影响圆锥破碎机的片状粒子的一些因素外文文献翻译、中英文翻译

翻译部分英文原文 TECHNICAL NOTESOME FACTORS WHICH AFFECT THE GENERATION OF FLAKY PARTICLES BY A CONE CRUSHERACAPLING and NBBARRETTTDepartment of Mining and Mineral Engineering，University of Leeds，Leeds LS2 9JT，UK Lindley Plant，Heage，Derbyshire，UK (Received 6 October 1995,accepted 15 March 1996)ABSTRACTThe products from a series of pilot scale tests have been analysed for size and flakiness to evaluate some of the factors affecting the generation of flaky material in a cone crusherTwo different feed sources characterised in terms of resistance to crushing and tensile failure were used to evaluate the influence of crusher setfeed rate and of material type on the resultant product characterKeywordsIndustrial minerals；crushing；particle morphology；comminutionINTRODUCTIONAggregate producers must meet both size and shape specificationsThe BS Flakiness Index F.I.= Mass flaky material in range100 / Total mass material in range (1)avoids a rigorous definition of particle shape by simply assigning particles according to their ability to pass a special slotted gaugeThe shape of crushed product depends on the material characteristics and the comminution methodEarly work concluded that impact machines give the least and cone crushers the most flaky product and low reduction ratios favour the production of nonflaky product【2】Cone crushers have much lower running costs particularly for harder abrasive materials and are in widespread use in the aggregate industryTHE PROGRAMME OF WORKWork has been undertaken with the Objective of evaluating the effects of feed rate and crusher setting on the generation of flaky material by a cone crusher from two different natural materialsTwo feed rates and five crusher sets covering the range of the machine were usedThe lower feed rate ensured free crushing，with particles crushed independently and loaded directly by the crusher facesA higher level allowed material build up in the crusher feed cavity giving choked conditions where loading is achieved through a particle bedTHE MATERIALSThe two feed materials were of similar sizeThe first contained two major rock types；carboniferous limestone 77，and millstone grit(gritstone)，23(Redland Aggregates，Masham，North Yorkshire)，the second also contained two major rocks；a metamorphic type known locally as granite，88and shale，12(Tarmac，Cliff Hill Quarry，Leicestershire)Particle characterisationFlakiness Index【1】determination was undertaken for all materials larger than 40 mmFor smaller sizes，a microscope was used to distinguish flaky particles and the index determined from the weights of the two categoriesA conversion factor was established between the methodsSize analysis of all materials was determined by standard sieve analysisCrushabilityThe simpler Rock Impact Hardness Number (RIHN)【3】was used rather than the recommended aggregate strength tests【4】which require extensive laboratory apparatusIts linear relationship with tensile strength 【5】，suggests a good correlation with generation of particles by cleavage，an important mechanism in the generation of flaky particles 【6】The Crushability Work Index(CWI)【7】was determined for comparisonBoth Cliff Hill species were substantially harder than those from MashamTHE PILOT SCALE TESTS Tests were conducted using a Standard Symons 2-foot Cone Crusher fitted with a fine bowl having a feed opening of 572 thinand recommended minimum discharge setting of 64 mm，【8】Products and feed for each of twenty tests were analysed for size and shapeDISCUSSION OF RESULTSFull analytical results，presented elsewhere【9】，allow the characterisation of the products in terms of 1) the mass fraction in each size fraction2) the flakiness index of each fraction3) the flakiness index of the total product4) the distribution of flaky and nonflaky material by sizeand permitted the identification of conditions favourable for the generation of nonflaky materialFactors affecting size distribution of productThe Masham product was generally finer than that from the harder Cliff Hill material due，in part，to its crushing behaviourOnly the Masham material showed any difference between feed rates，generating more fines during choke feedingThe granular structure of this material would tend to encourage thisA tendency for the crushing faces to be forced apart by the harder Cliff Hill feed under crowded conditions would reduce its production of finesFactors affecting Flakiness Index of different sizes The pattern illustrated in