Iron ore tailings filled polypropylene (PP) composites were produced using the compo-indirect squeeze casting (C-ISC) process. Particle sizes 150, 212 and 300 μm where considered for different volume fractions of 5% ...Iron ore tailings filled polypropylene (PP) composites were produced using the compo-indirect squeeze casting (C-ISC) process. Particle sizes 150, 212 and 300 μm where considered for different volume fractions of 5% to 30% at intervals of 5%. The tensile and impact behavior of the produced composites were investigated, experimentally, by carrying out uniaxial tensile and izod impact tests to obtain tensile strength, elongation at break, modulus of elasticity and impact strength. Empirical data were compared with results obtained from models proposed by Nielsen, Bigg and Einstein. The experimental results show that elongation at break for iron ore tailings filled PP reduces with increasing 150 μm particle size. Tensile strength reduces with increasing filler. The Bigg equation exhibited improved predictability with decreasing particle size of filler in PP;while the Einstein equation which assumes poor adhesion gives the best prediction of modulus of elasticity with increasing particle size in PP. Izod impact strength decreases with particle size but increases with increasing volume content of iron ore tailings from 5% to 25% for each particle size considered.展开更多
As a new type of ironmaking raw materials,carbon composite iron ore hot briquette(CCB) is the product of fine iron ore and fine coal by hot briquetting process.On basis of experimental research on the manufacturing an...As a new type of ironmaking raw materials,carbon composite iron ore hot briquette(CCB) is the product of fine iron ore and fine coal by hot briquetting process.On basis of experimental research on the manufacturing and metallurgical properties of CCB,this study focused on the application of CCB to blast furnace ironmaking and newly-developed shaft furnace smelting reduction processes.Firstly,the metallurgical properties of CCB are experimentally tested and compared with the common iron-bearing burdens.Then,the effects of charging CCB on blast furnace operation are numerically analyzed by means of multi-fluid blast furnace model,and the flowchart and pilot test of CCB-Shaft furnace smelting reduction process are briefly introduced.展开更多
The two-dimensional infiltration experiment was carried out by means of digital image technology.The evolution process of the wetting body was described.The wetted front distance and the time show a very significant p...The two-dimensional infiltration experiment was carried out by means of digital image technology.The evolution process of the wetting body was described.The wetted front distance and the time show a very significant power function relationship.The horizontal wetted distance is larger than the vertical wetted distance in the initial stage.Then,the vertical distance of the wetted body gradually approaches to the horizontal distance.The infiltration distance decreases as the content of fine particles increases.The wetted front migration rate curve shows a three-stage change law,and it increases with the increase of coarse particle content.The directional velocity ratio is defined.The initial value of horizontal infiltration rate is larger than that of vertical one,and then the vertical infiltration rate is gradually close to the horizontal value.The empirical relationship between the characteristic particle size and the stable infiltration rate is established,which provides a theoretical basis for the prediction of the stable infiltration rate in in-situ leaching.展开更多
The Kalatongke Cu-Ni sulfide deposits located in the East Junggar terrane, northern Xinjiang, western China are the largest magmatic sulfide deposits in the Central Asian Orogenic Belt （CAOB）. The chemical and carbo...The Kalatongke Cu-Ni sulfide deposits located in the East Junggar terrane, northern Xinjiang, western China are the largest magmatic sulfide deposits in the Central Asian Orogenic Belt （CAOB）. The chemical and carbon isotopic compositions of the volatiles trapped in olivine, pyroxene and sulfide mineral separates were analyzed by vacuum stepwise-heating mass spectrometry. The results show that the released volatiles are concentrated at three temperature intervals of 200-400°C, 400-900°C and 900-1200°C. The released volatiles from silicate mineral separates at 400-900°C and 900-1200°C have similar chemical and carbon isotopic compositions, which are mainly composed of H2O （av. ~92 mol%） with minor H2, CO2, H2S and SO2, and they are likely associated with the ore-forming magmatic volatiles. Light δ13CCO2 values （from -20.86‰ to -12.85‰） of pyroxene indicate crustal contamination occurred prior to or synchronous with pyroxene crystallization of mantlederived ore-forming magma. The elevated contents of H2 and H2O in the olivine and pyroxene suggest a deep mantle-originated ore-forming volatile mixed with aqueous volatiles from recycled subducted slab. High contents of CO2 in the ore-forming magma volatiles led to an increase in oxygen fugacity, and thereby reduced the solubility of sulfur in the magma, then triggered sulfur saturation followed by sulfide melt segregation; CO2 contents correlated with Cu contents in the whole rocks suggest that a supercritical state of CO2 in the ore-forming magma system under high temperature and pressure conditions might play a key role in the assemblage of huge Cu and Ni elements. The volatiles released from constituent minerals of intrusion 1# have more CO2 and SO2 oxidized gases, higher CO2/CH4 and SO2/H2S ratios and lighter δ13CCO2 than those of intrusions 2# and 3#. This combination suggests that the higher oxidation state of the volatiles in intrusion 1# than intrusions 2# and 3#, which could be one of key ore-forming factors for large amounts of ores and high contents of Cu and Ni in intrusion 1#. The volatiles released at 200-400°C are dominated by H2O with minor CO2, N2＋CO and SO2, with δ13CCO2 values （-25.66‰ to -22.98‰） within the crustal ranges, and are considered to be related to secondary tectonic-hydrothermal activities.展开更多
Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based o...Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based on the iron nugget process. The present work describes a further optimization of the conditions used in the previous study. The effects of CaO on the reduction-melting behavior and properties of the boron-rich slag are presented. CaO improved the reduction of boron-bearing iron concentrate/carbon composite pellets when its content was less than lwt%. Melting separation of the composite pellets became difficult with the CaO content increased. The sulfur content of the iron nugget gradually decreased from 0.16wt% to 0.046wt% as the CaO content of the pellets increased from 1wt% to 5wt%. CaO negatively affected the iron yield and boron extraction efficiency of the boron-rich slag. The mineral phase evolution of the boron-rich slag during the reduction-melting separation of the composite pellets with added CaO was also deduced.展开更多
