worlds largest cone crushers go into service at african mine | e & mj
As ore grades decline at mines worldwide, more ore needs to be processed to obtain the same amount of the valuable contained mineral and to meet production targets. This often results in increased processing costs and can prove problematic for miners. Metso said it is responding to this challenge by developing larger, more energy-efficient equipment for minerals processing. One example of this effort is the MP2500, billed as the worlds largest cone crusher, two of which will be installed at First Quantum Minerals Ltd.s Sentinel copper mine in Zambia. The installation is scheduled to be fully operational in early 2015, under a contract valued at 10 million euros received in 2013.
Metso said the MP2500 was selected for Sentinel because it can process large volumes of rock as a single machine. It saves costs as fewer crushers, related infrastructure and maintenance are needed for achieving the same or increased amount of production. According to the company, the MP2500 crusher has the largest feed opening ever offered in this type of crusher, enabling it to accept bigger chunks of rock than traditional crushers and decreasing energy consumption in the comminution process.
MP2500s are designed for use in secondary and tertiary crushing and, according to the company, can be linked with other Metso products to create a simplified, cost-effective process flow for high-production sites. For example, in order to duplicate the performance of two MP2500s, four of its 1,250-hp MP1250 crushers and associated infrastructure would be necessary. At Sentinel, the new cone crushers will be part of the secondary crushing circuit installed to maintain mill throughput in the face of harder ore being mined in the deeper areas of the pit. According to Metso, depending on the ore characteristics and SAG efficiency, the MP2500s could provide a throughout range of 3,0004,500 metric tons per hour (mt/h).
Development of the MP2500 represents a number of innovations in the area of health and safetysome based on discussions with FQML, according to Metso, perhaps the most significant is there is simply less equipment needed to be installed at the site, resulting in reduced maintenance activity.
Serviceability and ease of maintenance was also a focus during the design. Because of the size of the equipment, Metso had to develop a new method (patent pending) to remove the crushers socket that eliminated heating of the part in a difficult working space. This method also eliminates process variables associated with socket removal and reduces the overall stress on both the socket and main shaft. Metso also refined the existing jackbolt locknut design to reduce the amount of manual work necessary, adding hydraulics to simplify the process.
Metso said it is assisting the mine to guarantee efficient operation of the new crusher by stationing full-time field service engineers on-site for one year after commissioning and by stocking critical spare parts in Metsos distribution center in South Africa as well as on-site.
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crusher efficiency calculations
The following example demonstrates a method of selecting the components of an aggregate plant. Good component efficiency and part performance pre-evaluation is essential to a solid design. The aggregate production requires the consideration of several crushers, feeders and screens. This is not intended to be a typical situation, though it does involve common crusher and screen units often used in aggregate plants.
Quarry rock of 12 in. maximum size is to be handled in a two-stage crusher plant at the rate of 70 tons per hour. The maximum size of output is to be 1 in., and separation of materials over 1 in. size and the minus 1 in. in the output is required. Select a jaw crusher like those included in this table.
The screens to be considered are a 1-in. screen with an estimated capacity of 2.7 tph/sq ft and a 1-in. screen with a capacity of 2.1 tph/sq ft. The solution will include the selection of adequate and economical crushers for the two stages and the sizes of screens between them and below the secondary stage.
For the primary crusher a jaw crusher will probably be most economical. A jaw crusher, like 2036 in the Jaw Crusher Table here above, would be able to take the maximum 12 in. size quarry stone but it would not have the required 70 tph capacity needed. To have the needed capacity a jaw crusher like the 2042 or 2436 sizeswill have to be selected overloading the secondary crusher.
A grid chart or curve for the selected crusher shows that, for a 2-in. setting, 54% of the material will pass a 1-in. screen, or 46% will be retained (this is like Jaw Crusher capacity table abovewhere 48% passes a 1 in. screen). The 46% of 70 tph gives the 32 tph fed to the secondary crusher shown in Figure below as a roll crusher.
