Dry coal cleaning has generated renewed interest in scientific and coal mining communities alike due to water scarcity in many parts of the world and the numerous tailings ponds that have resulted from traditional wet coal preparation methods. Commercially available dry separation technologies such as air tables and air jigs are mostly effective in cleaning coarse coal with particle size larger than 6.35 mm. The smaller-than-6.35 mm fraction, which might be up to 20 to 40 percent of raw coal, is sent to the clean coal or tailings streams in a dry separation plant without any cleaning. The main objective of this study is to develop, design and fabricate a new density-based dry separator to effectively clean fine coal in the size range of smaller than 6.35 mm to larger than 1 mm.A difficult-to-clean coal sample with particle size smaller than 6.35 mm and flat-shaped shales as main rocks were used in this study. Using a laboratory-scale fluidization bed, the optimum air flow rate for fluidization of fine particles in air tables was found, which was much less than that for coarse coal. The perforations diameter and open area of the separating deck of the air table were also found to be critical for fine particle separation. These findings led to the development of a new air table named SIU Airtable for cleaning fine coal sized smaller than 6.35 mm and larger than 1 mm. The new air table has a unique air distribution and fluidization system for fine particles, along with adjustable vibration frequency and direction. It also has an optional extended section to lower the moisture content of high-moisture fine coal using part of the fluidization air. The experiments showed that an ash rejection of about 49 percent could be achieved with a combustible recovery of around 89 percent, indicating suitable separation. Furthermore, increasing ash rejection to 70 percent gives a combustible recovery of 72 percent, indicating that the separation performance of the new air table is close to the fine coal washability data.
{"title":"Development of a new fine particle dry separator","authors":"H. Akbari, Louis Ackah, M. Mohanty","doi":"10.19150/MMP.8289","DOIUrl":"https://doi.org/10.19150/MMP.8289","url":null,"abstract":"Dry coal cleaning has generated renewed interest in scientific and coal mining communities alike due to water scarcity in many parts of the world and the numerous tailings ponds that have resulted from traditional wet coal preparation methods. Commercially available dry separation technologies such as air tables and air jigs are mostly effective in cleaning coarse coal with particle size larger than 6.35 mm. The smaller-than-6.35 mm fraction, which might be up to 20 to 40 percent of raw coal, is sent to the clean coal or tailings streams in a dry separation plant without any cleaning. The main objective of this study is to develop, design and fabricate a new density-based dry separator to effectively clean fine coal in the size range of smaller than 6.35 mm to larger than 1 mm.A difficult-to-clean coal sample with particle size smaller than 6.35 mm and flat-shaped shales as main rocks were used in this study. Using a laboratory-scale fluidization bed, the optimum air flow rate for fluidization of fine particles in air tables was found, which was much less than that for coarse coal. The perforations diameter and open area of the separating deck of the air table were also found to be critical for fine particle separation. These findings led to the development of a new air table named SIU Airtable for cleaning fine coal sized smaller than 6.35 mm and larger than 1 mm. The new air table has a unique air distribution and fluidization system for fine particles, along with adjustable vibration frequency and direction. It also has an optional extended section to lower the moisture content of high-moisture fine coal using part of the fluidization air. The experiments showed that an ash rejection of about 49 percent could be achieved with a combustible recovery of around 89 percent, indicating suitable separation. Furthermore, increasing ash rejection to 70 percent gives a combustible recovery of 72 percent, indicating that the separation performance of the new air table is close to the fine coal washability data.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"77-86"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8289","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42128979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The modeling and simulation of semiautogenous (SAG) mills have been widely used in the design and optimization of mill performance in terms of its power draw, processing capacity and product size distribution. However, these models are solved under steady approximation and do not provide any information on mill charge distribution in real time. This paper attempts to characterize mill contents by solving Whiten’s first-order content-based model in the MATLAB/Simulink environment. The parameters in the model, such as breakage rate constant, discharge rate and appearance function, were estimated using process and design data collected from a gold mine operating in Alaska coupled with a nonlinear parameter estimation scheme. This model was then used to predict the dynamic responses of other key operational variables, such as mill power, bearing pressure, charge level and product size distribution. The transient response of mill behavior with respect to changes in feed size distribution, tonnage and mill feed water is also presented. This dynamic simulation approach can be used for practicing different control strategy and training purposes. The observed response of mentioned variables was validated using dynamic response data from the plant to encompass operational characteristics of SAG mill behavior.