The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite ar...The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite are collected after intervals of 3 to 4 hours. Large bauxite processing industries producing 1 million tons of pure aluminium can have three grinding mills. Thus, the total number of samples to be tested in one day reaches a figure of 18 to 24. The sample of bauxite ore coming from the grinding mill is tested for its particle size and composition. For testing the composition, the bauxite ore sample is first prepared by fusing it with X-ray flux. Then the sample is sent for X-ray fluorescence analysis. Afterwards, the crucibles are washed in ultrasonic baths to be used for the next testing. The whole procedure takes about 2 - 3 hours. With a large number of samples reaching the laboratory, the chances of error in composition analysis increase. In this study, we have used a composite sampling methodology to reduce the number of samples reaching the laboratory without compromising their validity. The results of the average composition of fifteen samples were measured against composite samples. The mean of difference was calculated. The standard deviation and paired t-test values were evaluated against predetermined critical values obtained using a two-tailed test. It was found from the results that paired test-t values were much lower than the critical values thus validating the composition attained through composite sampling. The composite sampling approach not only reduced the number of samples but also the chemicals used in the laboratory. The objective of improved analytical protocol to reduce the number of samples reaching the laboratory was successfully achieved without compromising the quality of analytical results.展开更多
Chemical(REE and major elements)and isotope(δ^(13)C,δ^(18)O)composition of carbonate manganese ores and manganese-bearing carbonates of the Usa deposit(Siberia,Russia)were studied.Received data on the composition of...Chemical(REE and major elements)and isotope(δ^(13)C,δ^(18)O)composition of carbonate manganese ores and manganese-bearing carbonates of the Usa deposit(Siberia,Russia)were studied.Received data on the composition of REE exhibit both the distinct negative(Ce/Ce*_(PAAS)<1)and positive(Ce/Ce*_(PAAS)>1)cerium anomalies and the positive Eu-anomaly(Eu/Eu*_(PAAS)>1).Negative Eu-anomalies are not observed.The contents of Mn,Fe,REE,and Ce-anomalies show a positive correlation with each other.Ce-anomalies and the amount of manganese and REE in relation to the carbon isotope composition(δ^(13)C)show a negative relationship and indicate that oxidized carbon of organic matter played an important role in the concentration of manganese and REE in manganese ores.The chemical and isotope composition of examined rocks indicates on secondary formation of Mnores.Two major phases and sources are distinguished in the ore-forming process characterized by diff erent chemical(REE and ore elements)and isotope composition:(i)highgrade manganese ores(with high contents of REE and light carbon isotope composition)and(ii)low-grade manganese ores(with low contents of REE and heavy carbon isotope composition).展开更多
Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So fa...Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So far, most mining and mineral beneficiation plants export raw materials only subjected to beneficiation process. Out of more than 200 deposits in Mongolia, 91 deposits had been explored with different methods and stages, and estimated the resource of 33 reserves. Without processing the iron ore, it is impossible to use it for steelmaking due to its high sulfur and phosphorus impurities. Therefore, to study the processing of iron ore deposits in Mongolia, we did a preliminary investigation of iron ore deposits and took samples from the Tamir Gol deposit with high silica and phosphorus content that is difficult to process. Then, conducted mineral analysis and determined the grain structure and beneficiation characteristics of Tamir Gol iron deposit. .展开更多
The high-value utilization of manganese ore tailings is of great significance for saving mineral resources and achieving environmental protection.Herein,an olivine LiFe_(0.5)Mn_(0.5)PO_(4)/rGO composite is synthesized...The high-value utilization of manganese ore tailings is of great significance for saving mineral resources and achieving environmental protection.Herein,an olivine LiFe_(0.5)Mn_(0.5)PO_(4)/rGO composite is synthesized by a simple precipitation method and subsequent high-temperature calcination process using the manganese ore tailings as raw material.The prepared LiFe_(0.5)Mn_(0.5)PO_(4)/rGO composite exhibits superior cycling stability(with 113.5 mAh·g^(-1)after 300 cycles at1.0C(1.0C=170 mA·g^(-1)))and superior rate performance(with 65.6 mAh·g^(-1)at 10.0C).Ex-situ XRD and electrochemical impedance spectroscopy(EIS)analyses evidence that the LiFe_(0.5)Mn_(0.5)PO_(4)/rGO material has excellent structural stability and electrochemical reversibility during charge and discharge processes.Furthermore,the LiFe_(0.5)Mn_(0.5)PO_(4)/rGO//graphite full Li-ion battery also exhibits excellent cycling stability indicating its potential commercialization value.展开更多
The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chi...The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic rcworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentary- metamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks arc introduced and compared with the orc-lead composition, so as to constrain the source of the ore lead. The result indicates that （1） sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their ^206pb/^204pb ratios arc within a range of 17.027- 17.317; ^207Pb/^204pb ratios, 15.451-15.786 and ^208Pb/^204pb ratios, 36.747-37.669; （2） the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks arc characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range, reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; （3） the sedimentary-metamorphic rocks in the mining district arc characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios arc obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic rcworking of these rocks; （4） Pb isotopic compositions of Late Proterozoic diorite-gabbro and Hercynian granite are higher than those of ores. Meanwhile, the Pb isotopic compositions of sulfides in the small-sized strata-penetrating mineralized veinlets formed at later stages arc completely consistent with that of sulfides in stratiform-banded ores, suggesting that these veiniets arc the product of autochthonous rcworking of the stratiform-banded ores during the period of metamorphism and the late magmatic superimposition-mineralization can be excluded; （5） amphibolite, whose protolith is basic volcanic rocks, has the same Pb isotopic compositions as ores, implying that ore lead was derived probably from basic volcanism. So, the source of ore-forming materials for the Huogeqi deposit is like that of the volcanic massive sulfide （VMS） deposits. However, the orebodies do not occur directly within the volcanic rocks, and instead they overlie the volcanic rocks, showing some differences from those typical VMS-type deposits.展开更多
Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxi...Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.展开更多
The article considers the some features of the Quaternary sediments mineral composition of the development areas of the erosion processes on the territory of the Tunkinsk’s depression.Main objectives of our research ...The article considers the some features of the Quaternary sediments mineral composition of the development areas of the erosion processes on the territory of the Tunkinsk’s depression.Main objectives of our research are to determine the entering forms of Na,Mg,Al,Si,P,S,K,Ca,Ti,Cr,Mn,Fe,Zn,Cu,Zr,and Ba in the composition of the investigated sediments.The mineral composition was studied by the method of an electron probe X-ray spectral microanalysis(XRM)using wave spectrometers,and the method of X-ray diffraction analysis.The localization centers of Cr,Cu,Zn,Zr,and Ba were established in the mineral composition of the studied sediments.Maximum content of BaO(14.42 wt%)was detected in alkali K-feldspar in the clay sediments of modern alluvial complex(aQ4).Crystallochemical formulas of different minerals were obtained.展开更多
Mass loss and direct reduction characteristics of iron ore-coal composite pellets under different technological parameters were investigated. Meanwhile, changes of iron phase at different temperatures were analyzed by...Mass loss and direct reduction characteristics of iron ore-coal composite pellets under different technological parameters were investigated. Meanwhile, changes of iron phase at different temperatures were analyzed by using X-ray diffraction （XRD）, and characteristics of crushed products were studied by using a scanning electron microscope （SEM）. The results showed that heating rate had little influence on the reduction, but the temperature played an important role in the reduction process. The mass loss rate increased rapidly from 800 to 1 100 ℃. The reduction process can be divided into three steps which correspond to different temperature ranges. Fe2 03 began to transform into Fe304 below 500 ℃, and FeO was reduced into Fe from 900 ℃. At 900 ℃, the reduction product showed a clear porous structure, which promoted the reduction progress. At 1000 ℃, the metallic Fe dominated the sample, and the reduction reached a very high degree.展开更多
Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simu...Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.展开更多
A preliminary survey of silver isotopic composition in four polymetallic ores in eastern China shows a larger variation inδ^(109)Ag from-0.014‰to+0.983‰,which is within the total ranges for the entire respective or...A preliminary survey of silver isotopic composition in four polymetallic ores in eastern China shows a larger variation inδ^(109)Ag from-0.014‰to+0.983‰,which is within the total ranges for the entire respective ore deposit types worldwide.The diversity of silver isotopic compositions in oredeposits reported here and previous studies seemed to preclude simple isotopic links to particular sources,but reflected the silver isotope fractionation in transport-and deposit-related processes instead.Theδ^(109)Ag values in supergene samples from the Qixiashan Pb-Zn-Ag polymetallic deposit are more positive,in consistent with the statistical δ^(109)Ag distribution from-0.4‰to+2.2‰in 36 pieces of supergene ore samples around the World,which reflects the diverse controls on silver isotope fractionation from the first-order thermodynamic effect,reduction-mediated reaction,remobilization of silver with surficial low-temperature weathering processes.The hypogene samples in Dazhuangzi orogenic Au-Ag ore deposit,have δ^(109)Ag values close to 0,which implies that equilibrium partitioning associated with metal sources at the high-temperature does not result in a resolvable difference in silver isotopic compositions.By contrast,the hypogene samples which are dominated by pyrite without visible silver minerals (i.e.,skarn iron ore deposit in Edongnan) have shown the largest variation range of δ^(109)Ag,followed by that from the porphyry copper ore in Zijinshan.It could be concluded that the surface adsorption and/or lattice substitution are important factors to control Ag isotope fractionation in oreforming processes,especially for skarn deposits with only pyrite.The perspective of silver isotope shows great potentials to understand the processes that lead to the concentrations of metals to economic levels and to constrain the physicochemical conditions during ore-mineralization in metallic ore-deposits.展开更多
The Bipindi iron ore district is located in the central section of the Nyong Complex at the northwestern margin of the Congo Craton in Southwest Cameroon.This iron district contains numerous iron mineralization hosted...The Bipindi iron ore district is located in the central section of the Nyong Complex at the northwestern margin of the Congo Craton in Southwest Cameroon.This iron district contains numerous iron mineralization hosted by the Mewongo,Bibole,Kouambo,and Zambi banded iron formations(BIFs).These BIFs contain magnetite as the main iron ore mineral associated with pyrite,and gangue minerals are quartz with minor chlorite and amphibole.The origin of iron ore from these BIFs was investigated using a combination of in-situ magnetite and whole-rock chemistry.The studied BIF ore samples have a narrow range of TFe between 30.90 wt.%and 43.20 wt.%,indicating a low-grade ore.The geochemical signatures of magnetite such as low contents of base metals(e.g.,Cu,Co,V,and Zn)and low Co/Zn ratios<0.85 indicate a hydrothermal origin.Combined with the geochemical features of these BIFs,e.g.,high Fe/Ti and Fe/Al ratios(mean>600 and>75,respectively),we suggest that magnetite was derived from a mixture of seawater and~0.1%low-temperature hydrothermal fluids in an oxidizing environment.Collectively,low-temperature hydrothermal and later metamorphic fluids were necessary for the transformation of the protolith Nyong Complex BIFs to iron ore.展开更多
