The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as th...The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as the collector has been investigated. The results show that the selectivity of these collectors for these three calcareous minerals falls in the order： DDDAC 〉 DDBAC 〉 DTAC. A significantly different flotation response of scheelite compared to the other two calcareous minerals was observed over the pH range from 7 to 8 for DDDAC as the collector. A concentrate containing 41.40% W03 could be produced from a feed mixture containing 23.22% WO3 at the DDDAC concentration of 4.0× 10^-4 mol/L. The WO3 recovery was 92.92% under these conditions. The results of zeta potential measurements suggest that electrostatic interactions are the main forces between DDDAC and the minerals. When the concentration of DDDAC is from 2× 10^-4 to 4×10-3 mol/L large differences in adsorption density, and adsorption kinetics, of DDDAC onto scheelite, calcite, and fluorite provide desirable conditions for achieving high selectivity.展开更多
Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network charac...Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network characteristics of topsoil,weathered,and semiweathered layers of ionic rare earth ore in southern Jiangxi Province were explored in this study.The effect of leaching operation on the pore structure was investigated,and main factors affecting the seepage were analyzed.Results showed that the semiweathered layer presents a dense structure and a small number of unconnected pores.Pores of topsoil and weathered layers are mainly long and narrow column openings with some planar fractures.Even pore distribution and large size span were observed.Compared with the weathered layer,the topsoil layer demonstrates larger voids,smaller average pore volume and equivalent radius,and fewer coordination throats;however,the average equivalent radius of the throat in the topsoil layer is larger and largescale channels exist through ore body vertically.Hence,permeability of the topsoil layer is significantly higher than that of the weathered layer.Colloidal clay minerals migrate easily and the occurrence of silting in the small porosity blocks the throat and significantly decreases the permeability of the ore body in the leaching process.The equivalent radius of the throat is the key to the seepage.Reducing the migration of fine particles is an effective measure to protect the throat and shorten the leaching period.展开更多
Under the background of increasingly scarce ore worldwide and increasingly fierce market competition,developing the mining industry could be strongly restricted.Intelligent ore sorting equipment not only improves ore ...Under the background of increasingly scarce ore worldwide and increasingly fierce market competition,developing the mining industry could be strongly restricted.Intelligent ore sorting equipment not only improves ore use and enhances the economic benefits of enterprises but also increases the ore grade and lessens the grinding cost and tailings production.However,long-term research on intelligent ore sorting equipment found that the factors affecting sorting efficiency mainly include ore information identification technology,equipment sorting actuator,and information processing algorithm.The high precision,strong anti-interference capability,and high speed of these factors guarantee the separation efficiency of intelligent ore sorting equipment.Color ore sorter,X-ray ore transmission sorter,dual-energy X-ray transmission ore sorter,X-ray fluorescence ore sorter,and near-infrared ore sorter have been successfully developed in accordance with the different characteristics of minerals while ensuring the accuracy of equipment sorting and improving the equipment sorting efficiency.With the continuous improvement of mine automation level,the application of online element rapid analysis technology with high speed,high precision,and strong anti-interference capability in intelligent ore sorting equipment will become an inevitable trend of equipment development in the future.Laser-induced breakdown spectroscopy,transientγneutron activation analysis,online Fourier transform infrared spectroscopy,and nuclear magnetic resonance techniques will promote the development of ore sorting equipment.In addition,the improvement and joint application of additional high-speed and high-precision operation algorithms(such as peak area,principal component analysis,artificial neural network,partial least squares,and Monte Carlo library least squares methods)are an essential part of the development of intelligent ore sorting equipment in the future.展开更多