{"title":"Dynamic modeling and simulation of a SAG mill for mill charge characterization","authors":"V. Srivastava, G. Akdogan, T. Ghosh, R. Ganguli","doi":"10.19150/MMP.8287","DOIUrl":"https://doi.org/10.19150/MMP.8287","url":null,"abstract":"The modeling and simulation of semiautogenous (SAG) mills have been widely used in the design and optimization of mill performance in terms of its power draw, processing capacity and product size distribution. However, these models are solved under steady approximation and do not provide any information on mill charge distribution in real time. This paper attempts to characterize mill contents by solving Whiten’s first-order content-based model in the MATLAB/Simulink environment. The parameters in the model, such as breakage rate constant, discharge rate and appearance function, were estimated using process and design data collected from a gold mine operating in Alaska coupled with a nonlinear parameter estimation scheme. This model was then used to predict the dynamic responses of other key operational variables, such as mill power, bearing pressure, charge level and product size distribution. The transient response of mill behavior with respect to changes in feed size distribution, tonnage and mill feed water is also presented. This dynamic simulation approach can be used for practicing different control strategy and training purposes. The observed response of mentioned variables was validated using dynamic response data from the plant to encompass operational characteristics of SAG mill behavior.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"61-68"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8287","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45607197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nano clay mineral particles such as kaolinite — with primary particles typically smaller than 2 µm in size — can cause significant problems in flotation processes and tailings disposal, including the processing of Florida phosphate rock and Canadian oil sands. In this study, the consolidated state of flocculated kaolinite sediment was examined, and high-resolution X-ray microtomography (HRXMT) was applied to describe the structure of the consolidated sediment. Using this tomographic information, the complex geometry of the channel network structure for the consolidated flocs was established for the first time. With the establishment of the experimental channel network structure, permeabilities were estimated by flow simulation using the Lattice Boltzmann method. Results for kaolinite sediment with and without polymer are compared and discussed.Results for flocculated kaolinite sediment in a gravitational field are also presented and discussed. The results show that as polymer dosage increases, the permeability of flocculated kaolinite sediment increases, and as suspension pH increases, the permeability of flocculated kaolinite sediment decreases.
{"title":"Simulated permeability of flocculated kaolinite sediments from X-ray tomographic images","authors":"J. Dong, C. L. Lin, J. D. Miller","doi":"10.19150/MMP.8053","DOIUrl":"https://doi.org/10.19150/MMP.8053","url":null,"abstract":"Nano clay mineral particles such as kaolinite — with primary particles typically smaller than 2 µm in size — can cause significant problems in flotation processes and tailings disposal, including the processing of Florida phosphate rock and Canadian oil sands. In this study, the consolidated state of flocculated kaolinite sediment was examined, and high-resolution X-ray microtomography (HRXMT) was applied to describe the structure of the consolidated sediment. Using this tomographic information, the complex geometry of the channel network structure for the consolidated flocs was established for the first time. With the establishment of the experimental channel network structure, permeabilities were estimated by flow simulation using the Lattice Boltzmann method. Results for kaolinite sediment with and without polymer are compared and discussed.Results for flocculated kaolinite sediment in a gravitational field are also presented and discussed. The results show that as polymer dosage increases, the permeability of flocculated kaolinite sediment increases, and as suspension pH increases, the permeability of flocculated kaolinite sediment decreases.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"13-18"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43990265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In flotation practices, as particles become finer, such as smaller than 20 µm, process efficiency declines markedly. Selective agglomeration of fine particles is a technique to enhance the recovery of fine valuable minerals in flotation circuits. Different agglomerating methods have been introduced and tested. One method that has recently received much attention is to make use of magnetic force to aggregate fine particles. A selective aggregation of fine paramagnetic particles, such as sulfide minerals, can be achieved in the high-intensity magnetic field prior to or during flotation. The method is simple, selective and effective for fine particles and has low operational cost, though a minimum magnetic susceptibility for fine grains is required to promote the process.In this paper, the implementation of the ProFlote magnetic conditioning device in Boliden’s Garpenberg old concentrator in Sweden, where a complex massive sulfide ore is treated, is presented and discussed based on Boliden’s Garpenberg plant. The results showed an increase in the flotation recovery of fine valuable minerals. Zinc (Zn) production was increased by between 1,100 and 1,500 t/a, while salable yearly silver (Ag) production was increased by 1,500 kg. The copper (Cu) grade in the final concentrate was increased by 1 percent, while reductions in its Zn and lead (Pb) grades were obtained. Moreover, considerable reduction in Zn deportment to the final tail was observed.
