Based on the separation and backfilling system of coal and gangue, the mineral material impact experiments were conducted utilizing the hardness difference between coal and gangue according to the uniaxial compression...Based on the separation and backfilling system of coal and gangue, the mineral material impact experiments were conducted utilizing the hardness difference between coal and gangue according to the uniaxial compression experiments. The broken coal and gangue particles were collected and screened by different size meshes. The particle size distributions of coal and gangue under different impact velocities were researched according to the Rosin-Rammler distribution. The relationships between separation indicators and impact velocities were discussed. It is found from experiments that there is a fully broken boundary of coal material. The experimental results indicate that the Rosin-Rammler distribution could accurately describe the particle size distribution of broken coal and gangue under different impact velocities, and there is a minimum overlap region when the impact velocity is 12.10 m/s which leads to the minimum mixed degree of coal and gangue, and consequently the benefit of coal and gangue separation.展开更多
The effect of grinding on the spodumene flotation was investigated. The flotation response of spodumene ground by different mills was different, due to the variation of metal ions on spodumene surfaces caused by grind...The effect of grinding on the spodumene flotation was investigated. The flotation response of spodumene ground by different mills was different, due to the variation of metal ions on spodumene surfaces caused by grinding environments and/or impurities. The samples were subjected to acid pickling treatment to remove most of the metal ions from the surfaces, and then all samples showed the same poor flotation response, which confirmed the significance of surface metal ions. Metal ion impurities may come from both grinding environments and lattice substitutions in spodumene. Density functional theory (DFT) calculation revealed that Fe and Ca could exist as lattice substitutions on the spodumene surface while Mg substitution is unlikely to occur. Furthermore, Fe is considered to be active site for the absorption of sodium oleate on the spodumene surface. Morphology analysis showed differences in particle size and shape for samples ground by different mills, resulting in different amounts of exposed surfaces. The particle size, cleavage characteristics caused by grinding environments, and metal ion impurities originated from grinding and isomorphous substitutions, play significant roles in the chemisorption of collector on the spodumene surface.展开更多
Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investiga...Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types(high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO_2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.展开更多
The extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which ...The extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which affect the quantity and quality of products.To improve the aluminum recovery process,the leaching kinetics of CMW with hydrochloric acid was studied.A shrinking core model was used to investigate aluminum and iron dissolution kinetics.Based on the kinetic characteristics,a process for recovering aluminum was proposed and tested experimentally.It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures(40-80℃) and by diffusion process at higher temperatures(90-106℃).The iron dissolution process is dominated by surface reaction at 40-100℃.The results show that iron could be dissolved or separated by concentrated hydrochloric acid.Fine grinding will improve aluminum dissolution significantly.展开更多
When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars....When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars.Using numerical simulations,this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths,and established a relation describing the stress distribution in the web pillar.The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed.In combination with the failure characteristics of the pillar yield zone,this relationship was used to explore the instability mechanism of web pillars.Finally,the optimal retaining widths of the web pillars were determined.Based on the modeling results,a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed.Additionally,the web pillar instability criterion was derived.By analyzing the ultimate strength of the web pillars,a formula for calculating the yield zone width either side of the pillars was established.Using the instability criterion of web pillars in highwall mining,a reasonable pillar width can be deduced theoretically,providing significant guidance on the application of highwall mining technology.展开更多
基金Project(2012AA062102)supported by High-Tech Research and Development Program of ChinaProject(KYLX_1379)supported by the Innovation Training Project of Graduate Student in Jiangsu Province,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Based on the separation and backfilling system of coal and gangue, the mineral material impact experiments were conducted utilizing the hardness difference between coal and gangue according to the uniaxial compression experiments. The broken coal and gangue particles were collected and screened by different size meshes. The particle size distributions of coal and gangue under different impact velocities were researched according to the Rosin-Rammler distribution. The relationships between separation indicators and impact velocities were discussed. It is found from experiments that there is a fully broken boundary of coal material. The experimental results indicate that the Rosin-Rammler distribution could accurately describe the particle size distribution of broken coal and gangue under different impact velocities, and there is a minimum overlap region when the impact velocity is 12.10 m/s which leads to the minimum mixed degree of coal and gangue, and consequently the benefit of coal and gangue separation.
