An ore-blending optimization model for the sintering process is an intelligent system that includes iron ore characteristics, expert knowledge and material balance. In the present work, 14 indices are proposed to repr...An ore-blending optimization model for the sintering process is an intelligent system that includes iron ore characteristics, expert knowledge and material balance. In the present work, 14 indices are proposed to represent chemical composition, granulating properties and high temperature properties of iron ores. After the relationships between iron ore characteristics and sintering performance are established, the "two-step" method and the simplex method are introduced to build the model by distinguishing the calculation of optimized blending proportion of iron ores from that of other sintering materials in order to improve calculation efficiency. The ore-blending optimization model, programmed by Access and Visual Basic, is applied to practical production in steel mills and the results prove that the present model can take advantage of the available iron ore resource with stable sinter yield and quality performance but at a lower cost.展开更多
The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results sh...The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (Delta T) and the softening start temperature (T (10%)) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO center dot SiO2 and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.展开更多
This paper aims to evaluate the diesel oil consumption between 2008 and 2015 in the production of iron ore in Brazil, creating correlations between energy intensity (production), economy and checking the impact of fue...This paper aims to evaluate the diesel oil consumption between 2008 and 2015 in the production of iron ore in Brazil, creating correlations between energy intensity (production), economy and checking the impact of fuel prices on the commodity. During the analyzed period, the years 2008-2009 indicated economic crises, which interfered in the price and the commercialization of iron ore products. The physical intensity was 0.2% higher than the economic intensity. In the period from 2010 to 2014, economic activity remained more stable, with a decreasing trend, mainly due to the increase of iron ore prices. The physical intensity is much higher than the economic intensity influenced by the expansion of the Chinese economy. The year of 2014 indicated the end of the high iron ore price cycle and the beginning of supply and demand stabilization with consequent reduction in prices. In 2015, the market entered the stabilization phase, with a continuous reduction in unit production costs and transportation logistics. There was an abrupt change due to the strong increase of the economic intensity due to the fall of the international prices of iron ore. The diesel oil consumption plays a vital role in the scenario of cost reduction in iron ore production and a deeper analysis must be done in order to discover some options to change the energy matrix.展开更多
Herein,micro iron ore tailings(micro-IOTs)were prepared by wet-grinding and applied to improve sulphoaluminate cement(SAC)performance.The physicochemical properties of micro-IOTs were investigated by particle size ana...Herein,micro iron ore tailings(micro-IOTs)were prepared by wet-grinding and applied to improve sulphoaluminate cement(SAC)performance.The physicochemical properties of micro-IOTs were investigated by particle size analysis,XRD,and XPS.The hydrates trait and the hydration mechanism of micro-IOTs-SAC composite were studied by XRD,TGA,MIP,and SEM.The results demonstrated that micro-IOTs with an average grain diameter of 517 nm could be obtained by wet-grinding.The setting time of SAC gradually decreased with increasing micro-IOTs content.By adding 2%micro-IOTs,the compressive strengths of SAC pastes were enhanced about 22%and 10%at 4 h and 28 d,respectively.Moreover,the addition of micro-IOTs accelerated ettringite precipitation and changed its morphology,resulting in early strength improvement of the binary system.And increased later strength by micro-IOTs was closely related to the high content of AH_(3),fine pore structure,and high hydration degree of SAC.The findings suggested one new approach to utilize iron ore tailings in cementbased materials.展开更多
This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic sep...This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.展开更多
