外文翻译--在非圆柱辊式破碎机中粉碎.doc

内蒙古工业大学本科毕业设计说明书学校代码： 10128学 号： 本科毕业设计外文文献翻译（ 学生姓名：学 院：机械学院系 别：机械系专 业：机械电子工程班 级：机电09指导教师： 讲师二 一 三 年 六 月原文：COMMINUTION IN A NON-CYLINDRICAL ROLL CRUSHER*P. VELLETRI and D.M. WEEDON Dept. of Mechanical & Materials Engineering, University of Western Australia, 35 Stirling Hwy,Crawley 6009, Australia. E-mail .au Faculty of Engineering and Physical Systems, Central Queensland University, PO Box 1319Gladstone, Qld. 4680, Australia(Received 3 May 2001; accepted 4 September 2001)Velletri and Weedon, 2000 P. Velletri and D.M. Weedon, Preliminary investigations into a roll crusher with non-cylindrical rolls, Proc. Minprex 2000 International Congress on Mineral Processing and Extractive Metallurgy, AIMM, Melbourne (2000), pp. 321328.ABSTRACTLow reduction ratios and high wear rates are the two characteristics most commonly associated with conventional roll crushers. Because of this, roll crushers are not often considered Jor use in mineral processing circuits, and many of their advantages are being largely overlooked. This paper describes a novel roll crusher that has been developed in order to address these issues.Referred to as the NCRC (Non-Cylindrical Roll Crusher), the new crusher incorporates two rolls comprised of an alternating arrangement of plane and convex or concave surfaces. These unique roll profiles improve the angle of nip, enabling the NCRC to achieve higher reduction ratios than conventional roll crushers. Tests with a model prototype have indicated thar even for very hard ores, reduction ratios exceeding l0:l can be attained. In addition, since the comminution process in the NCRC combines the actions of roll and jaw crushers there is a possibility O that the new profiles may lead to reduced roll wear rates. 2001 Elsevier Science Ltd. All rights reserved.Keywords: Comminution; crushingINTRODUCTIONConventional roll crushers suffer from several disadvantages that have led to their lack of popularity in mineral processing applications. In particular, their low reduction ratios (typically limited to about 3:1) and high wear rates make them unattractive when compared to other types of comminution equipment, such as cone crushers. There are, however, some characteristics of roll crushers that are very desirable from a mineral processing point of view. The relatively constant operating gap in a roll crusher gives good control over product size. The use of spring-loaded rolls make these machines tolerant to uncrushable material (such as tramp metal). In addition, roll crushers work by drawing material into the compression region between the rolls and do not rely on gravitational feed like cone and jaw crushers. This generates a continuous crushing cycle, which yields high throughput rates and also makes the crusher capable of processing wet and sticky ore. The NCRC is a novel roll crusher that has been developed at the University of Western Australia in order to address some of the problems associated with conventional roll crushers. The new crusher incorporates two rolls comprised of an alternating arrangement of plane and convex or concave surfaces. These unique roll profiles improve the angle of nip, enabling the NCRC to achieve higher reduction ratios than conventional roll crushers. Preliminary tests with a model prototype have indicated that, even for very hard ores,reduction ratios exceeding 10:I can be attained (Vellelri and Weedon, 2000). These initial findings were obtained for single particle feed. where there is no significant interaction between particles during comminution. The current work extends the existing results by examining multi-particle comminution in the NCRC. It also looks at various other factors