cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.6152258
title: Evaluation of internal corrosion in a Brazilian iron ore slurry pipeline based on the characterization of scales and tubercles

description: Abstract The transport capacity of long-distance slurry pumping systems is directly related to the roughness of the pipe. In this context, corrosion plays an important role, especially when dealing with old pipes. Chemical, mineralogical and microstructural analyses were performed on materials removed from the internal surface of an iron ore slurry pipeline in order to access their composition and to check if they were a result of internal pipeline corrosion. This pipeline has been operating since 1977. It was found that the tubercles formed on the internal wall of the pipe presented botryoidal magnetite as their essential composition. As the amount of magnetite is very low in the transported slurry and magnetite with botryoidal morphology is not present in the processed iron ore, it was concluded that this magnetite is a result of a corrosion process occurring on the internal wall of the pipeline.
DOI: 10.6084/m9.figshare.6152012
title: Characterization of iron ore pellets by multimodal microscopy and image analysis

description: Abstract A correlative approach employing optical microscopy and scanning electron microscopy is proposed for the quantification of phases and pores in iron ore pellets. Combining mosaic images covering the full cross-sections of pellets, obtained with both techniques, it is possible to improve the discrimination of pores, quartz and silicates. First, the images must be carefully registered to show the exact same regions. The procedure for registration, discrimination and quantification was developed with Fiji open source software. A qualitative and quantitative analysis confirmed the advantages of the correlative method as compared to the individual techniques.
DOI: 10.6084/m9.figshare.6152012.v1
title: Characterization of iron ore pellets by multimodal microscopy and image analysis

description: Abstract A correlative approach employing optical microscopy and scanning electron microscopy is proposed for the quantification of phases and pores in iron ore pellets. Combining mosaic images covering the full cross-sections of pellets, obtained with both techniques, it is possible to improve the discrimination of pores, quartz and silicates. First, the images must be carefully registered to show the exact same regions. The procedure for registration, discrimination and quantification was developed with Fiji open source software. A qualitative and quantitative analysis confirmed the advantages of the correlative method as compared to the individual techniques.
DOI: 10.6084/m9.figshare.6152402
title: Evaluating the hot metal dephosphorization efficiency of different synthetic slags using phosphorus partition ratio, phosphate capacity and computational thermodynamics

description: Abstract Phosphate capability (CP) and phosphorus partition ratio (LP) are usually used to evaluate the thermodynamic efficiency of dephosphorization slags with different compositions in hot metal pretreatment. However, these parameters are only useful in equilibrium conditions, and they are not accurate when they are used to evaluate slag efficiency in industrial processes. The current study evaluated the hot metal dephosphorization efficiency of different synthetic slags in experimental tests at 1400ºC. This evaluation was made by using CP and LP, and by the computational thermodynamic software FactSage 6.4. This software allows to calculate the amount of liquid and solid present in the slag, which directly affects kinetic reactions. Therefore, even the computational thermodynamic software calculations are from considering the equilibrium, which in these cases can be used to explain the kinetic behavior of the processes. The obtained results allow concluding that CP and LP are valid, but only when they are used for equilibrium calculations; and that they should not be used to measure slag efficiency in industrial processes. A parameter named Dephosphorization Factor (FDeP) was developed based on data determined by computational thermodynamics. It was developed to be related to the dephosphorization efficiency. The results obtained in the current study allow to conclude that the initial synthetic slags, which presented higher CaO activity value, higher liquid quantity and FeO activity, will be the most efficient ones. And allow to conclude too, that the higher the factor, the greater the slag dephosphorization efficiency.
DOI: 10.6084/m9.figshare.6152402.v1
title: Evaluating the hot metal dephosphorization efficiency of different synthetic slags using phosphorus partition ratio, phosphate capacity and computational thermodynamics

description: Abstract Phosphate capability (CP) and phosphorus partition ratio (LP) are usually used to evaluate the thermodynamic efficiency of dephosphorization slags with different compositions in hot metal pretreatment. However, these parameters are only useful in equilibrium conditions, and they are not accurate when they are used to evaluate slag efficiency in industrial processes. The current study evaluated the hot metal dephosphorization efficiency of different synthetic slags in experimental tests at 1400ºC. This evaluation was made by using CP and LP, and by the computational thermodynamic software FactSage 6.4. This software allows to calculate the amount of liquid and solid present in the slag, which directly affects kinetic reactions. Therefore, even the computational thermodynamic software calculations are from considering the equilibrium, which in these cases can be used to explain the kinetic behavior of the processes. The obtained results allow concluding that CP and LP are valid, but only when they are used for equilibrium calculations; and that they should not be used to measure slag efficiency in industrial processes. A parameter named Dephosphorization Factor (FDeP) was developed based on data determined by computational thermodynamics. It was developed to be related to the dephosphorization efficiency. The results obtained in the current study allow to conclude that the initial synthetic slags, which presented higher CaO activity value, higher liquid quantity and FeO activity, will be the most efficient ones. And allow to conclude too, that the higher the factor, the greater the slag dephosphorization efficiency.
DOI: 10.6084/m9.figshare.6152204
title: Measurement uncertainty of plane-strain fracture toughness KIC testing by the Monte Carlo Method