The Agios Athanasios ore deposit is located within the wider area of Ieropigi in Kastoria, Greece. The specific ore deposit is developed in form of layers between ophiolites and Tertiary molassic conglomerates. The ma...The Agios Athanasios ore deposit is located within the wider area of Ieropigi in Kastoria, Greece. The specific ore deposit is developed in form of layers between ophiolites and Tertiary molassic conglomerates. The main mineralogical components are hematite, goethite, quartz, and secondarily, garnierite, lizardite, saponite, willemzeite and sepiolite, while scarcers are chromite, calcite and nepouite. Nickel is mainly found in garnierite, willemzeite and nepouite, which in coexistence with quartz are the main components in the binder material of the ore. For the mineral processing gravimetric and magnetic separations are used in the size of fractions -8 + 4 mm, -4 + 1 mm, -1 + 0.250 mm and -0.250 + 0.063 mm. The chemical and mineralogical analysis in combination with microscopic examination showed that mineral processing by gravimetric separation gave the most satisfactory results for the size fraction -1 + 0.250 mm.展开更多
Locating the mineral processing plant near a mine is the most important parameter that affects the whole process.Many factors,and their preferences,should be considered in this stage.The factors include economical,geo...Locating the mineral processing plant near a mine is the most important parameter that affects the whole process.Many factors,and their preferences,should be considered in this stage.The factors include economical,geological,technical,environmental and tectonic parameters.A multi-criteria decision making method is necessary to rank the alternatives.In this paper we describe how plant location is selected by using the Analytic Hierarchy Process(AHP).This method,with eight criteria,was used to select a location for the mineral processing plant at the Sangan iron ore mine(phase 1).Three alternatives for the processing plant were evaluated.The main criteria were distance from the mine,access to heavy machinery transport,the amount of excavation required for grading,bed mixture capacity,belt conveyor length,distance from the tailing dam,distance from the waste dumps and surface water diversion requirements.Finally,the alternatives were ranked and the best location was proposed.展开更多
Processing of Iranian high sulfur iron ore is problematic in minerals industry. The iron ores were studied by the means of polarizing microscopy, chemical analysis, X-ray diffraction. The study shows that the iron ore...Processing of Iranian high sulfur iron ore is problematic in minerals industry. The iron ores were studied by the means of polarizing microscopy, chemical analysis, X-ray diffraction. The study shows that the iron ores have high grade of iron, and complex structures. XRD showed that the iron ore consists of metallic minerals such as magnetite with a small amount of hematite and limonite and non-metallic minerals as serpentine, chlorite, and talc. The average particle size of magnetite crystals is 0.182 mm. The ore contains 1.62% sulfur as harmful impurity in form of pyrite mineral. Due to the isomorphism of magnesium and iron, magnetite mono crystal grade is lower than 68%, and difficult to be physically upgraded to a higher-grade iron concentrate using the available mineral processing technologies.展开更多
The properties of iron ores used in ironmaking process have been drastically changed in the past couple of decades.Especially,the change has become significant in the last few years because of the considerable increas...The properties of iron ores used in ironmaking process have been drastically changed in the past couple of decades.Especially,the change has become significant in the last few years because of the considerable increase in the world steel production.The property change of the iron ore is mainly caused by the depletion of the hard and high-grade lump hematite ores.It has led to the increasing use of ores containing a larger amount of goethite/limonite,i.e.,hydro-oxides of iron.Typically,the proportion of pisolitic ores,which are course limonitic ores,has remarkably increased by several times in Japan.Further,large deposits of the fine goethite ores called Marra Mamba have been developed in Australia and exported to Asian countries.Such trends will be continued in future.Since the change of the ore properties affects not only to the productivity and yield of the sinter but also its metallurgical properties in the blast furnace,further improvement in the sintering technology/ process is required including the preliminary treatment process of raw materials.In order to make wide researches concerning the above issues,the research project 'New Sintering Process through Designing of Composite Granulation & Bed Structure' was formed in the ISIJ,which was the collaborative project between Japanese steel companies and several universities.The project was started in 2005 and carried on the wide range of studies for three and half years.Its main objects are the characterization of pisolitic/goethitic ores and the understanding the behavior during the iron ore sintering process.Further,considering the ore characteristics,some basic researches on the optimum designs of raw material blending,granulation,bed structure,and the metallurgical properties of the produced sinter were performed.The project have invented the technical principle of a new sintering