In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no sign...In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no significant effect on soil physical properties but a significantly negative impact on soil chemical properties. The results of high-throughput sequencing demonstrate that exogenous yttrium significantly decreases the number of OTUs, ACE, Chao 1, and Shannon indices while increases the Simpson index（P 〈 0.05）, indicating the low soil microbial diversity. The relative abundances of soil microbes are significantly changed at phylum and genus level. Principal component analysis（PCA） showed the significant difference of microbial community between yttrium treatments（YCl_3-250 and YCl_3-500） and non-yttrium treatment（CK） and the similarity of that between YCl_3-250 and YCI_3-500. Proteobacteria and Bacteroidetes are found to be the most tolerant phyla to exogenous yttrium while Verrucomicrobia the most sensitive phylum. Redundancy analysis（RDA） results suggest that exogenous yttrium affects soil microbiota only through changing the soil chemical properties but not soil physical properties, and C/N ratio is the key environmental factor.展开更多
The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigat...The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigated by means of solution chemistry, ultraviolet spectrophotometry(UV), inductively coupled plasma atomic emission spectrometry(ICP-AES) and X-ray photoelectron spectroscopy(XPS). It is observed that dolomite with different size fractions has depressing effect on hematite flotation using sodium oleate as collector, and dolomite could be the "mineral depressant" of hematite using sodium oleate as collector. The reasons for that are concerned with sodium oleate consumption and the adsorption onto hematite of dissolved species of dolomite.展开更多
The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ...The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)calculations.The X-ray photoelectric spectroscopy(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption mechanisms.First,the oxygen content in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and galena.Then,sulfite ions were chelated with lead ions to form PbSO_(3)in solution.The hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than galena.The interaction between sulfite ions and lead ions could effectively inhibit the activation of sphalerite.In addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of perxanthate.However,sulfite ions hardly depressed the flotation of ga lena and could promote the flotation of galena to some extent.This study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.展开更多
Mn and Li were selectively extracted from the manganese-rich slag by sulfation roasting−water leaching.The extraction mechanisms of Mn and Li were investigated by means of XRD,TG−DSC,and SEM−EDS.73.71%Mn and 73.28%Li ...Mn and Li were selectively extracted from the manganese-rich slag by sulfation roasting−water leaching.The extraction mechanisms of Mn and Li were investigated by means of XRD,TG−DSC,and SEM−EDS.73.71%Mn and 73.28%Li were leached under optimal experimental conditions:acid concentration of 82 wt.%,acid-to-slag mass ratio of 1.5:1,roasting temperature of 800°C,and roasting time of 2 h.During the roasting process,the manganese-rich slag first reacted with concentrated sulfuric acid,producing MnSO_(4),MnSO_(4)·H_(2)O,Li_(2)Mg(SO_(4))_(2),Al_(2)(SO_(4))_(3),and H_(4)SiO_(4).With the roasting temperature increasing,H_(4)SiO_(4) and Al_(2)(SO_(4))_(3) decomposed successively,resulting in generation of mullite and spinel.The mullite formation aided in decreasing the leaching efficiencies of Al and Si,while increasing the Li leaching efficiency.The formation of spinel,however,decreased the leaching efficiencies of Mn and Li.展开更多
Slurry electrolysis(SE),as a hydrometallurgical process,has the characteristic of a multitank series connection,which leads to various stirring conditions and a complex solid suspension state.The computational fluid d...Slurry electrolysis(SE),as a hydrometallurgical process,has the characteristic of a multitank series connection,which leads to various stirring conditions and a complex solid suspension state.The computational fluid dynamics(CFD),which requires high computing resources,and a combination with machine learning was proposed to construct a rapid prediction model for the liquid flow and solid concentration fields in a SE tank.Through scientific selection of calculation samples via orthogonal experiments,a comprehensive dataset covering a wide range of conditions was established while effectively reducing the number of simulations and providing reasonable weights for each factor.Then,a prediction model of the SE tank was constructed using the K-nearest neighbor algorithm.The results show that with the increase in levels of orthogonal experiments,the prediction accuracy of the model improved remarkably.The model established with four factors and nine levels can accurately predict the flow and concentration fields,and the regression coefficients of average velocity and solid concentration were 0.926 and 0.937,respectively.Compared with traditional CFD,the response time of field information prediction in this model was reduced from 75 h to 20 s,which solves the problem of serious lag in CFD applied alone to actual production and meets real-time production control requirements.展开更多
