矿井型选煤厂外文翻译---重介质旋流器.docx

附录A 译文重介质旋流器G.J.de Korte and J. Engelbrecht摘 要：由荷兰国有能源化学公司发明的重介质旋流器在20世纪40年代已经被大量应用在矿物加工行业中单元处理上。重介质旋流器的应用是从钻石、铁矿、铬铁矿相对较高的密度到相对密度低于1时塑料的分离而变化的。尽管它的设计简单，但是重介质旋流器并没有被完全了解，并且继续提高重介质旋流器的工作仍然在继续。长远发展的主要目的集中在提高旋流器的效率和处理量。重介质旋流器的性能是有许多参数决定的，并且在这章里将讨论其中一些因素的影响。旋流器的外形尺寸近代，我们见证了旋流器直径增加到1500mm的程度，并且这些旋流器正被广泛应用在煤炭加工处理作业中，特别是在澳大利亚。更大的直径也意味着更大的入料，更大的溢流口和底流口，从而更大粒度物料給入旋流器。表1中定义了荷兰国有能源化学公司生产重介质旋流器的标准尺寸和当前产品趋势。表1 标准旋流器的外形尺寸参数荷兰国有能源化学公司推荐目前产品趋势旋流器直径达到1500mm入料口尺寸0.2旋流器直径0.2、0.25或0.3旋流器直径分离区直径0.43旋流器直径0.43或0.50旋流器直径旋流器筒长度0.5旋流器直径0.52.5旋流器直径底流管直径0.3旋流器直径0.30.4旋流器直径大多数旋流器制造商仍然坚持荷兰国有能源化学公司的建议以及生产符合玛泰集团规格尺寸的标准旋流器。然而，我们却需求有一个拥有更大容量、能够处理更大物料、用更多吸热材料制造的旋流器。后者则要求适用，因为现代采煤方法中缺少选择性，在煤炭开采过程中混入更多的顶层以及底层页岩以及更多低储量煤的开采。例如在印度，原煤中包含了相当大比例的高密度岩石。在表1中表明了由于这些要求而改变旋流器的外形尺寸来反应当前发展趋势。表2展示了南非玛泰集团的两种实用旋流器的入料量以及最大入料尺寸。表2中给出的值都是基于如下：表2 玛泰集团旋流器的尺寸和容量旋流器直径/mm标准处理能力旋流器高处理能力旋流器最大煤炭入料粒度/mm煤炭入料/t/h最大煤炭入料粒度/mm煤炭入料/t/h510345451996104181611456604497661757104711471207800531498027090062196943551000672491004541150773511156381300874681308541450976081451108 相当于前九次标称旋流器直径的入料 待测体积中介质与煤的比例为3.5：1 入料煤固体的相对密度为1.6在图1中展示了一台1450mm直径的玛泰旋流器。图1 玛泰集团直径为1450的旋流器尽管较大的旋流器能够处理大的入料粒度到140mm，但是这些粒度可能导致堵塞问题。旋流器通常处理最大粒度为50mm的特定粒度入料。这可能是由于在用泵将大颗粒物料打入旋流器中存在困难。分选粒度以及分选密度变化分选粒度的定义是当低于有效回收率的较小颗粒的粒度开始明显减少时的特定粒度。Bosman（1994）提供了和旋流器直径相关的近似分离粒度，如图2所示。Bosman仅仅包括直径到800mm的旋流器，而在图中的曲线表上已经扩展为代表1500mm直径的旋流器。图2 分选粒度与旋流器直的对应曲线图3 南非旋流器的特定粒度与不合格率的对应曲线分选粒度定义的问题就是它仅仅表明效率明显下降，没有量化的减少。这个可能的错误（EPM）不仅仅是旋流器直径的作用，还是给料压力、介质密度、介质粘度、颗粒形状和密度以及最大入料粒度等等。许多实际的数据来自于南非，他们主要利用直径为610mm的旋流器的操作而或得数据的（de Korte2007a），这些数据被总结在图3中，其中表明了由于入料微粒变小，缺陷确实变大了。定义分选粒度导致一些人相信重介质旋流器不能够处理小于分选密度和小于3mm部分的煤炭分选，例如，应当筛选出旋流器的入料和用仅仅需水单元处理像螺旋选矿和摇床选矿。这也导致了这个行业不情愿采用大直径旋流器。在实际中，随着粒度减小效率也降低，但是重介质旋流器的效率仍然比螺旋选矿和摇床选矿的效率高。表3显示了重介质旋流器和仅仅需水的单元的相对效率数据（de Korte和Bosman2006）。表3 重介质旋流器与以水为介质设备的比较参数以介质为基础以水为基础800mm旋流器800mm旋流器800mm旋流器800mm旋流器800mm旋流器两级旋流器两级螺旋选矿返流选矿摇床选矿尺寸/mm30.520.53130.5163.350.21210.130.530.5误差0.0430.0790.0210.0310.0260.0540.1500.1010.104分选密度（SG50）1.5631.7501.3121.3801.3501.7431.8001.6301.672误差（SG50）0.0280.0450.0160.0220.0190.0310.0830.0620.062同时分选密度随着作为特定直径旋流器中特定粒度函数的效率改变而改变的，图4显示了一种610mm直径旋流器的特定结果，这个特定结果是作为特定粒度函数的规范EPM和相对分选密度被给出的。图4 特定粒度、标准误差和相对分选密度的对应曲线如图5所示，在分选密度方面的转变是重要的发现，与重介质旋流器相比以水为介质的分选设备如跳汰机、螺旋选矿机和后边的设备分选效果更显著。图5 特定粒度与重介质旋流器和跳汰机的相对分选密度的对应曲线应用旋流器通常用于处理材料粒度在大约20mm和0.5mm之间。大直径旋流器的出现使较粗材料的处理成为可能。然而，与用泵传送大颗粒物料有关的问题仍然限制重介质旋流器中处理物料的上限为大约50mm。在产品需要按粒度分的地方，仍然习惯于布置重介室并且通过重介旋流器分选小颗粒物料。对于重介质旋流器0.5mm总是被作为实际分选下限的粒度尺寸。然而，用重介质旋流器将煤处理的小于0.5mm有显著的效果。建在比利时Winterslag和Tertre 、美国Marrowbone 、南非Greenside 、澳大利亚 Curragh 的选煤厂可以作为证据。不幸的是这些厂子并不像预期的那么好。最近在磁选机的进展促使恢复了重介质旋流器在优质煤炭加工中的应用。用重介质旋流器可以获得的分选效率优于仅仅用水的操作单元，例如，螺旋选矿和摇床选矿。由于这个原因，在南非正在建设一个新的优质重介选煤厂。大直径旋流器以及粗介质在细粒重介分选的成功应用是多级优质煤处理，这导致了一个全部有效的过程。（de Korte2002）。由于重介质旋流器的分离效率高，它们是处理难处理原煤的可供选择的方法。它们也被应用在产品的价格决定着能够获得的最高的收益领域。越来越多的重介质旋流器被应用在这些国家如印度和在美国易选煤中重介质旋流器的广泛应用就是这的证据。