Crushing

A SEMINAR PM CRUSHING PROCESS

1. CRUSHING Guided by: Submitted by: Mr. Pushpraj Singh Kaurav Pratyush Kumar Mohanta S.O.S Earth Science M.Sc. 3rd Sem Jiwaji University, Gwalior

2. CONTENTS Introduction to Crushing Types of Crushing Jaw Crushers : (a) Blake Crusher (b)Dodge Crusher Blake versus Dodge crushers –advantages and disadvantages Factors affecting efficiency of crushers Gyratory Crushers Comparision between jaw and gyratory crushers Cone Crushers Hammer Mill or Pulverator Stamps Spring Rolls Sledging Rolls Manual Crushing Conclusion Bibliography

3. CRUSHER A crusher is a multi dimensional machine which is designed to reduce large size materials into smaller size materials . Crushers may be used to reduce the size, or change the form of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials . Crushers are normally low speed machines that are designed for breaking large lumps of ores and stones, even aving a size with a diameter of over one and half meter. The purpose of crusher is to reduce the size of the materials for making them usable in construction or industrial use, or for extraction of valuable minerals trapped within a ore matrix.

4. Cont… Crushing is the process of transferring a force amplified by mechanical advantage through a material made of molecules that bond together more strongly ,and resist deformation more, than those in the material being crushed do. Crushing devices hold material between two parallel or tangent solid surface, and apply sufficient force to bring the surface together to generate enough energy within the material being crushed so that its molecules separate from or change alignment in relation to (deformation), each other . There are four basis ways to reduce material. Impact Attrition Shear Compression

5. IMAGE SOURCE : https://aparnaenterprisesltd.com/brands/apa https://aparnaenterprisesltd.com/brands/aparna-crusher/rna-crusher/ https://www.directindustry.com/prod/rubble-master-hmh/product-56767-1920576

6. TYPES OF CRUSHING Jaw Crushers Gyratory Crushers Cone Crushers Sledging Rolls Hammer Mills Stamps Spring Rolls Manual Methods Of Breaking

7. Jaw Crushers The jaw crushers mainly divides into 2 types :Blake Crushers, Dodge Crushers . A. Blake Crushers : The essential parts comprise- Fixed jaw (Mn steel) Jaws (Swing jaw ) Mn steel Eccentric Flywheel Pitman Toggle Fixed support for toggle Exit Feed

8. Conti… The fly wheel is actuated by a prime mover. The pitamen attached to the eccentric also moves up and down carrying the toggle with it . Since one end of the toggle is fixed, the movable jaw, attached to the other end, moves back and forth from the fixed jaw. Thus any material lodge in the throat of the crusher is broken up.

9. I Image Source https://www.911metallurgist.com/blog/blake-jaw-crusher Jaw crushers

10. Image Source: https://www.jxscmine.com/jaw-crusher-handbook / https://www.911metallurgist.com/blog/dodge-crusher s Dodge Crusher

11. Dodge Crusher The dodge type of crusher is also similar but the swing jaw is pivoted at the bottom. The important parts are : Fixed jaw (Mn steel) Mouth of crusher Movable jaw Axle for jaw Fly wheel Pitman Eccentric

12. Conti… When the fly wheel(5) rotates, the pitman(6) moves up and down, on the eccentric. This causes the lever arm(8), attached to the moveable jaw(3), to move up and down ,while the upper portion of the jaw, which is pivotted at its lower end, swings forward and backward. The feed, dropped into the throat, is delivered at X . Jaw plates, for crushers, are made of chilled iron, white iron, high carbon .

13. Blake versus Dodge crushers-advantages and disadvantages The Blake crusher delivers a product in which the sizes are variable; as the lower portion of the jaw opens and closes. The Dodge crusher delivers a more uniform size of product as the opening at lower end is fixed. The capacity is less for the Dodge crusher as compared to the Blake of same size. Nipping(holding material at the mouth) is less effective in the Dodge and larger lumps jump out by slipping. Sticky ore tends to clog in the Dodge crusher .

14. Factors affecting efficiency of crushers Width of discharge opening-this is varied by adjusting the toggles in the Blake, or by inserting wedges in the Mn steel cheek plate of the Dodge crusher . The throw varies from 3/8 in. in the small crushers to 1 in. in the larger machines, but the maximum throw is about three times. Brittle rocks, like quartzite, and granite, require minimum throw, whereas tough rocks like ,trap, limestone and rocks which resist compression like shale, etc, require larger throw . Speed has no market effect on the efficiency, but at higher speeds, the efficiency drops. Size of feed depends on the gape, nip angle, and the angle, of the mouth opening which is about 24 degree. Taking these into consideration, the largest size of the individual piece of rock ,should not exceed 80 to 90 % of the gape .Larger fragments tend to clog the mouth.

15. Gyratory crushers Gyratory crushers were developed after jaw crushers to supply the crushing machines of higher capacities. The crushing action of gyratory crushers is similar to that of jaw crushers ,since in this case also the moving crushing element approaches and recedes from a fixed crushing element. But the relative motion of the crushing faces is due to the gyration of the eccentrically mounted cone. Some tangential force and simple squeeze are also incorporated. Interaction between particles takes place and as a result the ore crushed against. These are 3 types of gyratory crushers: Suspended spindle, Supported spindle, Fixed spindle .

16. Image Source: https://na.hazemag.com/gyratory-crusher-2/ Gyratory crushers

17. Gyratory Crusher

18. Comparision between jaw & Gyratory crushers Cost of the gyratory crusher is only 29 to 72% of that of the jaw crusher of the same capacity. Cost of installation of the gyratory machine is less. The housing ,for the gyratory machines, costs more as it occupies more space. Feed arrangements for the gyratory crusher are simpler than for the jaw crusher. The gyratory machines are more efficient than the jaw machines and more so, when working on full load . Maintenance costs are more for the gyratory machines. The gyratory crusher can work more efficiently where the material tends to break in slabs. The general rule or thumb rule is that if tonnage per hour is less than 0.115,then a jaw crusher is to be preferred.