The influence of gangue compositions (mainly composed of SiO2,CaO,MgO and Al2O3)on the reduction kinetics of carbon-bearing iron ore pellets was estimated at 1373-1473 K in N2 atmosphere.The results showed that gangue...The influence of gangue compositions (mainly composed of SiO2,CaO,MgO and Al2O3)on the reduction kinetics of carbon-bearing iron ore pellets was estimated at 1373-1473 K in N2 atmosphere.The results showed that gangue content and each component distribution affected the pellets reduction process.The reduction rate was found to follow a linear correlation with quaternary basicity R4 [mass ratio of (CaO +MgO)to (SIO2 +Al2O3)]of the carbon-beating iron ore pellets;also,the content of SiO2 solid solution in iron oxide had a significant impact on the reduction rate.At the same reduction temperature,a higher R4 resulted in a lower SiO2 free content,weakening its inhibitory effect on the Boudouard reaction.The reduction temperature of Fe2SiO4 could be reduced by increasing the contents of CaO and MgO,improving the iron oxide reduction as well as the precipitation and growth of the iron grains.The g'angue content and .component distribution showed no effect on the rate-controlling step of the reduction;however,the apparent activation energy of reaction decreased with increasing quaternary basicity.When R4 increased from 0.15 to 0.67,the apparent activation energy decreased from 228.51 to 193.66 kJ/mol.展开更多
The mining of placer iron ore greatly influences the surrounding desert grassland.In Agdala Town,Qinghe County,Xinjiang,the soil seed bank is severely damaged,and the utilization and productivity of desert grasslands ...The mining of placer iron ore greatly influences the surrounding desert grassland.In Agdala Town,Qinghe County,Xinjiang,the soil seed bank is severely damaged,and the utilization and productivity of desert grasslands are almost zero,which seriously affects the safety of the ecological environment and the development of local animal husbandry.It is very important to supplement soil seed banks to enhance the species composition of desert grasslands after ecological restoration.In this study,the effects of the seed bank,species composition,and seed burial depth on the seedling emergence rate at placer iron ore site before and after artificial seed bank replenishment were compared using the germination tray method.The original soil seed bank in the study area contained only four species,which were all annual plants.The dominant species were Salsola ruthenica and Corispermum orientale,and the soil seed bank density was very small.The emergence regularity of the soil seed bank was closely related to water content,and the emergence of annual vegetation was explosive.Seed burial depth affected the emergence rate of perennial grass,and we determined that a burial depth of 0–5 cm was the most effective for emergence.This indicates that seedling emergence of artificially supplemented soil seed bank can be completed within 7 days if the sowing depth is appropriate;sowing depths greater than 5 cm affect seed germination.These findings provide a basis for selecting species to populate large areas.展开更多
The influence of iron ore characteristics on FeO formation during sintering was examined mainly in terms of chemical composition and the melting characteristics of iron ores. Statistical regression and X-ray diffracti...The influence of iron ore characteristics on FeO formation during sintering was examined mainly in terms of chemical composition and the melting characteristics of iron ores. Statistical regression and X-ray diffraction were used to further explain the specific effect of iron ore characteristics on FeO formation. The results indicate that LOI （loss on ignition） in iron ores have a positive influence on FeO formation by promoting the sintering process of Fe2O3 decomposing and reducing. Silica contents in iron ores play a determining role in final content of FeO in sinter. The melting characteristics of iron ores significantly affect FeO formation during sintering.展开更多
A procedure for evaluating the susceptibility of raw materials for the process of sintering of iron ore mixes is presented. The procedure relies on the evaluation of the amount and quality of the finest grain fraction...A procedure for evaluating the susceptibility of raw materials for the process of sintering of iron ore mixes is presented. The procedure relies on the evaluation of the amount and quality of the finest grain fraction. The method is based on determination of particular grain fractions. For the grain less than 0.15 mm, the determination of the a- mount is performed using an IPS （Infrared Particles Sizer） grain size analyzer and for the grain larger than 0.15 ram, the fraction is determined using the （wet and dry） screening methods. This allows for quantity assessment of the quality of material in terms of its susceptibility to self-pelletizing by calculating Total Ability for SelPPelletizing （TASP） index fT. The presented method, in combination with the grain size and chemical analyses, can serve for evaluation of suitability of raw material and mixes for the sintering process. Furthermore, the TASP index for 10 types of iron ores and concentrates was determined. The usability of the TASP index was verified by determination of its impact on yield of sintering process both in laboratory and in industry scale.展开更多
文摘Iron ore tailings filled polypropylene (PP) composites were produced using the compo-indirect squeeze casting (C-ISC) process. Particle sizes 150, 212 and 300 μm where considered for different volume fractions of 5% to 30% at intervals of 5%. The tensile and impact behavior of the produced composites were investigated, experimentally, by carrying out uniaxial tensile and izod impact tests to obtain tensile strength, elongation at break, modulus of elasticity and impact strength. Empirical data were compared with results obtained from models proposed by Nielsen, Bigg and Einstein. The experimental results show that elongation at break for iron ore tailings filled PP reduces with increasing 150 μm particle size. Tensile strength reduces with increasing filler. The Bigg equation exhibited improved predictability with decreasing particle size of filler in PP;while the Einstein equation which assumes poor adhesion gives the best prediction of modulus of elasticity with increasing particle size in PP. Izod impact strength decreases with particle size but increases with increasing volume content of iron ore tailings from 5% to 25% for each particle size considered.
