陶瓷球为磨矿介质的立式搅拌磨磨矿特性研究

研磨介质作为立式螺旋搅拌磨的重要组成部分,其种类直接影响磨机的磨矿特性。以立式螺旋搅拌试验磨机为研究对象,采用CFD-DEM方法建立矿浆与研磨介质的流固耦合仿真模型,对氧化铝陶瓷球和高铬钢球两种研磨介质进行磨矿过程仿真研究,分析介质球的运动速度、碰撞力、碰撞次数以及螺旋搅拌器的转矩。利用试验磨机进行磨矿试验,检测38μm和45μm下的物料筛下累积量并计算磨机的磨矿吨功耗。结果表明,在相同填充率的条件下,以陶瓷球为磨矿介质的立式搅拌磨磨矿吨功耗小于以钢球为磨矿介质的吨功耗,但磨矿处理量较低;当陶瓷球的填充率提高时,磨矿吨功耗会提高,同时磨矿处理量也有所提高。     

立式搅拌磨机磨矿机理研究进展

立式搅拌磨机是一种高效率、低能耗的细磨和超细磨磨矿设备,相对于卧式球磨机,立式搅拌磨机在节省能量消耗方面具有显著的优越性,被广泛应用于矿山领域的精矿再磨和第二、第三段磨矿作业。为了促进立式搅拌磨机的优化与开发,本文介绍了立式搅拌磨机的运行工作原理,系统总结了立式搅拌磨机研磨理论和磨矿介质运动状态研究成果,综述了搅拌器转速、介质填充率、磨矿介质属性、搅拌器属性等工作参数与结构参数对立式搅拌磨机磨矿过程和研磨效果的影响,分析了立式搅拌磨机关键技术参数的选择条件,为立式搅拌磨机的机理研究与发展提供参考。     

立式螺旋搅拌磨机选型试验研究

采用实验室立式螺旋搅拌磨机对石英砂进行磨矿试验研究,初步确定适合该机型的运行参数。对新疆某铁精矿进行选型试验研究,得到该矿石的单位磨矿能耗为11.82 k W·h/t,根据试验结果推荐选用装机功率为630 k W的KLM-630型立式螺旋搅拌磨机作为该项目的细磨设备。该磨机自投入运行以来完全能满足工艺指标要求,表明利用实验室立式螺旋搅拌磨机测定矿石的单位磨矿能耗,可为工业立式螺旋搅拌磨机的选型提供科学的指导依据。     

基于相似理论的大型干法立式搅拌磨仿真分析

立式搅拌磨大型化发展成为必然趋势,但设备的大型化分析对计算资源需求较高,难以直接进行数值模拟.在相似理论的基础上,确定了模型与原型所需遵循的相似准则,依此得出磨机各参数的相似系数,建立相似模型,并应用CFD-DEM多学科耦合方法进行数值模拟,从而完成对大型化设备的工作特性研究.仿真结果与试验数据基本一致,验证了相似模型...     

某铁矿石立式搅拌磨机与球磨机磨矿能耗对比研究

立式螺旋搅拌磨机通常用来作为粗精矿再磨或者原矿细磨设备,很少用作粗磨。利用立式螺旋搅拌磨机对某铁矿石进行粗磨试验研究,并与球磨机磨矿效果进行了对比,以研究这两种磨机对该铁矿石的粗磨效果。研究表明,在适度的粒度范围内,立磨机与球磨机都具有各自的优势,都能够达到高效节能的磨矿效果。     

铁矿石在搅拌磨机和球磨机中细粒级磨矿效果的对比试验研究

介绍了某铁矿石物料在JU-2.2立式螺旋搅拌磨试验机和标准Bond球磨功指数试验机中的磨矿试验过程及试验结果,分析了2种磨矿方式磨矿效果的差异。试验证明,在细粒级磨矿中,立式螺旋搅拌磨机的磨矿效果明显优于球磨机。     

基于离散元的立式辊磨机粉磨性能研究

为提升立式辊磨机粉磨性能,在分析得出辊盘配合形式、磨辊个数、转速为粉磨性能主要影响因素后,以颗粒黏结建模思想构建物料模型,将黏结键断裂数作为评价指标,基于离散元软件EDEM进行单因素实验与正交实验。运用MATLAB做回归分析,建立黏结键断裂数与磨辊个数和转速的函数关系模型与响应曲面图,然后将正交试验得出的最优方案代入计算,最后通过仿真验证最优方案的粉磨效率。结果表明:立式辊磨机的粉磨效率受辊盘配合形式的影响,且随着磨辊数与转速的增大而提升,仿真试验也验证了最佳方案的可行性,为立式辊磨机的设计提供了参考。     

KLM型立式螺旋搅拌磨机的研究与应用

根据立磨机结构和工作原理,结合细磨作业立式螺旋搅拌磨机设计要求,选择KLM系列立磨机主要结构参数,通过对筒体、螺旋搅拌机构等关键部件的结构设计解决大型立磨机研制中的关键技术问题。介绍KLM系列立磨机在铁矿和铜钼矿选矿再磨中的应用情况。     

基于ANSYS立磨机螺旋搅拌机构的分析与优化

在实验室试验确定立磨机工况基础上,基于有限元分析软件ANSYS对某KLM立式螺旋搅拌磨机螺旋搅拌机构进行了分析和优化,使螺旋底板最大应力降低约60%,强度大大增加,为螺旋搅拌结构设计提供了理论参考和技术支持。     

