【作者】 张国旺；

【导师】 黄圣生；

【作者基本信息】 中南大学 ， 矿物加工工程， 2005， 博士

【摘要】 超细搅拌磨机是一种高效节能的超细粉碎设备,是目前制备亚微米粉体或浆料的主要工业生产方法,所以,研制产品粒度细、粒度分布均匀、处理量大、能耗省的工业大型超细搅拌磨机就显得非常重要。但是至今没有形成超细搅拌磨机的设计理论,对其基础理论也研究得较少,这阻碍了超细搅拌磨机的工程放大和应用。因此,本文在系统地评述了超细粉体、超细粉碎设备和超细搅拌磨机的现状和发展的基础上,围绕超细搅拌磨机的结构和工艺参数,从理论模拟建立、粉磨理论研究、设备研制开发、试验研究和应用实践等方面进行了研究工作,其主要内容如下: 本文对超细搅拌磨机基本结构、粉磨机理和性能参数进行了详细分析,研究认为:超细搅拌磨机主要是以摩擦粉碎为主。在磨机中,应力强度是一个非常重要的参数,通过对棒式和螺旋式搅拌磨机的应力强度分析,得出不同类型的搅拌磨机具有不同的应力强度,因而适应不同的物料粉碎。对磨矿区域研磨介质球的受力和速度分析,得出磨矿作用主要发生在环形磨矿区域,提出了速度梯度大磨矿效果好,而不是以往的速度大磨矿效果好的概念,为工业型超细搅拌磨机的结构放大和优化设计提供了理论基础。 利用计算流体力学方法(CFD法)对超细搅拌磨机进行了流场仿真数值模拟,分析了盘式、棒式、螺旋式三种搅拌器的流场特性(速度梯度、流场的剪切率分布和粘性耗散率等)。通过综合分析,发现棒式搅拌磨机流场圆周方向速度梯度最大,流场的剪切率分布均匀性最好,是速度梯度大、应力分布均匀和阻力较小的一种磨机。流场仿真数值模拟分析为超细搅拌磨机的参数优化设计和工程放大提供了一种新方法。 通过采用不同搅拌器的对比试验,表明棒式搅拌磨机的研磨效果较好,这与流场数值的模拟结果是一致的,验证了模型的建立和模拟分析的正确性和可靠性。在3600L大型超细搅拌磨机,在研磨重钙时,条件相同的前提下采用棒式搅拌器的能耗比盘式搅拌器节省15%-17%,处理能力提高13%-15%。 提出了工业型超细搅拌磨机的结构工程放大方法,应用综合放大原则,对其结构参数和工艺参数进行了优化,搅拌器采用棒式搅拌基本结构,确定了最佳的更多还原

【Abstract】 Ultrafine stirred mill is a kind of ultrafine grinding equipment with high efficiency and energy conservation, ultrafine grinding is the main industrial equipment to produce submicron powder or submicron pulp, the powder produced by this machine has the advantages of fine particle size, granularity distribution uniformity,great throughput and low energy consumption.hence, the manufacture of large-scale industrial ultrafine stirred mill is very important. But there are still no the design theory of ultrafine stirred mill and the few study of the basic theory, this status hinders the engineering enlargement and the application of ultrafine stirred mill. Therefore, this paper systematically reviewed the present status and the development of ultrafine powder, ultrafine comminution equipment and ultrafine stirred mill. On the basis of literatures, inclosing the structure of ultrafine stirred mill and the process parameter, much work had been done to the foundation of theory simulation,the study of comminution theory,the analysis of experiments,the equipment development and the practical application, the following are the main contents of this paper:The paper analyzed the basic structure, the comminution mechanism and the capability parameter of the ultrafine stirred mill in detail. The following are the conclusions: attrition comminution is the main mode of the ultrafine stirred mill. In the cavum of this machine, the stress intensity is a very important parameter. The conclusion can be educed by analying the stress intensity of the stick type and the spiral type of the stirred mill that different types of the stirred mill have different stress intensity, adapting to different material comminution. The paper concluded that the effect of abrading mineral mainly accured in the area of the annular abrading mineral and put forward the conception that large shear rate of dispersion can reach good effect of abrading mineral by analyzing the strength and speed of the medium ball in the area of the comminution, butnot former conclusion that large rapidity lead to good effect, this provided the basic theory for structural enlargement and optimizing design of the industrial ultrafine stirred mill.Computational fluid dynamics(CFD) method was utilized to the fiowfield numerical simulation of ultrafine stirred mill, the flowfield characters(velocity gradient, shear rate dispersion of flowfield and the dissipative force of viscosity and so on) of three kinds of stirrer(disc type, stick type and spiral type) were analyzed.Through the generalized analysis,discovered the stick-like stirred mill flowfield circumference direction velocity gradient in the largest way and the flowfield cutting rate distribution uniformity best,this is a kind of stirred mill with big velocity gradient ,uniform stress distribution and small resistance.The analysis of the flowfield simulation provided a new method for parameter optimization design and project enlargement of the ultrafine stirred mill.Through doing some contrast experiments by using different mixer, indicated that the stick-like stirred mill had good grinding effect,this result was consistent with the result of flowfield numerical simulation and confirmed that the accuracy and the reliability of the model establishment and the simulation analysis.In the 3600L large-scale ultrafine stirred mill,grinding the calcium carbonate and under the same condition,the enegy consumption can save 15%-17%,the throughput can inhance 13%-15% by using stick-like mixer comparing to using the disc-like mixer.It was proposed that the structural engineering enlargement method, the application synthesis enlargement principle of the industry ultrafine stirred mill, carried on the optimization to its design parameter and craft parameter; used the stick-like stir basic structure;determined the best ratio of high to diameter of the tube body and the topmost line speed of the mixer;designed and R&D 3600L large-scale ultrafine stirred mill by above analysis.Through the engineering practical application on ultrafine comminution to calcium carbonate and barite,confirmed that the structuredesign of the machine was reasonable and its parameter was superior.This kind of machine had been promoted and applied more than 10 sets in Shan dong,Guang zhou and Hunan.In order to more extend the applied areas of the ultrafine stirred mill, two kind of minerals, pyrite(as the submicron catalyst for the direct liquefaction of coal) and calcium carbonate(as the coarse whiting pulp for the pigment of paper manufacture coating), were experimented by this machine. The technical process, technical parameter and main influencing factor of ultrafine stirred mill were researched in detail. The submicron pyrite oil thick liquid(d50 ^ 0.7um)manufactured by the optimized late-mode ultrafine stirred mill can be regarded as the submicron catalyst for the direct liquefaction of coal;the submicron calcium carbonate(dso^ 0.6um) also manufactured by the optimized late-mode ultrafine stirred mill can be regarded as the pigment of paper manufacture coating.更多还原