文摘As a new type of ironmaking raw materials,carbon composite iron ore hot briquette(CCB) is the product of fine iron ore and fine coal by hot briquetting process.On basis of experimental research on the manufacturing and metallurgical properties of CCB,this study focused on the application of CCB to blast furnace ironmaking and newly-developed shaft furnace smelting reduction processes.Firstly,the metallurgical properties of CCB are experimentally tested and compared with the common iron-bearing burdens.Then,the effects of charging CCB on blast furnace operation are numerically analyzed by means of multi-fluid blast furnace model,and the flowchart and pilot test of CCB-Shaft furnace smelting reduction process are briefly introduced.
基金Projects(51764014,11902127)supported by the National Natural Science Foundation of ChinaProject(201810407004)supported by the National Undergraduate Innovation Training Program of ChinaProject(GJJ180457)supported by Jiangxi Education Department,China。
文摘The two-dimensional infiltration experiment was carried out by means of digital image technology.The evolution process of the wetting body was described.The wetted front distance and the time show a very significant power function relationship.The horizontal wetted distance is larger than the vertical wetted distance in the initial stage.Then,the vertical distance of the wetted body gradually approaches to the horizontal distance.The infiltration distance decreases as the content of fine particles increases.The wetted front migration rate curve shows a three-stage change law,and it increases with the increase of coarse particle content.The directional velocity ratio is defined.The initial value of horizontal infiltration rate is larger than that of vertical one,and then the vertical infiltration rate is gradually close to the horizontal value.The empirical relationship between the characteristic particle size and the stable infiltration rate is established,which provides a theoretical basis for the prediction of the stable infiltration rate in in-situ leaching.
基金financially supported by NSF of China(Grant 41072056, 40772058, 91014003, 40534020 and40772062)Key Projects of China Geological Survey(1212011121092)MOE (311010)
文摘The Kalatongke Cu-Ni sulfide deposits located in the East Junggar terrane, northern Xinjiang, western China are the largest magmatic sulfide deposits in the Central Asian Orogenic Belt （CAOB）. The chemical and carbon isotopic compositions of the volatiles trapped in olivine, pyroxene and sulfide mineral separates were analyzed by vacuum stepwise-heating mass spectrometry. The results show that the released volatiles are concentrated at three temperature intervals of 200-400°C, 400-900°C and 900-1200°C. The released volatiles from silicate mineral separates at 400-900°C and 900-1200°C have similar chemical and carbon isotopic compositions, which are mainly composed of H2O （av. ~92 mol%） with minor H2, CO2, H2S and SO2, and they are likely associated with the ore-forming magmatic volatiles. Light δ13CCO2 values （from -20.86‰ to -12.85‰） of pyroxene indicate crustal contamination occurred prior to or synchronous with pyroxene crystallization of mantlederived ore-forming magma. The elevated contents of H2 and H2O in the olivine and pyroxene suggest a deep mantle-originated ore-forming volatile mixed with aqueous volatiles from recycled subducted slab. High contents of CO2 in the ore-forming magma volatiles led to an increase in oxygen fugacity, and thereby reduced the solubility of sulfur in the magma, then triggered sulfur saturation followed by sulfide melt segregation; CO2 contents correlated with Cu contents in the whole rocks suggest that a supercritical state of CO2 in the ore-forming magma system under high temperature and pressure conditions might play a key role in the assemblage of huge Cu and Ni elements. The volatiles released from constituent minerals of intrusion 1# have more CO2 and SO2 oxidized gases, higher CO2/CH4 and SO2/H2S ratios and lighter δ13CCO2 than those of intrusions 2# and 3#. This combination suggests that the higher oxidation state of the volatiles in intrusion 1# than intrusions 2# and 3#, which could be one of key ore-forming factors for large amounts of ores and high contents of Cu and Ni in intrusion 1#. The volatiles released at 200-400°C are dominated by H2O with minor CO2, N2＋CO and SO2, with δ13CCO2 values （-25.66‰ to -22.98‰） within the crustal ranges, and are considered to be related to secondary tectonic-hydrothermal activities.
