Kind Of Ore Research Articles

Research on Grinding Law and Grinding Parameters Optimization of Polymetallic Complex Ores

Grinding plays an important role in mining, construction, metallurgy, chemical, coal and other basic industries. In terms of beneficiation, grinding is the most energy consuming operation. So, reasonable grinding conditions according to the properties of ores is the key to obtain good grinding results and reduce energy consumption and resource waste. In this paper, Tongkeng and Gaofeng polymetallic complex ores are taken as research objects, and the effects of grinding law based on single factor condition test and the grinding parameters optimization based on response surface method were studied for two kinds of ores. The results show that grinding time is a significant factor affecting the particle size composition. The suitable grinding concentration of Tongkeng ore and Gaofeng ore is 70% and 75%, respectively. The effect of mill filling ratio on Gaofeng ore is not obvious. The rotational rate has little effect on the grinding technical efficiency. The regression model equations obtained by response surface method are extremely significant, and the relative errors of prediction are all within 1%, indicating high reliability of fitting equations. The order of influencing factors of the two ores is as follows: grinding time > filling ratio > grinding concentration. For Tongkeng ore, the optimized grinding conditions are grinding time 5.4 min, grinding concentration 67% and filling ratio 35%. For Gaofeng ore, the optimized grinding conditions are grinding time 3.8 min, grinding concentration 73% and filling ratio 34%.

Vibrational (Infrared, Raman) and Thermogravimetric Study of Copper Ore from the Deposit at Tchirozerine, Agadez (Niger)

Agadez is the mining region of the republic of Niger in which all kinds of ore are found. Copper would have been exploited and refined in Niger in the 15th century in the province of Azelik, region of Agadez. In this context, it is important to use mew techniques to characterize the mineralogical variability of copper ore. The collected sample was analyzed by X-ray diffraction, Thermogravimetric analysis and spectroscopies (infrared and Raman). The results of the X-ray diffraction of the ore show that the sample corresponds to an association between brochantite and biotite, dominated by brochantite. The thermogravimetric analysis indicates that the sample was stable up to 200°C and above this temperature, the solid decomposed in a series of three decomposition stages. Raman and infrared spectroscopies show the fundamental vibration of sulfate ion which functioning as a unidentate because the effective symmetry is lowered to C3v.  

Complex, multi-stage mineralization processes in the giant Bayan Obo REE-Nb-Fe deposit, China

The Bayan Obo REE-Nb-Fe deposit with giant rare earth reserves, still has no unified understanding of the REE and Nb-bearing mineral evolution and the division of mineralization stages, due to the complicated metallogenic process and the huge controversy on the important issues such as the origin of ore-hosting dolomite. In this work, the whole process of carbonatite magma solidification and mineralization is divided into six stages: coarse dolomitic facies, fine dolomitic facies, disseminated mineralization, banded mineralization, massive mineralization and vein mineralization. The mineralogical composition and paragenesis of various types of rocks and ores have been systematically studied using the automatic mineral analysis technology-Advanced Mineral Identification and Characterization System (AMICS), supplemented by optical microscopy and cathodoluminescence. In order to establish the internal relationship between different stages, trace elements of six kinds of rocks and ores were analyzed. The mineralogical studies show that the rare earth minerals appear in the order of transition from the phosphate minerals in the brine-melt stage (fine dolomitic facies), through the fluorcarbonate minerals in the hydrothermal stage (disseminated, banded and massive mineralization), to the Ba-fluorcarbonate minerals in the Paleozoic vein mineralization, and all of these are generally associated with apatite, baryte, fluorite, aegirine and quartz. The distribution of niobium minerals in all kinds of ores is in the form of disseminated grains, and there is no obvious paragenetic relationship with other minerals, which indicate that niobium mineralization may only be related to the content of niobium in hydrothermal solution. The geochemical data show that all types of rocks and ores have positive anomalies of Ba and Nb, negative anomalies of U, Ta, Sr, Zr and Y. From coarse dolomitic facies to massive mineralization, the content of REE, Nb and Th increases, the content of Sr decreases, and the ratio of (La/Yb)N and (La/Nd)N increases, all of which change continuously. Vein mineralization has similar (La/Nd)N and (La + Ce + Pr)N/REE ratios compared with coarse dolomitic facies and has a wide range of Sr, Th, Nb and REE compositions, and elemental ratio and content of vein mineralization are within the distribution range of ore-hosting dolomite and different types of mineralization. Based on the above, it is considered that the main mineralization body at Bayan Obo was formed in the process of auto-metasomatism of Mesoproterozoic igneous carbonatite, while vein mineralization was the product of homogenization and re-precipitation of early ore-forming material by the Paleozoic fluids, without the addition of exogenous metallogenic materials.

