Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribut...Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribution(PSD)of ground coal is a key parameter in the preparation of slurries as it determines the settling behavior of the particles and viscosity of the coal-water mixture.There are several methods available for representation and evaluation of particle size analysis data.However,fractal theory provides a means by which the entire PSD of comminuted materials can be quantified by using of a specific and exact value.In this paper,a volume-based fractal model was deduced to characterize the PSD of the coal which is ground in a specially designed comminution cell.During the size reduction process,the inlet pressures up to 276 MPa were used.展开更多
It has been an established fact that comminution processes, crushing and grinding, are most energy intensive processes which account for more than half of the total energy consumed in mineral industries.Various altern...It has been an established fact that comminution processes, crushing and grinding, are most energy intensive processes which account for more than half of the total energy consumed in mineral industries.Various alternative pre-treatment methods have been tried by experts around the globe. Although these methods yielded positive results in terms of reduction in energy consumption in crushing and particularly, in grinding operations at laboratory scale, their industrial application still remains an unresolved issue and challenge. Present review paper describes each one of these methods along with outcome of earlier studies and issues that need to be addressed through further rigorous experimental investigation.It also suggests the direction in which future studies can be carried out to meet the primary objective of making comminution processes more energy efficient than today they are.展开更多
We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with c...We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.展开更多
Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was...Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.展开更多
The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the com...The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the comminution of mica because cavitation abrasive water jet can make full use of the three effects mentioned above. Besides high speed impacting among particles,cavitation and shearing were also enhanced due to the divergent angle at the outlet of the cavitation nozzle.A JME-200CX transmission electron microscope was used for observing the size distribution of particles.Variance analysis on the experimental results indicates that the effect of cavitation is much more significant than that of collision.The effect of pressure on comminution results becomes less with the decrease of the particle size.展开更多
A new concept named computational comminution is proposed in thispaper, which is different from the traditional studies on materialsprocessing procedure such as the study based on theoretic models, thestudy based on e...A new concept named computational comminution is proposed in thispaper, which is different from the traditional studies on materialsprocessing procedure such as the study based on theoretic models, thestudy based on experiment models, which is based on informationmodels. Some key technologies applied to mate- rials processingprocedure such as artificial neural networks, fuzzy sets, geneticalgorithms and visualization techn- ology are also presented, and afusing methodology of these new technologies is studied. Applicationin the cement grinding process of Horomill shows that results in thispaper are efficient.展开更多
Based upon the aspect of continuous damaging,the process of ore comminution may be des- cribed as the growth and propagation of the microcracks in the ore grains under external load- ing,and a theoretical expression h...Based upon the aspect of continuous damaging,the process of ore comminution may be des- cribed as the growth and propagation of the microcracks in the ore grains under external load- ing,and a theoretical expression has been developed on the relationship between the grain size distribution and the total energy consumption during entire ore comminution process.The en- ergy consumed totally may be considered consisting of two portions,i.e.with fresh crack sur- faces growth and with crack propagation.The proposed expression seems to be an advance over previous conventional ones,especially that from the viewpoint of energy distribution.展开更多
The comminution mechanism of hard kaolin from Enshi District in China Hubei Province is investigated through applying comminution theory and basing on the ore properties of the kaolin. The technique and effectiveness ...The comminution mechanism of hard kaolin from Enshi District in China Hubei Province is investigated through applying comminution theory and basing on the ore properties of the kaolin. The technique and effectiveness of comminution are introduced according to the practice of ultra-fine comminution with impact comminutor. The results show that the circuit comminutor unit has advantages of simple technological process, being easily controlled, high effectiveness and so on.展开更多
The cavitation abrasive water jet was used in the comminution ofmica. By applying a cavitation nozzle in the abrasive water jetsystem to enhance the effect of cavitation and friction, bettercomminution results were ob...The cavitation abrasive water jet was used in the comminution ofmica. By applying a cavitation nozzle in the abrasive water jetsystem to enhance the effect of cavitation and friction, bettercomminution results were obtained. The JME-200CX transmission elec-tron microscope was used for observing the size distribution ofparticles. As using cavitation abrasive water jet, the relativecomminution effect is raised by more than 25/100 compared with usingabrasive water jet only. It can be concluded that the effect ofcavitation is much more significant than that of impacting in thecomminution of mica.展开更多