description: Abstract The reliable determination of materials' mechanical properties is a fundamental factor for their application in engineering, and the estimation of the measurement uncertainty in testing laboratories has a direct impact on the interpretation of the results. Recent literature demonstrates that one of the most widely used methodologies for uncertainty estimation, the Guide to the Expression of Uncertainty in Measurement (GUM), has limitations, especially in cases where the mathematical model has a high degree of non-linearity. Furthermore, it makes approximations for the final probability distribution. In these cases, it is recommended that the measurement uncertainty is determined by the Monte Carlo Method (MCM), which considers the propagation of the distribution rather than the propagation of uncertainties. Thus, given the limitations of the GUM method and the importance of estimating the measurement uncertainty of mechanical tests, this work aims to implement the measurement uncertainty estimation for the plane-strain fracture toughness (KIC) test of metallic materials through the Monte Carlo Method. The results of the work confirm the importance of estimating the measurement uncertainty of fracture toughness tests.
DOI: 10.6084/m9.figshare.6152204.v1
title: Measurement uncertainty of plane-strain fracture toughness KIC testing by the Monte Carlo Method

description: Abstract The reliable determination of materials' mechanical properties is a fundamental factor for their application in engineering, and the estimation of the measurement uncertainty in testing laboratories has a direct impact on the interpretation of the results. Recent literature demonstrates that one of the most widely used methodologies for uncertainty estimation, the Guide to the Expression of Uncertainty in Measurement (GUM), has limitations, especially in cases where the mathematical model has a high degree of non-linearity. Furthermore, it makes approximations for the final probability distribution. In these cases, it is recommended that the measurement uncertainty is determined by the Monte Carlo Method (MCM), which considers the propagation of the distribution rather than the propagation of uncertainties. Thus, given the limitations of the GUM method and the importance of estimating the measurement uncertainty of mechanical tests, this work aims to implement the measurement uncertainty estimation for the plane-strain fracture toughness (KIC) test of metallic materials through the Monte Carlo Method. The results of the work confirm the importance of estimating the measurement uncertainty of fracture toughness tests.
DOI: 10.6084/m9.figshare.6152219
title: Assessment of viscosity calculation for calcium-silicate based slags using computational thermodynamics

description: Abstract This study focuses on the viscosity calculation of molten slags using computational thermodynamics. Different slag systems and their measured viscosities from different references were used and compared with those obtained through FactSage software. To calculate the viscosity of each slag the Viscosity module available in FactSage 6.4 was used. In order to perform the evaluation of computational thermodynamics in viscosity calculation, six different slag systems were presented, all of which were formed of calcium-silicate melts. In total, 162 slags, in temperatures ranges from 1423 K (1150 ºC) to 2089 K (1816 °C) were presented for all slag systems. The software showed a tendency to produce viscosity values lower than those found in the literature measured by an experimental method. The relative deviation between the measured and calculated viscosity values is in the range of 13.31 to 37.53% for evaluated systems. Considering all references and systems, the average deviation between measured and calculated viscosities is 23.61%, which, according to literature, is an acceptable value. The CaO-SiO2-Al2O3 and CaO-SiO2-FeO systems showed the best agreement between the experimental method and the method calculated through FactSage 6.4 with a very good fitting between viscosity values.
DOI: 10.6084/m9.figshare.6151472
title: Replacement of fluorspar in the desulfurization of hot metal

description: Abstract In the steel industry, lime is used as a desulfurizing agent and fluorspar as flux in the hot metal desulfurization process. However there are environmental concerns regarding the use of fluorspar, even when its harmful effects are not fully known. In order to reduce such risks and also to anticipate possible future restrictions, which could undermine the sustainability of steel production, it is proposed to replace the fluorspar for alternative materials in the composition of the desulfurizing lime based mixture. For this purpose new mixtures using aluminum dross, ilmenite, sodalite and ulexite were tested, comparing them with a reference mixture containing fluorspar. The impact of these mixtures on the refractories commonly used in hot metal pretreatment was also checked, since this is an important cost parameter for the steel industries. The laboratory tests showed ulexite as a feasible substitute since the lime (84.03%) - ulexite (10.97%) - graphite (5%) mixture presented the highest desulfurization ratio and low refractory wear (less than the standard fluorspar mixture). The sodalite mixture was the worst by comparison. The ilmenite and aluminum dross mixtures showed similar behavior when compared to the fluorspar mixture.
DOI: 10.6084/m9.figshare.6151472.v1
title: Replacement of fluorspar in the desulfurization of hot metal