Relationship between Uranium Minerals and Pyrite and Its Genetic Significance in the Mianhuakeng Deposit, Northern Guangdong Province

Granite-related uranium ore is an important uranium resource type in China and worldwide. Whether the uranium geochemical theory “U6+ oxidative migration and U4+ reductive precipitation” is applicable to the granite-related uranium mineralization theory has not been determined. Detailed field and petrographic work, as well as scanning electron microscopy energy spectrum analysis, are conducted in this study to analyze the relationship between uranium minerals and pyrite from different ore types and evaluate the mechanism for the precipitation and enrichment of uranium in the Mianhuakeng uranium deposit of northern Guangdong. Uranium ore bodies in the Mianhuakeng deposit generally occur as vein-filling or vein-disseminated types. Four different kinds of ores are recognized: fluorite, carbonate, siliceous, and reddening types. Despite differences in the mineral assemblages, veined ores share similar characteristics and show that uranium minerals (1) occur in the central part or periphery of vein-filling ores or in interphase arrangements with syn-ore fluorite, quartz, or calcite veins; (2) occur as veinlets or are disseminated in cataclastic altered granite; (3) are inlaid with gangue minerals, primarily calcite, fluorite, and microcrystalline quartz; and (4) are closely associated with pyrite in aggregates or relatively independent states, forming straight boundaries with syn-ore gangue minerals that have euhedral and intact crystals and show mosaic growth features. All these results indicate that both pyrite and uranium minerals are co-crystallized products of the ore-forming fluid. Combined with previous research suggesting that the reducing fluid was sourced from mantle, this study shows that decreased pressure and temperature, as well as changes in pH and the solubility (saturation) of changes, rather than the redox reaction, caused the uranium precipitation in the Mianhuakeng deposit.

Nickel Bioleaching at Elevated pH: Research and Application

Biohydrometallurgy has broad application prospect in the treatment of low-grade nickel sulfide ore. However, quite a number of nickel sulfide deposits are associated with basic gangue minerals such as contain olivine, serpentine. The high basic gangue minerals will lead to a higher acid consumption and make it difficult to bioleach at pH below 2.5. It is crucial to improve processes and adapt bacteria with this kind of ore. This paper reviews the experimental researches and industrial applications for bioleaching of the high acid consumption nickel sulfide ores. It is suggested that bioleaching at elevated pH will have similar leaching rate compared with pH below 2.5, meanwhile the cost will be decreased remarkably due to a lower acid consumption and less dissolved impurity ions.

The Processing of Low Grade Nickel Ore from South East Sulawesi

The deposit of nickel ore in Indonesia is very abundant. High grade ore has been processed to produce ferronickel, but low grade nickel ore is still left as by product without being processed. This kind of ore has been attempted to be processed through atmospheric leaching and carbon reduction, separately. In atmospheric leaching process, it is found that iron and nickel can be separated from other minerals through leaching in acid media. The performance of process is influenced by certain process variables such as temperature and acid concentration. At high temperature and high acid concentration, at least 80 % of nickel and 95 % of iron can be extracted in less than 3 hours. The recovery profile of nickel and iron are similar. Nickel and iron extraction increase with an increase in acid concentration and temperature. Another type of process, reduction smelting, results in sponge iron that can be smelted to produce iron-nickel alloy. The ore was reduced by carbon at temperature range of 800 - 1200 °C. The progress of reduction reaction between oxide minerals and carbon depends on reduction temperature. At high temperature, the reduction reaction takes place rapidly. The reduced ores was smelted to obtain iron-nickel alloy.