A twin-roll crusher is selected, like those given inthe Roll Crusher capacityTable above, to serve as the reduction crusher. The smallest, 24 x 16 roll crusher shown in theRoll Crusher capacity Table above has enough capacity with a setting of 1 in. but the maximum size feed will be too large, that is, the stage of reduction is not large enough. The maximum size of feed coming from the discharge of the primary crusher with a setting of 2 is about 3 in. as may be found in this Table.
Considering a 30-in. diameter roll crusher the maximum size particle that can be nipped with the roll crusher set at 1 in. according to this Equation is F = 0.085(15) + 1.0 = 2.28 in. <3 in. feed. It will take larger than a 40-in. diameter roll crusher. A better solution would be to use a larger jaw crusher set at 1 in., then a roll crusher from the Roll Crusher capacityTable above could be used. If the output of this crushing process should have less material of the +1-in. size, the larger crusher could be operated with a closed circuit. That is, the oversize in the output could be recirculated through the roll crusher without exceeding the rated capacity of the crusher. Then all material leaving that crusher with a 1-in. setting would be of a minus 1-in. size.
Another possible solution to this problem would be to use a gyratory crusher for the primary crushing stage. A gyratory like Telsmith model1110 could be set at 1 in. in an open circuit with a capacity for 260 tph. The maximum size of stone in the output is estimated to be approximately 2 1/8 in. Then all the output from the primary crusher could be nipped by a 40 in. diameter twin-roll crusher with a 1-in. setting according to the Roll Crusher capacityTable above. The specifications and manufactured limitations, rather than economy, generally govern the selection of crushers.
To find the required areas of screen, the rate of feed of material as well as gradation of the feed must be known. The 1-in. screen under the jaw crusher is the top deckno deck correction factor will be necessary. Therefore, the 1-in. screen will need to be at least 70/2.7 = 29.9 sq ft in area. It must be at least 36 in. wide for an 18 x 36 jaw crusher. So a 4-ft by 8-ft screen would be acceptable. The 1-in. screen is a second deck for the 38 tph from the jaw crusher, so the deck correction factor is 0.90 and that screen capacity is 2.1 x 0.9 = 1.89 tph/sq ft.
The screen area needed under the jaw crusher is 38/1.89 = 20.1 sq ft. For the 1-in. screen below the roll crusher the capacity has no correction factor and the area needed is 32/2.1 = 15.2 sq ft. To handle the output from a 40 x 24 roll crusher the screen will have to be at least 24 in. wide. Perhaps it will be more effective to use one continuous screen of at least 20.1 + 15.2 = 35.3 sq ft. A 4-ft by 10-ft 1 in. screen should be satisfactory.
cone crushers | mclanahan
A Cone Crusher is a compression type of machine that reduces material by squeezing or compressing the feed material between a moving piece of steel and a stationary piece of steel. Final sizing and reduction is determined by the closed side setting or the gap between the two crushing members at the lowest point. As the wedge or eccentric rotates to cause the compression within the chamber, the material gets smaller as it moves down through the wear liner as the opening in the cavity gets tighter. The crushed material is discharged at the bottom of the machine after they pass through the cavity.
A Cone Crusher will deliver a 4:1 to 6:1 reduction ratio. As we set the closed side setting tighter to create a finer output, we also reduce the volume or throughput capacity of the machine. Generally speaking, multiplying the closed side setting by two is a good guide to the top size of the gradation exiting the machine.
The technology that makes a MSP Cone Crusher outperform competitive cones on the market is the combination of all of the factors of performance i.e. balanced eccentric, higher speeds, fulcrum point position, and stroke. By using sound engineering with years of field testing a truly tried and tested new Cone Crusher has emerged.
A balanced eccentric coupled with a fulcrum point ideally placed over the crushing chamber yields highly effective compression crushing. This allows higher eccentric speeds to maximize performance without disruptive forces. The eccentric stroke is designed to work with the eccentric speed and fulcrum position to produce higher yields and minimize recirculating loads. The torque and resultant crushing forces are as effective as virtually any Cone Crusher on the market.