description: Abstract In the steel industry, lime is used as a desulfurizing agent and fluorspar as flux in the hot metal desulfurization process. However there are environmental concerns regarding the use of fluorspar, even when its harmful effects are not fully known. In order to reduce such risks and also to anticipate possible future restrictions, which could undermine the sustainability of steel production, it is proposed to replace the fluorspar for alternative materials in the composition of the desulfurizing lime based mixture. For this purpose new mixtures using aluminum dross, ilmenite, sodalite and ulexite were tested, comparing them with a reference mixture containing fluorspar. The impact of these mixtures on the refractories commonly used in hot metal pretreatment was also checked, since this is an important cost parameter for the steel industries. The laboratory tests showed ulexite as a feasible substitute since the lime (84.03%) - ulexite (10.97%) - graphite (5%) mixture presented the highest desulfurization ratio and low refractory wear (less than the standard fluorspar mixture). The sodalite mixture was the worst by comparison. The ilmenite and aluminum dross mixtures showed similar behavior when compared to the fluorspar mixture.
DOI: 10.6084/m9.figshare.6152372
title: The use of RPAS - Remotely Piloted Aircraft Systems in the topographic mapping for mining

description: Abstract In the light of the technological transformations that have been occurring in the field of Remote Sensing, the objective of this study was to evaluate the feasibility and the quality of the results that could be achieved in the topographic modeling of the terrain with a Remotely Piloted Aircraft Systems (RPAS) survey in open-pit mines. The mining activity imposes the recurring topographic survey of mined and service areas that require volume evaluation in an interval of at least one month. In this context, the expectation of adopting traditional remote sensing methods for surveying, instead of land surveys, has always been great. The restrictions on the adoption of the conventional photogrammetric or airborne laser scanning (ALS) methods were related to the need for recurring surveys, which are never simple with the use of manned aerial platforms. In this context, the RPAS opens a window of opportunity that should not be ignored, being the main reason for the case study reported here. The essential data set of the research results from the direct confrontation between two digital terrain models: the first obtained with the RPAS survey executed in 2016 and another one of the same area obtained by a laser aerial survey performed in 2012, which was considered as a quality benchmark. The results recommended that the implementation of mapping solutions with RPAS consider the quality constraints of the photogrammetry in order to improve final results with the theoretical and operational knowledge that underpin the photogrammetric process.
DOI: 10.6084/m9.figshare.6152372.v1
title: The use of RPAS - Remotely Piloted Aircraft Systems in the topographic mapping for mining

description: Abstract In the light of the technological transformations that have been occurring in the field of Remote Sensing, the objective of this study was to evaluate the feasibility and the quality of the results that could be achieved in the topographic modeling of the terrain with a Remotely Piloted Aircraft Systems (RPAS) survey in open-pit mines. The mining activity imposes the recurring topographic survey of mined and service areas that require volume evaluation in an interval of at least one month. In this context, the expectation of adopting traditional remote sensing methods for surveying, instead of land surveys, has always been great. The restrictions on the adoption of the conventional photogrammetric or airborne laser scanning (ALS) methods were related to the need for recurring surveys, which are never simple with the use of manned aerial platforms. In this context, the RPAS opens a window of opportunity that should not be ignored, being the main reason for the case study reported here. The essential data set of the research results from the direct confrontation between two digital terrain models: the first obtained with the RPAS survey executed in 2016 and another one of the same area obtained by a laser aerial survey performed in 2012, which was considered as a quality benchmark. The results recommended that the implementation of mapping solutions with RPAS consider the quality constraints of the photogrammetry in order to improve final results with the theoretical and operational knowledge that underpin the photogrammetric process.
DOI: 10.6084/m9.figshare.6151463
title: Comparison between the application of the conventional mine planning and of the direct block scheduling on an open pit mine Project

description: Abstract Historically, since the 60's, traditional mine planning consists of several distinct stages: 1) Definition of the ultimate pit - the portion of the blocks that results in the greatest total value; 2) Pushback selection - based on the generation of nested pits, obtained with the change in the value of the ore price; 3) Long-term production scheduling. Although considered quite satisfactory, this methodology presents some flaws: The stages, even if considered individually optimal, may not be when put together. The opportunity cost is not considered and the cut-off is fixed. Due to the recent computational advances, a new technique has been growing and is more reliable: the direct block sequencing. In this methodology, the steps are consolidated into only one process, improving the economic results, reducing the total execution time and obtaining, in fact, an optimal planning. The aim of this work is to compare the results of the two planning methods applied in a database of a Brazilian iron ore mine and to show the real advantages and disadvantages of each one. To solve the direct block sequencing technique, Doppler was used, a tool developed by Delphos Mine Planning Laboratory, located at the University of Chile. The traditional methodology was executed through Whittle software. Lastly, a medium-term scheduling was performed using Deswik software.
DOI: 10.6084/m9.figshare.6151463.v1
title: Comparison between the application of the conventional mine planning and of the direct block scheduling on an open pit mine Project