Figure 1 was observed in all casesProduct flakiness of 100% at the largest size，falls as size decreases，passing through a minimum，before then increasingAll larger particles tend to be flaky but at decreasing set particles of similar size have to be increasingly flaky (thin) to enable passage through the crusher cavityFor the Masham feed the flakiness of coarser sizes is slightly lower for choke feeding，more especially at finer setssuggesting that under these conditions flaky material is more likely to be broken as a consequence of the restricted opportunities for favourable orientation within the crushing chamberFig1 Flakiness Index versus size-Masham Products for different feed rates and crusher setsIn all cases the size at which flakiness index is a minimum is broadly related crusher set，increasing as the crusher set increasesOverall product flakiness，calculated as the weighted mean of the index for individual size fractions is generally less under choke feeding，and reduces as set decreasesFactors affecting sizes for peak production Fig2 Product distribution by shape and size-Masham choke feeding ac stated stated sets An alternative measure of product character given by the distribution of flaky (F) and nonflaky(N) material by size，illustrated in Figure 2，also reveals differences in behaviourExamination of the data revealed，despite the scatter of the results，that for both materials（1）peak production(both shapes)is related to set and in all cases tends to increase and occur in larger sizes as set increases（2）peak flake production occurs in a size larger than that for nonflakePeak flake and non-flake production is similar under different feed conditions with the Cliff Hill material but increases and occurs at higher sizes as set increaseswhilst for the Masham feed maximum production occurs at increasing size but flake production decreases whilst non-flake increasesChoke feeding conditions，especially at finer sets，tends to result in more nonflake and 1ess flake production although the effect on the Cliff Hill material is noticeable only at the finest setLarge sizes consist almost entirely of flaky material which escapes breakage due to favourable orientationGeneral DiscussionIf the form of the product size distribution is similar then a smaller crusher set should reduce overall flakiness since any increase in flakiness of the coarser sizes will be counter balanced by an increased proportion of nonflaky finer sizesFor the Masham feed this tends to be the caseThe results for Cliff Hill are 1ess clearEarlier work 2suggested that flakiness decreases at high feed rates and also at larger crusher setsThese results appear to contradict the latter findingHowever overall flakiness masks the effects on individual size fractions，some of which may not be required as productLarger sized ftaky particles generated by crushing at large sets could presumably be removed by screening leaving the finer nonflake as productThe increased peak nonflake production for larger crusher sets with the weaker Masham material suggests that these conditions favour the generation of a product，following rejection of coarse sizes by screening，of low flakinessContrary to earlier work 2 the minimum flakiness size is always less than the size at which total production is a maximum and does not correspond to the size of maximum nonflake productionEquivalence of these two sizes would clearly generate the maximum quantity of nonflaky product，normally the objectiveThe ratio of maximum production sizes to minimum flakiness size allows examination of the effect of crushing conditions on nonflake production，shown in Figure 3，revealing a broad trend for these sizes to approach each other as crusher set decreasesThis suggests that the most favourable conditions occur for smaller sets，that iS high reduction ratiosAlthough peak nonflake production increases as set increases it is accompanied by greater flake product in the same sizeThe dilemma then is whether the requirement is maximum production of nonflake and that generation of flaky material in the same size is not a problemin which case a low reduction ratio seems to be requiredor whether the minimum flakiness index iS requiredthat is the generation of flaky material iS to be minimised in a particular sizeIf this is the case then a much smaller set seems to produce the required resultThe choice then is between maximum production of nonflake or minimum flakiness indexIn reality a compromise between the