Synchronous Volatilization of Sn, Zn, and As, and Preparation of Direct Reduction Iron (DRI) from a Complex Iron Concentrate via CO Reduction

Sn-, Zn-, and As-bearing iron ores are typical complex ores and are abundantly reserved in China. This kind of ore is difficult to use effectively due to the complicated relationships between iron and the other valuable metal minerals. Excessive Sn, Zn, and As contents would adversely affect ferrous metallurgy operation as well as the quality of the products. In this study, thermodynamic calculations revealed that it was feasible to synchronously volatilize Sn, Zn, and As via CO reduction. Experimental results showed that preoxidation was necessary for the subsequent reductive volatilization of Zn from the pellets, and the proper preoxidation temperature was 700–725°C under air atmosphere. Synchronous volatilization of Sn, Zn, and As was realized by roasting under weak reductive atmosphere after the pellets were preoxidized. The volatilization ratios of 75.88% Sn, 78.88% Zn, and 84.43% As were obtained, respectively, under the conditions by reduction at 1000°C for 100 min with mixed gas of 50% CO + 50% CO2 (in vol.). A metallic pellet (direct reduction iron) with total iron grade of 87.36%, Fe metallization ratio of 89.27%, and residual Sn, Zn, and As contents of 0.071%, 0.009%, and 0.047%, respectively, was prepared. Sn and As were mainly volatilized during weak reductive atmosphere roasting, and those volatilized in the metallization reduction process were negligible. Most of Zn (78.88%) was volatilized during weak reductive atmosphere roasting, while the metallization reduction process only contributed to 16.10% of total Zn volatilization.

Experimental Research on Bonding Intensity of Iron Ores in the Sintering Process

The bonding intensity of four kinds of ores from Brazil, Australia and South Africa is researched in this study, and the influence factors are analyzed. The results show that, the ores of different types have apparently differences in bonding intensity, ores from Brazil and South Africa have high bonding intensity, while ores from Australia have low bonding intensity; The foundation of generation of effective liquid is adequate liquid phase fluidity and the lower porosity of core ore; The ratio of porosity of core ore and the index of liquid phase fluidity has negative correlation with the bonding intensity.

二次硫化銅鉱の浸出促進

The purpose of this study is to clarify the differences in leaching behavior among various kinds of secondary copper sulfide ores. Leaching experiments were carried out in a sulphuric acid solution at different pH values, temperatures and concentrations of ferric ion using three kinds of ores. The grain size of the copper minerals in these ores was measured by QEMSCAN™. Although copper minerals in these ores consisted mainly of chalcocite, copper leaching rates varied greatly depending on each ore. In particular, the difference of leaching rates was more than 4 times in the early leaching stage.In the case of the slower leaching rate, the copper extraction could be increased from 15% to 58% after 0.5 days at 40°C and initial pH of 1.0 with 250mg/l of additional ferric ion.In the case of the faster leaching rate, the leaching rate could be increased by increasing the temperature and/or decreasing pH. However, the increase of the leaching rate was almost independent of additional ferric ion throughout the leaching stage. Furthermore, it was found that the grain size of copper minerals in the case of the slower leaching rate was about 1.5 to two times as coarse as that in the case of the faster leaching rate. It is concluded that, from the standpoint of reaction efficiency, the copper leaching behavior in the early leaching stage would be very sensitive to the grain size of copper minerals more than other leaching factors.

Chasing Elusive Society

Now, as in C. Wright Mills' times, the job of sociological imagination is a simultaneous, reciprocal translation between private and public stories: a translation of the individually faced and privately tackled problems into public, collectively confronted issues and of public interests into the individually pursued life strategies. Since its inception, the place of sociology has been in the 'agora,' that private-public meeting place, where, (as Cornelius Castoriadis kept reminding us) the olkos and the ecclesia come face to face, hoping to make themselves understood to each other through a principal yet benevolent, and above all attentive dialogue. The raw stuff processed by sociological imagination is human experience. The end product of sociological imagination (called 'social reality') is cast of the metal smelted from the ore of experience. Though its chemical substance cannot but reflect the composition of the ore, the contents of the product also bear the mark of the smelting process which divides the ore's ingredients into useful product and waste, while its shape depends on the mould (that is, the cognitive frame) into which melted metal has been poured. The products of sociological imagination, imagined social realities, may therefore vary in composition and shape even if the same experience supplies the raw material for the processing. Not any social reality, though, can be melted and moulded from the given ore of human experience: one may expect contemporaneous products, however different they might otherwise be, to carry a 'family resemblance' betraying their common origins. But we can also suppose that once the deposits of a certain kind of ore are depleted and a different type of ore is fed into the furnaces, the smelting techniques would be, sooner or later, modified and the moulds recast.