Several special mechanical properties,such as dilatancy and compressibility,of cemented paste backfill(CPB)are controlled by its internal microstructure and evolution.The mesoscopic structure changes of CPB during the...Several special mechanical properties,such as dilatancy and compressibility,of cemented paste backfill(CPB)are controlled by its internal microstructure and evolution.The mesoscopic structure changes of CPB during the development process were investigated.On the basis of the scanning electron microscopy(SEM)and mechanical test results of CPB,the particle size information of CPB was extracted,and a two-dimensional particle flow code(PFC)model of CPB was established to analyze the evolution rule of mesoscopic parameters during CPB development.The embedded FISH language in PFC was used to develop a program for establishing a PFC model on the basis of the SEM results.The mesoscopic parameters of CPB samples at different curing times,such as coordination number(C_(n)),contact force chain,and rose diagram,were obtained by recording and loading and used to analyze the intrinsic relationship between mesoscopic parameter variations and macroscopic mechanical response during CPB development.It is of considerable significance to establish the physical model of CPB using the PFC to reveal the mesoscopic structure of CPB.展开更多
The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the inte...The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the interaction coefficients between particles and the contact surface play important roles in the pneumatic conveying and CFD-DEM simulation.In order to build the semblable shape models and obtain the accurate interaction coefficients of large coal particles,this article establishes the con tact model by the particle overlap method and describes the mathematical model of the shape characteristics for large coal particle.The particle models are simulated by adopting the multi-index mixed orthogonal experiments.The accumulation density,the porosity and the error between simulation and experiment are taken as the indexes,and the particle models and the particle contact coefficients are taken as the orthogonal test factors.As a result,three more accurate particle models and their interaction coefficients are obtained,which provide the model basis for the pneumatic conveying of large coal particles.展开更多
As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO–SiO_(2)slags,this work investigated the activity coefficient of NiO in S...As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO–SiO_(2)slags,this work investigated the activity coefficient of NiO in SiO_(2)-saturated Mn O–Si O_(2)slag and Al_(2)O_(3)-saturated Mn O–SiO_(2)–Al_(2)O_(3)slag at 1623 K with controlled oxygen partial pressure levels of 10^(-7),10^(-6),and 10^(-5)Pa.Results showed that the solubility of nickel oxide in the slags increased with increasing oxygen partial pressure.The nickel in the Mn O–Si O_(2)slag and Mn O–Si O_(2)–Al_(2)O_(3)slag existed as Ni O under experimental conditions.The addition of Al_(2)O_(3)in the Mn O–Si O_(2)slag decreased the dissolution of nickel in the slag and increased the activity coefficient of Ni O.Furthermore,the activity coefficient of Ni O(γN_(i O)),which is solid Ni O,in the Si O_(2)saturated Mn O–Si O_(2)slag and Al_(2)O_(3)saturated Mn O–Si O_(2)–Al_(2)O_(3)slag at 1623 K can be respectively calculated asγN_(i O)=8.58w(Ni O)+3.18 andγN_(i O)=11.06w(Ni O)+4.07,respectively,where w(Ni O)is the Ni O mass fraction in the slag.展开更多
The present study considers the so-called air deck blasting,one of the most commonly used techniques for the improvement of blasting efficiency in mining applications.In particular,it aims to improve the operating con...The present study considers the so-called air deck blasting,one of the most commonly used techniques for the improvement of blasting efficiency in mining applications.In particular,it aims to improve the operating conditions of large-scale equipment,increase the efficiency of the slope enlarging process,and reduce the mining cost.These objectives are implemented through a two-fold approach where,first,a program for slope enlarging based on the middle air-deck charge blasting-loosening technology is proposed,and second,the physical mechanism responsible for the stress wave attenuation in the rock is analyzed in the framework of a Holmquist–Johnson–Cook constitutive model.Field test results verify that the proposed approach is highly efficient and economical when used in medium-hard rock blasting and thus provides a basis for the practical implementation of slope enlargement for high benches in Open-Pit Mines.展开更多
To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20vol% CO 80vol% CO2 gas mixture in a mic...To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20vol% CO 80vol% CO2 gas mixture in a micro-fluidized bed to examine the process of the selective conversion of hematite to magnetite. The micro-structural characteristics of the magnetite phase were investigated using scanning electron microscopy (SEM) and the Brunauer, Emmett, and Teller (BET) method, and the thickness of the magnetite layer was measured and evaluated using statistical analysis. The experimental results showed that the fresh magnetite nuclei were dense needles of different lengths, and the original hematite grains became porous after complete reduction to the magnetite phase. The thickness of the mag- netite layer increased with an increase in reduction temperature and reduction time. The growth kinetics of the magnetite layer was investi- gated, and the value of the activation energy E was estimated to be 28.33 kJ/mol.展开更多