two requirements will often generate the maximum product of the required specification and close control on the set of the crushing machines will be required to ensure optimum conditions are met at all timesThe large variation in the data leads to a degree of uncertainty in relation to its interpretation and reflects the difficulty of obtaining data in relation to large sized material，nevertheless it is believed that some important trends have been identified which are of relevance to the performance of cone crushersThe work here highlights the importance of gathering further information in order properly to quantify these effectsFig3 Size ratio versus crusher setCONCLUSIONSThe broad conclusions reached from the current work can be summarised as follows；1.Maximum flakiness occures at the maximum product size and reaches a minimum at a smaller size，related to crusher set，before increasing in the finer size ranges2.Flakiness of a specific size fraction increases as crusher set decreases in the coarser size range but decreases for the finer size ranges3.Choke feeding results in lower flakiness only for small crusher sets in the coarser sizesThis effect is reduced for the harder material4.The size where maximum material is generated increases as set increasesThe minimum flakiness size is always less than the size for maximum production of nonflake which in turn is less than the size for maximum flake production5.As crusher set decreases there is a tendency for the size at which maximum production of nonflake occurs more closely to approach the size for minimum flakinessACKNOWLEDGEMENTSThanks are due to Warren Spring Laboratories (DTI) for the support of this work.REFERENCES1.BS 812Testing AggregatesPnn 1Methods for determining particle size and shapeBritishStandards Institute，London(1975)2.Shergold，HE，A study ol the granulators used in the production of roadmaking aggregatesDeptScientific and Industrial Research，Road Research Laboratory，Technical Paper 44，HMSO(1959)3.Brook。N，Fines measurement of the impact testing of rocks，nfJRock MechMinScfGeomechAbstr，23(4)，333(1986)4. BS 812Testing AggregatesPart 2 Methodsfor determining physical propertiesBritish Standards Institute，London(1 975)5. TownhillRewston，PHamis，A，The relationship between Rock Impact Hardness NumberfRIHN)and tensile strengthLeeds University Mining Association Journal，l 19(1988)6. Kelly，EGSpottiswood，DIJ，The breakage function；what is it reaUy?Minerals Eng，3(5)，405(1990)7. Bond，FC，Crushing and grinding calculations-part 1BritChemEng，6(6)，378(1990)8. Nordberg Symons Cone Crusher Process Manual，Bulletin No 1 10，Nordberg ManufacturingCompany，Milwaukee9. Barrett，NB，The computer simulation of cone crusher circuits for the aggregate industryPhD Thesis，University of Leeds，Sept1992中文译文影响圆锥破碎机的片状粒子的一些因素摘 要人们从一系列小规模等级测试的产品尺寸和薄片状上来分析和评估影响圆锥破碎机世代薄片材料的一些因素。两种不同进料来源的特征根据破碎的阻力和拉伸的损坏来评价破碎装置、进料率和材料类型对破碎产物的影响。关键字：工业的，矿石，决定性，粒子生态学，破碎介 绍所有的生产者都必须遵守尺寸和形状规范。英国标准中片状指数为： F.I.=（片状材料质量/总体材料质量）100根据微粒的能力来通过一种特殊的狭槽测量，这种简单的分配粒子要避免对微粒的外形作严格的定义。压碎的产品形状依赖于材料的性质和压碎的方法。早期的研究工作得出的结论是冲击机械的给料最少但圆锥破碎机可产生最薄的的产品, 而且对无薄片产品有较低的缩减比。圆锥破碎机的运行成本很低，尤其对坚硬的研磨材料而言。所以这种破碎机在整个工业中被广泛的应用。工作的程序在对进料速率和破碎机设置客观评估的基础上，工作已经开始实施，其中，圆锥破碎机能把两种不同的自然原料破碎成一种片状的物料。两种进料速率和五种破碎装置覆盖了一系列使用的破碎机械，很低的进料速度确保了自由破碎的进行，粒子被独立的压碎而且直接被破碎面装载，更高水平的破碎是原材料在装填完成时被堵塞的情况下允许破碎机进料腔增大。原材料两种进给原材料有着相似的尺寸，第一种包括两种主要的岩石类型，77的含煤石灰石和和23的磨石沙砾（即砂岩，红土聚集体，马萨姆，英国约克郡 北部），第二种也包括两种主要的岩石类型， 88变质的众所周知的花岗岩，和12的泥板岩（悬崖希尔采石场，英国中部的州） 。粒子特征片状指标对所有大于4 mm 的材料有用。对更小尺寸的来说，显微镜用来辨别薄片的微粒，片状指标用来确定两种类型的重量。然后在方法中建立一种转换因数。经过标准的过滤，所有材料的的尺寸分析就确立了。破碎能力简单的岩石冲击硬度值（RIHN）可以被直接应用，而不需要大量试验装置仪器的集中强度测试，它与抗拉强度的线性关系，小规模等级测试这种测试是用两脚的进料口尺寸为57.2mm的标准圆锥破碎机来进行的。它的最小理论出料粒度为6.4mm,每进行20次测试试验，就对破碎产物和进给原料的尺寸和形状上的变化进行一次分析。结果讨论由上述试验，我们经过全面的分析，认为影响产物粒度的主要因素有一下几个方面：(1)质量分率在粒度级份额中所占的几率；(2)每个质量分率所占几率的片状指标；(3)整个产物中片状指标；(4)片状材料和非片状材料在尺寸上的分布；以上是可以证明有利于非片状物料产生的条件。影响产品尺寸分布的因素马萨姆（地名）生产的原料一般要好于从悬崖或石山上采集的坚硬的原料，部分原因就在于它们的特性不同。在过饱进料中，只有马萨姆原料向我们展示了进给速率之间的任何不同之处，就是产物变得更细小了。这也许是马萨姆原料具有规则的结构引起的希尔悬崖采石场坚硬的原材料在过饱进料中有被强制破碎的趋势，从而影响了产品的粒度。影响不同形状粒度的因素图1向我们展示的可以适用于任何情况。产品的粒度在破碎之前是100，为最大，经过破碎后就会减小,出料后是最小。所有的大尺寸粒子更倾向于成薄片状，但是有相近尺寸粒子的必须逐渐的成薄片（变薄），以致于能够通过破碎腔。对马萨姆原材料来说，它过饱进料时的产品比较粗糙的尺寸要小一些，尤其当破碎机的设置达到良好的状态时更明显。这样我们也可以得到一个推论：在过饱进料的情况下，只要严格控制破碎腔中对薄片材料破碎的有利方位,它更容易被破碎的完全。图一马萨姆原料在不同进给速率和破碎设置时的产品粒度尺寸在所有的情况下，片状指数都是最小的尺寸，这在很大程度上都与破碎机的设置有关。它随着破碎机设置的增大而增大，对所有的片状产物，在过饱进料时，对它们统计的个体粒度份额都有明显地减小，而且随着破碎机的设置的减小而减小。影响产品最大粒度的因素薄片材料和非薄片材料的的产物尺寸特性的分布，如图二所示，也向我们揭露了一些行为上的不同。图二破碎机的设置一定时，马萨姆原料在过饱进料的情况下产品形状和尺寸的分布尽管结果有些分散，但仔细分析图中表明的数据，我们就会发现两组原材料：(1) 产物的