Assignment front page for the student of university of Gujrat

1. Assignment #: 01 Roll #: 11013323-031



Subject code:
CHT-313
Topic of Assignment:
“primary and secondary crusher and Grinders”

Subject Name:
“Partical Technology”

Submitted to:
“Engr.Waqas Qamar”

Submitted by:
“Ateeq Ahmad”

Submission date:
18/11/2013




Marks
Department of Chemical Engineering (BS.Technology)

2. Content
1) Primary Crusher
a) Jaws crusher
i) Dodge type jaw crusher
ii) Blake type jaw crusher
b) Gyratory Crusher
c) Rolling crusher
d) Toothed roll crusher
2) Secondary crusher
a) Hammer mills
b) Impacted
c) Rolling compression machine
d) Attrition mills
3) Grinder
a) Fluid energy mill
b) Afiraled mills
c) Colloid mill

3. 1. Primary Crusher:
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust.
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 (as in rock ore), so that pieces of
different composition can be differentiated. 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 surfaces, and apply sufficient force to bring the surfaces together to generate enough
energy within the material being crushed so that its molecules separate from (fracturing), or change alignment
in relation to (deformation), each other. The earliest crushers were hand-held stones, where the weight of the
stone provided a boost to muscle power, used against a stone anvil. Querns and mortars are types of these
crushing devices.
Primary crushing reduces this run-of-mine rock to a more manageable size. The different types of
primary crushers are: jaw crushers, gyratory crushers, impact crushers, and autogenous crushers.
Crushing is the first step in converting shot rock into usable products. Essentially, crushing is no
more than taking large rocks and reducing them to small pieces. Crushing is sometimes continued
until only fines remain.
Mining operations use crushers, commonly classified by the degree to which they fragment the
starting material, with primary and secondary crushers handling coarse materials, and tertiary and
quaternary crushers reducing ore particles to finer gradations. Each crusher is designed to work with
a certain maximum size of raw material, and often delivers its output to a screening machine which
sorts and directs the product for further processing. Typically, crushing stages are followed by
milling stages if the materials need to be further reduced. Additionally rock breakers are typically
located next to a crusher to reduce oversize material too large for a crusher. Crushers are used to
reduce particle size enough so that the material can be processed into finer particles in a grinder. A
typical processing line at a mine might consist of a crusher followed by a SAG mill followed by a ball
mill. In this context, the SAG mill and ball mill are considered grinders rather than crushers.
At some operations, all the crushing is accomplished in one step, by a primary crusher. At other
operations, crushing is done in two or three steps, with a primary crusher that is followed by a
secondary crusher, and sometimes a tertiary crusher.
There are several different types of primary crushers, however, there are many similarities in the job
procedures followed by crusher operators.
Raw material, of various sizes, is brought to the primary crusher by rear-dump haul units, or carried
by a wheel front-end loader. Primary crushing reduces this run-of-mine rock to a more manageable
size. The different types of primary crushers are: jaw crushers, gyratory crushers, impact crushers,
and autogenous crushers.

a) Jaws crusher:
A jaw crusher uses
compressive force for
breaking of particle. This
mechanical pressure is
achieved by the two jaws
of the crusher of which
one is fixed while the other
reciprocates. A jaw or
toggle crusher consists of a
set of vertical jaws, one
jaw is kept stationary and

4. is called as fixed jaw while the other jaw, called as swing jaw, moves back and forth relative to it.
The volume or cavity between the two jaws is called as the crushing chamber. The movement of the
swing jaw can be quite small, since complete crushing is not performed in one stroke. The inertia
required to crush the material is provided by a weighted flywheel that moves a shaft creating an
eccentric motion that causes the closing of the gap. Jaw crushers are heavy duty machines and
hence need to be robustly constructed. The outer frame is generally made of cast iron or steel. The
jaws themselves are usually constructed from cast steel. They are fitted with replaceable liners
which are made of manganese. Steel or Ni-hard (a Ni-Cr alloyed cast iron). Jaw crushers are usually
constructed in sections to ease the process transportation if they are to be taken underground for
carrying out the operations.
Application area: mining, building, railway, highway, metallurgy, chemistry
Processing stage: primary crushing
Crushing material: limestone, gypsum, talcum, calcite, bauxite, granite, slag, iron ore etc.
(<Moh’s harness 8)
Crushing ratio: 4-6
Main components: body frame, movable jaw, fixed jaw
Protection type: toggle plate Quickwear parts: high manganese steel