Lead Isotopic Compositions of Atmospheric Suspended Particulate Matter in Nagoya City as Measured by HR-ICP-MS

Lead isotope ratios in atmospheric suspended particulate matter (SPM) collected in Nagoya City were measured by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) after microwave-assisted acid digestion. Before analyzing SPM samples, the present method was evaluated by analyzing standard reference material (SRM 981) for common lead isotopic standard from NIST. The analytical results for 207Pb/206Pb and 208Pb/206Pb for SRM 981 were 0.9160±0.0006 and 2.136±0.003, respectively, which were almost coincident with the certified values of 0.91464±0.00033 and 2.1681±0.0008, respectively. The lead isotope ratios in SPM samples collected daily in Nagoya University were analyzed in order to elucidate their origins, and the results were compared with various kinds of ores. It was found that most SPM samples showed some mixed compositions of lead isotope ratios of lead ores from USA and Australia, which suggested utilization of large amount of lead ores imported from these two countries. On the other hand, some samples showed mixed compositions of lead ores from Asian continent, which might be resulted from the long-range transportation of atmospheric SPM from Asian continent to Japan.

Lead Isotopic Compositions of Atmospheric Suspended Particulate Matter in Nagoya City as Measured by HR-ICP-MS

Lead isotope ratios in atmospheric suspended particulate matter (SPM) collected in Nagoya City were measured by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) after microwave-assisted acid digestion. Before analyzing SPM samples, the present method was evaluated by analyzing standard reference material (SRM 981) for common lead isotopic standard from NIST. The analytical results for 207Pb/206Pb and 208Pb/206Pb for SRM 981 were 0.9160±0.0006 and 2.136±0.003, respectively, which were almost coincident with the certified values of 0.91464±0.00033 and 2.1681±0.0008, respectively. The lead isotope ratios in SPM samples collected daily in Nagoya University were analyzed in order to elucidate their origins, and the results were compared with various kinds of ores. It was found that most SPM samples showed some mixed compositions of lead isotope ratios of lead ores from USA and Australia, which suggested utilization of large amount of lead ores imported from these two countries. On the other hand, some samples showed mixed compositions of lead ores from Asian continent, which might be resulted from the long-range transportation of atmospheric SPM from Asian continent to Japan.

Amelioration of the mineral compositions and microstructures of the special ore sinters

Mineral compositions and microstructures of fluorine-bearing magnetite concentrate and vanadiumtitanomagnetite concentrate are studied. The results show that a boride and a catalytic oxidation agent have great effects on ameliorating the mineral compositions and microstructures of these sinters, and the catalytic agent is more effective. Comparing these two kinds of ores, the performance of fluorine-bearing magnetite concentrate is better. Addition of 0.01% catalyst into fluorine-bearing magnetite concentrate can increase calcium ferrite content from 15%–20% up to 34%–39%, and its microstructure changes from large cavities and thin framework into intermediate cavities and thick framework, and the microcracks disappear.