Spiral bevel gears provide the turning force to the eccentric. The spiral gear is mounted on a sturdy countershaft of the Cone Crusher, which rides in bronze bushings. The gears are precision cut for quiet operation. Misalignment problems are eliminated.
The MSP Cone Crusher features one of the largest volume displacements by a crusher head. When there is a large volume of material displaced this way, it means that more material is crushed in each cycle, more material can be fed to fill the larger void left when the crushing head recedes, and more material flows through the crusher due to the larger throughput and gyrating cycles allowing material to drop further. The benefits of high efficiency, greater crushing force and high capacity coupled with the durability the market expects are the reasons why this design is the best way to increase your productivity and profitability.
Sleeve bearings make removal and installation of the MSP Cone Crusher head and main shaft simple. The tapered main shaft fits into a large opening at the upper end of the tapered eccentric bushing. The shaft does not require precise alignment. It can be inserted from a vertical position and will self-align.
With the MSP Cone Crushers automatic hydraulic overload relief system, the crusher immediately opens in the event of an overload. This action reduces the crushing pressure, allowing the obstruction to pass through the chamber. After the chamber has been cleared, the hydraulic control system automatically returns the crusher to its original setting. Shock loads on the crusher are reduced for longer component life.
MSP Cone Crushers are built to make your operations run more smoothly and easily. Its simple and easy to read control panel provides you with the necessary information to properly run your crusher. For example, the MSP Cone Crusher shows you the exact cone setting to allow the operator to stay on top of a critical set point.
To enhance your Cone Crusher's life and maintain optimal crushing capacities, an automatic liner change reminder is included for your convenience. When the new mantle and liners are installed, the automated reminder is reset. As the crusher operates, the system will track production capacities and calculate the liner wear rate. When the cone liners reach the maximum wear point, it sends a flashing reminder to 'change cone' on the cone setting meter. After the wear parts are changed, simply reset the automated reminder system and continue efficient, reliable crushing.
The MSP Cone Crushers are built heavier than most competitive Cone Crushers. The extra weight means lower stress on the machine, which results in longer operational life. There is no question that the proper use of mass makes for more durable crushers. Additionally, a broad array of manganese liners is offered for each size MSP Cone. A unique and patented feature allows the Liners to fit without the use of any backing material. Improved Chamber matching with crusher feeds virtually eliminates any trial and error.
All these factors combine to give producers more effective compression crushing. This reduces liner wear, which reduces wear cost and allows higher yields, resulting in decreased overall cost per ton of finished product.
In the Symons principle, which is utilized by the MSP Cone Crusher, each cycle is timed so that the feed material and the upward thrust of the crushing head meet at the moment of maximum impact. The optimum speed of gyration and the large eccentric throw produce two important results: 1) the rapidly closing head catches the falling feed material and delivers the extremely high crushing force and 2) on the other side of the chamber the rapidly receding head allows material to fall freely to the next point of impact or exit the chamber. The combination of superior crushing force and free flow of material in the MSP Cone Crusher results in production levels that are unsurpassed and means lower power consumption per ton.
Ten years of testing went into the final combination of speed, stroke, and head angle to deliver the most efficient use of power. Greater efficiency delivers lower power consumption, reduced cost per ton, less maintenance and higher profits.
The power input imparted by the driven eccentric results in a bearing force in opposition to the crushing force at a point on the lower portion of the main shaft. The bearing force as it is transmitted to the main shaft provides the required moment to crush the rock. The distance between the bearing force and the fulcrum point is called the force arm. The longer the force arm, the greater the momentum, which produces a greater crushing force.
Crushing loads are distributed over a large spherical bearing. The socket liner keeps full contact with the crushing head ball and carries all of the vertical component and part of the horizontal. The long force arm, represented by the main shaft, reduces the load transmitted through the eccentric bushing.