description: Abstract Historically, since the 60's, traditional mine planning consists of several distinct stages: 1) Definition of the ultimate pit - the portion of the blocks that results in the greatest total value; 2) Pushback selection - based on the generation of nested pits, obtained with the change in the value of the ore price; 3) Long-term production scheduling. Although considered quite satisfactory, this methodology presents some flaws: The stages, even if considered individually optimal, may not be when put together. The opportunity cost is not considered and the cut-off is fixed. Due to the recent computational advances, a new technique has been growing and is more reliable: the direct block sequencing. In this methodology, the steps are consolidated into only one process, improving the economic results, reducing the total execution time and obtaining, in fact, an optimal planning. The aim of this work is to compare the results of the two planning methods applied in a database of a Brazilian iron ore mine and to show the real advantages and disadvantages of each one. To solve the direct block sequencing technique, Doppler was used, a tool developed by Delphos Mine Planning Laboratory, located at the University of Chile. The traditional methodology was executed through Whittle software. Lastly, a medium-term scheduling was performed using Deswik software.
DOI: 10.6084/m9.figshare.6152036
title: Simultaneous use of direct and reverse flotation in the production of iron ore concentrate plant

description: Abstract The exploitation of low-grade iron ore deposits represents the current scenario for this business. Thus arise several types of research that aim at improvements and innovations as solutions to such situation. Therefore, herein, suggested is an alternative route for iron ore flotation that targets a higher mass recovery with concentrate within the market specification. First, the sample was deslimed at 38 µm and with the underflow a cut was performed in the 74 µm cyclone in order to separate the coarse particles from the fine. With the coarse particles, i.e. with the underflow, there a reverse flotation was carried on obtaining a concentrate with 67.7% of Fe and 0.9% of SiO2. In the fine particle overflow, direct flotation was done, generating a low-quality concentrate with 40.9% of Fe and 39.7% of SiO2. The mass recovery in direct flotation was 88% and in the reverse flotation was 61.1%. The concentrate generated from two flotations had a mass recovery of 67.4% with a content of Fe of 53.4% and 21.6% SiO2.
DOI: 10.6084/m9.figshare.6152036.v1
title: Simultaneous use of direct and reverse flotation in the production of iron ore concentrate plant

description: Abstract The exploitation of low-grade iron ore deposits represents the current scenario for this business. Thus arise several types of research that aim at improvements and innovations as solutions to such situation. Therefore, herein, suggested is an alternative route for iron ore flotation that targets a higher mass recovery with concentrate within the market specification. First, the sample was deslimed at 38 µm and with the underflow a cut was performed in the 74 µm cyclone in order to separate the coarse particles from the fine. With the coarse particles, i.e. with the underflow, there a reverse flotation was carried on obtaining a concentrate with 67.7% of Fe and 0.9% of SiO2. In the fine particle overflow, direct flotation was done, generating a low-quality concentrate with 40.9% of Fe and 39.7% of SiO2. The mass recovery in direct flotation was 88% and in the reverse flotation was 61.1%. The concentrate generated from two flotations had a mass recovery of 67.4% with a content of Fe of 53.4% and 21.6% SiO2.
DOI: 10.6084/m9.figshare.6152003
title: Classical and stochastic mine planning techniques, state of the art and trends

description: Abstract Determination of the best possible ultimate pit for an open pit mine is a fundamental subject that has undergone a highly evolutionary process, reviewed in this study, since the correct choice carries substantial economic impact for the industry. The correct choice can be very beneficial for project analysis, whereas an incorrect choice has the potential to mask huge financial and economic future losses that could render a project unfeasible. The advent of computers in the 1960s allowed sophisticated analysis for the selection of the best ultimate pit determination, under specific modifying factors such as economic, social, environmental, and political, but only in deterministic situations, i.e., when the problem and variables for the ultimate pit determinations were considered deterministically and almost always based on average values. Techniques such as the Lerchs-Grossman algorithm and mixed-integer programming are among many standard tools now used by the mineral industry. Geological uncertainty and the associated risks as well as the need to consider the appropriate time to mine a block during a mine operation have a significant impact on the net present value of the resulting ultimate pits. Stochastic aspects embed a probabilistic component that varies in time and are now under intense investigation by researchers, who are creating algorithms that can be experimented with and tested in real mine situations. One can expect that once these algorithms demonstrate their efficiency and superior results, they will readily dominate the industry.