Size Reduction

Question 1

Impacts to power consumption and wear machine

Answer 1

Hardness

Question 2

Power required is directly proportional to material crushing strength

Answer 2

Crushing strength

Question 3

Normal force acts for granular materials, tearing action for fibrous materials

Answer 3

Structure

Question 4

5 to 50% moisture content means low flowability

Answer 4

Moisture Content

Question 5

Stickier materials tend to clog on the equipment

Answer 5

Stickiness

Question 6

Tendency of material to fracture

Answer 6

Friability

Question 7

Measure of friction coefficient of the material

Answer 7

Soapiness

Question 8

Handled via wet grinding or with an inert material

Answer 8

Explosive Material

Question 9

Particle size from 2 to 96 inches or more

Answer 9

Coarse

Question 10

Particle size from 1 to 3 inches

Answer 10

Intermidiate

Question 11

Particle size from 0.25 to 0.5 inches

Answer 11

Fine

Question 12

For hard solids to coarse size with relatively few fines

Answer 12

Compression / Crushing

Question 13

Result to coarse, medium, fine product

Answer 13

Impact

Question 14

For reduction of fibrous materials

Answer 14

Disintegration

Question 15

Results to very few fines from soft and non-abrasive materials

Answer 15

Attrition or Rubbing

Question 16

Produces definite size and shape, few or almost no fines

Answer 16

Cutting

Question 17

With use of large excess water; fine stage of reduction

Answer 17

Wet Grinding

Question 18

Crushed product is quickly removed, preventing fines build-up

Answer 18

Free Crushing

Question 19

Crusher is equipped with a hopped and kept filled

Answer 19

Choke Feeding

Question 20

Oversized particles are not returned for further reduction

Answer 20

Open circuit operation

Question 21

Oversized particles are returned for further reduction

Answer 21

Closed circuit operation

Question 22

Break solid materials into lumps by compression

Answer 22

Crushing

Question 23

With two jaws forming V-shaped chamber; mainly for primary crushing of hard materials

Answer 23

Jaw Crusher

Question 24

With cone-shaped pestle swinging in a larger cone-shaped bowl; used for crushing of hard ores and minerals

Answer 24

Gyratory Crushers

Question 25

Made of two rolls rotating towards each other at either same or different speed; usually used in coal crushing

Answer 25

Roll Crushers

Question 26

Reduces feed to powder by impact or attrition

Answer 26

Grinders

Question 27

A heavy duty hammer mill performing by impact only, not with attrition, yielding more equidimensional particles relative to jaw and gyratory crushers

Answer 27

Impactors

Question 28

Uses impact and attrition as mode of size reduction; for fibrous materials, hard rocks and sticky materials

Answer 28

Hammer Mills

Question 29

Particles crushed by rolling member and the face of a ring

Answer 29

Rolling Compression Mils

Question 30

Soft solids are rubbed between flat surfaces of rotating circular disks

Answer 30

Attrition Mills

Question 31

Operates continuously or by batch for abrasive materials

Answer 31

Tumbling Mills

Question 32

Used when definite size is required

Answer 32

Cutter

Question 33

With horizontal rotor of flying knives; generates regularly shaped particles

Answer 33

Knife Cutters

Question 34

Work required is proportional to the new surface created.

Answer 34

Rittinger’s Law

Question 35

Work required is proportional to the square root of the surface to volume ratio of the product

Answer 35

Bond’s Law

Question 36

Work required is proportional to the logarithmic of size reduction ratio

Answer 36

Kick’s Law