Dust exposure indices and lung function changes in Longshoremen and Dock workers

A group of Dutch harbor workers involved in loading and unloading bulk products from sea vessels such as coal, cokes, and some other products like alumina, borax, phosphate ore, and vermiculite was studied. Exposures were characterized by personal and environmental monitoring. This information was subsequently used to estimate several dust exposure indices and to study relationships with lung function variables and respiratory symptoms. Average respirable dust exposure levels ranged from 0.3-4.0 mg/m3. Workers involved in unloading products from sea vessels were exposed to the highest dust levels. Supervisors and workers with tasks in the dock had an intermediate to low exposure. Office workers had the lowest exposure to respirable dust. Inhalable dust levels were considerably higher and average exposures ranged from 0.3-80 mg/m3. The ranking of occupational titles by inhalable dust exposure was almost identical to the rank order of respirable dust levels. Workers with higher current and cumulative dust exposures tended to have a lower lung function, and only shortness of breath had a statistically significant relationship with current and cumulative inhalable dust exposure. In general, relationships between lung function and inhalable dust levels tended to be somewhat stronger in terms of statistical significance, because inhalable dust is an estimate of dust deposition in the upper airways and lung function is a measurable parameter of airway obstruction in that region. However, the differences with respirable dust were minimal, and variability in dust exposure levels was extremely large for this population. It was concluded that harbor workers involved in unloading ships containing coal and various kinds of ore can be exposed to high dust levels. Relationships between dust exposure and lung function illustrate that these exposures are a respiratory hazard. Our finding that inhalable dust levels have a somewhat stronger relationship with lung function level than respirable dust levels deserves further attention.

Leaching of oxidized zinc ores in various media

The leaching of various oxidized zinc ores in different solvents has been studied in laboratory tests by agitation leaching and in some cases by percolation leaching. Some tests have also been carried out on synthetic zinc compounds. The comparison of the leaching of four different Belgian ores in sulfuric acid, sulfurous acid, ammonium hydroxide and sodium hydroxide, shows that the better results are obtained with sulfuric acid and with caustic soda when the concentration of the latter is high enough. All the ores respond very well to leaching except one which is very rich in iron and can be processed only with concentrated caustic soda. Mineralogical studies have shown that smithsonite is completely leached but that hemimorphite is refractory to leaching in any solvent studied. The leaching in alkaline media (ammonia, caustic soda, diethylenetriamine) has been studied on five different ores. It is confirmed that hemimorphite is difficult to dissolve. Good results are obtained only with caustic soda at high temperature. In ammoniacal solutions, the presence of ammonium carbonate enhances the leaching of hemimorphite but decreases the leaching of smithsonite. The optimum concentration of diethylenetriamine is 250 g/l. Caustic soda leaching tests were carried out on pure compounds and showed that ZnO, Zn(OH) 2, PbO, PbCO 3 and 2PbCO 3βPb(OH) 2 dissolve very rapidly and completely, that the leaching of Zn 2SiO 4 is controlled by kinetics and that the leaching of ZnS, PbS and PbSiO 4 is very poor, their solubility product being very quickly attained. The percolation leaching by sulfuric acid has been tested on Belgian ores and the good results obtained support the idea that this kind of ore could be successfully treated in this way.

Aeromagnetics, geology and ore environments, II. Magnetite and ore environments

“Ore environment”, in the sense that is usually used by geophysicists, signifies a region that is perceived to be favourable for certain kinds of ores and is large enough to be recognizable from airborne surveys. The aim of this article is to inquire whether or under what circumstances such regions can be identified from airborne magnetometer surveys as a result of characteristic features of their magnetic mineralogy. Greenstone belts and former greenstone belts can usually be recognized in large-scale aeromagnetic surveys due to their overall deficiency in magnetite compared with normal granitoid rocks. The low magnetite capacity of greenstone belt rocks is recognizable even under high grade metamorphic facies conditions. Massive, concordant, pyritic CuZn sulfide ores are found within greenstone belts (or former greenstone belts), usually within felsic volcanic or sedimentary zones, and are frequently associated with small beds of metasediments that are rich in iron or in iron and manganese. These beds are 1–10 m thick, continuous over distances of 100 m to a few kilometers, and may extend to distances of 10 km or more away from the ore zone along its strike. The iron may be in the form of pyrite, hematite or magnetite; but magnetite is the most common iron mineral in medium or high grade metamorphic terrains. These units often cause weak anomalies which can be detected by high quality aeromagnetic surveys. Porphyry CuMo sulfide ores are associated with felsic-intermediate plutons and are characterized by concentrically zoned patterns of alteration and mineralization. Aeromagnetic exploration guides to these deposits include the identification of potential porphyry districts by large-scale zoning of igneous rocks from mafic to felsic types as one proceeds towards the centre of the district, and the recognition of concentric patterns of alteration and mineralization having diameters 1–10 km. Some porphyry deposits have a weak “magnetite halo”, and some have magnetite-bearing skarns around the rim of the pluton. Volcanic-associated gold ore deposits occur within greenstone belts or former green-stone belts. They are spatially associated with ultramafic flows, alteration, major fault zones, and feldspar-porphyry intrusions. The ores are believed to besyngenetic-diagenetic Aeromagnetic exploration guides to deposits of this type, which include most of the Canadian deposits, include identification of greenstone belts and delineation of mafic, felsic and sedimentary volcanic phases within the belt, recognition of alteration zones and fault zones, identification of small, felsic porphyry stocks, and delineation of altered mafic/ultramafic layers within the volcanic regions. These and other examples suggest that the “ore environment” concept as previously defined, namely, a region several tens of kilometers in extent in which an experienced interpreter can recognize favourable patterns in the opaque oxide mineralogy, is valid. Used in this way, magnetite can be a useful pathfinder to certain types of ores, and the “aeromagnetic ore environment” has the potential of becoming a practical exploration concept.

