Numerical Simulation and Optimization of the Gas-Solid Coupled Flow Field and Discharging Performance of Straw Crushers

The quality of crushing,power consumption,and discharging performance of a straw crusher are greatly influenced by the characteristics of its internalflowfield.To enhance the straw crusher’sflowfield properties and improve the efficiency with which crushed material is discharged,first,the main structural parameters influencing the airflow in the crusher are discussed.Then,the coupled gas-solidflowfield in the straw crusher is numerically calculated through solution of the Navier-Stokes equations and application of the discrete element method(DEM).Finally,the discharge performance index of the crusher is examined through detailed analysis of the crushed material dynamics.Additionally,a multi-island genetic algorithm is used to optimize the structure and operational factors that have significant effects on the discharge performance.With optimization,the accumulation rate of crushed materials in the bottom region of the straw crusher decreases by 20.08%,and the massflow rate at the discharge outlet increases by 11.63%.

STUDIES ON SINTERING TECHNOLOGY OF HAMMERS OF FOOD HAMMER MILL

A new kind of process sintering process is dealt with manufacturing hammers of the hammer mill. Metallurgical products and single factor parameters are systematically studied in this paper. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. Experimental results provide important theoretical guidance and experimental data for its further application.

Multi-object optimization design for differential and grading toothed roll crusher using a genetic algorithm

Our differential and grading toothed roll crusher blends the advantages of a toothed roll crusher and a jaw crusher and possesses characteristics of great crushing,high breaking efficiency,multi-sieving and has,for the moment,made up for the short- comings of the toothed roll crusher.The moving jaw of the crusher is a crank-rocker mechanism.For optimizing the dynamic per- formance and improving the cracking capability of the crusher,a mathematical model was established to optimize the transmission angleγand to minimize the travel characteristic value m of the moving jaw.Genetic algorithm is used to optimize the crusher crank-rocker mechanism for multi-object design and an optimum result is obtained.According to the implementation,it is shown that the performance of the crusher and the cracking capability of the moving jaw have been improved.

A comparison of strategic mine planning approaches for in-pit crushing and conveying, and truck/shovel systems

In a global environment where energy and labor are becoming increasingly expensive, continuous mining systems such as In-Pit Crushing and Conveying(IPCC) systems have been advanced as offering a real alternative to conventional truck haulage systems. The implementation of IPCC systems in hard rock operations in open pit mines however requires different and more comprehensive planning approaches in order to adequately reflect the practical aspects associated with these. This paper investigates the impact that these approaches may have on the implementation of IPCC systems on a basic metalliferous deposit amenable to open pit exploitation. A strategic life of mine plan to provide numerous economic indicators for each approach is analyzed and compared to traditional truck haulage systems. The mine planning and evaluation process highlights the increased overall resource recovery that may accompany the use of IPCC systems. This investigation also provides insights into the issues associated with IPCC and the scale and type of operation and orebody that is likely to provide a feasible alternative to truck haulage.

Influence of some rock strength properties on jaw crusher performance in granite quarry

The influence of rock strength properties on Jaw Crusher performance was carried out to determine the effect of rock strength on crushing time and grain size distribution of the rocks.Investigation was conducted on four different rock samples namely marble,dolomite,limestone and granite which were representatively selected from fragmented lumps in quarries.Unconfined compressive strength and Point load tests were carried out on each rock sample as well as crushing time and size analysis.The results of the strength parameters of each sample were correlated with the crushing time and the grain size distribution of the rock types.The results of the strength tests show that granite has the highest mean value of 101.67 MPa for Unconfined Compressive Strength(UCS) test,6.43 MPa for Point Load test while dolomite has the least mean value of 30.56 MPa for UCS test and 0.95 MPa for Point Load test.According to the International Society for Rock Mechanic(ISRM) standard,the granite rock sample may be classified as having very high strength and dolomite rock sample,low strength.Also,the granite rock has the highest crushing time(21.0 s) and dolomite rock has the least value(5.0 s).Based on the results of the investigation,it was found out that there is a great influence of strength properties on crushing time of rock types.

New testing methodology for the quantification of rock crushability:Compressive crushing value(CCV)

Crushing is a size reduction process that plays a key role in both mineral processing and crushing–screening plant design. Investigations on rock crushability have become an important issue in mining operations and the manufacture of industrial crusher equipment. The main objective of this research is to quantify the crushability of hard rocks based on their mineralogical and mechanical properties. For this purpose, the mineralogical, physical, and mechanical properties of various hard rocks were determined. A new compressive crushing value(CCV) testing methodology was proposed. The results obtained from CCV tests were compared with those from mineralogical inspections, rock strength as well as mechanical aggregate tests. Strong correlations were found between CCV and several rock and aggregate properties such as uniaxial compressive strength(UCS), the brittleness index(S_(20)), and aggregate impact value(AIV). Furthermore, the relationship between the mineralogical properties of the rocks and their CCVs were established. It is concluded that the proposed testing methodology is simple and highly repeatable and could be utilized as a pre-design tool in the design stage of the crushing process for rock quarries.

Application of analytical hierarchy process to selection of primary crusher

Selection of crusher required a great deal of design based on the mining plan and operation input. Selection of the best primary crusher from all of available primary crushers is a Multi-Criterion Decision Making （MCDM） problem, in this paper, the Analytical Hierarchy Process （AHP） method was used to selection of the best primary crusher for Golegohar Iron Mine in Iran. For this reason, gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impactor, hammer mill and feeder breaker crushers were considered as alternatives and capacity, feed size, product size, rock compressive strength, abrasion index and mobility of crusher were considered as criteria. As a result of our study, the gyvratory crusher was offered as the best primary crusher for the studied mine.