基金supported by the State Key Program of National Natural Science Foundation of China (No. 50834006)
文摘The flotation separation of scheelite from fluorite and calcite using dodecyltrimethylammonium chloride （DTAC）, dodecyldimethylbenzylammonium chloride （DDBAC）, or didodecyldimethylammonium chloride （DDDAC） as the collector has been investigated. The results show that the selectivity of these collectors for these three calcareous minerals falls in the order： DDDAC 〉 DDBAC 〉 DTAC. A significantly different flotation response of scheelite compared to the other two calcareous minerals was observed over the pH range from 7 to 8 for DDDAC as the collector. A concentrate containing 41.40% W03 could be produced from a feed mixture containing 23.22% WO3 at the DDDAC concentration of 4.0× 10^-4 mol/L. The WO3 recovery was 92.92% under these conditions. The results of zeta potential measurements suggest that electrostatic interactions are the main forces between DDDAC and the minerals. When the concentration of DDDAC is from 2× 10^-4 to 4×10-3 mol/L large differences in adsorption density, and adsorption kinetics, of DDDAC onto scheelite, calcite, and fluorite provide desirable conditions for achieving high selectivity.
基金supported by the National Natural Science Foundation of China(Nos.51774153,92062110)National Key Research and Development Program of China(No.2021YFC2901702)。
文摘Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network characteristics of topsoil,weathered,and semiweathered layers of ionic rare earth ore in southern Jiangxi Province were explored in this study.The effect of leaching operation on the pore structure was investigated,and main factors affecting the seepage were analyzed.Results showed that the semiweathered layer presents a dense structure and a small number of unconnected pores.Pores of topsoil and weathered layers are mainly long and narrow column openings with some planar fractures.Even pore distribution and large size span were observed.Compared with the weathered layer,the topsoil layer demonstrates larger voids,smaller average pore volume and equivalent radius,and fewer coordination throats;however,the average equivalent radius of the throat in the topsoil layer is larger and largescale channels exist through ore body vertically.Hence,permeability of the topsoil layer is significantly higher than that of the weathered layer.Colloidal clay minerals migrate easily and the occurrence of silting in the small porosity blocks the throat and significantly decreases the permeability of the ore body in the leaching process.The equivalent radius of the throat is the key to the seepage.Reducing the migration of fine particles is an effective measure to protect the throat and shorten the leaching period.
基金supported by the National Science and Technology Support Program of China(No.2012BAC11B07)the Jiangxi Science and Technology Innovation Base Plan(No.20212BCD42017)。
文摘Under the background of increasingly scarce ore worldwide and increasingly fierce market competition,developing the mining industry could be strongly restricted.Intelligent ore sorting equipment not only improves ore use and enhances the economic benefits of enterprises but also increases the ore grade and lessens the grinding cost and tailings production.However,long-term research on intelligent ore sorting equipment found that the factors affecting sorting efficiency mainly include ore information identification technology,equipment sorting actuator,and information processing algorithm.The high precision,strong anti-interference capability,and high speed of these factors guarantee the separation efficiency of intelligent ore sorting equipment.Color ore sorter,X-ray ore transmission sorter,dual-energy X-ray transmission ore sorter,X-ray fluorescence ore sorter,and near-infrared ore sorter have been successfully developed in accordance with the different characteristics of minerals while ensuring the accuracy of equipment sorting and improving the equipment sorting efficiency.With the continuous improvement of mine automation level,the application of online element rapid analysis technology with high speed,high precision,and strong anti-interference capability in intelligent ore sorting equipment will become an inevitable trend of equipment development in the future.Laser-induced breakdown spectroscopy,transientγneutron activation analysis,online Fourier transform infrared spectroscopy,and nuclear magnetic resonance techniques will promote the development of ore sorting equipment.In addition,the improvement and joint application of additional high-speed and high-precision operation algorithms(such as peak area,principal component analysis,artificial neural network,partial least squares,and Monte Carlo library least squares methods)are an essential part of the development of intelligent ore sorting equipment in the future.