基金Project(51674290)supported by the National Natural Science Foundation of ChinaProject(201606370130)supported by the China Scholarship CouncilProject(2016zzts107)supported by the Fundamental Research Funds for the Central Universities of Central South University,China
文摘The effect of grinding on the spodumene flotation was investigated. The flotation response of spodumene ground by different mills was different, due to the variation of metal ions on spodumene surfaces caused by grinding environments and/or impurities. The samples were subjected to acid pickling treatment to remove most of the metal ions from the surfaces, and then all samples showed the same poor flotation response, which confirmed the significance of surface metal ions. Metal ion impurities may come from both grinding environments and lattice substitutions in spodumene. Density functional theory (DFT) calculation revealed that Fe and Ca could exist as lattice substitutions on the spodumene surface while Mg substitution is unlikely to occur. Furthermore, Fe is considered to be active site for the absorption of sodium oleate on the spodumene surface. Morphology analysis showed differences in particle size and shape for samples ground by different mills, resulting in different amounts of exposed surfaces. The particle size, cleavage characteristics caused by grinding environments, and metal ion impurities originated from grinding and isomorphous substitutions, play significant roles in the chemisorption of collector on the spodumene surface.
基金the financial support of National Iranian Copper Industries Company (N.I.C.I.Co.)
文摘Misreported pyrite into copper concentrates dramatically declines copper grade and recovery. Copper flotation can be also more complicated if flotation feed comes from an elevated-pyritic copper ore. In this investigation, the effect of two different ore types(high pyritic and low pyritic feeds) was studied on rougher stage of industrial copper flotation circuit. Samples were taken from different streams and the structure of chalcopyrite within the pyrite and non-sulfide gangue minerals was examined in various size fractions for mentioned ore types. Results indicated that 72% and 56% of the total floated pyrite was transferred to concentrate in first four cells in the low and high pyritic feeds, respectively. Whereas, this proportion for floated SiO_2 in last ten cells was detected as 72% and 71%, respectively. A detailed interpretation of the effect of locked particles in different size fractions on rougher flotation cells is studied from industrial point of view.
基金Supported by the National High Technology Research and Development Program of China(2011AA06A103)the National Natural Science Foundation of China(21306109)
文摘The extrartion of aluminum from coal mining waste(CMW) is an important industrial process.The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material,which affect the quantity and quality of products.To improve the aluminum recovery process,the leaching kinetics of CMW with hydrochloric acid was studied.A shrinking core model was used to investigate aluminum and iron dissolution kinetics.Based on the kinetic characteristics,a process for recovering aluminum was proposed and tested experimentally.It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures(40-80℃) and by diffusion process at higher temperatures(90-106℃).The iron dissolution process is dominated by surface reaction at 40-100℃.The results show that iron could be dissolved or separated by concentrated hydrochloric acid.Fine grinding will improve aluminum dissolution significantly.
基金This project was supported by the National Natural Science Foundation of China under Project No.51874160,LNTU20TD-01the“Millions of Talents Project”of Liaoning Province China.
文摘When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars.Using numerical simulations,this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths,and established a relation describing the stress distribution in the web pillar.The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed.In combination with the failure characteristics of the pillar yield zone,this relationship was used to explore the instability mechanism of web pillars.Finally,the optimal retaining widths of the web pillars were determined.Based on the modeling results,a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed.Additionally,the web pillar instability criterion was derived.By analyzing the ultimate strength of the web pillars,a formula for calculating the yield zone width either side of the pillars was established.Using the instability criterion of web pillars in highwall mining,a reasonable pillar width can be deduced theoretically,providing significant guidance on the application of highwall mining technology.