Experiment about ultrafine comminution in theory of vertiginous current of bulk material has successfully performed by a lately developed vertical shaft centrifugal autogenous grinder. The results of tested several ma...Experiment about ultrafine comminution in theory of vertiginous current of bulk material has successfully performed by a lately developed vertical shaft centrifugal autogenous grinder. The results of tested several materials are analyzed, moreover. the comminution mechanism and the affecting factors of ultrafine comminution are analyzed.展开更多
[Objective] The research aimed to explore the effects of comminution technology on the dissolution of active components from compound feed additive of Strobi/anthes cusia. [Method] Using active component adenosine in ...[Objective] The research aimed to explore the effects of comminution technology on the dissolution of active components from compound feed additive of Strobi/anthes cusia. [Method] Using active component adenosine in principal herb S. cusia and chlorogenic acid in minister drug Lonicera japonica Thunb. as dissolution indices,the effects of ultrafine comminution on the dissolution degree of compound feed additive of S. cusia were analyzed. [ Result] The dissolution degree of adenosine and chlorogenic acid in ultra micro particles were obviously higher than that of common particles. Ultrafine comminution could significantly quicken the dissolution rate of adenosine and chlorogenic acid in compound feed additive of S. cusia, shorten the extraction time, avoid the breakage of active components in long-time extraction process,and meanwhile saved the energy greatly. [ Conclusion] The ultrafine comminution technology could obviously increase the dissolution degree of active components in compound feed additive of S. cusia.展开更多
Granular material mechanics,finite element analysis and crushing theory are applied to study the compressive comminution mechanism of particle beds in this paper.This is a new method by which we have established an eq...Granular material mechanics,finite element analysis and crushing theory are applied to study the compressive comminution mechanism of particle beds in this paper.This is a new method by which we have established an equivalent model of granular material,determined the values and distributions of contact forces and discovered a crushing law.The model has been tested on the newly designed equipment and proved to be correct.Some new characteristics and laws of compressive comminution of particle beds have been found.展开更多
The fractal model of rock comminution is presented with Mandelbrot's fractal geometry.The results show that it is difficult for those with only a linear similarity ratio to fit practical situations.The comminution...The fractal model of rock comminution is presented with Mandelbrot's fractal geometry.The results show that it is difficult for those with only a linear similarity ratio to fit practical situations.The comminution prob ability of the central part should be considered so the geometric meaning of the constant in Gaudin-Schuhmann's distribution function can be explained more clearly.展开更多
This paper provides a summary of the current comminution circuit and its development trend,focusing the discussion on the comminution circuit selection for the No.3 concentrator with 60000 t/d througput in the Dexing ...This paper provides a summary of the current comminution circuit and its development trend,focusing the discussion on the comminution circuit selection for the No.3 concentrator with 60000 t/d througput in the Dexing Copper Mine.Based on the large amount of information and data on autogenous grinding tests and conventional grinding practices in the Dexing Copper Mine,the comparison results for various comminution circuits as well as the authors suggestions for the comminution system are presented.展开更多
基金supported by the Missouri University of Science and Technology/Waterjet Laboratory and funded by the China Postdoctoral Science Foundation(Grant No.2014M552555XB)Doctoral Program in Xi’an University of Science and Technology(Grant No.2013QDJ039).
文摘Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribution(PSD)of ground coal is a key parameter in the preparation of slurries as it determines the settling behavior of the particles and viscosity of the coal-water mixture.There are several methods available for representation and evaluation of particle size analysis data.However,fractal theory provides a means by which the entire PSD of comminuted materials can be quantified by using of a specific and exact value.In this paper,a volume-based fractal model was deduced to characterize the PSD of the coal which is ground in a specially designed comminution cell.During the size reduction process,the inlet pressures up to 276 MPa were used.
基金the support provided by Indian Institute of Technology,Kharagpur
文摘It has been an established fact that comminution processes, crushing and grinding, are most energy intensive processes which account for more than half of the total energy consumed in mineral industries.Various alternative pre-treatment methods have been tried by experts around the globe. Although these methods yielded positive results in terms of reduction in energy consumption in crushing and particularly, in grinding operations at laboratory scale, their industrial application still remains an unresolved issue and challenge. Present review paper describes each one of these methods along with outcome of earlier studies and issues that need to be addressed through further rigorous experimental investigation.It also suggests the direction in which future studies can be carried out to meet the primary objective of making comminution processes more energy efficient than today they are.
基金The support from both the Research Foundation for Returning Scholars of Chinathe China Postdoctoral Science Foundation
文摘We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.
文摘Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.