that influence the performance of the NCRC and exploresthe effectiveness of using the NCRC for the processing of mill scats.PRINCIPLE OF OPERATIONThe angle of nip is one of the main lectors effecting the performance of a roll crusher. Smaller nip angles are beneficial since they increase the likelihood of particles being grabbed and crushed by the rolls. For a given feed size and roll gap, the nip angle in a conventional roll crusher is limited by the size of the rolls. The NCRC attempts to overcome this limitation through the use of profiled rolls, which improve the angle of nip at various points during one cycle (or revolution) of the rolls. In addition to the nip angle, a number of other factors including variation m roll gap and mode of comminution were considered when selecting the roll profiles. The final shapes of the NCRC rolls are shown in Figure I. One of the rolls consists of an alternating arrangement of plane and convex surfaces, while the other is formed from an alternating arrangement of plane and concave surfaces.The shape of the rolls on the NCRC result in several unique characteristics. The most important is that, for a given particle size and roll gap, the nip angle generated m the NCRC will not remain constant as the rolls rotate. There will be times when the nip angle is much lower than it would be for the same sized cylindrical rolls and times when it will be much higher. The actual variation in nip angle over a 60 degree roll rotation is illustrated in Figure 2, which also shows the nip angle generated under similar conditions m a cylindrical roll crusher of comparable size. These nip angles were calculated for a 25ram diameter circular particle between roll of approximately 200ram diameter set at a I mm minimum gap. This example can be used to illustrate the potential advantage of using non-cylindrical rolls. In order for a particle to be gripped, the angle of nip should normally not exceed 25 . Thus, the cylindrical roll crusher would never nip this particle, since the actual nip angle remains constant at approximately 52 . The nip angle generated by the NCRC, however, the below 25 once as the rolls rotate by (0 degrees. This means that the non-cylindrical rolls have a possibility of nipping the particle 6 times during one roll revolution.EXPERIMENTAL PROCEDUREThe laboratory scale prototype of the NCRC (Figure 3) consists of two roll units, each comprising a motor, gearbox and profiled roll. Both units are mounted on linear bearings, which effectively support any vertical component of force while enabling horizontal motion. One roll unit is horizontally fixed while the other is restrained via a compression spring, which allows it to resist a varying degree of horizontal load.The pre-load on the movable roll can be adjusted up to a maximum of 20kN. The two motors that drive the rolls are electronically synchronised through a variable speed controller, enabling the roll speed to be continuously varied up to 14 rpm (approximately 0.14 m/s surface speed). The rolls have a centre-to-centre distance ,at zero gap setting) of I88mm and a width of 100mm. Both drive shafts are instrumented with strain gauges to enable the roll torque to be measured. Additional sensors are provided to measure the horizontal force on the stationary roll and the gap between the rolls. Clear glass is fitted to the sides of the NCRC to facilitate viewing of the crushing zone during operation and also allows the crushing sequence to be recorded using a high-speed digital camera.Tests were performed on several types of rocks including granite, diorite, mineral ore, mill scats and concrete. The granite and diorite were obtained from separate commercial