基金the financial support of the National Natural Science Foundation of China (Grant Nos. 51274033 and 51374024)
文摘Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based on the iron nugget process. The present work describes a further optimization of the conditions used in the previous study. The effects of CaO on the reduction-melting behavior and properties of the boron-rich slag are presented. CaO improved the reduction of boron-bearing iron concentrate/carbon composite pellets when its content was less than lwt%. Melting separation of the composite pellets became difficult with the CaO content increased. The sulfur content of the iron nugget gradually decreased from 0.16wt% to 0.046wt% as the CaO content of the pellets increased from 1wt% to 5wt%. CaO negatively affected the iron yield and boron extraction efficiency of the boron-rich slag. The mineral phase evolution of the boron-rich slag during the reduction-melting separation of the composite pellets with added CaO was also deduced.
文摘The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite are collected after intervals of 3 to 4 hours. Large bauxite processing industries producing 1 million tons of pure aluminium can have three grinding mills. Thus, the total number of samples to be tested in one day reaches a figure of 18 to 24. The sample of bauxite ore coming from the grinding mill is tested for its particle size and composition. For testing the composition, the bauxite ore sample is first prepared by fusing it with X-ray flux. Then the sample is sent for X-ray fluorescence analysis. Afterwards, the crucibles are washed in ultrasonic baths to be used for the next testing. The whole procedure takes about 2 - 3 hours. With a large number of samples reaching the laboratory, the chances of error in composition analysis increase. In this study, we have used a composite sampling methodology to reduce the number of samples reaching the laboratory without compromising their validity. The results of the average composition of fifteen samples were measured against composite samples. The mean of difference was calculated. The standard deviation and paired t-test values were evaluated against predetermined critical values obtained using a two-tailed test. It was found from the results that paired test-t values were much lower than the critical values thus validating the composition attained through composite sampling. The composite sampling approach not only reduced the number of samples but also the chemicals used in the laboratory. The objective of improved analytical protocol to reduce the number of samples reaching the laboratory was successfully achieved without compromising the quality of analytical results.
基金accomplished in accordance with the Research Program of the Geological Institute of the Russian Academy of Sciences。
文摘Chemical(REE and major elements)and isotope(δ^(13)C,δ^(18)O)composition of carbonate manganese ores and manganese-bearing carbonates of the Usa deposit(Siberia,Russia)were studied.Received data on the composition of REE exhibit both the distinct negative(Ce/Ce*_(PAAS)<1)and positive(Ce/Ce*_(PAAS)>1)cerium anomalies and the positive Eu-anomaly(Eu/Eu*_(PAAS)>1).Negative Eu-anomalies are not observed.The contents of Mn,Fe,REE,and Ce-anomalies show a positive correlation with each other.Ce-anomalies and the amount of manganese and REE in relation to the carbon isotope composition(δ^(13)C)show a negative relationship and indicate that oxidized carbon of organic matter played an important role in the concentration of manganese and REE in manganese ores.The chemical and isotope composition of examined rocks indicates on secondary formation of Mnores.Two major phases and sources are distinguished in the ore-forming process characterized by diff erent chemical(REE and ore elements)and isotope composition:(i)highgrade manganese ores(with high contents of REE and light carbon isotope composition)and(ii)low-grade manganese ores(with low contents of REE and heavy carbon isotope composition).
文摘Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So far, most mining and mineral beneficiation plants export raw materials only subjected to beneficiation process. Out of more than 200 deposits in Mongolia, 91 deposits had been explored with different methods and stages, and estimated the resource of 33 reserves. Without processing the iron ore, it is impossible to use it for steelmaking due to its high sulfur and phosphorus impurities. Therefore, to study the processing of iron ore deposits in Mongolia, we did a preliminary investigation of iron ore deposits and took samples from the Tamir Gol deposit with high silica and phosphorus content that is difficult to process. Then, conducted mineral analysis and determined the grain structure and beneficiation characteristics of Tamir Gol iron deposit. .
基金financially supported by the National Natural Science Foundation of China(No.51964012)。
文摘The high-value utilization of manganese ore tailings is of great significance for saving mineral resources and achieving environmental protection.Herein,an olivine LiFe_(0.5)Mn_(0.5)PO_(4)/rGO composite is synthesized by a simple precipitation method and subsequent high-temperature calcination process using the manganese ore tailings as raw material.The prepared LiFe_(0.5)Mn_(0.5)PO_(4)/rGO composite exhibits superior cycling stability(with 113.5 mAh·g^(-1)after 300 cycles at1.0C(1.0C=170 mA·g^(-1)))and superior rate performance(with 65.6 mAh·g^(-1)at 10.0C).Ex-situ XRD and electrochemical impedance spectroscopy(EIS)analyses evidence that the LiFe_(0.5)Mn_(0.5)PO_(4)/rGO material has excellent structural stability and electrochemical reversibility during charge and discharge processes.Furthermore,the LiFe_(0.5)Mn_(0.5)PO_(4)/rGO//graphite full Li-ion battery also exhibits excellent cycling stability indicating its potential commercialization value.
基金supported jointly by the Bureau of Resources and Environment,Chinese Academy of Sciences(KZCX3-SW-125)the National Natural Science Foundation of China(Grant No,40172037).