process, namely MEBIOS(Mosaic EmBedding Iron Ore Sintering Process),characterized by the composite granulation and bed-structure,aiming to cope with the drastic shift of the ore properties.Another big issue fallen on the steel industry is the global warming.CO,emission from steelmaking industry occupies about 15%of the total value of the artificial emissions in Japan and therefore its reduction is urgently required.In order examine the possibility to minimize or to reduce further the CO_2 emission from the iron ore sintering process,the research project 'Technological Principle for Low-Carbon Sintering' has been formed since 2009 in the ISIJ.In this project,the analyses of the combustion rates of carbonaceous materials and heat transfer in the sintering bed are first examined by referring the previous studies.Further,experimental works will be conducted on the combustion/oxidation characteristics of biomass charcoal,some organic wastes,steel can scraps,mill scale and partially reduced iron ores as alternative agglomeration reagents of coke and anthracite coal.The effect of their use on the sintering process will be evaluated systematically.It is expected that the structural changes of the sintering bed is considerably different between carbonaceous materials,which disappear during combustion leaving a little amount of ash components and metallic iron bearing materials,which increase the mass and volume during its oxidation. Previous studies showed that the use of metallic iron bearing materials such as steel can scrap and mill scale led to significant decreases in the production rate.This project examines the characteristics of such changes of the sintering bed structure and mineral phases and main process parameters,which govern such phenomena.Further, it searches for a new process principle to overcome the demerits and realize the significant reduction of CO_2 emissions from the iron ore sintering process.In the symposium,summary of activities and the major results and progresses of the above two research projects will be introduced.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
Benthic foraminiferal assemblages have been used to determine the effects of Iran ore tailing pollution on the marine environment. The present paper attempts to unveil pollution impact as responded by foraminiferal sp...Benthic foraminiferal assemblages have been used to determine the effects of Iran ore tailing pollution on the marine environment. The present paper attempts to unveil pollution impact as responded by foraminiferal species of Uppateru estuary. The faunal data thus generated is compared with earlier data sets for possible adverse effects. There has been substantial reduction in total foraminiferal number (TFN), from 574 in 2006 to 213 in 2008 species (st.no.3) per10 gram sediment. Even the total species number (TSN) decreased from 27 in (st.no.8) 2006 to 8 (st.no.1) in 2008. Ammonia accounted for its share (68%), followed by Elphidium (7.4%) and Quinqueloculina (6.5%). These genera are considered to be robust and opportunistic type in the study area. This faunal variation in terms of density (TFN) may be owing to the pollution caused by iron ore tailing. This study also supports the view that benthic foraminiferal biota can be used as a tool to monitor marine pollution in general and estuarine environment in specific.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
The relationship of time to minerals composition in sinters is investigated by mineragraphy are claritied observation and component analysis, and the effects of temperature and atmosphere on mineralization process. Re...The relationship of time to minerals composition in sinters is investigated by mineragraphy are claritied observation and component analysis, and the effects of temperature and atmosphere on mineralization process. Results are obtained as follows. The initial melt forms below the eutectic temperature of CaO·Fe2O3 and CaO·2Fe2O3, which is complex substance containing Ca, Fe, Si and Al, rather than the binary calcium ferrite melt. Minerals composition of binding phase is related to local content of silica in melt, which is influenced by temperature. Appearance of the melt promotes the transition from hematite to magnetite, which then alters the mechanism of calcium ferrite formation. Before the formation of magnetite, the contents of Fe and Ca within the multiple calcium ferrite decrease with temperature, but in the case of magnetite presence, the content of Fe increases solely with increase of temperature and decrease of oxygen potential. Temperature and atmosphere determine minerals composition together, and bring influence on sintering process in different ways. It can be deduced that temperature affects kinetics of the mineralization process, but atmosphere just plays a role in thermodynamics.展开更多