What is the Moh’s harness?
The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through
the ability of a harder material to scratch a softer material.
 Jaw crusher Main Features and Benefits:
1) High reliability
2) Flexible capacity
3) Simple structure and easy to operate
4) Over-loading protection
5) Easy replacement of wear and spare parts
6) Long service time
7) High efficiency
8) Wide ranges of choices

 How Jaw Crusher works:
Jaw crusher reduces large size rocks or ore by
compressing, a fixed jaw, mounted in a “V”
alignment is the stationary breaking surface, while
the moveable jaw plate exerts force on the rock by
compressing it against the fixed jaw plate. The
space at bottom of the “V”, aligned jaw plate， is
the output size gap, or the maximum size of the
crushed product.
Due to the features of simple structure, reliable
performance, convenient maintenance and safe
use, our jaw crushers of various models are widely
used in the crushing operation in metallurgy, mining, building materials, chemical industries and
cement enterprises.

 Classification of jaws crusher:
Jaw crushers are classified on the basis of the position of the pivoting of the swing jaw

5. 1. Blake crusher-the swing jaw is fixed at the upper position
2. Dodge crusher-the swing jaw is fixed at the lower position
3. Universal crusher-the swing jaw is fixed at an intermediate position
i) Dodge type jaw crusher:
In the Dodge type jaw crushers, the jaws are farther apart at the top than at the bottom, forming a
tapered chute so that the material is crushed progressively smaller and smaller as it travels
downward until it is small enough to escape from the bottom opening. The Dodge jaw crusher has a
variable feed area and a fixed discharge area which leads to choking of the crusher and hence is
used only for laboratory purposes and not for heavy duty operations.
ii) Blake type crusher:
The Blake crusher was patented by Eli Whitney Blake in 1858. The Blake type jaw crusher has a fixed
feed area and a variable discharge area. Blake crushers are of two types- single toggle and double
toggle jaw crushers.
a. Single toggle jaws crusher:
In the single toggle jaw crushers, the swing jaw is suspended on the eccentric shaft which leads to a
much more compact design than that of the double toggle jaw crusher. The swing jaw, suspended
on the eccentric, undergoes two types of motion- swing motion towards the fixed jaw due to the
action of toggle plate and vertical movement due the rotation of the eccentric. These both motions,
when combined, lead to an elliptical jaw motion. This motion is useful as it assists in pushing the
particles through the crushing chamber. This phenomena leads to higher capacity of the single
toggle jaw crushers but it also results in higher wear of the crushing jaws. These type of jaw crushers
are preferred for the crushing of softer particles.
b. Double toggle jaw crushers:
In the double toggle jaw crushers, the oscillating motion of the swing jaw is caused by the vertical
motion of the pitman. The pitman moves up and down. The swing jaw closes, i.e., it moves towards
the fixed jaw when the pitman moves upward and opens during the downward motion of the
pitman. This type is commonly used in mines due to its ability to crush tough and abrasive materials.
b) Gyratory Crusher
A gyratory crusher is similar in basic concept to a jaw crusher,
consisting of a concave surface and a conical head; both
surfaces are typically lined with manganese steel surfaces. The
inner cone has a slight circular movement, but does not rotate;
the movement is generated by an eccentric arrangement. As
with the jaw crusher, material travels downward between the
two surfaces being progressively crushed until it is small enough
to fall out through the gap between the two surfaces.
A gyratory crusher is one of the main types of primary crushers
in a mine or ore processing plant. Gyratory crushers are
designated in size either by the gape and mantle diameter or by
the size of the receiving opening. Gyratory crushers can be used
for primary or secondary crushing. The crushing action is caused
by the closing of the gap between the mantle line (movable) mounted on the central vertical spindle
and the concave liners (fixed) mounted on the main frame of the crusher. The gap is opened and
closed by an eccentric on the bottom of the spindle that causes the central vertical spindle to gyrate.

6. The vertical spindle is free to rotate around its own axis. The
crusher illustrated is a short-shaft suspended spindle type,
meaning that the main shaft is suspended at the top and that
the eccentric is mounted above the gear. The short-shaft
design has superseded the long-shaft design in which the
eccentric is mounted below the gear.
Application area: mining, cement, coal, metallurgic
material, construction material, road building, and petroleum
& chemical industries
Processing stage: primary and secondary crushing
Crushing material: limestone, gypsum, talcum, coal, calcite, bauxite, granite, slag, iron ore etc.
(<Moh’s harness 9)
Crushing ratio: 5
Main components: Step bearing, ShellPinion shaft, Mantle, Main Shaft Sleeve, Main Shaft
Working principle: the gap between movable cone and fixed cone changes with the rotation of
main shaft, thus the material is squeezed to the required size
Discharge opening: 150mm~170mm

c) Rolling crusher:
A factory or machine in which metal is rolled into sheets, bars, or other forms.
1. (Engineering / Metallurgy) a mill or factory where ingots of heated metal are passed between
rollers to produce sheets or bars of a required cross section and form.
2. (Engineering / Metallurgy) a machine having rollers that may
be shaped to reduce ingots, etc., to a required cross section
and form.
 Advanced Design, High Performance Roller Crusher
Roller crushers are used mainly for crushing easily fractured
materials such as soft limestone, chalk, and clay to between
1/3 and 1/5 of its original size.