文摘The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies arc stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic rcworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentary- metamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks arc introduced and compared with the orc-lead composition, so as to constrain the source of the ore lead. The result indicates that （1） sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their ^206pb/^204pb ratios arc within a range of 17.027- 17.317; ^207Pb/^204pb ratios, 15.451-15.786 and ^208Pb/^204pb ratios, 36.747-37.669; （2） the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks arc characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range, reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; （3） the sedimentary-metamorphic rocks in the mining district arc characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios arc obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic rcworking of these rocks; （4） Pb isotopic compositions of Late Proterozoic diorite-gabbro and Hercynian granite are higher than those of ores. Meanwhile, the Pb isotopic compositions of sulfides in the small-sized strata-penetrating mineralized veinlets formed at later stages arc completely consistent with that of sulfides in stratiform-banded ores, suggesting that these veiniets arc the product of autochthonous rcworking of the stratiform-banded ores during the period of metamorphism and the late magmatic superimposition-mineralization can be excluded; （5） amphibolite, whose protolith is basic volcanic rocks, has the same Pb isotopic compositions as ores, implying that ore lead was derived probably from basic volcanism. So, the source of ore-forming materials for the Huogeqi deposit is like that of the volcanic massive sulfide （VMS） deposits. However, the orebodies do not occur directly within the volcanic rocks, and instead they overlie the volcanic rocks, showing some differences from those typical VMS-type deposits.
文摘Using variety of modern testing methods, the processing mineralogical characteristics for a lead and zinc oxide ore in Sichuan were studied systematically. The chemical analysis result shows that the lead and zinc oxide content exceeding the minimum industrial grade and iron ore, total iron content reaches a minimum industrial grade and associated with gold and silver; The mineralogical analysis result shows that lead and zinc mineral composition and configuration are very complexity. The zinc minerals and zinciferous minerals are sphalerite, hemimorphite, Smithsonite, Hydrozincite, zinc chlorite, limonite, zinc dolomite and zincocalcite; lead minerals and plumbiferous minerals are mainly galena, cerussite, anglesite, limonite and Coronadite; The minerals disseminated grain size are very fine and mineral dissemination characteristics are very complex ; expected theoretical recoveries for lead and zinc were 72% and 67% respectively. The results of this study provide basic data and theoretical basis for ore dressing.
文摘The article considers the some features of the Quaternary sediments mineral composition of the development areas of the erosion processes on the territory of the Tunkinsk’s depression.Main objectives of our research are to determine the entering forms of Na,Mg,Al,Si,P,S,K,Ca,Ti,Cr,Mn,Fe,Zn,Cu,Zr,and Ba in the composition of the investigated sediments.The mineral composition was studied by the method of an electron probe X-ray spectral microanalysis(XRM)using wave spectrometers,and the method of X-ray diffraction analysis.The localization centers of Cr,Cu,Zn,Zr,and Ba were established in the mineral composition of the studied sediments.Maximum content of BaO(14.42 wt%)was detected in alkali K-feldspar in the clay sediments of modern alluvial complex(aQ4).Crystallochemical formulas of different minerals were obtained.
基金Sponsored by Fundamental Research Funds for the Central Universities of China(FRF-SD-12-007B)National Science and Technology Support Plan in the 12th Five-year of China(2011BAE13B09)
文摘Mass loss and direct reduction characteristics of iron ore-coal composite pellets under different technological parameters were investigated. Meanwhile, changes of iron phase at different temperatures were analyzed by using X-ray diffraction （XRD）, and characteristics of crushed products were studied by using a scanning electron microscope （SEM）. The results showed that heating rate had little influence on the reduction, but the temperature played an important role in the reduction process. The mass loss rate increased rapidly from 800 to 1 100 ℃. The reduction process can be divided into three steps which correspond to different temperature ranges. Fe2 03 began to transform into Fe304 below 500 ℃, and FeO was reduced into Fe from 900 ℃. At 900 ℃, the reduction product showed a clear porous structure, which promoted the reduction progress. At 1000 ℃, the metallic Fe dominated the sample, and the reduction reached a very high degree.
文摘Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.
基金supported by the National Natural Science Foundations of China(Nos.41973005,41673001)China National Space Administration(CNSA)(No.D020205)。
文摘A preliminary survey of silver isotopic composition in four polymetallic ores in eastern China shows a larger variation inδ^(109)Ag from-0.014‰to+0.983‰,which is within the total ranges for the entire respective ore deposit types worldwide.The diversity of silver isotopic compositions in oredeposits reported here and previous studies seemed to preclude simple isotopic links to particular sources,but reflected the silver isotope fractionation in transport-and deposit-related processes instead.Theδ^(109)Ag values in supergene samples from the Qixiashan Pb-Zn-Ag polymetallic deposit are more positive,in consistent with the statistical δ^(109)Ag distribution from-0.4‰to+2.2‰in 36 pieces of supergene ore samples around the World,which reflects the diverse controls on silver isotope fractionation from the first-order thermodynamic effect,reduction-mediated reaction,remobilization of silver with surficial low-temperature weathering processes.The hypogene samples in Dazhuangzi orogenic Au-Ag ore deposit,have δ^(109)Ag values close to 0,which implies that equilibrium partitioning associated with metal sources at the high-temperature does not result in a resolvable difference in silver isotopic compositions.By contrast,the hypogene samples which are dominated by pyrite without visible silver minerals (i.e.,skarn iron ore deposit in Edongnan) have shown the largest variation range of δ^(109)Ag,followed by that from the porphyry copper ore in Zijinshan.It could be concluded that the surface adsorption and/or lattice substitution are important factors to control Ag isotope fractionation in oreforming processes,especially for skarn deposits with only pyrite.The perspective of silver isotope shows great potentials to understand the processes that lead to the concentrations of metals to economic levels and to constrain the physicochemical conditions during ore-mineralization in metallic ore-deposits.