Cooling process of iron ore pellets in a circular cooler has great impacts on the pellet quality and systematic energy exploitation. However, multi-variables and non-visualization of this gray system is unfavorable to...Cooling process of iron ore pellets in a circular cooler has great impacts on the pellet quality and systematic energy exploitation. However, multi-variables and non-visualization of this gray system is unfavorable to efficient production. Thus, the cooling process of iron ore pellets was optimized using mathematical model and data mining techniques. A mathematical model was established and validated by steady-state production data, and the results show that the calculated values coincide very well with the measured values. Based on the proposed model, effects of important process parameters on gas-pellet temperature profiles within the circular cooler were analyzed to better understand the entire cooling process. Two data mining techniques—Association Rules Induction and Clustering were also applied on the steady-state production data to obtain expertise operating rules and optimized targets. Finally, an optimized control strategy for the circular cooler was proposed and an operation guidance system was developed. The system could realize the visualization of thermal process at steady state and provide operation guidance to optimize the circular cooler.展开更多
Selection of crusher required a great deal of design based on the mining plan and operation input.Selection of the best primary crusher from all of available primary crushers is a Multi-Criterion Decision Making(MCDM)...Selection of crusher required a great deal of design based on the mining plan and operation input.Selection of the best primary crusher from all of available primary crushers is a Multi-Criterion Decision Making(MCDM) problem. In this paper, the Analytical Hierarchy Process(AHP) method was used to selection of the best primary crusher for Golegohar Iron Mine in Iran. For this reason, gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impactor, hammer mill and feeder breaker crushers were considered as alternatives and capacity, feed size, product size, rock compressive strength, abrasion index and mobility of crusher were considered as criteria. As a result of our study, the gyratory crusher was offered as the best primary crusher for the studied mine.展开更多
The emission of dioxins from the iron ore sintering process is the largest emission source of dioxins, and the reduction in dioxin emission from the iron ore sintering process to the environment is increasingly import...The emission of dioxins from the iron ore sintering process is the largest emission source of dioxins, and the reduction in dioxin emission from the iron ore sintering process to the environment is increasingly important. Three approaches to control the emission of dioxins were reviewed: source control, process control, and terminal control. Among them, two terminal control technologies, activated carbon adsorption and selective reduction technology, were discussed in detail. Following a comparison of the reduction technologies, the terminal control method was indicated as the key technology to achieve good control of dioxins during the sintering process. For the technical characteristics of the sintering process and flue gas, multiple methods should be collectively considered, and the most suitable method may be addition of inhibitors + ultra-clean dust collection (electrostatic precipitation/bag filter) + desulphurization + selective catalytic reduction to sufficiently remove multiple pollutants, which provides a direction for the cooperative disposal of flue gas pollutants in future.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
文摘An ore-blending optimization model for the sintering process is an intelligent system that includes iron ore characteristics, expert knowledge and material balance. In the present work, 14 indices are proposed to represent chemical composition, granulating properties and high temperature properties of iron ores. After the relationships between iron ore characteristics and sintering performance are established, the "two-step" method and the simplex method are introduced to build the model by distinguishing the calculation of optimized blending proportion of iron ores from that of other sintering materials in order to improve calculation efficiency. The ore-blending optimization model, programmed by Access and Visual Basic, is applied to practical production in steel mills and the results prove that the present model can take advantage of the available iron ore resource with stable sinter yield and quality performance but at a lower cost.
基金financially supported by the National Basic Research Program of China (No. 2012CB720401)the National Natural Science Foundation of China (U1260202)
文摘The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (Delta T) and the softening start temperature (T (10%)) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO center dot SiO2 and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.