基金Project supported by the National Science&Technology Pilslar Program of China during the Twelfth Five-year Plan Period(2012BAC11B07)National Science&Technology Benefiting Program of China(2013GS360203)+5 种基金"Gan Po 555 Project"Leading Talents Training Program,Outstanding Doctoral Dissertation Project Fund of JXUST(YB2016005)Innovation Special Fund for Graduate of Jiangxi Province(YC2014-B059)the Sciences&Technologies Landing Plan of Jiangxi Province for Universities(KJLD14042)the Technology Support Plan of Jiangxi Province(20151BBG70005)the National Natural Science Foundation of China(51564023,21407070)High-end Foreign Experts Project(GDW20177200147)
文摘In this study, we selected yttrium as the representative of REEs to investigate the impacts of exogenous yttrium on soil physicochemical properties and microbiota. The results showed that exogenous yttrium has no significant effect on soil physical properties but a significantly negative impact on soil chemical properties. The results of high-throughput sequencing demonstrate that exogenous yttrium significantly decreases the number of OTUs, ACE, Chao 1, and Shannon indices while increases the Simpson index（P 〈 0.05）, indicating the low soil microbial diversity. The relative abundances of soil microbes are significantly changed at phylum and genus level. Principal component analysis（PCA） showed the significant difference of microbial community between yttrium treatments（YCl_3-250 and YCl_3-500） and non-yttrium treatment（CK） and the similarity of that between YCl_3-250 and YCI_3-500. Proteobacteria and Bacteroidetes are found to be the most tolerant phyla to exogenous yttrium while Verrucomicrobia the most sensitive phylum. Redundancy analysis（RDA） results suggest that exogenous yttrium affects soil microbiota only through changing the soil chemical properties but not soil physical properties, and C/N ratio is the key environmental factor.
基金Project(51374079)supported by the National Natural Science Foundation of ChinaProject(KKSY201521031)supported by Talent Cultivation Foundation of Kunming University of Science and Technology,ChinaProject(2015Y067)supported by Foundation of Yunnan Educational Committee,China
文摘The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigated by means of solution chemistry, ultraviolet spectrophotometry(UV), inductively coupled plasma atomic emission spectrometry(ICP-AES) and X-ray photoelectron spectroscopy(XPS). It is observed that dolomite with different size fractions has depressing effect on hematite flotation using sodium oleate as collector, and dolomite could be the "mineral depressant" of hematite using sodium oleate as collector. The reasons for that are concerned with sodium oleate consumption and the adsorption onto hematite of dissolved species of dolomite.
基金financially supported by the National Natural Science Foundation of China(No.52074356)Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2023-06)+5 种基金the National Key R&D Program of China(No.2022YFC2904500)the Science and Technology Innovation Program of Hunan Province,China(No.2022RC1183)Changsha Science and Technology Project,China(Outstanding Innovative Youth Training Program)Innovation driven program of Central South University(No.2023CXQD002)National 111 Project(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University Project(No.50621747)。
文摘The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)calculations.The X-ray photoelectric spectroscopy(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption mechanisms.First,the oxygen content in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and galena.Then,sulfite ions were chelated with lead ions to form PbSO_(3)in solution.The hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than galena.The interaction between sulfite ions and lead ions could effectively inhibit the activation of sphalerite.In addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of perxanthate.However,sulfite ions hardly depressed the flotation of ga lena and could promote the flotation of galena to some extent.This study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.