19. Image Source: https://www.jxscmine.com/difference-between-jaw-crusher-and-gyratory-crusher https://www.ftmmachinery.com/blog/what-are-the-differences-between-the-7-types-of-crushers.html

20. Cone Crusher Cone crusher was developed in 1920’s and since then it has gained wide acceptance and now it is regarded as the standard crushing appliance in the intermediate range. This is very much like a coffee grinder in principle, and the essential parts are- Feed hopper Feed distributor tray Fixed jaw Breaking head Spindle axle Bevel gear drive for the breaking head Pulley drive

21. Conti… The cone crushers are made in two types, i.e. (a) standard (b)short head These differ mainly in the shape of the crushing cavities. The standard crushers are used for the reduction of coarser feeds, and the product is usually in the range of 6 and 60 mm.

22. Image Source: https://www.rockprocessing.sandvik/en/crushology/the-knowledge-hub/crushing-chambers/cone-crusher-basics-in-4-minutes Cone crusher

23. Hammer mill or Pulverator The machine comprises a rotor(1),which consists of two circular discs(2),to which the hammers(3) are pivoted. The rotor is rotated about the axle. A grate or grizzly(4) is placed at the lowest position and the discharge passes swing out, under the action of centrifugal forces and the material lying on the breaker plate(6), is stuck and it disintegrates.

24. Image Source www.solidswiki.com/index.php?title=File:Hammer-crusher.gif https://www.indiamart.com/proddetail/hammer-crusher-23086449548 Hammer mill or Pulverator

25. Stamp Stamps are in principle large size pestle and mortar. The pestle is acruated mechanically-either by steam or compressed air directly. When stamp is lifted by a cam and drops down by gravity, it is called a gravity stamp. In the gravity stamp the cam(3),on rotation ,lifts the pestle.

26. Conti.. While lifting, a rotary motion is also imparted, to the pestle by the cam. The mortar is provided with screen(6),on one side so that only the undersize material flows out, while the coarser fraction is retained for further breaking & crushing.

27. Stamp Mill, Murphy Park, Sunnyvale, CA Image Source : https://commons.wikimedia.org/wiki/File:Stamp_mill_ore_crusher_(Orphan_Girl_Mine,_Butte,_Montana,_USA).jpg

28. Spring Rolls The roll essentially comprises two rollers(1) and (2) steel cased (x) mounted on a common frame (7). The roller (2) is rigidly fixed by bolts, while the roller (1) is mounted on a sliding block, which moves on the frame (7). The moveable roll (1), is kept in contact with roll (2) by the pull of a tension bar (3), provided with springs. Both the rollers are driven by pulleys but the pulley for roller (1)is smaller than that of roller (2) (fixed roller). Thus, the speed, of the moveable roller ,is greater than that of the fixed roller . A feed hopper is attached at the median position between the rollers .

29. The angle of nip generally is about 25 degree, and the diameter of rolls required, may be got from the formula t= d+D /40 where t=the maximum thickness of feed, d=the setting of the rollers, i.e , space between them, D=diameter of rollers The reduction ratio varies from 1 to 2, in general , but it is slightly more for heavy duty rolls . Capacity of a roll, T=R

30. Image Source https://www.williamscrusher.com/products/roll-crushers https://sinonine.wordpress.com/2018/05/03/roll-crusher-and-hpgr Spring rolls

31. Sledging Rolls Single roll crusher is like a roll and also like a crusher in its functions. This type is the sledging roll(2) is a breaking plate and hinged at (1). It is held in position by a tension bolt (5) tightened with springs(6). A roller (4), provided with hard teeth , is rotated by gearing through pulley and belt arrangement. Material which is dropped into the mouth (3), is pulverised as it gets between the breaking plate (2) and the roller (4). The roller speed is 200 to 300 ft per Min . This type of crusher is used for fairly soft rocks e.g- Limestone, shale ,clays .

32. Manual Crushing Breaking or crushing is also carried out manually. Sledging is the process of breaking rocks with sledge hammers which are 10-16 lbs ,in weight. Spalling is reducing 6-8 in lumps to 2 0r 3 in. sizes with the help of 2 to 3 lb. hammers . Cobbing is further reduction of sizes from 2 to 3 in to less . Explosives are also used in breaking up large boulders. Pile driver type of breakers were used earlier ,but these are not popular now .In pile driver type of breakers ,a heavy solid iron cylinder was lifted up, by a pulley block, and dropped suddenly on the rock .Shattering was produced in this manner . Heating and quenching is one of the earliest methods of breaking rock, used by man, for mining. This method was also practised, by the miners, in India .This methods is reported to be efficient in liberating and breaking quartz of high purity.

33. Image Source : https://www.researchgate.net/figure/Clean-Tech-Mining-Practices-A-Manual-crushing-of-ore-with-mortar-and-pestle-B_fig4_257408840 Gold separation using magnets. (A) Ore from the connecting pipe and centrifuge is collected and panned. (B) Sediment containing gold and iron. (C) A speaker magnet is used to remove iron and magnetic species. (D) After separation, mostly gold remains.

34. Conclusion The modern crusher range is ideal for shaping applications including making chips, sands, concrete manufacture and glass recycling. The range includes both horizontal and vertical impact crushers. They are used as primary, secondary or tertiary crushers depending on the Producers final –product-size needs.

35. BIBILIOGRAPHY Arogyaswamy, RNP.,1996: Course in Mining Geology Jain, S.K., 1986: Ore Processing

36. THANK YOU