 The Fields Of Application:
Double roll crushers are used for both, primary and secondary
crushing. They guarantee a strictly defined final grain size with
a minimum of fine grains.

 The Feed Materials:
Raw materials, secondary materials and byproducts such as coke, sinter, coal, soft to medium-hard
rock, ore, chalk, broken glass and similar products.

 How To Work With Double Roller Crusher?
The motor drives the fixed roller and movable roller to work via reducer and coupling. Materials are
put into the space between the two rollers via the feed entrance. As the two rollers inward turning,
the input materials are crushed, pressed, ground, and at last come out from the base of the
machine.

7. Rolling mills are machines which are used to process metal. They vary in size from bench-mounted
hand-cranked mills used by jewelers to massive rolling mills utilized in industrial metals production
and processing. The primary function of a rolling mill is to shape the metal being passed through the
mill in some way, and many come with attachments and accessories which can be used for different
types of tasks. Both hot and cold rolling mills are available for different metalworking applications.
A basic rolling mill is designed to produce sheet metal. The metal is passed between two tough
cylinders numerous times, with the distance between the cylinders
being decreased with each pass so that the metal becomes thinner
and thinner. Using a rolling mill, an ingot of aluminum can be
transformed into aluminum foil. Rolling mills are used to make
sheet metal in a variety of thicknesses, and they can also be used
to create custom sizes in a workshop by a metalworker who does
not want to keep an array of sizes on hand.
Rolling mills can also be used to produce wire. The wire may be
square, octagonal, or otherwise shaped by its passage through the
rolling mill. In this case, the metal is moved through a series of progressively smaller slots in the
rolling mill as it is
cranked through.
Rolling mills may also
cut metal with a
cutting attachment
which can be used to
create uniform
standardized cuts.
Rolling is a metal
forming process in which metal stock is passed through a pair of rolls. Rolling is classified according
to the temperature of the metal rolled. If the temperature of the metal is above
its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the
metal is below its recrystallization temperature, the process is
termed as cold rolling. In terms of usage, hot rolling processes
more tonnage than any other manufacturing process, and cold
rolling processes the most tonnage out of all cold
working processes.
There are many types of rolling processes, including ring
rolling, roll bending, roll forming, profile rolling, and controlled
rolling
A rolling mill, also known as a reduction mill or mill, has a
Roller

8. common construction independent of the specific type of rolling being performed
Work rolls
Backup rolls - are intended to provide rigid support required by the working rolls to prevent
bending under the rolling load
Rolling balance system - to ensure that the upper work and back up rolls are maintain in proper
position relative to lower rolls
Roll changing devices - use of an overhead crane and a unit designed to attach to the neck of the
roll to be removed from or inserted into the mill.
Mill protection devices - to ensure that forces applied to the backup roll chocks are not of such a
magnitude to fracture the roll necks or damage the mill housing
Roll cooling and lubrication systems
Pinions - gears to divide power between the two spindles, rotating them at the same speed but
in different directions
Gearing - to establish desired rolling speed
Drive motors - rolling narrow foil product to thousands of horsepower
Electrical controls - constant and variable voltages applied to the motors
Coilers and uncoilers - to unroll and roll up coils of metal
Slabs are the feed material for hot strip mills or plate mills and blooms are rolled to billets in a billet
mill or large sections in a structural mill. The output from a strip mill is coiled and, subsequently,
used as the feed for a cold rolling mill or used directly by fabricators. Billets, for re-rolling, are
subsequently rolled in either a merchant, bar or rod mill. Merchant or bar mills produce a variety of
shaped products such as angles, channels, beams, rounds (long or coiled) and hexagons.
d) Toothed roll crusher
Toothed roll crusher is suitable for crushing raw coal in coal, metallurgy, mine, chemistry and
building materials industry especially in large coal mines and coal dressing plants. Toothed roll
crusher has very big crushing ability, and the electromotor is connected with the reducer with Limit
type hydraulic coupler to prevent dynamic overload, so that the sensor is safe and reliable. The
adjustment of the space between the two rolls belongs to hydraulic adjustment and the bearing of
the rolls are lubricated centrally. The toothed roll crusher has the advantages of small size, big
crushing ratio, low noise, simple structure and convenient maintenance and the features of high
productivity, even granularity of the crushed materials, low over-crushing rate and flexible over-load
protection.
 Performance Characteristics
1. Compared with other types of crushers, this series of crusher has many advantages such as big
crushing ratio, no requirement for the water content of the materials to be crushed, low noise, low
vibration, low energy consumption, small coverage size and simple and convenient maintenance.
2. It is equipped with hydraulic automatic yielding device which can effectively prevent the iron from
damaging the roll and prevent wood and soft materials from damaging the normal work of the roll.