基金supported by the National Natural Science Foundation of China (No.51704038)the State-Owned Enterprise Electric Vehicle Industry Alliance,China (No.JS-211)the Changsha Science and Technology Project,China (No.kq1602212)。
文摘Mn and Li were selectively extracted from the manganese-rich slag by sulfation roasting−water leaching.The extraction mechanisms of Mn and Li were investigated by means of XRD,TG−DSC,and SEM−EDS.73.71%Mn and 73.28%Li were leached under optimal experimental conditions:acid concentration of 82 wt.%,acid-to-slag mass ratio of 1.5:1,roasting temperature of 800°C,and roasting time of 2 h.During the roasting process,the manganese-rich slag first reacted with concentrated sulfuric acid,producing MnSO_(4),MnSO_(4)·H_(2)O,Li_(2)Mg(SO_(4))_(2),Al_(2)(SO_(4))_(3),and H_(4)SiO_(4).With the roasting temperature increasing,H_(4)SiO_(4) and Al_(2)(SO_(4))_(3) decomposed successively,resulting in generation of mullite and spinel.The mullite formation aided in decreasing the leaching efficiencies of Al and Si,while increasing the Li leaching efficiency.The formation of spinel,however,decreased the leaching efficiencies of Mn and Li.
基金financially supported by the National Natural Science Foundation of China(No.51974018the Open Foundation of the State Key Laboratory of Process Automation in Mining and Metallurgy(No.BGRIMM-KZSKL-2022-9).
文摘Slurry electrolysis(SE),as a hydrometallurgical process,has the characteristic of a multitank series connection,which leads to various stirring conditions and a complex solid suspension state.The computational fluid dynamics(CFD),which requires high computing resources,and a combination with machine learning was proposed to construct a rapid prediction model for the liquid flow and solid concentration fields in a SE tank.Through scientific selection of calculation samples via orthogonal experiments,a comprehensive dataset covering a wide range of conditions was established while effectively reducing the number of simulations and providing reasonable weights for each factor.Then,a prediction model of the SE tank was constructed using the K-nearest neighbor algorithm.The results show that with the increase in levels of orthogonal experiments,the prediction accuracy of the model improved remarkably.The model established with four factors and nine levels can accurately predict the flow and concentration fields,and the regression coefficients of average velocity and solid concentration were 0.926 and 0.937,respectively.Compared with traditional CFD,the response time of field information prediction in this model was reduced from 75 h to 20 s,which solves the problem of serious lag in CFD applied alone to actual production and meets real-time production control requirements.
基金financially supported by the National Natural Science Foundation of China(Nos.51874229,52074212,51674188,51504182,51404191,and 51405381)the Natural Science Basic Research Plan of Shaanxi Province of China(Nos.2015JQ5187,2018JQ5183,and 2018JM5161)+3 种基金the Scientific Research Program funded by the Shaanxi Education Department(No.15JK1466)the China Postdoctoral Science Foundation(No.2015M582685)the Outstanding Youth Science Fund of Xi’an University of Science and Technology(No.2018YQ2-01)supported by the National Research Council of Science&and Technology(NST)grant by the Korea Korean government(MSIP)(No.CRC-16-38502-KICT)。
文摘Several special mechanical properties,such as dilatancy and compressibility,of cemented paste backfill(CPB)are controlled by its internal microstructure and evolution.The mesoscopic structure changes of CPB during the development process were investigated.On the basis of the scanning electron microscopy(SEM)and mechanical test results of CPB,the particle size information of CPB was extracted,and a two-dimensional particle flow code(PFC)model of CPB was established to analyze the evolution rule of mesoscopic parameters during CPB development.The embedded FISH language in PFC was used to develop a program for establishing a PFC model on the basis of the SEM results.The mesoscopic parameters of CPB samples at different curing times,such as coordination number(C_(n)),contact force chain,and rose diagram,were obtained by recording and loading and used to analyze the intrinsic relationship between mesoscopic parameter variations and macroscopic mechanical response during CPB development.It is of considerable significance to establish the physical model of CPB using the PFC to reveal the mesoscopic structure of CPB.
基金the Natural Science Foundation ofjiangsu Province(BK20170241)the National Natural Science Foundation of China(51705222 and 51675521)supported by the State Key Laboratory of Process Automation in Mining&Metallurgy and the Beijing Key Laboratory of Process Automation in Mining&Metallurgy(BGRIMM-KZSKL-2019-07).
