron formations are the world's most important source of iron ore. Despite their great economic importance, the origin of these deposits has remained rather enigmatic. Results of preliminary investigations into the geological setting, petrography and geochemistry of BIF-hosted high-grade hematite iron ore deposits in South Africa, India, Western Australia and Brazil reveal distinct similarities, suggest ing a very similar mode of hydrothermal and supergene-modified hydrothermal origin for most BIF-hosted highgrade hematite ore deposits. Differences between the deposits of this type are largely the result of varying intensities of supergene modification in Late Cretaceous to Tertiary times. Notable exceptions are the deposits in the Griqualand West region of South Africa, including the giant Sishen deposit, that are regarded to be of ancient supergene origin.

Iron ore supplies to the United Kingdom iron and steel industry

The pattern of iron ore sources for the United Kingdom iron and steel industry has evolved in response to both national and worldwide technical developments and discoveries. In the earliest times ores came from numerous locations and supported small, local industries. Production grew rapidly from the mid-eighteenth century, especially after coke replaced charcoal as a reductant. Output became focused increasingly on the large resources of bedded phosphoric ironstones of central and eastern England; this was accelerated by the improved transport offered by the canal and railway networks. The low-phosphorus replacement hematite ores of Cumbria and South Wales were also exploited, especially to meet the requirements of the acid Bessemer process. Imports began in the mid-nineteenth century, initially from Europe and North Africa, and both domestic and imported ores were used on a substantial scale for many years. Dependence on imports became complete with the adoption of the Linz-Donawitz steelmaking process in the 1960s and 1970s. At about the same time mining and ocean freight developments enabled the use of ores from worldwide sources. In recent years ore supplies have come mainly from Australia, Brazil, Canada and South Africa. Most of the supply is sintering fines, with considerable quantities of lump ore and some pellets.Major technological changes in the short to medium term are not expected. There may be less lump ore available, but changes in blast-furnace practice, such as coal injection, may make it less desirable. In the longer term ores may have to be accepted with slightly higher phosphorus levels. Eventually, alternative processes to the blast-furnace may come to have a greater impact.

Phosphorus distribution in BIF-derived iron ores of Hamersley Province, Western Australia

The Brockman Iron Formation is one of the most important sources of iron ore in Australia. The usable reserves are limited, however, by high phosphorus levels within some of the orebodies. Understanding of the nature and distribution of this phosphorus is critical when techniques are being devised to upgrade the ores for ironmaking. Although some of the phosphorus is present as secondary apatite and other less common phosphates, it has been known for some time that the majority of the phosphorus in Brockman iron ores is associated with goethite, in amounts often exceeding 1%. It has now been shown that phosphorus levels are dependent not only on the amount of goethite but also on the microtextural types of goethite in the ore. Extensive microanalytical studies of a wide range of ore types have established that the highest phosphorus levels are consistently associated with late-formed colloform goethite in cracks and pore networks. Preliminary studies by scanning transmision electron microscopy reveal that high phosphorus levels are limited to goethite composed of ultrafine crystallites. Where dehydration or recrystallization of the goethite has occurred it typically results in expulsion of the contained phosphorus. The implications of these findings for phosphorus removal are discussed.

Combined use of thermal and surface analyses

In order to attempt the location of the iron ore sources exploited at Tharros (Sardinia) during the Phoenician-Punic period and to elucidate some chemical aspects of the iron ore smelting process, the iron ore outcrops of Monte Ferru located near to this archaeological site, have been first sampled and then, differential thermal analysis (DTA) and thermogravimetry (TG) have been used for simulating and studying the iron ore smelting process under a carbon monoxide atmosphere. Furthermore, in order to obtain a qualitative identification of minerals present in the iron bearing rocks and for obtaining some thermochemical data, the smelting process has been carried out also under air and Ar-5% H2 atmospheres. The microchemical aspects involved during the smelting process of the iron ore to crude iron, the formation and the chemistry of new no metallic phases that results from the smelting, i.e. the slags, and the final product of the pyrometallurgical process have been identifiedvia small area X-ray photoelectron spectroscopy (SA-XPS), X-ray induced Auger electron spectroscopy (XAES) and scanning electron microscopy + energy dispersive spectroscopy (SEM + EDS). These results are compared with those obtained from the characterisation of the smelting slags found during the excavation of the archaeological site of Tharros and a relationship is found.

Competitiveness and prospects for the African mining industry

Since the 1960s the Kédia mines have been the main source of iron ore for Mauritania. In the 1970s SN1M, the Mauritanian state enterprise responsible for the mining of the country's iron ore, concerned about the eventual depletion of its reserves at Kédia, and at the urging of its European customers, undertook to develop new iron‐ore deposits at the Guelbs. The deposits at the Guelbs, however, were low‐grade magnetite ore as opposed to the high‐grade hematite ore at Kedia, and were much more costly to mine and process. The cost of the Guelbs project and its failure to meet production targets have strained the resources of SNIM to a financial and technical breaking point. The paper suggests that one solution to SNIM's difficulty may be to mothball the Guelbs project and to develop instead other deposits in the vicinity of the Guelbs.