基于离散单元法立式螺旋搅拌磨机内介质运动学研究进展

阐述了立式螺旋搅拌磨机的结构组成及工作原理、离散单元法的基本原理和最新发展情况,国内外基于离散单元法对搅拌磨机内介质运动学的研究进展,浅析了存在问题及发展方向。     

基于CFD超细磨用搅拌装置关键参数影响研究

在分析超细磨技术要求的前提下,通过分析盘式、螺旋式、叶轮式、棒式四种常用搅拌装置型式,确定了盘式是较为适合的超细磨用搅拌装置。利用计算机仿真流体力学建立了仿真分析模型,进行仿真分析。通过仿真得到了搅拌装置的流场分布状态和输入功率变化情况,重点分析了转速、搅拌元件直径、间距、面积比与流场、功率间的影响关系及变化范围。通过仿真明确了搅拌转速的范围为300~800r/min,搅拌元件直径的范围在150~170mm,搅拌元件间距的范围为30mm左右,空隙面积比的范围为0.15~0.35。各参数的确定为实验和工业中超细磨技术和设备的研发奠定了基础。     

Assessing the stirred mill design space

In the context of the mining industry, smaller grain size and other mineralogical characteristics have motivated the need to grind finer. In order to address this need, the interest in fine grinding technologies has grown over the last 20 years as is illustrated by a growing body of knowledge on stirred milling. Emphasis in recent years has been on the use of computationally intensive modeling and simulation methods such as the discrete element method (DEM) and computational fluid dynamics (CFDs). However, due to the computational requirements of these two methods, initiating a study that spans the stirred mill design space would take a lot of computational effort and time. Therefore the goal of this paper is to propose and apply a simplified stirred mill model that will then be used to assess configurations in the stirred mill design space.To this end, a stirred mill model was proposed based on the assumption that the main if not only mechanism of ore breakage is shear. As the basis of this model is the fluid mechanics definition of shear stress, the stirred mill power model became a function of viscosity, mill speed and a new parameter called shear volume. An initial validation using published data indicated the shear based power model correlated well with measured power.Establishing a morphological chart to delimit the stirred mill design space indicated that 24 design and operating conditions can be assess using the established shear volume measure. The results indicated for the mill configurations tested that a change in stirred mill liner design can potentially increase shear volume and power from 14% to 290% as compared to smooth chamber liners.     

立磨机磨矿机理研究

本文分析了立磨机内磨矿介质的运动状态,分别讨论了磨矿介质在两个磨矿区域产生的不同磨剥作用,分析结果表明增大螺旋叶片直径和转速,减小螺旋升角有助于提高立磨机磨矿效率,但是为了能使立磨机磨矿效率最大化的同时降低磨矿能耗,必须综合考虑各种磨矿因素才能确定合理的结构参数和运行参数。     

基于MATLAB/Simulink的立磨机批次磨矿的建模与仿真研究

以总体平衡模型为基础, 使用动态系统模拟仿真软件MATLAB/Simulink对立磨机批次磨矿过程进行了建模与仿真。基于马钢集团东山选厂铁粗精矿实验室立磨机批次磨矿试验结果计算了碎裂分布函数b_ij和碎裂速率函数S_i。使用该模型对立磨机批次磨矿和连续磨矿分别进行了仿真运算, 两种情况的仿真结果与实测数据吻合良好, 为该模型应用到立磨机与旋流器组成的闭路磨矿分级系统的建模与仿真研究奠定了基础。     

DEM modelling of the dynamics of mill startup

Speed is one of the important parameters in tumbling ball mills because it affects the dynamic motion of the balls within the mill. In turn the motion of the balls affects the distribution of the forces and thus the power draft of the mill. The main objective of this work is to model the dynamics of mill startup using the discrete element method (DEM). To achieve the experimental objective speed and torque as a function of time during mill startup were measured experimentally. A 0.55 m diameter mill was used to perform the experimental analysis. Load volume, J of 0% and 20% and mill speed of 70%, 100%, 120% and 150% of the critical are analyzed in detail. The DEM software, MillSoft (by Rajamani) was used to model the experimental results. During the experiments, the mill was allowed to ramp from rest until it reached the setpoint; after this it continued at constant speed. We have developed good dynamic models of mill speed. The experiments show that torque is the same for all conditions up to the point where each attains steady state, because the ramp rate is constant. The final torque for speeds greater than 100% of the critical speed (experiments and simulations) is not zero because only one layer of balls centrifuges in the time used. The experimental and the simulated torque compare well. Overall the dynamics of mill startup can be modelled with semiquantitative accuracy using DEM.     

Is media shape important for grinding performance in stirred mills?

Models for understanding the basic concepts of fine grinding and how they apply to the design of stirred media mills have not yet matured. While spherical media in tower mills has previously been studied, real grinding media shape in stirred mills can range from spherical (steel/ceramic balls) to highly non-spherical (sand or slag) resulting in very different media and grinding dynamics. Handling the contact mechanics of non-spherical particles is a challenge for numerical models, and very few studies dealing with non-spherical particle shape exist in the literature. Discrete Element Method (DEM) simulations of dry media flow in a pilot-scale tower mill are performed for four cases with different shaped grinding media, in order to understand how flow and energy utilisation within a stirred mill depend on media shape. Differences in media transport, stress distribution, energy dissipation, and liner wear were observed in the tower mill for the spherical and non-spherical cases. A significant departure from sphericity of the media leads to strong dilation of the bed, reduced bulk density, and a reduction in active volume and collisional power levels leading to a reduction in power draw for the mill. In addition, highly non-spherical media tend to pack tightly near the mill walls forming a near solid layer around the inside of the mill shell which results in poorer transport and mixing, as well as increased wear rates on the screw impeller. Grinding performance in stirred mills appears to deteriorate strongly when using highly non-spherical media.