附录B 外文文献Dense-Medium CyclonesG.J.de Korte and J. EngelbrechtABSTRACTThe dense-medium cyclone, first developed by the Dutch State Mines (DSM) in the Netherlands in the 1940s, has firmly established itself as the processing unit of choice in many minerals industries. Application of the dense-medium cyclone ranges from the recovery of diamonds, iron ore, and chromite at high relative densities (RDs) through the separation of plastics at RDs below 1.Despite its simple design , the dense-medium cyclone is not fully understood, and work aimed at improving knowledge about cyclone behavior continues. The main focus of further development is intended for making cyclones more efficient and increasing throughput capacity. The performance of dense-medium cyclones is controlled by many parameters, and the influence of some of these factors is discussed in this chapter. CYCLONE DIMENSIONSRecent times have seen cyclone diameters increasing to the point where 1500mm-diameter cyclones are being used in many coal processing applications, particularly in Australia. The larger diameter also implies larger feed, overflow, and underflow openings and thus allows larger particles to be fed to cyclones. DSM standard dimensions and current manufacturing trends for dense medium cyclones are defined in Table 1.Most cyclone manufacturers still adhere to the DSM recommendations and Multotec “standard” cyclones are manufactured to these dimensions. However, there is a demand for cyclones having higher capacity, the ability to process larger feed particles, and the ability to handle higher amounts of sink material. The latter requirement applies because modern mining methods are less selective and include more roof and floor shale in the coal mined and because more low-grade reserves are being mined. In India, for example raw coal contains fairly large proportions of high-density material. As a result of these requirements cyclone dimensions are changing to reflect the current trends shown in Table 1.Table 2 presents relevant coal feed capacity and maximum feed size for the two types of cyclones available from Multotec (South Africa). The values given in Table 2 are based on the following: Equivalent feed head of nine times the nominal cyclone diameter Volumetric medium to coal ratio of 3.5:1 Feed coal solids relative density (RD) of 1.6A 1450-mm-diameter Multotec cyclone is shown in Figure l.Although the larger cyclones can handle large feed particles up to 140 mm, these particles can cause hang-up problems. Cyclones normally operate with a typical feed top size of 50 mm. This is probably because of the difficulty in pumping large particles to the cyclone.BREAKAWAY SIZE AND CUT-DENSITY SHIFTThe breakaway size is defined as the particle size below which the recovery efficiency for the smaller particles starts todecrease significantly. Bosman (1994) provides an approximate breakaway size versus cyclone diameter, as shown in