文摘The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the comminution of mica because cavitation abrasive water jet can make full use of the three effects mentioned above. Besides high speed impacting among particles,cavitation and shearing were also enhanced due to the divergent angle at the outlet of the cavitation nozzle.A JME-200CX transmission electron microscope was used for observing the size distribution of particles.Variance analysis on the experimental results indicates that the effect of cavitation is much more significant than that of collision.The effect of pressure on comminution results becomes less with the decrease of the particle size.
文摘A new concept named computational comminution is proposed in thispaper, which is different from the traditional studies on materialsprocessing procedure such as the study based on theoretic models, thestudy based on experiment models, which is based on informationmodels. Some key technologies applied to mate- rials processingprocedure such as artificial neural networks, fuzzy sets, geneticalgorithms and visualization techn- ology are also presented, and afusing methodology of these new technologies is studied. Applicationin the cement grinding process of Horomill shows that results in thispaper are efficient.
文摘Based upon the aspect of continuous damaging,the process of ore comminution may be des- cribed as the growth and propagation of the microcracks in the ore grains under external load- ing,and a theoretical expression has been developed on the relationship between the grain size distribution and the total energy consumption during entire ore comminution process.The en- ergy consumed totally may be considered consisting of two portions,i.e.with fresh crack sur- faces growth and with crack propagation.The proposed expression seems to be an advance over previous conventional ones,especially that from the viewpoint of energy distribution.
文摘The comminution mechanism of hard kaolin from Enshi District in China Hubei Province is investigated through applying comminution theory and basing on the ore properties of the kaolin. The technique and effectiveness of comminution are introduced according to the practice of ultra-fine comminution with impact comminutor. The results show that the circuit comminutor unit has advantages of simple technological process, being easily controlled, high effectiveness and so on.
基金financially supported by China Postdoctoral Science Foundation (June 2001, No.29).
文摘The cavitation abrasive water jet was used in the comminution ofmica. By applying a cavitation nozzle in the abrasive water jetsystem to enhance the effect of cavitation and friction, bettercomminution results were obtained. The JME-200CX transmission elec-tron microscope was used for observing the size distribution ofparticles. As using cavitation abrasive water jet, the relativecomminution effect is raised by more than 25/100 compared with usingabrasive water jet only. It can be concluded that the effect ofcavitation is much more significant than that of impacting in thecomminution of mica.
文摘Experiment about ultrafine comminution in theory of vertiginous current of bulk material has successfully performed by a lately developed vertical shaft centrifugal autogenous grinder. The results of tested several materials are analyzed, moreover. the comminution mechanism and the affecting factors of ultrafine comminution are analyzed.
基金funded by Guangdong Science and Technology Study Program(2010B090400529)
文摘[Objective] The research aimed to explore the effects of comminution technology on the dissolution of active components from compound feed additive of Strobi/anthes cusia. [Method] Using active component adenosine in principal herb S. cusia and chlorogenic acid in minister drug Lonicera japonica Thunb. as dissolution indices,the effects of ultrafine comminution on the dissolution degree of compound feed additive of S. cusia were analyzed. [ Result] The dissolution degree of adenosine and chlorogenic acid in ultra micro particles were obviously higher than that of common particles. Ultrafine comminution could significantly quicken the dissolution rate of adenosine and chlorogenic acid in compound feed additive of S. cusia, shorten the extraction time, avoid the breakage of active components in long-time extraction process,and meanwhile saved the energy greatly. [ Conclusion] The ultrafine comminution technology could obviously increase the dissolution degree of active components in compound feed additive of S. cusia.
文摘Granular material mechanics,finite element analysis and crushing theory are applied to study the compressive comminution mechanism of particle beds in this paper.This is a new method by which we have established an equivalent model of granular material,determined the values and distributions of contact forces and discovered a crushing law.The model has been tested on the newly designed equipment and proved to be correct.Some new characteristics and laws of compressive comminution of particle beds have been found.
基金supported by the National Natural Science Foundation
文摘The fractal model of rock comminution is presented with Mandelbrot's fractal geometry.The results show that it is difficult for those with only a linear similarity ratio to fit practical situations.The comminution prob ability of the central part should be considered so the geometric meaning of the constant in Gaudin-Schuhmann's distribution function can be explained more clearly.
文摘This paper provides a summary of the current comminution circuit and its development trend,focusing the discussion on the comminution circuit selection for the No.3 concentrator with 60000 t/d througput in the Dexing Copper Mine.Based on the large amount of information and data on autogenous grinding tests and conventional grinding practices in the Dexing Copper Mine,the comparison results for various comminution circuits as well as the authors suggestions for the comminution system are presented.