锥段结构对旋流器内部流场和分级性能的影响

水力旋流器最早可追溯到上世纪50年代,它是一种将压力能转化为动能且伴随着能量损失的装备,因其占地面积小、无运动部件、分级效率高等优点被广泛应用于煤炭分选、石油、化工等各类分选行业中,但由于其自身结构的限制以及外界工况的变化,分级精度难以保证,旋流器主要有柱段、锥段、溢流口、底流口和进料体组成,其中,锥段结构作为旋流器的主要分离区域,是影响旋流器分级性能的主要因素之一,因此,本文针对常规旋流器分级精度低、运行能耗高的问题,提出了一种改进旋流器锥段的方法用于提高旋流器分级性能,通过数值计算法呈现了直线型、抛物线型和双曲线型锥段结构旋流器对内部流场特性和分离性能的影响规律。数值结果表明：采用抛物线锥段可使其旋流器的切向速度和轴向速度减小,降低乱流的发生概率,流场稳定性得到有效提升,双曲线锥段内部流场不稳定,不利于颗粒的平稳运行。抛物线型旋流器零速包络面外移,细内旋流空间变大,细颗粒得到充分分离,分级精度得到一定提升。相比于常规型和双曲线型,抛物线型旋流器具有较小的湍流强度,颗粒稳定性得到有效提升,同时,抛物线型旋流器的陡度指数从0.61提升为0.72,旋流器分级精度得到大幅提升,由于其分离空间的变大,切割粒径稍有增大。     

对称双进口旋流器流场特征及分离性能

传统单进口旋流器存在流场不稳定、分离精度低等问题。创新旋流器结构、优化流场性能、提高分离 精度是当前旋流器应用的迫切需求。为了解决传统单进口旋流器对流场冲击大而引起的流场波动不稳定问题,提 出了一种对称双进口旋流器结构型式。采用数值模拟方法,通过 RSM 湍流模型、VOF 和 Mixture 多相流模型,对两 种进口结构的旋流器流场特征及分离性能进行了对比研究,结果表明：对称双进口旋流器的零速包络面和旋流流 场更加均匀,可以为颗粒迁移运动创造更加稳定的分级、分选条件;对称双进口旋流器流场静压、湍动能、轴向速度 和切向速度比传统旋流器均有不同程度的提高,其中对分离起主导作用的切向速度最大值提高了 16.90%,有效增 大了离心强度,强化了分离效果;入口速度为 7.5 m/s 时,10 μm 微细颗粒溢流分级效率较传统结构提高了 4.82 个百 分点,15 μm 微细颗粒溢流分级效率较传统结构提高了 11.34 个百分点。研究结果对丰富旋流器结构型式,进一步 提高旋流分离性能具有一定的指导意义。     

新型旋流器在再磨分级系统的应用实践

新型旋流器采用蜗壳预分级进料体和锥形溢流管两项新结构,使颗粒在进料腔体内实现了从外到内、由粗至细的排列,增大了粗、细颗粒分别进入底流和溢流的几率,有效提高了分级效率。在金堆城钼业百花岭选矿厂再磨分级工艺段的应用实践中表明：在同等作业条件下,相比普通旋流器,新型旋流器的分级溢流产品-0.038 mm粒级含量提高0.25个百分点,分级效率提高2.63个百分点。     

新型旋流器在再磨分级系统的应用实践

新型旋流器采用蜗壳预分级进料体和锥形溢流管两项新结构,使颗粒在进料腔体内实现了从外到内、由粗至细的排列,增大了粗、细颗粒分别进入底流和溢流的几率,有效提高了分级效率。在金堆城钼业百花岭选矿厂再磨分级工艺段的应用实践中表明：在同等作业条件下,相比普通旋流器,新型旋流器的分级溢流产品-0.038 mm粒级含量提高0.25个百分点,分级效率提高2.63个百分点。     

新型旋流器在磨矿分级回路中的应用

新型旋流器依靠调控进料颗粒空间预排列和调整分级空间大小两项新技术,使颗粒在进料腔体内实现了从外到内、由粗至细的排列,增大了粗、细颗粒分别进入底流和溢流的几率,有效提高了分级效率,并在分级区内减小了紊流程度,降低了能量消耗。在江西铜业集团两个选矿厂的工业应用表明,同等工况条件下,相比进口旋流器,获得分级溢流产品-74μm含量提高2%～3%、分级质效率提高5%的生产指标。在湖北三鑫金铜选矿厂的工业应用中验证了其优良的分级性能。     

螺旋线进料体旋流器在某选矿厂分级作业改造中的应用

针对珲春紫金曙光金铜矿选矿厂三系列磨矿-分级作业存在的一次分级溢流细度粗、分级效率低和循环负荷大等问题,采用新型螺旋线进料体旋流器替代原渐开线进料体旋流器进行一次分级改造。结果表明,改造后一次和二次分级溢流细度均明显增大,分级效率提升,降低了循环负荷,提高了磨机处理能力,底流夹细现象也得到改善。经湍流强度和颗粒轨迹线数值模拟验证,说明螺旋线进料体旋流器较渐开线进料体旋流器具有较大优势。     

海王精细分级旋流器在某特大型铁矿细粒磨矿分级工艺中的应用

针对常规旋流器存在的分级效率低、循环负荷过高等问题,威海市海王旋流器有限公司研发了应用于高浓度、细颗粒、窄粒级分级的精细分级旋流器。该旋流器采用螺旋线进料、复合锥体等多项专利技术,并用于某特大型铁矿细粒磨矿分级工艺中,达到了提高分级效率、降低沉砂夹细量及减轻矿物过磨的目的,得到了更高的精矿品位,为系统提产创造了有利条件。     

新型螺旋线进料体旋流器在德兴铜矿尾矿回收厂的应用

研究了新型螺旋线进料体旋流器在德兴铜矿尾矿回收厂的使用效果,与传统的渐开线式旋流器相比,新型旋流器能够减少旋流器入料口阻力,并实现预先分级作用.对比试验结果表明螺旋线进料体旋流器的分级质效率高于传统旋流器分级质效率7.96个百分点,效率曲线陡度指数高0.044个百分点,溢流中-74μm含量提高了7个百分点.     

湍流对旋流器分离和分级的影响

根据旋流器的流场理论,分析了旋流器内湍流运动对物料分离效率和分级精度的影响,介绍了降低湍流强度的一些方法。     

平底结构对水力旋流器流场特性及分离性能影响

基于数值模拟对比了渐缩平底旋流器与复合锥角旋流器流场特性,探究平底结构对水力旋流器流场的影响。结果表明,两种水力旋流器压强分布和切向速度分布基本一致,而空气柱附近压强梯度存在差异;渐缩平底旋流器溢流管下方湍流强度较低而底流口附近则相反;渐缩平底旋流器柱-锥交界面的空气柱附近轴向速度较高,导致其分流比较低。实验室旋流分离试验结果表明,平底结构能有效抑制溢流跑粗和底流夹细现象,显著提高分级效率,改善水力旋流器分离性能。     

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