maj 20 2015

Mathematical simulation of grinding the ore process

Kategoria: Wiadomościcassie1759 @ 14:26

Mathematical simulation of grinding the ore process

Grinding model based on the use of computers to solve the grinding circuit equipment operating indicators, the process of impact factors and process parameters.The grinding process simulation is most important is the scaling of the mill, from laboratory tests or small specifications mill data obtained to calculate the production of industrial production mill, grinding power, product size, the media system indicators and parameters of the appropriate speed of the mill.Main application in the calculation of grinding dynamics, the distribution function of grinding time and grinding principle of linear superposition.Because many factors affect the grinding process, many of which factors influence on the grinding index still can not make accurate quantitative calculation, resulting in many algorithms.To sum up the main three types of algorithms, the conventional algorithm, and grinding the ore the overall balance of dynamics simulation algorithm and conversion factor method.1. Conventional algorithm for the calculation of criteria to select a test to get the grinding constant, then multiplied by a correction factor, the experimental data of the small-scale transition to the mill index of industrial production.Ore mill degrees in essence the computing mill grinding constant, which is characterized by different grinding conditions under which its value remains unchanged or changes by a certain percentage.The most commonly used constant grinding into three categories, namely: the volume constant (also known as more than productivity) (q, t / m cube h); power constant, such as the Bond work index w2, kw h / t, or energy efficiency e , t / (kw h); area constant, such as the Thompson index. .Coal mill simulation the Bernhard Grove index.The advantages of the conventional algorithm is simple, easy; shortcomings can not calculate the size distribution of grinding minerals, while the correction factor with the different algorithms have different values, so the deviation is also larger. Constant grinding, conventional algorithm is divided into a volumetric method, the Bond work index and the Energy Efficiency Act. The most commonly used for the first two. (1) the volumetric method Lizarazu Karimov by the Soviet Union, former Soviet Union and China-Canton for the introduction.Mathematical expression of this algorithm were under the standard conditions of the design and selection of books than the productivity of t / (m cubic h); kg, for grinding material wear coefficient, is known by the test measurements; Kd for the mill diameter correction factor; Kty mill type correction factor; Ff, Kp mill feed particle size and product size correction factor; Kq similar system as the driving force, ie, mill design and standard transfer rate of the medium filling rate is different introduced a correction factor; Kq ore specific gravity correction factor.The calculated deviation is mainly derived from the selected values ??of the correction factor is appropriate, especially Kf Kp correction factor value has not yet been a good solution. (2) Bond work index 1961 Bond based on the cracks broken theory, the proposed algorithm.The method has been widely used later in the world mineral processing industry.Bond simulation algorithm is established on the basis of a large number of experimental data, and therefore within the scope of its test data more realistic.The disadvantage of this method are: the calculation results are totally different cylinder diameter greater than 4.0m mill; wet grinding power calculations deviation; grinding minerals can not be calculated particle size distribution; work index determination complicated.The method of calculation procedures are as follows: the first step, determined by the Bond work index mill Ball Mill Work Index Wib or rod mill power index Wir.The first step, measured by the Bond work index mill, ball mill power refers Wib or index Wir.The second step to calculate the standard mill (D = 2.44m) the transition to the operating needs in the industrial conditions selected mill work index (power) of Wx.Where in the Px in Fx, respectively, for 80% of ground product sifted materials and feed particle size; ki is the correction factor in different ground conditions;, k1 dry, wet ground correction factor; k2, for the grinding circuit the introduction of the correction factor; k3 mill diameter correction factor; k4 for the mill feed particle size is too large correction factor; k5 correction factor for the product size; k6 crushing ratio correction factor; K7, for the broken loop correction factor.Have had the experience of the correction factor formula.When the grinding circuit using single-segment mill broken loop correction factor.Have had the experience of the correction factor formula.When the grinding circuit using a single-stage ball milling, ball mill feed coarse grain size,[url=]Crushing Plant[/url] feed particle size determination of the ball mill work index equal to 2.1mm difference between the two is too large, thus using the calculation of single-stage ball mill power consumption should be index .Instead of the ball mill index formula.

crusher (3) energy efficiency under the Energy Efficiency Act, the design uses the energy efficiency of the mill Ex (t / kw h) The calculation of ex = estKgKfKp where: Est, standard mill energy efficiency standard ore, t / KW h; other symbols have the same meaning.The selection of the mill to grind mineral and new to the material of a specified grain size content.The energy efficiency of the method is relatively simple, the Determination of standard energy efficiency is more difficult, the determination of particle size of the power is not enough, the calculation will have a larger deviation.2. The overall balance of the dynamics simulation algorithm proposed in the late 1970s, this simulation grinding the substance of the mine loop indicators.

crusherAccording to the material to be ground rupture function (B) the selection function (S), the material in the mill residence time distribution function (C), the basic parameters of the classification function (D) and material transfer function (D) grinding circuit simulation.This approach not only can be used to select, calculate the mill specifications, and can forecast feed grain size, changes in operating conditions on the grinding of the mineral particle size.However, this algorithm exist following some of the major defects: BS function value and nature of the ore, operational factors, it is difficult to calculate the exact value realistic, and the large amount of experimental work; In addition, although a six seven Method, but the results are not ideal,[url=]Flotation Process[/url] resulting in the calculation when you need to be amended to adjust.Measured: b, s, rtd, c and d of each function value is an approximation under certain conditions, the calculation also requires the use of a correction factor of five or six to be adjusted.This simulation algorithm is still under study to improve.Overall balance of the grinding dynamics simulation to calculate the basic formula of grinding circuit, respectively, continuous working mill products, materials and mill within the material of Part I of grain yield level; r for material balance in the mill; si To select a function s matrix element values, its significance for the probability of rupture of the feed grain; bij rupture biovB matrix element values, the significance of product i in grain size from the compound of the i-level rupture from the valence number.Style of solving very complex, in general there are two ways; for the sake of analysis solution; another way for the use of numerical methods approximate solutions.According to S, BRTD, C and D are all functions of different calculation methods of the simulation algorithm pairs varied.For the closed circuit continuous grinding circuit with the following formula simulation to calculate the product particle size distribution.3. Conversion coefficient method established by the China Professor Chen Bingchen its basic guiding ideology is: According to dimensional analysis can prove that the mill than productivity p, the conversion relationship between the Bond work index Wi energy efficiency e of the three, and thus rectifiable similar to the quasi-number; Based on the above conversion relations can be established by the experimental data obtained in industrial mill operating parameters, structural parameters.Has established the conversion factor method simulation rod mill, ball mill industrial grinding circuit parameters of the computer software, the software for different times of grinding kinetics study, can be simulated to calculate q, e, w and Industrial wear mine all the parameters of the circuit,Jaw crusher including the grinding of mineral particle size distribution.This method not only the testing effort, and the high accuracy of calculation results.This article addresses :/ / .cn/S515.html



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