quarries; the former had been pre-crushed and sized, while the latter was as-blasted rock. The first of the ore samples was SAG mill feed obtained from Normandy Minings Golden Grove operations, while the mill scats were obtained from Aurora Golds Mt Muro mine site in central Kalimantan. The mill scats included metal particles of up to 18ram diameter from worn and broken grinding media. The concrete consisted of cylindrical samples (25mm diameter by 25ram high) that were prepared in the laboratory in accordance with the relevant Australian Standards. Unconfined uniaxial compression tests were performed on core samples (25mm diameter by 25mm high) taken from a number of the ores. The results indicated strength ranging from 60 MPa for the prepared concrete up to 260 MPa for the Golden Grove ore samples.All of the samples were initially passed through a 37.5mm sieve to remove any oversized particles. The undersized ore was then sampled and sieved to determine the feed size distribution. For each trial approximately 2500g of sample was crushed in the NCRC. This sample size was chosen on the basis of statistical tests, which indicated that at least 2000g of sample needed to be crushed in order to estimate the product P80 to within +0.1ram with 95% confidence. The product was collected and riffled into ten subsamples, and a standard wet/dry sieving method was then used to determine the product size distribution. For each trial, two of the sub-samples were initially sieved. Additional sub-samples were sieved if there were any significant differences in the resulting product size distributions.A number of comminution tests were conducted using the NCRC to determine the effects of various parameters including roll gap, roll force, feed size, and the effect of single and multi-particle feed. The roll speed was set at maximum and was not varied between trials as previous experiments had concluded that there was little effect of roll speed on product size distribution. It should be noted that the roll gap settings quoted refer to the minimum roll gap. Due to the non-cylindrical shape of the rolls, the actual roll gap will vary up to 1.7 mm above the minimum setting (ie: a roll gap selling of l mm actually means 1-2.7mm roll gap).译文：在非圆柱辊式破碎机中粉碎P. VELLETRI and D.M. WEEDON 机械与材料工程，西澳大利亚大学，斯特林HWV35部，克劳利6009，澳大利亚。电子邮箱.au工程学院和物理系统，中央昆士兰大学，邮政信箱1319格莱斯顿，QLD。 4680，澳大利亚（2001年5月3日收稿，2001年9月4日接受）韦莱特里和威登，2000年P.韦莱特里和D.M.威登，与非圆柱辊，PROC的辊式破碎机进行初步调查。 Minprex2000选矿和冶炼，AIMM，墨尔本国际大会（2000年），页321-328。摘 要 低的破碎比和高的磨损率是与传统的破碎机相联系的很常见的两个特性。因为这点，在矿石处理流程的应用中，很少考虑到它们，并且忽略了很多它们的优点。本文描述了一个已被发展起来的新颖的对辊破碎机，旨在提出这些论点。作为NCRC,这种新式破碎机结合了两个辊筒，它们由一个交替布置的平面和一个凸的或者凹的表面组成。这种独特的辊筒外形提高了啮合角，使NCRC可以达到比传统辊式破碎机更高的破碎比。用一个模型样机做的试验表明：即使对于非常硬的矿石，破碎比任可以超过10。另外，既然在NCRC的破碎处理中结合了辊式和颚式破碎机的作用，那就有一种可能：那种新的轮廓会带来辊子磨损率的降低。 关键字：粉碎；破碎介 绍传统的辊筒破碎机因为具有几个缺陷而导致了其在矿石处理应用中的不受欢迎。尤其是当与其它的一些破碎机比起来，诸如圆锥破碎机等，它们的低破碎比（一般局限在3以内）和高的磨损率使它们没有吸引力。然而，从矿石处理这一点来说，辊筒破碎机有一些非常可取的特点：辊筒破碎机的相对稳定的操作宽度可以很好控制产物粒度。弹簧承重的辊子的使用使这些机器容许不可破碎的物料（诸如夹杂金属等）。另外，辊筒破碎机是这样工作的：将物料牵引至辊子之间的挤压区而不是象圆锥和颚式破碎机那样依靠重力。这产生了一个连续的破碎周期，避免了高通过率，同时也使破碎机可处理潮湿的和胶粘的物料。 NCRC是一种新颖的破碎机，发明于澳大利亚西部大学，为得是提出一些与传统辊筒破碎机相联系的一些问题。新的破碎机结合了两个辊子，由间隔布置的平面和凸的或者凹的表面组成。这种独特的辊子轮廓提高了啮合角，使NCRC可达到比传统辊筒破碎机更高的破碎比。用一个模型样机的初步试验已表明：即使非常硬的物料，超过10的破碎比也可以实现。这些初期的发现是通过单一颗粒进给而获得的，在破碎中没有显著的物块间的相互作用。目前的工作在NCRC中用多物块试验延伸了现存的结果。同时也顾及了各种其他因素：影响NCRC特性和探索NCRC在选矿处理中使用效率。操作原理 啮合角是影响辊筒破碎机性能的重要因素之一。小的啮合角是有利的，因为它们增大了物块被辊筒抓住的可能性。对于一个给定的入料粒度和辊隙，传统的辊筒破碎机的啮合角受限于辊筒的尺寸。NCRC试图通过有特殊轮廓的辊筒克服这种限制，这种轮廓提高了辊筒在一转中变化点的啮合角。至于啮合角，在选择辊面时，很多其他的因素，包括变化的辊隙，破碎的方式都考虑了。最终NCRC辊筒形状如图1所示。其中一个辊子由间隔布置的平面和凸面组成，而另一个是由间隔布置的平面和凹面组成。 NCRC辊筒的形状导致了几个独特的特点。其中最重要的就是在辊筒转动时，对于一个给定物块粒度和辊隙，NCRC所产生的啮合角将不再保持稳定。时而啮合角比相同尺寸的圆柱辊筒低很多，时而高很多。辊子转动中啮合角的实际变化量超过60度，如图2所示，图2也表示了相同情况下，可相比尺寸的圆柱辊筒