基金supported by the Central South University Postdoctoral Research Fund(No.22020084)。
文摘The Bipindi iron ore district is located in the central section of the Nyong Complex at the northwestern margin of the Congo Craton in Southwest Cameroon.This iron district contains numerous iron mineralization hosted by the Mewongo,Bibole,Kouambo,and Zambi banded iron formations(BIFs).These BIFs contain magnetite as the main iron ore mineral associated with pyrite,and gangue minerals are quartz with minor chlorite and amphibole.The origin of iron ore from these BIFs was investigated using a combination of in-situ magnetite and whole-rock chemistry.The studied BIF ore samples have a narrow range of TFe between 30.90 wt.%and 43.20 wt.%,indicating a low-grade ore.The geochemical signatures of magnetite such as low contents of base metals(e.g.,Cu,Co,V,and Zn)and low Co/Zn ratios<0.85 indicate a hydrothermal origin.Combined with the geochemical features of these BIFs,e.g.,high Fe/Ti and Fe/Al ratios(mean>600 and>75,respectively),we suggest that magnetite was derived from a mixture of seawater and~0.1%low-temperature hydrothermal fluids in an oxidizing environment.Collectively,low-temperature hydrothermal and later metamorphic fluids were necessary for the transformation of the protolith Nyong Complex BIFs to iron ore.
基金National Natural Science Foundation of China (Grant Nos.51574002 and 51404005)Natural Sciences and Engineering Research Council of Canada (NSERC)and Science without borders/CNPq (L.Dessbesell).
文摘The influence of gangue compositions (mainly composed of SiO2,CaO,MgO and Al2O3)on the reduction kinetics of carbon-bearing iron ore pellets was estimated at 1373-1473 K in N2 atmosphere.The results showed that gangue content and each component distribution affected the pellets reduction process.The reduction rate was found to follow a linear correlation with quaternary basicity R4 [mass ratio of (CaO +MgO)to (SIO2 +Al2O3)]of the carbon-beating iron ore pellets;also,the content of SiO2 solid solution in iron oxide had a significant impact on the reduction rate.At the same reduction temperature,a higher R4 resulted in a lower SiO2 free content,weakening its inhibitory effect on the Boudouard reaction.The reduction temperature of Fe2SiO4 could be reduced by increasing the contents of CaO and MgO,improving the iron oxide reduction as well as the precipitation and growth of the iron grains.The g'angue content and .component distribution showed no effect on the rate-controlling step of the reduction;however,the apparent activation energy of reaction decreased with increasing quaternary basicity.When R4 increased from 0.15 to 0.67,the apparent activation energy decreased from 228.51 to 193.66 kJ/mol.
基金The Project of Xinjiang Uygur Autonomous Region(2020D01A38)。
文摘The mining of placer iron ore greatly influences the surrounding desert grassland.In Agdala Town,Qinghe County,Xinjiang,the soil seed bank is severely damaged,and the utilization and productivity of desert grasslands are almost zero,which seriously affects the safety of the ecological environment and the development of local animal husbandry.It is very important to supplement soil seed banks to enhance the species composition of desert grasslands after ecological restoration.In this study,the effects of the seed bank,species composition,and seed burial depth on the seedling emergence rate at placer iron ore site before and after artificial seed bank replenishment were compared using the germination tray method.The original soil seed bank in the study area contained only four species,which were all annual plants.The dominant species were Salsola ruthenica and Corispermum orientale,and the soil seed bank density was very small.The emergence regularity of the soil seed bank was closely related to water content,and the emergence of annual vegetation was explosive.Seed burial depth affected the emergence rate of perennial grass,and we determined that a burial depth of 0–5 cm was the most effective for emergence.This indicates that seedling emergence of artificially supplemented soil seed bank can be completed within 7 days if the sowing depth is appropriate;sowing depths greater than 5 cm affect seed germination.These findings provide a basis for selecting species to populate large areas.
文摘The influence of iron ore characteristics on FeO formation during sintering was examined mainly in terms of chemical composition and the melting characteristics of iron ores. Statistical regression and X-ray diffraction were used to further explain the specific effect of iron ore characteristics on FeO formation. The results indicate that LOI （loss on ignition） in iron ores have a positive influence on FeO formation by promoting the sintering process of Fe2O3 decomposing and reducing. Silica contents in iron ores play a determining role in final content of FeO in sinter. The melting characteristics of iron ores significantly affect FeO formation during sintering.
文摘A procedure for evaluating the susceptibility of raw materials for the process of sintering of iron ore mixes is presented. The procedure relies on the evaluation of the amount and quality of the finest grain fraction. The method is based on determination of particular grain fractions. For the grain less than 0.15 mm, the determination of the a- mount is performed using an IPS （Infrared Particles Sizer） grain size analyzer and for the grain larger than 0.15 ram, the fraction is determined using the （wet and dry） screening methods. This allows for quantity assessment of the quality of material in terms of its susceptibility to self-pelletizing by calculating Total Ability for SelPPelletizing （TASP） index fT. The presented method, in combination with the grain size and chemical analyses, can serve for evaluation of suitability of raw material and mixes for the sintering process. Furthermore, the TASP index for 10 types of iron ores and concentrates was determined. The usability of the TASP index was verified by determination of its impact on yield of sintering process both in laboratory and in industry scale.