9. 3. It is equipped with intelligent clearing device which can automatically remove the materials
sticking on the chamber wall using the working
intervals.
4. This machine adopts
mechanical, equipment and hydraulic protective
device and interlocking device, thus effectively
protecting the electromotor, crusher and the
whole system.
5. This product becomes the first choice of the
heat-engine plant to replace import crushing
equipment due to its advantages of high efficiency,
energy conservancy and environment protection.
It is suitable for crushing crisp materials with
medium and low hardness such as soft coal, blind coal, lignite and gangue and also suitable for
processing sinter, coke, slag, shale and limestone.
 Working Principle
Toothed roll crusher is mainly composed of driving tooth, reducer, hydraulic coupler, electromotor,
motor-driven fuel feed pump, passive toothed roll, arch toothed plate, side toothed plate, and side
toothed plate base, lower frame and velometer.
Toothed roll crusher mainly splits and crushes the
materials using unique wear-resisting toothed roll
rotating with high speed, forming high-productivity
mechanism. This toothed roll crusher is mainly composed
of driving device, rack part, crushing roll, and mechanical
spring device and link gear. Toothed roll crusher has very
big crushing ability, and the electromotor is connected
with the reducer with Limit type hydraulic coupler to
prevent dynamic overload, so that the sensor is safe and
reliable. The adjustment of the space between the two rolls belongs to hydraulic adjustment and the
bearing of the rolls are lubricated centrally.
2) Secondary Crusher
This crusher is usually for re-crushing the primary crusher run smaller or rejects from the primary
crusher run.
a) Hammer Crusher Overview
Hammer crusher also called hammer mill crushes by the collisions between high-speed hammer and
material, which features in its simple structure, high reduction ration, high efficiency, ect. The
hammer crushers were developed for the both dry and wet crushing of brittle, medium-hard
materials for the mining, cement, coal, metallurgic, construction material, road building, and
Petroleum & Chemical industries.
Application area: mining, construction, metallurgy, chemistry, cement, coal
Processing stage: primary crushing

10. Crushing material: Coal gangue, coke, slag, limestone, phosphate rock, salt, whiting, gypsum
stains, alum, brick and tile, calcite, bauxite, granite, iron ore etc. (<100Mpa)
Main components: frame ,rotor, grizzly bar, Impeller bar,and other adjustment equipment
Quickwear parts: high manganese steel
 Hammer Crusher Detail Info
Hammer crusher application
Hammer crusher is applicable for both dry
and wet crushing, and it is widely used for
medium or fine crushing for medium hard
and brittle materials by departments of
mine, cement, coal, building material,
metallurgy, chemical industry, road
construction, gas chemical industry and
thermal power generation, etc. Coal gangue,
coke, slag, limestone, phosphate rock, salt, whiting, gypsum stains, alum, brick and tile, etc. can be
crushed by this equipment. The compression strength of the materials shall not exceed 100MPa,
while the moisture content shall be lower than 15%.
Hammer crusher Parts
Hammer crusher consists of frame ,rotor, grizzly bar, Impeller bar,and other adjustment equipment.
 Hammer Crusher Working
Principle
The main working part of hammer crusher is
rotors with hammer. The rotors consist of main
shaft, disk, pin shaft and hammers. The motor
drives the rotors to rotate quickly in the
crushing cavity. Raw materials enter the
crusher through the feed opening and are
stricken, impacted, cut and ground by the high-
speed hammer to small size. There is a
screening plate under the rotor, so that
materials with size smaller than the screen mesh will be screened out and others are left to be
further hammered and ground until reach the standard size. The size of the final product can be
adjusted by changing the screening plate. The gap between the rotors and the screening plate can
also be adjusted according to different requirement.
a) Impacted
Impact crushers, which are also called hammer mills, break rock
by impacting the rock with hammers that swing on a rotating
shaft. The practical use of impact crushers is limited to soft
materials, such as phosphate, gypsum, weathered shales, etc.
Impact crushers cannot handle as large a top sized material as
jaw, or gyratory, crushers can; however, impact crushers can