Capacities and product gradations produced by Cone Crushers are affected by the method of feeding, characteristics of the material fed, speed of the machine, power applied, and other factors. Hardness, compressive strength, mineral content, grain structure, plasticity, size and shape of feed particles, moisture content, and other characteristics of the material also affect production capacities and gradations. Gradations and capacities are most often based on a typical, well-graded choke feed to the crusher. Well-graded feed is considered to be 90% to 100% passing the closed side feed opening, 40% to 60% passing the midpoint of the crushing chamber on the closed side (average of the closed side feed opening and closed side setting), and 0 to 10% passing the closed side setting. Choke feed is considered to be material located 360 degrees around the crushing head and approximately 6 above the mantle nut. Maximum feed size is the average of the open side feed opening and closed side feed opening.
Minimum closed side setting may vary depending on crushing conditions, the compressive strength of the material being crushed, and stage of reduction. The actual minimum closed side setting is that setting just before the bowl assembly lifts minutely against the factory recommended pressurized hydraulicrelief system.
Overall, industry acceptance of the Symons principle and performance, the McLanahan Cone Crusher works to deliver lower recirculating loads at higher tonnage rates with lower maintenance costs by combining:
A general rule of thumb for applying Cone Crushers is the reduction ratio. A crusher with coarse style liners would typically have a 6:1 reduction ratio. Thus, with a 34 closed side setting, the maximum feed would be 6 x 34 or 4.5 inches. Reduction ratios of 8:1 may be possible in certain coarse crushing applications. Fine liner configurations typically have reduction ratios of 4:1 to 6:1.
The difference between the volume displaced by the crushing head when it is fully closed and fully open is called the displacement volume. A large displacement volume results in greater capacity because:
In order to maintain the maximum levels of capacity, gradation, and cubical product, a Cone Crusher must be choke-fed at all times. The best way to keep a choke-feed to the ConeCrusher is with a surge bin (or hopper) and feeder that are located prior to the crusher. Choke-feeding is almost impossible to achieve without a hopper and feeder.
There are a number of different criteria to consider when selecting the right chambers for your crushing needs. However, the one that must always be considered isthat you have a well-graded feed to the chamber. A well-graded feed is generally thought to be 90 to 100% passing the closed-side feed opening, 40 to 60% passing the midpoint, and 0 to 10% passing the closed-side setting.
One thing you should never do is place a new concave liner in a crusher with a worn mantleor place a new mantle in a crusher with a concave liner. Why? If you have properly selected the replacement component, you will change the complete profile of the Cone Crusher by mating new and worn components. The receiving opening will tend to close down, restricting the feed from entering the chamber and causing a reduction in tons per hour.
If the liner is wearing evenly throughout the chamber, you should consider changing out the manganese when it has worn down to about 1" (2.5 cm) thick at the bottom. At about 3/4" to 5/8" (1.9 to 1.6 cm) thick, the manganese will crack, causing the backing material to begin to disintegrate. This, in turn, will cause the liners to break loose. If this should happen, continued operation could destroy the seat on the support bowl or the head of the Cone Crusher.
McLanahan Symons Principle (MSP) Cone Crushers utilize a
combination of improved factors of performance, which are enhanced by the
Symons Principle of crushing, as well as the latest hydraulic features and
electrical features that create a modern, efficient, reliable and durable Cone Crusher
that ultimately leads to a faster ROI. MSP Cone Crushers are designed to make
your operation run more smoothly and easily, as well as ensuring lower
operating costs and minimal downtime so that MSP Cone Crushers are more
frequently fully operational and processing optimal amounts of material.
Efficiency can be defined by the ratio of the work done by a machine to the energy supplied to it. To apply what this means to your crusher, in your reduction process you are producing exactly the sizes your market is demanding. In the past, quarries produced a range of single-size aggregate products up to 40 mm in size. However, the trend for highly specified aggregate has meant that products have become increasingly finer. Currently, many quarries do not produce significant quantities of aggregate coarser than 20 mm; it is not unusual for material coarser than 10 mm to be stockpiled for further crushing.