Crushing (sa book)

Question 1

____ is that operation or group of operations in a Mineral Beneficiation plant whose object is to reduce large lumps to fragments, the coarsest particles in the crushed product being ____ inch or more in size. The size of coarsest particles is ____ inch in many cases.

Answer 1

Crushing
1/20
1/2

Question 2

The crushing action in all crushing machines (crushers) results from??

Answer 2

from forces applied to the particles by some moving part working against a stationary or some other moving part

Question 2

It is the first stage of size reduction.

Answer 2

Crushing

Question 2

is generally a dry operation and is usually performed in two or three stages.

Answer 2

Crushing

Question 2

defined as the ratio of the maximum size of the particle in the feed to the maximum size of the particle in the product.

Answer 2

Reduction Ratio

Question 3

a convenient measure for comparing the performance of different crushers.

Answer 3

Reduction Ratio

Question 4

Jaw crusher, Gyratory crusher.

Answer 4

Primary Crusher

Question 5

Reduction gyratory, Cone crusher, Rolls crusher.

Answer 5

Secondary Crusher

Question 6

Short-head cone crusher.

Answer 6

Tertiary Crusher

Question 7

Impact Crushers

Answer 7

Fine Crusher

Question 8

Bradford Breaker, Toothed Roll crusher.

Answer 8

Special Crusher

Question 9

Special crushers are designed for specific ores, for example, rotary breaker and toothed rolls crusher for ____ and gravity stamps for ____ milling.

Answer 9

Coal
gold ore

Question 10

____ consist of two jaw plates set at an acute angle, called ____, to each other which forms a crushing chamber.

Answer 10

Jaw Crushers
angle of nip

Question 11

Motion to the swing jaw is transmitted by ____ working on an eccentric toggles.

Answer 11

Pitman

Question 12

It refers to the maximum angle subtended by the approaching jaws or roll surfaces at which a piece of ore or material can be gripped and crushed.

Answer 12

Angle of Nip

Question 13

If the swing jaw is pivoted at the top, it has a fixed receiving area and variable discharge area and is known as a ____.

Answer 13

Blake Crusher

Question 14

If the swing jaw is pivoted at the bottom, it has a fixed discharge area and variable receiving area and is known as a ____

Answer 14

Dodge Crusher

Question 15

If the swing jaw is pivoted at an intermediate position, it has both variable receiving and discharge areas and is known as a ____.

Answer 15

Universal Crusher

Question 16

In a Blake crusher, the distance between the two jaw plates at the feed opening is known as ____.

Answer 16

Gape

Question 17

The distance between the two jaw plates at the discharge opening is known as ____.

Answer 17

Set

Question 18

The minimum distance is called ____ and maximum distance is called ____. The maximum amplitude of swing of the jaw is known as ____.

Answer 18

Closed Set
Open Set
Throw

Question 19

In the mining industry, ____ are used to crush the run-of-mine ore to a size suit able for transportation.

Answer 19

Jaw Crushers

Question 20

In a ____ the inner conical shell is pointing up and outer conical shell is pointing down. The reduction ratio varies from ____.

Answer 20

Gyratory Crusher
3 to 10

Question 20

They consist of two vertical truncated conical shells of which the outer hallow conical shell is ____ and the inner solid conical shell is made to ____

Answer 20

Stationary
Gyrate

Question 20

____ is the modification of gyratory which has straight or curved heads and concaves and used for secondary crushing. The fine ____ crusher can also be used forTertiary Crushing.

Answer 20

Reduction Gyratory Crusher

Question 21

The ____ is a modified gyratory.

Answer 21

Cone Crusher

Question 22

____ is the most widely used type of cone crusher.

Answer 22

Simons Cone Crusher | yes with S

Question 23

2 forms of Simons Cone Crusher

Answer 23

Standard cone crusher and Short-head cone crusher

Question 24

has a steeper head angle to prevent choking of finer material.

Answer 24

Short Head Cone Crusher

Question 25

has stepped liners to allow a coarser feed

Answer 25

Standard Cone Crusher

Question 26

The ____ is another type having a spherical steel head and used for tertiary crushing

Answer 26

Telsmith Gyrasphere

Question 27

____ consists of two smooth heavy horizontal cylinders revolving towards each other and the feed material is nipped between the rolls and pulled downward through the rolls by friction.

Answer 27

Roll Crusher

Question 28

The distinguished feature of a roll crusher is that the material is crushed ____ only whilst it is passing through the crushing chamber.

Answer 28

ONE TIME ONLY

Question 29

____ crushers are generally used for fine crushing whereas corrugated or ____ crushers are used for coarse crushing of soft materials.

Answer 29

Smooth-surface roll crushers toothed roll crushers

Question 29

____ roll crusher and ____ roll crusher are the two types of toothed roll crushers used for crushing ____.

Answer 29

Single toothed Double toothed coal

Question 29

____ reduce the particles by impact forces applied through sharp blows of fixed or free swinging hammers revolving about central rotor at high speed to the free falling particles against stationary surfaces

Answer 29

Impact crushers

Question 30

They are used for relatively soft, friable, and sticky ores such as phosphates, limestone, clay, graphite and coal.

Answer 30

Impact Crusher

Question 30

In ____, rolls are subjected to high pressure so that comminution takes place by compressive forces as well as by inter-particle breakage. The force applied to the crushing zone is controlled by a ____.

Answer 30

High Pressure Grinding Rolls Hydro-pneumatic springs

Question 31

____ are usually operated dry

Answer 31

Crushers

Question 32

avoids the production of excessive fines by limiting the number of contacts.

Answer 32

Free Crushing

Question 33

When the material fed to the crusher is at a high rate, the crusher is ____ and it prevents the complete discharge of crushed product.

Answer 33

Choked

Question 34

____ may be conducted in open or closed circuit.

Answer 34

Crushing

Question 35

the feed material is reduced by one crusher. The product of this crusher is screened and only oversize material is crushed by another crusher of small size as the throughput (the quantity of material crushed in a given time) is less.

Answer 35

Open Circuit Crushing Operation

Question 36

the oversize material from the screen is fed back to the same crusher.

Answer 36

Closed Circuit Crushing Operation

Question 37

The quantity of the oversize material fed back to the crusher is called as

Answer 37

Circulating Load

Question 38

expressed as a percentage of the quantity of feed material. It is to be noted that the throughput of the crusher is more than that of the crusher used in open circuit crushing operation and equal to the quantity of feed material plus the quantity of oversize material fed back from the screen

Answer 38

Circulating Load