XJM-S45型浮选机叶轮参数与流场模拟及结构优化研究

运用CFD软件对XJM-S45型浮选机初始样机进行了数值模拟,通过改变叶轮结构和参数,计算在不同叶轮结构和参数下浮选机的流场特征参数值,由叶轮排液量、功率等流场特征参数值随叶轮结构及参数的变化关系,确定了XJM-S45型浮选机叶轮最佳转速为136 r/min,叶轮最佳叶片数目为8片,叶轮下层叶片的最佳后倾角度为原始角度增大5°,实现了XJM-S45型浮选机叶轮的结构优化。     

浮选机内部气—液两相流场特性研究

本物浮选过程中的多相流体特征直接影响矿物分选效率,针对有效容积为0.1m~3的充气机械搅拌式浮选机,运用计算流体力学对浮选机内部气-液两相流体特性进行数值模拟计算,分析了矿物浮选过程中复杂的流体特性。基于CFX流场数值模拟软件,建立了气-液两相流场数值模拟策略,通过对比标准k-ε湍流模型和RNG k-ε湍流模型,确定了离散气相-零方程、连续液相标准k-ε湍流模型的数学模型,探究了不同表面张力、曳力相间作用力对浮选机内部气—液两相流场特性的影响,模拟了充气强度和搅拌强度对浮选机内部气—液两相流场的影响。研究结果表明:表面张力系数在浮选机内部气-液两相流场数值模拟研究中影响很小,选定较为常用的表面张力系数0.073为模拟标准;Grace曳力模型适合充气机械搅拌式浮选机气-液两相流场的数值模拟;浮选机充气速度应小于2.0 m/s时,此时气相流场速度分布较均匀,气相逸散性较好;浮选机转子转速每增加50 rpm转子和定子表面受压大约增加300 Pa,中等转速450 rpm适合该类型浮选机的浮选作业,气-液两相流体特性模拟结果将为浮选工艺参数的设定提供基础理论指导。     

浮选柱在微细粒锡石浮选中的应用研究

采用浮选柱对0.037~0.01 mm微细粒锡石进行了浮选试验研究,并对比了相同条件下浮选机和浮选柱的选别指标。结果表明,在给矿锡品位1.15%、浮选浓度30%条件下,经浮选柱一粗、一扫和一精作业,可获得锡品位25.50%、回收率82.46%的锡精矿;与浮选机相比,锡精矿品位可以提高8.0个百分点,回收率提高6.6个百分点。     

基于试验和数值分析的浮选机停留时间分布特性研究

浮选机停留时间分布研究对于认识大型浮选机内短路和死区等异常流动具有重要意义。本文采用示踪试验的方法研究了实验室和工业浮选机的停留时间分布特性。电导率示踪法可以有效应用于实验室浮选机的RTD研究,而荧光示踪法可以解决工业浮选机三相体系下的RTD研究。应用CFD方法研究了动态体系下浮选机的流态特征,揭示了示踪剂在浮选机内的流动过程,CFD方法揭示出浮选机内的停留时间分布特征与理想搅拌反应器相似,说明具有很好的搅拌混合效果。在世界最大的680m3浮选机开展了停留时间分布特征研究,平均停留时间达到理想平均停留时间的89%,说明浮选机内短路和死区等异常流动较少。     

离心浮选机的研究进展

阐述了国内外离心浮选机及其重要组件气泡发生器的研究成果和发展现状,介绍了德国充气式浮选机、Thomas离心浮选机、XMP浮选机、因莫夫浮选机及新型自吸气式离心浮选机的工作原理、结构形式与特点,并分析了离心浮选机的发展的方向。     

浮选机内气液两相流数值模拟

基于群体平衡理论和CFD数值计算方法,考虑不同尺寸气泡及气泡间聚并与破碎,建立了气液两相流的CFD-PBM耦合模型。应用该模型和Fluent软件对某铝厂的KYFⅡ-40型机械搅拌充气式浮选机内的矿浆-气泡两相流进行数值模拟,获得了其两相流场、气含率和气泡尺寸分布等信息。模拟结果表明,在生产工艺条件下,浮选机内的流体在转子带动下形成上下两个循环流场;气含率保持在0.1左右,壁面附近及循环流场的中心处气含率偏高,并沿气液混合区向气液分离区减少;气液混合区的气泡变化以破碎为主,气泡较小,分离区的气泡变化以聚并为主,且气泡尺寸逐渐增大;气泡尺寸总体上呈多峰分布,其主峰对应的气泡直径位于3~4mm之间,有利于提高浮选生产效率。     

颗粒粒径对浮选机固—液两相流场分布特征影响研究

针对充气机械搅拌式浮选机,运用CFD流体模拟软件进行了颗粒粒径对浮选机固—液两相流场分布特征的影响研究。通过模拟分析可知:离散相矿物颗粒与连续液相两相之间相互作用较小,流场分布特征基本保持一致,微细粒矿物颗粒粒径对浮选机内部固—液两相流场特性影响较小。转子及定子表面压力分布值与颗粒粒径有较大的关系,且在此处区域附近湍流动能较大,保证了矿物颗粒在该区域的较好分散性。     

自吸气浮选机模拟研究

为加深对自吸气浮选机槽体内的流场结构及性能参数的认识,运用CFD仿真技术对自吸气浮选机槽内气-液两相流进行了模拟研究。以实验室JJF-0. 2 m~3自吸气浮选机为原型进行仿真建模,采用六面体网格对整个模型进行网格划分的网格数量为1. 6×10~6。采用Euler-Euler双流体模型对气-液两相流进行稳态模拟仿真,运输方程的计算运用商业软件ANSYS-FLUENT软件。自吸气浮选机的吸气速率不能预先设定,需要通过模拟结果给出。我们设定气相为单一粒径的气泡,直径为1 mm。模拟过程中监测了叶轮区的气含率及功耗,结果表明浮选机处于良好的操作状态。分析了槽内不同区域的气含率云图及速矢量图,对自吸气浮选机内的流场有一个直观的认识。     

KYF型浮选机单一液相流体特性模拟研究

针对KYF型充气机械搅拌式浮选机,选定标准k-ε湍流模型对浮选机内部单一液相流场进行了数值模拟,并在不同搅拌强度下分析了浮选机内部单一液相流场速度、压力、湍流与涡流强度等分布特征,为浮选工艺参数的设定提供基础理论指导。     

自吸式浮选机叶轮叶片数量的选取

自吸式浮选机的叶轮结构参数与其性能参数的关系复杂。采用CFD模拟及试验的方法，以JJF浮选机的星型径向叶轮为基础模型，分析了叶轮叶片数量对自吸式浮选机内部流场特征及性能的影响。结果表明：叶片数量不影响流场的循环结构，都能形成适宜矿物悬浮及运输矿化泡沫的流场环境；叶片数量为4, 6, 8, 10时，随叶片数量增加，循环筒和竖筒内液相的轴向流速、湍动能、压力差及浮选机的循环量和功耗逐渐增大；当叶片数量增加至12时，由于叶片之间的间距过小，排液量下降，液相的轴向流速、湍动能、压力差及浮选机循环量开始减小，但功耗继续增大；在样本范围内，叶轮的叶片数量为10时，浮选机的循环量最大；在误差允许的范围内，不同叶片数量叶轮的性能参数模拟值与试验值较为吻合。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586