文摘The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the interaction coefficients between particles and the contact surface play important roles in the pneumatic conveying and CFD-DEM simulation.In order to build the semblable shape models and obtain the accurate interaction coefficients of large coal particles,this article establishes the con tact model by the particle overlap method and describes the mathematical model of the shape characteristics for large coal particle.The particle models are simulated by adopting the multi-index mixed orthogonal experiments.The accumulation density,the porosity and the error between simulation and experiment are taken as the indexes,and the particle models and the particle contact coefficients are taken as the orthogonal test factors.As a result,three more accurate particle models and their interaction coefficients are obtained,which provide the model basis for the pneumatic conveying of large coal particles.
基金Project (2022YFC2904101) supported by the National Key R&D Program of ChinaProject (51974359) supported by the National Natural Science Foundation of ChinaProject (CX20220205) supported by the Postgraduate Scientific Research Innovation Project of Hunan Province,China。
基金financially supported by the National Natural Science Foundation of China(No.51704038)。
文摘As a part of the fundamental study related to the reduction smelting of spent lithium-ion batteries and ocean polymetallic nodules based on MnO–SiO_(2)slags,this work investigated the activity coefficient of NiO in SiO_(2)-saturated Mn O–Si O_(2)slag and Al_(2)O_(3)-saturated Mn O–SiO_(2)–Al_(2)O_(3)slag at 1623 K with controlled oxygen partial pressure levels of 10^(-7),10^(-6),and 10^(-5)Pa.Results showed that the solubility of nickel oxide in the slags increased with increasing oxygen partial pressure.The nickel in the Mn O–Si O_(2)slag and Mn O–Si O_(2)–Al_(2)O_(3)slag existed as Ni O under experimental conditions.The addition of Al_(2)O_(3)in the Mn O–Si O_(2)slag decreased the dissolution of nickel in the slag and increased the activity coefficient of Ni O.Furthermore,the activity coefficient of Ni O(γN_(i O)),which is solid Ni O,in the Si O_(2)saturated Mn O–Si O_(2)slag and Al_(2)O_(3)saturated Mn O–Si O_(2)–Al_(2)O_(3)slag at 1623 K can be respectively calculated asγN_(i O)=8.58w(Ni O)+3.18 andγN_(i O)=11.06w(Ni O)+4.07,respectively,where w(Ni O)is the Ni O mass fraction in the slag.
文摘The present study considers the so-called air deck blasting,one of the most commonly used techniques for the improvement of blasting efficiency in mining applications.In particular,it aims to improve the operating conditions of large-scale equipment,increase the efficiency of the slope enlarging process,and reduce the mining cost.These objectives are implemented through a two-fold approach where,first,a program for slope enlarging based on the middle air-deck charge blasting-loosening technology is proposed,and second,the physical mechanism responsible for the stress wave attenuation in the rock is analyzed in the framework of a Holmquist–Johnson–Cook constitutive model.Field test results verify that the proposed approach is highly efficient and economical when used in medium-hard rock blasting and thus provides a basis for the practical implementation of slope enlargement for high benches in Open-Pit Mines.
基金financially supported by the National Science Foundation of China (Nos. 51734005 and 51674065)the China Postdoctoral Science Foundation (No. 2018M631812)Open Foundation of State Key Laboratory of Mineral Processing, Beijing General Research Institute of Mining & Metallurgy Group, China (No. BGRIMM-KJSKL-2019-09)
文摘To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20vol% CO 80vol% CO2 gas mixture in a micro-fluidized bed to examine the process of the selective conversion of hematite to magnetite. The micro-structural characteristics of the magnetite phase were investigated using scanning electron microscopy (SEM) and the Brunauer, Emmett, and Teller (BET) method, and the thickness of the magnetite layer was measured and evaluated using statistical analysis. The experimental results showed that the fresh magnetite nuclei were dense needles of different lengths, and the original hematite grains became porous after complete reduction to the magnetite phase. The thickness of the mag- netite layer increased with an increase in reduction temperature and reduction time. The growth kinetics of the magnetite layer was investi- gated, and the value of the activation energy E was estimated to be 28.33 kJ/mol.