Figure 2. Bosman includes cyclones only up to 800 mm in diameter, and the graph has been extended to represent cyclones of 1500-mm diameter in the figure.One problem with the breakaway size definition is it indicates only that the efficiency decreases significantly, without quantifying this decrease. The probable error (EPM ecart probable moyen) is a function not only of cyclone diameter but also of feed pressure, medium density, medium viscosity, particle shape and density, top size of particles in the feed and so forth. Actual data from a number of South African operations (de Korte 2007a), using mostly 610-mm-diameter cyclones, are summarized in Figure 3, which indicates that the imperfection does deteriorate significantly as the size of feed particles gets smaller.Defining the breakaway size has led some people to believe that dense-medium cyclones are not capable of beneficiating coal that is smaller than the breakaway size and that the minus-3-mm size fraction, for example, should be screened out of the cyclone feed and processed with water-only units such as spirals or teeter-bed separators (TBSs). It has also contributed to the industry being reluctant to adopt large-diameter cyclones. In reality, the efficiency does drop off as particles become smaller, but the efficiency obtained in dense-medium cyclones is still much better than that obtainable from spirals or TBSs. Table 3 shows the comparative efficiency data (de Korte and Bosman 2006) for dense medium cyclones and water-only units.Simultaneously with the change in efficiency as a function of particle size for a specific cyclone diameter, there is a concurrent shift in the cut density (SG50), Figure 4 shows a typical result for a 610-mm-diameter cyclone where both the normalized EPM and the relative cut density are given as a function of particle size.APPLlCATIONSCyclones were traditionally used to process material between approximately 20mm and 0.5mm. The advent of large-diameter cyclones now allows coarser material to be processed. However, the problems associated with pumping large particles still limit the upper size of material processed in dense-medium cyclones to approximately 50 mm. Where sized products are needed, it is still customary to install a dense-medium bath and to process only the small material via dense-medium cyclones.On the lower end of the size scale, 0.5 mm was always considered the practical limit for dense-medium cyclones. However, there have been significant efforts to process coal finer than 0.5 mm with dense-medium cyclones. The plants built at Winterslag and Tertre in Belgium, Homer City and Marrowbone in the United States, Greenside in South Africa, and Curragh in Australia serve as proof. Unfortunately the results obtained from these plants were not always as good as expected. Recent advances in magnetic separators have prompted renewed inter