文摘This paper aims to evaluate the diesel oil consumption between 2008 and 2015 in the production of iron ore in Brazil, creating correlations between energy intensity (production), economy and checking the impact of fuel prices on the commodity. During the analyzed period, the years 2008-2009 indicated economic crises, which interfered in the price and the commercialization of iron ore products. The physical intensity was 0.2% higher than the economic intensity. In the period from 2010 to 2014, economic activity remained more stable, with a decreasing trend, mainly due to the increase of iron ore prices. The physical intensity is much higher than the economic intensity influenced by the expansion of the Chinese economy. The year of 2014 indicated the end of the high iron ore price cycle and the beginning of supply and demand stabilization with consequent reduction in prices. In 2015, the market entered the stabilization phase, with a continuous reduction in unit production costs and transportation logistics. There was an abrupt change due to the strong increase of the economic intensity due to the fall of the international prices of iron ore. The diesel oil consumption plays a vital role in the scenario of cost reduction in iron ore production and a deeper analysis must be done in order to discover some options to change the energy matrix.
基金This work was supported by University Natural Science Research Project of Anhui Province(KJ2019A0171)National Natural Science Foundation of China(Grant No.52005009)+1 种基金Anhui Province Natural Science Funds for Youth Fund Project(2008085QE273)Anhui Province Key Research and Development Project(202004e11020003).
文摘Herein,micro iron ore tailings(micro-IOTs)were prepared by wet-grinding and applied to improve sulphoaluminate cement(SAC)performance.The physicochemical properties of micro-IOTs were investigated by particle size analysis,XRD,and XPS.The hydrates trait and the hydration mechanism of micro-IOTs-SAC composite were studied by XRD,TGA,MIP,and SEM.The results demonstrated that micro-IOTs with an average grain diameter of 517 nm could be obtained by wet-grinding.The setting time of SAC gradually decreased with increasing micro-IOTs content.By adding 2%micro-IOTs,the compressive strengths of SAC pastes were enhanced about 22%and 10%at 4 h and 28 d,respectively.Moreover,the addition of micro-IOTs accelerated ettringite precipitation and changed its morphology,resulting in early strength improvement of the binary system.And increased later strength by micro-IOTs was closely related to the high content of AH_(3),fine pore structure,and high hydration degree of SAC.The findings suggested one new approach to utilize iron ore tailings in cementbased materials.
文摘This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.
文摘The Agios Athanasios ore deposit is located within the wider area of Ieropigi in Kastoria, Greece. The specific ore deposit is developed in form of layers between ophiolites and Tertiary molassic conglomerates. The main mineralogical components are hematite, goethite, quartz, and secondarily, garnierite, lizardite, saponite, willemzeite and sepiolite, while scarcers are chromite, calcite and nepouite. Nickel is mainly found in garnierite, willemzeite and nepouite, which in coexistence with quartz are the main components in the binder material of the ore. For the mineral processing gravimetric and magnetic separations are used in the size of fractions -8 + 4 mm, -4 + 1 mm, -1 + 0.250 mm and -0.250 + 0.063 mm. The chemical and mineralogical analysis in combination with microscopic examination showed that mineral processing by gravimetric separation gave the most satisfactory results for the size fraction -1 + 0.250 mm.
文摘Locating the mineral processing plant near a mine is the most important parameter that affects the whole process.Many factors,and their preferences,should be considered in this stage.The factors include economical,geological,technical,environmental and tectonic parameters.A multi-criteria decision making method is necessary to rank the alternatives.In this paper we describe how plant location is selected by using the Analytic Hierarchy Process(AHP).This method,with eight criteria,was used to select a location for the mineral processing plant at the Sangan iron ore mine(phase 1).Three alternatives for the processing plant were evaluated.The main criteria were distance from the mine,access to heavy machinery transport,the amount of excavation required for grading,bed mixture capacity,belt conveyor length,distance from the tailing dam,distance from the waste dumps and surface water diversion requirements.Finally,the alternatives were ranked and the best location was proposed.