{"title":"Magnetic conditioning of sulfide minerals to improve recovery of fines in flotation — a plant practice","authors":"H. Manouchehri","doi":"10.19150/MMP.8057","DOIUrl":"https://doi.org/10.19150/MMP.8057","url":null,"abstract":"In flotation practices, as particles become finer, such as smaller than 20 µm, process efficiency declines markedly. Selective agglomeration of fine particles is a technique to enhance the recovery of fine valuable minerals in flotation circuits. Different agglomerating methods have been introduced and tested. One method that has recently received much attention is to make use of magnetic force to aggregate fine particles. A selective aggregation of fine paramagnetic particles, such as sulfide minerals, can be achieved in the high-intensity magnetic field prior to or during flotation. The method is simple, selective and effective for fine particles and has low operational cost, though a minimum magnetic susceptibility for fine grains is required to promote the process.In this paper, the implementation of the ProFlote magnetic conditioning device in Boliden’s Garpenberg old concentrator in Sweden, where a complex massive sulfide ore is treated, is presented and discussed based on Boliden’s Garpenberg plant. The results showed an increase in the flotation recovery of fine valuable minerals. Zinc (Zn) production was increased by between 1,100 and 1,500 t/a, while salable yearly silver (Ag) production was increased by 1,500 kg. The copper (Cu) grade in the final concentrate was increased by 1 percent, while reductions in its Zn and lead (Pb) grades were obtained. Moreover, considerable reduction in Zn deportment to the final tail was observed.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"46-54"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48495981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-grade iron ore received from the West Singhbhum area of Jharkhand state in India was used to develop a beneficiation flow sheet to remove alumina (Al2O3) and silica (SiO2) from the ore to get iron (Fe)-rich product for steel plants. Mineral characterization showed that the main mineral constituents present in the head sample are goethite, limonite, hematite, quartz, clay and gibbsite. The head sample contained about 49.2 percent Fe, 8.79 percent alumina and 12.01 percent silica. The received iron ore sample is amenable to upgradation through beneficiation to get pellet grade concentrate. The beneficiation process was established, involving crushing, screening, jigging, spiral separation, size reduction, desliming and magnetic separation. The process showed significant enrichment in Fe values to 63.5 percent Fe in concentrate, from 49.2 percent Fe. From the developed flow sheet, it is possible to obtain pellet grade fines with 63.5 percent Fe, 2.92 percent SiO2 and 2.61 percent Al2O3 with 50.6 percent weight recovery. The overall tailing loss is 49.4 percent with 34.3 percent Fe, 21.28 percent SiO2 and 14.64 percent Al2O3.
