To accomplish this reduction in size takes several steps or stages of crushing and grinding. Primary crushing is the first of these stages. Generally speaking there are two types of primary crushers, lets compare them: GYRATORY CRUSHER or a JAW CRUSHER. Although they dont look anything like they do have similarities that put them into the same class of crusher.
Their CRUSHING SPEEDS are the same, 100 to 200 revolutions per minute. They both break the ore by COMPRESSION. That is they both break the rock by squeezing it until it breaks. On the average their final product will measure about seven inches at its widest point. And finally they both can be built to accept a rock up to sixty inches across.
Even if they are much alike, each of the two types of crushers has its own uniqueness. Because of this difference each type of crusher has its own environment that it operates best or at least better in, than the other.As an example, a gyratory crusher can be fed from two sides and handle ore that tends to slab. Also its design allows a higher speed motor with a high reduction ratio between the motor and the crushing surface. This is an important consideration as it means money saved in energy costs. A jaw crusher on the other hand requires a flywheel to store energy but can be used on the tougher ores due to its box frame construction. To be effective it must be fed from one side only but it handles square block-like ore well.
There is another comparison that should be taken into consideration, that is the amount of space that each takes. The Jaw crusher is the smaller of the two and its single feed point will make it a logical choice for underground workings. In the actual operation of the crushers, they both have similarities as well as differences so lets take each one separately and discuss its design and its problems. Considering the title of this chapter is Primary Crushing (Gyratory) we should discuss that one first.
In the introduction I mentioned that the purpose of a concentrator was to produce a concentrate of which ever mineral was being mined. To be able to recover this mineral it is necessary to reduce the ore in size until the mineral is LIBERATED. This means that the ore must be reduced in size until it is fine enough to be able to separate the mineral from the unwanted rock. In the Vocabulary of the metallurgist, at this point of the operation the unwanted rock will be termed the GANGUE material. You will notice that the terminology used for the ore will change depending upon the stage of concentration. The reason for this is to keep technical communication accurate.
The 911MPEJAC23is aSmallJaw Crusher of 2.25 X 3manufactured to easily crush any rock from 2 (50mm) down to a D50 of 700 micron (28 Mesh) which also correspond to acrushed discharge P80 size of 80% passing 1400 microns or 14 mesh. The discharge opening (closed-side-setting) of this 55mm X 75mm big-small crusher you can adjusted with a wrench. With a short throw at a quick 525 RPM (speed eccentric overhead), this small rock crushercan almostpulverize without dusting of your run-of-the-mill, chain beating, hammermillsmall prospectorsoften buy.
The Small 911MPEJAC23is a2.25 X 3 Jaw Crushermanufactured to easily crush any rock from 2 (50mm) down to a D50 of 700 micron (28 Mesh) which also correspond to acrushed discharge P80 size of 80% passing 1400 microns or 14 mesh. The discharge opening (closed-side-setting) of this 55mm X 75mm big-small crusher you can adjusted with a wrench. With a short throw at a quick 525 RPM (speed eccentric overhead), this small rock crushercan almostpulverize without dusting of your run-of-the-mill, chain beating, hammermillsmall prospectorsoften buy. With a rated capacity to crush 25 lbs (12 kg) of material per hour,this portable and lightweight (35 lbs.), is perfect for low volume metallurgical sample preparation or any small home laboratory a gold prospector would have in his garage. At 80% < 14 mesh, the discharge from this small crushing machine is mostlyliberated and ready for panning or shaking table. Allsmall jaw crushers come with an operating manual, pulley, preinstalledabrasion-resistantAR450jaw plates. This economic crusher is sold without the 1 HPmotornor mounting supports. All crushers are offered with gas/diesel engine or electric motor. If you decide to do-it- yourself, just be sure to ratio your speed/sheaves to have 525 RPM on the jaws and your rock crusheris set to crush.
The Small 2x3 Jaw Crusher is designed to crush rock and rock like aggregates from 1.5 size down to 50 Mesh size depending on selected output setting. In order to maintain the long life and high performance standards your Crusher is designed for, it is essential to carefully observe and adhere to the following operating and maintenance instructions.
When testing aggregates, ores, coal, and coke in geotechnical or construction materials testing laboratories, sample preparation often involves the reduction of particle sizes from the initial bulk or field sample. Many of these materials are hard, tough, or brittle, so crushing them to smaller sizes is an ideal application for robust, rugged, and durable jaw crushers.
All jaw crushers operate on the same straightforward principle; two hard-faced heavy plates or jaws crush large particles between them. One powered jaw reciprocates in an elliptical motion opposite a stationary jaw mounted in the frame.
During an operating cycle, the gap between the two jaws opens; a particle drops in, the jaws close in and crush the particle. Further crushing of the fractured pieces continues until particles are small enough to fall through the bottom opening by gravity. The jaws face each other at a slight vertical angle, so particles become smaller as they progress toward the bottom.
A simple adjustment of the distance between the two jaws regulates the final sample size. The term final size can be a little vague. It refers to the approximate maximum particle size at completion of crushing, but the size range and distribution can vary considerably based on the material properties of the sample.
The selection of the best jaw crusher for your application will naturally be governed by the particle size, volume, and properties of your bulk material, along with the desired particle size and quantity of the final sample. The size of the jaw plates limits the particle size capacity and determines the size of the feed opening. In general, maximum particle sizes are about 70-80% of the feed opening, but this can vary by manufacturers and models. Jaw materials are available in a variety of materials to adapt to the hardness and toughness properties of samples and to extend service life.
Small Crushers: For applications where reduced quantities of materials with smaller top sizes and final sizes are needed, these smaller jaw crushers fit the bill. Their compact size allows easy positioning anywhere in the lab, even on a benchtop.
Large Crushers: When size capacity and throughput are the most sought-after features, these units are the best choice. Options for power by gasoline or Diesel engines mean the crushers can work on-site at remote laboratories or pilot plants.Get in Touch with Mechanic