文摘Processing of Iranian high sulfur iron ore is problematic in minerals industry. The iron ores were studied by the means of polarizing microscopy, chemical analysis, X-ray diffraction. The study shows that the iron ores have high grade of iron, and complex structures. XRD showed that the iron ore consists of metallic minerals such as magnetite with a small amount of hematite and limonite and non-metallic minerals as serpentine, chlorite, and talc. The average particle size of magnetite crystals is 0.182 mm. The ore contains 1.62% sulfur as harmful impurity in form of pyrite mineral. Due to the isomorphism of magnesium and iron, magnetite mono crystal grade is lower than 68%, and difficult to be physically upgraded to a higher-grade iron concentrate using the available mineral processing technologies.
文摘The properties of iron ores used in ironmaking process have been drastically changed in the past couple of decades.Especially,the change has become significant in the last few years because of the considerable increase in the world steel production.The property change of the iron ore is mainly caused by the depletion of the hard and high-grade lump hematite ores.It has led to the increasing use of ores containing a larger amount of goethite/limonite,i.e.,hydro-oxides of iron.Typically,the proportion of pisolitic ores,which are course limonitic ores,has remarkably increased by several times in Japan.Further,large deposits of the fine goethite ores called Marra Mamba have been developed in Australia and exported to Asian countries.Such trends will be continued in future.Since the change of the ore properties affects not only to the productivity and yield of the sinter but also its metallurgical properties in the blast furnace,further improvement in the sintering technology/ process is required including the preliminary treatment process of raw materials.In order to make wide researches concerning the above issues,the research project 'New Sintering Process through Designing of Composite Granulation & Bed Structure' was formed in the ISIJ,which was the collaborative project between Japanese steel companies and several universities.The project was started in 2005 and carried on the wide range of studies for three and half years.Its main objects are the characterization of pisolitic/goethitic ores and the understanding the behavior during the iron ore sintering process.Further,considering the ore characteristics,some basic researches on the optimum designs of raw material blending,granulation,bed structure,and the metallurgical properties of the produced sinter were performed.The project have invented the technical principle of a new sintering process, namely MEBIOS(Mosaic EmBedding Iron Ore Sintering Process),characterized by the composite granulation and bed-structure,aiming to cope with the drastic shift of the ore properties.Another big issue fallen on the steel industry is the global warming.CO,emission from steelmaking industry occupies about 15%of the total value of the artificial emissions in Japan and therefore its reduction is urgently required.In order examine the possibility to minimize or to reduce further the CO_2 emission from the iron ore sintering process,the research project 'Technological Principle for Low-Carbon Sintering' has been formed since 2009 in the ISIJ.In this project,the analyses of the combustion rates of carbonaceous materials and heat transfer in the sintering bed are first examined by referring the previous studies.Further,experimental works will be conducted on the combustion/oxidation characteristics of biomass charcoal,some organic wastes,steel can scraps,mill scale and partially reduced iron ores as alternative agglomeration reagents of coke and anthracite coal.The effect of their use on the sintering process will be evaluated systematically.It is expected that the structural changes of the sintering bed is considerably different between carbonaceous materials,which disappear during combustion leaving a little amount of ash components and metallic iron bearing materials,which increase the mass and volume during its oxidation. Previous studies showed that the use of metallic iron bearing materials such as steel can scrap and mill scale led to significant decreases in the production rate.This project examines the characteristics of such changes of the sintering bed structure and mineral phases and main process parameters,which govern such phenomena.Further, it searches for a new process principle to overcome the demerits and realize the significant reduction of CO_2 emissions from the iron ore sintering process.In the symposium,summary of activities and the major results and progresses of the above two research projects will be introduced.
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.
文摘Benthic foraminiferal assemblages have been used to determine the effects of Iran ore tailing pollution on the marine environment. The present paper attempts to unveil pollution impact as responded by foraminiferal species of Uppateru estuary. The faunal data thus generated is compared with earlier data sets for possible adverse effects. There has been substantial reduction in total foraminiferal number (TFN), from 574 in 2006 to 213 in 2008 species (st.no.3) per10 gram sediment. Even the total species number (TSN) decreased from 27 in (st.no.8) 2006 to 8 (st.no.1) in 2008. Ammonia accounted for its share (68%), followed by Elphidium (7.4%) and Quinqueloculina (6.5%). These genera are considered to be robust and opportunistic type in the study area. This faunal variation in terms of density (TFN) may be owing to the pollution caused by iron ore tailing. This study also supports the view that benthic foraminiferal biota can be used as a tool to monitor marine pollution in general and estuarine environment in specific.