COMPLEX MODEL OF COPPER METALLOGENY IN MIDDLE-LOWER YANGTZE VALLEY AND ITS SIGNIFICANCE FOR ORE EXPLORATION

The middle-lower Yangtze Valley is a major metallogenic province of copper deposits in China. The major types of copper deposits in this area are: the sedimentary-reformational type, skarn type, porphyry type and volcanic type ore deposits. The complex model of copper metallogeny of the area is a dialectical synthesis in space, time and composition of several types of ore deposits. It is convenient for us in exploring and evaluating one type of ore deposit to consider the possibility of the presence of other types at the same time, and when one kind of ore is discovered, one must consider to search for another. Thus, the new approach to exploration may be developed and the potential of the orefield be expanded.

実験室用小型連続浮選試験機について

Laboratory-scale continuous flotation machines, which have eight cells, were developed to estimate actual performance data with small amount of ores in a laboratory. These machines are designed to be self-aerating and cell-to-cell type, in order to set various kind of circuits easily using eight cells.Continuous flotation tests with many kinds of ores were carried out and satisfactory results were obtained. Comparison with a locked cycle flotation test, a conventional method, is also described.The agreement with the results obtained by Agitair #48 and #60, popular commercial flotation machines, in roughing, scavenging, and cleaning circuits proves the laboratory-scale continuous flotation machines to offer the reliable information.

乾燥空気中での黒鉱の酸化現象

The two kinds of ores from UCHINOTAI ore deposits and each of their main mineral components were oxidized in dried air at temperatures from 200 to 700°C, respectively. The ores were ground under 200 mesh. The oxidation behaviors were observed by means of chemical analysis, X-ray diffraction, and thermobalance.1. The copper rich ore consisted mainly of copper pyrite and pyrite is found to be more oxidizable, and more easily sulphatized than the samples of simple pyrite or simple copper pyrite and behaves in the oxidation as in the case of the mixtures of copper pyrite and pyrite.2. The zinc rich ore consisted mainly of sphalerite, pyrite and minor copper pyrite behaves in the oxidation as in the case of the mixture of their components and the sulphatization of the ore is found to be stimulated by the presence of copper pyrite or pyrite in the ore.

合成Fayaliteに關する研究

For the purpose of ascertaining the properties of sintered iron ore, the authors synthesized fayalite and other specimens from ferric oxide and quartz sand by reduction method with solid carbon and CO-gas, and investigated their microstructure, reducibility and some other properties. The outline of the results obtained were as follows:-Fayalite could be synthesized by the reduction method, and crystalized thoroughly to form a lathlike shape, a pillar shape or an irregular polyhedral tabular shape. But, when the heating temperature was above the liquidus line of FeO-SiO2 diagram, fayalite and its eutectic matters were liable to present glassy state.In the other sintering test at 1000-1105°C of small briquettes which were made from the raw materials of coke powders and two kinds of ores, a peculiarly characteristic structure, which indicated the formation of Wüstit phase and metallic iron during sintering process, was recognized.