Rainy periods and bottom water stagnation initiating brine accumulation and metal concentrations, 2. Precambrian gold‐uranium ore beds and banded iron formations

I previously suggested that heavy runoff during the 12,500–7000 years B.P. tropical pluvial period generated bottom water quiescence and reducing conditions making possible sapropel formation, accumulation of brine originating at the sea bottom, and long‐term preservation of hydrothermal sulfides in the Red Sea Deeps. I hypothesized the same process to account for two Precambrian strata‐bound ores. In the Upper Witwatersrand paleoplacers, South Africa, gold and uranium eroded by running water from upstream greenstones, reached highest concentrations in association with organic matter in carbonaceous seams, and deposited in the distal end of fluvial fans during transgressive phases. I propose that the deep waters over these fans became anoxic when large, sudden floods stratified the water column. The organic matter thus locally preserved concentrated gold and uranium from the partial dissolution of the detrital metallic grains. In the Hamersley basin of Western Australia, banded iron formations (BIF) of the Dales Gorge Member are a major source of iron ore. Regularly fluctuating environmental conditions are shown by repetitious BIF and black shale macrobands. I propose that they were deposited in a confined, silled, deep basin connected with the open ocean. Before initiation of the lowest BIF deposition the active regional thermohaline circulation flushing the deep waters under a rather arid climate diluted and oxidized the Fe2+‐rich hydrothermal effluents exhaling from the basin floor. Then, during a strong wet period, heavy runoff scavenging volcanoclastics from the land surface lowered the basin surface water salinity and prevented deepwater renewal. The hydrothermal effluents began to accumulate and progressively concentrated in the quiescent and progressively oxygen‐depleted deep water. During this wet initial phase, the massive black, organic‐rich pyritic shale at the top of the Mount McRae Shale Member was deposited immediately and conformably underlying the lowest BIF macroband. When aridity returned, the quiescent deep water filling the basin to sill depth had become sufficiently dense to resist its displacement by reactivated vertical circulation. From Fe2+‐rich anoxic brine, Fe3+ was precipitated at the anoxic‐oxic interface near the photic zone base by biogenic photosynthesis or Fe2+ photooxidation and partially reduced to Fe2+ during its settling through the anoxic water mass. Thus the lowest BIF macroband of the Dales Gorge Member was formed. Once high bottom water density became established, black shale macrobands were formed during recurrent wet periods and BIF macrobands during the intervening arid intervals. The macrobands' wet‐arid periodicity is suggestive of control by Milankovitch‐type insolation variation. Mesobands and microbands point to shorter climatic cycles. Termination of the system is achieved only by tectonic movements.

Photo-oxidation of hydrated Fe2+—significance for banded iron formations

The Precambrian banded iron formations (BIFs) are the major iron ore sources on the Earth. They consist of extensive iron-rich and iron-poor layers within siliceous sedimentary rocks1,2. The banding has been attributed to variations in the conditions for precipitation of Fe2+ in ancient seas. The most favoured precipitating agent is oxygen3–8; this would lead in the first place to insoluble FeOOH. The variations might then arise from fluctuations in low levels of oxygen in the atmosphere8. Similar fluctuations could arise through the in situ photosynthetic activity of phytoplankton5. Alternatively, oxygen might have been a constant factor, the periodicity arising from a varying supply of iron to the zone of precipitation8–10. Another suggestion, that UV photons might have been the precipitating agent, without oxygen11, was based on the conversion of Fe2+ to Fe3+ by UV light (254 nm) in rather strongly acid conditions12,13. We have now tested this idea by photolysing Fe2+ in morerealistic near-neutral conditions. We report here that the presence of Fe(OH)+ becomes important, greatly enhancing previous estimates of the iron-precipitating power of early Precambrian sunlight, and suggesting that this sunlight would have been a sufficient precipitating agent for the iron found in BIFs.

Iron Sands from the Black Sea

The use of iron-bearing sands such as those of the Black Sea has often been thought of as an early source of iron ore by archaeo-metallurgists. Indeed Japan was an avid user of such material as late as the 19th century, and its use was being considered by the Turkish authorities in 1975.The black sands of the south side of the Black Sea are very extensive, and obvious to the layman because of their unusual nature. They are also highly magnetic and quite a high proportion can be picked up with the aid of a small permanent magnet. On two occasions samples were taken and examined for their iron content and to see how reducible they were, i.e. how easy it would be for early smiths to use them. The analysis of two batches is given in Table 1. The first sample was taken from near Kirazlik, which is 42 km. west of Trabzon, and the second from sites extending from 4 km. west of Ordu to 10 km. west of Ünye. It is clear that there is not much difference in the composition from the two sites which are about 100 km. apart.

Geographical Problems in the Iron and Steel Industry of the USSR

AbstractTechnological advances in the Soviet iron and steel industry are producing changes in the locational pattern of the industry. The increasing concentration of production in large iron and steel plants requires the use of large iron-mining establishments of the order of 30 million tons of crude ore. Iron and steel plants were once viewed in the Soviet Union as oriented toward the market of a particular economic region. But the growing plant capacity and a trend toward specialization in particular types of finished products tend to expand the marketing zone of individual plants far beyond the boundaries of single economic regions. Future planning of the industry is in terms of five basic iron and steel zones: Central Russia, Urals, South, Siberia and Kazakhstan, of which the Urals and the South are fully integrated and the three others are in varying stages of formation. The declining share of coke in the blast-furnace charge tends to shift the locational pattern increasingly toward iron-ore sources,...