Fuzzy TOPSIS method to primary crusher selection for Golegohar Iron Mine(Iran)

Selection of the crusher required a great deal of design regarding to the mine planning. Selection of suitable primary crusher from all of available primary crushers is a multi-criterion decision making(MCDM) problem. The present work explores the use of technique for order performance by similarity to ideal solution(TOPSIS) with fuzzy set theory to select best primary crusher for Golegohar Iron Mine in Iran. Gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impact crusher, hammer mill and feeder breaker crushers have been considered as alternatives. Also, the capacity, feed size, product size, rock compressive strength, abrasion index and application of primary crusher for mobile plants were considered as criteria for solution of this MCDM problem. To determine the order of the alternatives, closeness coefficient is defined by calculating the distances to the fuzzy positive ideal solution(FPIS) and fuzzy negative ideal solution(FNIS). Results of our work based on fuzzy TOPSIS method show that the gyratory is the best primary crusher for the studied mine.

Material Flow in Jaw Crusher

Jaw crusher is a kind of machine widely used in mining and aggregates industry,but it still has some shortcom- ings,such as liners wear,terrible power draw etc.The lack of research on material flow strongly limits the design improvement. The size reduction of the jaw crusher relies on the moving jaw movement that is a kind of complicated swing.Based on the move- ment analysis of the moving jaw and the single particle breakage characters,the material flow is analyzed.The measure of the breakage force is carried out.Material flow analysis is partly confirmed by the experimental results and some new information is also learned from the crushing force distribution.The job on the material flow will be helpful to the jaw crusher design improve- ment.

The continuous excavating technique system parameters optimization and economic assessment simulation model in open-pit mine

Based on the fundamental simulation theories and methods, this paper studies such questions as truck dispatching, discrete processing of belt system continuous haulage, belt system interlock, and economic assessment methods. On the basis of above studies, the paper establishes a simulation model for open pit mine semi continuous production technique system. The paper applies GPSS language to construct a simulation program, and the program has been successfully applied in a certain coalmine.

.NET程序汉化一例——Cookie Crusher的汉化

前天,在CNET下载到Cookie Crusher这个软件,发现是.net编写的,按照习惯,先检测程序是否被加壳,结果不错,没加,接着用EXEScope打开主程序,发现资源项目下只有图标和版本这两个东东:

A Novel Process for the Study of Breakage Energy versus Particle Size

The energy size relationship is examined, either as the specific energy required breaking a particulate material from an initial size d1 to a final size d2, where d is usually the d80 size, or as the specific energy required to break a single particle. The present work uses the results obtained using a controlled frequency centrifugal crusher to crush particles of a predetermined size class under different rotation frequencies related to the kinetic energy of the particles at the moment of crushing. The paper calculates the relationship between the rotation frequency and the kinetic energy of the particles before crushing and examines the size distribution of the products. The study results allow presenting the relationship between the kinetic energy of the particles and the mass of particles produced below the initial size class. The work also produces the optimum mathematical model that describes this relationship among three proposed ones. According to this model one can calculate the energy required breaking half of the initial mass below the initial size class and the corresponding specific energy is appointed to the average size of the class. The parameters of the mathematical model can be used to compare the grindability of the different materials. The process can be used as an alternative to the drop weight technique used so far for the study of the breakage energy of minerals and rocks.

Research on Structural Design of Coal Crusher House in Thermal Power Plant

This paper takes the specific characteristics of pulverized coal room in thermal power plant as the starting point,firstly,this paper analyzes the process layout and structure selection,and then the structural design and vibration design requirements of coal crusher house are introduced in this paper.Finally,based on the engineering example,a new structure form of vibration isolation design is creatively proposed,which provides a new design idea for the practical engineering design.

Performance test and process parameter optimization of 9FF type square bale straw crusher

In order to solve the problem of low productivity,unqualified segment length and high energy consumption during the process of crushing square bale straw caused by improper operation parameters,a 9FF square bale straw crusher was developed.In this study,by taking maize straw as the test material,the feeding speed,spindle speed of the crushing device and the state of the crushing device were taken as influence factors,and standard straw length rate,productivity per net working hour(hereinafter referred to as NWH)and energy consumption per ton of product as test indicators,the influence of the factors on the indicators were studied,and tests were carried out on the process of square bale straw crushing.By adopting the single factor test on the effect of the feeding speed,the spindle speed of the crushing device and the state of the crushing device on the test indicators,the suitable range of each factor was determined,respectively.Using the orthogonal test method,range method,variance method and comprehensive balance method,the experiment analyzed the significance of the influence of the three factors on various indicators and the order of priority.The test results showed that:the feeding speed was 5 m/min,spindle speed was 3000 r/min,and the state of the crushing device was a mixing cutter hammer,which was the best parameter combination(A1B1C1)for the processing technology of the square bale forage crusher.The standard straw length rate was 93.7%,and the productivity per NWH was 2.80 t/h,with energy consumption per ton of 4.72 kW·h/t,in which the standard straw length rate and productivity per NWH reached optimal values,and the energy consumption per ton of product was slightly higher than the optimal value in the experiment.The research results can provide a reference for the optimal design of the special crusher for square bale straw.