{"title":"Development of process for beneficiation of low-grade iron ore consisting of goethite","authors":"T. Umadevi, K. Abhishek, R. Sah, K. Marutiram","doi":"10.19150/MMP.8056","DOIUrl":"https://doi.org/10.19150/MMP.8056","url":null,"abstract":"Low-grade iron ore received from the West Singhbhum area of Jharkhand state in India was used to develop a beneficiation flow sheet to remove alumina (Al2O3) and silica (SiO2) from the ore to get iron (Fe)-rich product for steel plants. Mineral characterization showed that the main mineral constituents present in the head sample are goethite, limonite, hematite, quartz, clay and gibbsite. The head sample contained about 49.2 percent Fe, 8.79 percent alumina and 12.01 percent silica. The received iron ore sample is amenable to upgradation through beneficiation to get pellet grade concentrate. The beneficiation process was established, involving crushing, screening, jigging, spiral separation, size reduction, desliming and magnetic separation. The process showed significant enrichment in Fe values to 63.5 percent Fe in concentrate, from 49.2 percent Fe. From the developed flow sheet, it is possible to obtain pellet grade fines with 63.5 percent Fe, 2.92 percent SiO2 and 2.61 percent Al2O3 with 50.6 percent weight recovery. The overall tailing loss is 49.4 percent with 34.3 percent Fe, 21.28 percent SiO2 and 14.64 percent Al2O3.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"35-45"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45490638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Acosta-Flores, F. Lucay, L. Cisternas, E. Gálvez
Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each of the structures obtained in the previous phase is determined using a suitable model for the recovery at each cell or bank, which results in a mixed integer nonlinear programming (MINLP) model. The design of a copper concentration plant with eight species and the design of a zinc concentration plant with three species and five size fractions by species are used to validate the proposed methodology. The structure of the cells in the rougher and cleaner banks deliver structures that are novel.
{"title":"Two-phase optimization methodology for the design of mineral flotation plants, including multispecies and bank or cell models","authors":"R. Acosta-Flores, F. Lucay, L. Cisternas, E. Gálvez","doi":"10.19150/MMP.8055","DOIUrl":"https://doi.org/10.19150/MMP.8055","url":null,"abstract":"Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each of the structures obtained in the previous phase is determined using a suitable model for the recovery at each cell or bank, which results in a mixed integer nonlinear programming (MINLP) model. The design of a copper concentration plant with eight species and the design of a zinc concentration plant with three species and five size fractions by species are used to validate the proposed methodology. The structure of the cells in the rougher and cleaner banks deliver structures that are novel.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"24-34"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45504557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the results of an investigation into the influence of hydrodynamics on a preflotation process for the copper sulfide ore from the Fore-Sudetic Monocline deposits in Poland in a flotation machine. The main aim of the preflotation stage for Polish copper ore is to remove the easy-to-float organic matter — organic carbon — that causes serious problems in metallurgical processes. The organic matter is connected with the presence of shale ore. This paper describes the preflotation experiments conducted to investigate the effect of various stirrer speeds. The upgrading selectivity of copper and organic carbon were analyzed and compared. The results show that the effectiveness of separation between organic carbon and copper decreases with increased stirrer speed in the laboratory flotation machine. The more intensive the mixing of the flotation suspension, the lower the selectivity of the preflotation experiment. Lower stirrer speed probably provides lower mechanical entrainment and flotation of copper minerals.