11. make a finer sized product.
Impact crushers involve the use of impact rather than pressure to crush material. The material is
contained within a cage, with openings on the bottom, end, or
side of the desired size to allow pulverized material to escape.
Impact crusher (impactor crusher machine) is suitable for
materials whose compressive strength is under 360Mpa, and
particle size is less than 500mm. This kind of machine features
easy maintenance, high crushing ratio and crushing efficiency
etc. With end products in cubic shape, impact crushers are the
ideal crushers for aggregates processing in high-type highway
building, water conservancy and power construction.
Application area: road and railway building, dam, construction
Processing stage: secondary crushing
Crushing material: limestone, gypsum, talc etc. (<Moh’s harness 4)
Crushing ratio: 10-20
Main components: body frame, rotor, impact rack
Working principle: the rotor rotates at the high speed and hits the entering materials, which will be
shot back by the impact rack; the material is crushed due to the constant impact
Protection type: impact rack self weight
Quickwear parts: high manganese steel, high chromium steel
 Impact crusher application
Impact Crusher is the most common equipment of the stone
crushing production line , adopting the latest producing
technology, features many advantages: special structural
design, cubic shaped desired products, dealing with the
material with the side length 500mm, not more than 350Mpa
anti-pressure strength, Impact Crusher can be widely used in
crushing the coarse, midium, and fine material(E,g. granite, limestone, concrete).
Impact crusher main features and benefits
1. Energy-efficient.
2. Unique structure, keyless connection.
3. Blow bar made of high chromium steel, impact plate with
a special shape.
4. End products with cubical shape.
5. Easy operation and maintenance and high reliability.
 Impact Crusher Working Principle
The impact crusher uses plate hammer on the rapidly rotating rotor to generate high-speed impact
to crush the materials in the crushing cavity, and casts the crushed materials along tangential
direction to impact plate at the other end of the crushing cavity. The materials are crushed again,

12. and then, they return to the plate hammer to undergo the process above repeatedly.
The materials are bumping with each other when being sent between the plate hammer and the
impact plate. The materials become cracked, loose and then comminuted by knocking by the plate
hammer, impact with impact plate and bump between materials. The materials with grain size
smaller than the gap between impact plate and plate hammer will be discharged.
Classification of Impact crusher
Horizontal shaft impactor (HSI) / Hammer mill:
The HSI crushers break rock by impacting the rock with hammers that are fixed upon the outer edge
of a spinning rotor. HSI machines are sold in Stationary, trailer mounted and crawler mounted
configurations. HSI's are used in recycling, hard rock and soft materials. In earlier years the practical
use of HSI crushers is limited to soft materials and non abrasive materials, such as limestone,
phosphate, gypsum, weathered shales, however improvements in metallurgy has changed the
application of these machines.
Vertical shaft impactor (VSI):
VSI crushers use a different approach involving a high speed rotor with wear resistant tips and a
crushing chamber designed to 'throw' the rock against. The VSI crushers utilize velocity rather than
surface force as the predominant force to break rock. In its natural state, rock has a jagged and
uneven surface. Applying surface force (pressure) results in unpredictable and typically non-cubical
resulting particles. Utilizing velocity rather than surface force allows the breaking force to be applied
evenly both across the surface of the rock as well as through the mass of the rock. Rock, regardless
of size, has natural fissures (faults) throughout its structure. As rock is 'thrown' by a VSI Rotor against
a solid anvil, it fractures and breaks along these fissures. Final particle size can be controlled by 1)
the velocity at which the rock is thrown against the anvil and 2) the distance between the end of the
rotor and the impact point on the anvil. The product resulting from VSI Crushing is generally of a
consistent cubical shape such as that required by modern SUPERPAVE highway asphalt applications.
Using this method also allows materials with much higher abrasiveness to be crushed than is capable
with an HSI and most other crushing methods.
VSI crushers generally utilize a high speed spinning rotor at the center of the crushing chamber and
an outer impact surface of either abrasive resistant metal anvils or crushed rock. Utilizing cast metal
surfaces 'anvils' is traditionally referred to as a "Shoe and Anvil VSI". Utilizing crushed rock on the
outer walls of the crusher for new rock to be crushed against is traditionally referred to as "rock on
rock VSI". VSI crushers can be used in static plant set-up or in mobile tracked equipment.