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.
基金Item Sponsored by National Natural Science Foundation of China (50974012)National High Technology Research and Development Program of China (2006AA06Z125)
文摘The relationship of time to minerals composition in sinters is investigated by mineragraphy are claritied observation and component analysis, and the effects of temperature and atmosphere on mineralization process. Results are obtained as follows. The initial melt forms below the eutectic temperature of CaO·Fe2O3 and CaO·2Fe2O3, which is complex substance containing Ca, Fe, Si and Al, rather than the binary calcium ferrite melt. Minerals composition of binding phase is related to local content of silica in melt, which is influenced by temperature. Appearance of the melt promotes the transition from hematite to magnetite, which then alters the mechanism of calcium ferrite formation. Before the formation of magnetite, the contents of Fe and Ca within the multiple calcium ferrite decrease with temperature, but in the case of magnetite presence, the content of Fe increases solely with increase of temperature and decrease of oxygen potential. Temperature and atmosphere determine minerals composition together, and bring influence on sintering process in different ways. It can be deduced that temperature affects kinetics of the mineralization process, but atmosphere just plays a role in thermodynamics.
基金Item Sponsored by National Natural Science Foundation of China(51174253)
文摘Cooling process of iron ore pellets in a circular cooler has great impacts on the pellet quality and systematic energy exploitation. However, multi-variables and non-visualization of this gray system is unfavorable to efficient production. Thus, the cooling process of iron ore pellets was optimized using mathematical model and data mining techniques. A mathematical model was established and validated by steady-state production data, and the results show that the calculated values coincide very well with the measured values. Based on the proposed model, effects of important process parameters on gas-pellet temperature profiles within the circular cooler were analyzed to better understand the entire cooling process. Two data mining techniques—Association Rules Induction and Clustering were also applied on the steady-state production data to obtain expertise operating rules and optimized targets. Finally, an optimized control strategy for the circular cooler was proposed and an operation guidance system was developed. The system could realize the visualization of thermal process at steady state and provide operation guidance to optimize the circular cooler.
文摘Selection of crusher required a great deal of design based on the mining plan and operation input.Selection of the best primary crusher from all of available primary crushers is a Multi-Criterion Decision Making(MCDM) problem. In this paper, the Analytical Hierarchy Process(AHP) method was used to selection of the best primary crusher for Golegohar Iron Mine in Iran. For this reason, gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impactor, hammer mill and feeder breaker crushers were considered as alternatives and capacity, feed size, product size, rock compressive strength, abrasion index and mobility of crusher were considered as criteria. As a result of our study, the gyratory crusher was offered as the best primary crusher for the studied mine.
基金The authors acknowledge financial support from the Key Project of National Natural Science Foundation of China(U1660206) and General Program of National Natural Science Foundation of China (51674002).
文摘The emission of dioxins from the iron ore sintering process is the largest emission source of dioxins, and the reduction in dioxin emission from the iron ore sintering process to the environment is increasingly important. Three approaches to control the emission of dioxins were reviewed: source control, process control, and terminal control. Among them, two terminal control technologies, activated carbon adsorption and selective reduction technology, were discussed in detail. Following a comparison of the reduction technologies, the terminal control method was indicated as the key technology to achieve good control of dioxins during the sintering process. For the technical characteristics of the sintering process and flue gas, multiple methods should be collectively considered, and the most suitable method may be addition of inhibitors + ultra-clean dust collection (electrostatic precipitation/bag filter) + desulphurization + selective catalytic reduction to sufficiently remove multiple pollutants, which provides a direction for the cooperative disposal of flue gas pollutants in future.
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.