{"title":"Influence of hydrodynamics on preflotation process in flotation machine","authors":"A. Bakalarz, M. Duchnowska, W. Pawlos","doi":"10.19150/MMP.8054","DOIUrl":"https://doi.org/10.19150/MMP.8054","url":null,"abstract":"This paper presents the results of an investigation into the influence of hydrodynamics on a preflotation process for the copper sulfide ore from the Fore-Sudetic Monocline deposits in Poland in a flotation machine. The main aim of the preflotation stage for Polish copper ore is to remove the easy-to-float organic matter — organic carbon — that causes serious problems in metallurgical processes. The organic matter is connected with the presence of shale ore. This paper describes the preflotation experiments conducted to investigate the effect of various stirrer speeds. The upgrading selectivity of copper and organic carbon were analyzed and compared. The results show that the effectiveness of separation between organic carbon and copper decreases with increased stirrer speed in the laboratory flotation machine. The more intensive the mixing of the flotation suspension, the lower the selectivity of the preflotation experiment. Lower stirrer speed probably provides lower mechanical entrainment and flotation of copper minerals.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"19-23"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8054","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49388182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
From mine to mill, the 3D characterization of particles ranging in size from meters to micrometers is now possible. A brief review of X-ray tomography for mineral processing is given with recent advances considered, such as high-speed scanning and image analysis procedures to describe important particle properties, including size, shape and composition.Considering these new 3D characterization tools, applications in mineral processing are discussed for high-resolution X-ray microtomography (HRXMT) laboratory analysis of particles ranging from 20 mm to 5 µm, with a voxel resolution of about 1 µm, including (1) multiphase particle characterization by HRXMT and comparison with scanning electron microscopy (SEM), (2) particle damage state as a result of blasting/comminution, (3) liberation characterization to describe expected separation efficiency, (4) exposed grain surface area analysis to explain the flotation of locked particles, and (5) floc size, shape and water content for polymer-induced flocculation.Finally, applications in mineral processing for plant-site analysis using high-speed X-ray computed tomography (HSXCT) are examined, including, for example, coal washability analysis, the analysis of crusher plant products, and the analysis of pebble phosphate products from central Florida. Scanning rates on the order of 1 kg/min for particle sizes ranging from 150 mm to 1 mm are possible, with a voxel resolution of about 100 µm. For coarse particles smaller than 5 to 10 mm, high scanning rates of more than 300 t/h may be possible at a voxel resolution of about 1 mm.
{"title":"X-ray tomography for mineral processing technology - 3D particle characterization from mine to mill","authors":"J. D. Miller, C. L. Lin","doi":"10.19150/MMP.8052","DOIUrl":"https://doi.org/10.19150/MMP.8052","url":null,"abstract":"From mine to mill, the 3D characterization of particles ranging in size from meters to micrometers is now possible. A brief review of X-ray tomography for mineral processing is given with recent advances considered, such as high-speed scanning and image analysis procedures to describe important particle properties, including size, shape and composition.Considering these new 3D characterization tools, applications in mineral processing are discussed for high-resolution X-ray microtomography (HRXMT) laboratory analysis of particles ranging from 20 mm to 5 µm, with a voxel resolution of about 1 µm, including (1) multiphase particle characterization by HRXMT and comparison with scanning electron microscopy (SEM), (2) particle damage state as a result of blasting/comminution, (3) liberation characterization to describe expected separation efficiency, (4) exposed grain surface area analysis to explain the flotation of locked particles, and (5) floc size, shape and water content for polymer-induced flocculation.Finally, applications in mineral processing for plant-site analysis using high-speed X-ray computed tomography (HSXCT) are examined, including, for example, coal washability analysis, the analysis of crusher plant products, and the analysis of pebble phosphate products from central Florida. Scanning rates on the order of 1 kg/min for particle sizes ranging from 150 mm to 1 mm are possible, with a voxel resolution of about 100 µm. For coarse particles smaller than 5 to 10 mm, high scanning rates of more than 300 t/h may be possible at a voxel resolution of about 1 mm.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"35 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.8052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44282540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and fine in size, with more than 50 percent having particle size smaller than 2 µm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.
{"title":"The ultimate mineral processing challenge: Recovery of rare earths, phosphorus and uranium from Florida phosphatic clay","authors":"P. Zhang, H. Liang, Z. Jin, D. DePaoli","doi":"10.19150/MMP.7858","DOIUrl":"https://doi.org/10.19150/MMP.7858","url":null,"abstract":"Phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and fine in size, with more than 50 percent having particle size smaller than 2 µm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.","PeriodicalId":18536,"journal":{"name":"Minerals & Metallurgical Processing","volume":"34 1","pages":"183-188"},"PeriodicalIF":0.0,"publicationDate":"2017-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.19150/MMP.7858","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45439183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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