Particle technology lab report

PARTICLE TECHNOLOGY LAB REPORT 1
PARTICLE TECHNOLOGY LAB REPORT
Submitted to: Sir Haris
Nabeel Sultan (2015-CH-244)
University of Engineering and Technology, Lahore KSK Campus

Table of contents
Experiments:
1. Determination of apparent and real density of materials.
2. Granular analysis of material by sieving apparatus.
3. Solid handling bench apparatus experiment.
 Angle of repose
 Loading and unloading
 V-blender
4. Crushing of material of required size by jaw crusher and doing sieve
analysis on that material.
5. Ball mill and Pebble mill.
6. Cake filtration.
7. Double roll crusher.
8. Cyclone separator.
9. Helical ribbon mixer.

Experiment#1:
Determination of apparent and real density of materials.
Required Materials:
1. Measuring cylinder
2. Vibratory sieve
3. Solids object to study
Theory:
1. Density: Density is a characteristic property of a substance. The density of a
substance is the relationship between the mass of the substance and how
much space it takes up (volume). The mass of atoms, their size, and how
they are arranged determine the density of a substance.
Absolute density of material cannot be determined because of the empty
spaces(voids) present between the particle due to irregular shape of the particle.
As shown in the figure below
2. Apparent density: The mass per unit volume (or the weight per unit
volume) of a material, including the voids which are inherent in the
material is called apparent density.

3. Material density: The mass per unit volume (or the weight per unit volume)
of a material, not including the voids which are inherent in the material is
called real density or material density.
4. Methods of measuring real & apparent density: There are basically two
methods used for measuring real and apparent density.
 By using vibratory sieve apparatus: This method is preferred if the
solid material under study is water soluble e.g. sugar, salts etc.
 By using water and measuring cylinder: This method is preferred if
the material under study is not water soluble e.g. sand.
Procedure:
1. First weight the given sample of the solid.
2. After that place the sample in the measuring cylinder and determine the
volume of the sample which It occupied without compacting.
3. Then calculate the apparent density of the material by using formula.
Apparent density = ρ =
mass of particles
Volume of particle without compacting
4. To calculate the real density of material, determine the nature of
compound whether it is water soluble or not.
5. If the material is water soluble put the measuring cylinder containing
material over the vibratory sieve shaker the material.
6. Again note the volume of material and determine the real density by using
formula.
Real density = ρ =
mass of particles
Volume of particle after compacting
7. If the substance is not water soluble then the placed the material in the
measuring cylinder and pour water in it, water compacted the material and
then again note the volume of material in the cylinder and calculate the
real density by using above formula.
8. In the end calculate the crushing ratio of material by using formula.
Crushing ratio = Φ =
𝐴𝑝𝑝𝑎𝑟𝑒𝑛𝑡 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
𝑅𝑒𝑎𝑙 𝑑𝑒𝑛𝑠𝑖𝑡𝑦

Observation & Calculations:
Mass of given sample = m =500
Volume of given sample of material before compacting = V1=350
Volume of given sample of material after compacting = V2 =330
Apparent density of material = 𝜌 𝐴 =
m
V1
=1.43
Real density of material = 𝜌 𝑅 =
m
V2
=1.51
Crushing ratio = Φ =
ρA
ρR
=0.947
Result:
Apparent density of material = 𝜌 𝐴=1.43
Real density of material = 𝜌 𝑅 = 1.51
Crushing ratio = Φ =0.947
Table of apparent and real density of some materials
Materials taken Apparent density Real density
1 Sand 1.43 1.51
2 Sugar
3 Salt
Industrial applications:
1. Bridge construction:
During construction of bridges soil erosion is the biggest problem which the
engineer faces. This is due to the empty pores present between the
particles of the soils which when come in contact of water results in
lowering of ground. If the bridge is constructed in such soil its pillars will
settle down into the soil which result in bridge destruction. That’s why
before constructing the bridge the first thing which is done is the
compacting of the soil to make a solid base.

2. Construction of artificial island (Dubai palm island):
During construction of artificial island like palm island in Dubai it is highly
necessary that soil is highly compacted for this purpose engineer used
vibratory machines for compacting of soil to make a solid base of the island
so that it can face the heavy wave impact of the sea.
A figure below shows how engineer uses vibrator to compact the soil.
3. Crushing of material:
The material with high density is not easy to crush it required a large force
to crush them as compared to material with low density so the
determination of crushing ratio is very important.

4. There are also many disadvantages of soil compacting such as pipe
breakage, foundation erosion, basement and pool cracks as shown below
in the figure
___________________________________________________________________

Experiment#2:
Granular analysis of material by sieving apparatus.
Required Materials:
1. Stack of Sieves including pan and cover
2. Balance
3. Mechanical sieve shaker
4. Sample material under study
Theory:
A sieve analysis (or gradation test) is a practice or procedure used to separate
particle on the basis of particle size distribution (also called gradation) of a
granular material. The size distribution is often of critical importance to the way
the material performs in use.
This test is performed to determine the percentage of different grain sizes
contained within a soil. The mechanical or sieve analysis is performed to
determine the distribution of the coarser, larger-sized particles.
Procedure:
1. Take the dried sample of soil that weighs about 500 g.
2. Determine the mass of sample accurately. Wt. (g)
3. Prepare a stack of sieves. sieves having larger opening sizes (i.e.
lower mesh numbers) are placed above the ones having smaller
opening sizes (i.e. higher sieve numbers).
4. Make sure sieves are clean, if many soil particles are stuck in the
openings try to poke them out using brush.
5. Then put the sample of sand in the top of sieve of sieve stack and
cover its top with a lid.
6. Now put the stack in the sieve shaker and fix the clamps, adjust the
time on 10 to 15 minutes, frequency 50Hz and get the shaker going.
7. When the shaker time is over measure the mass retained over each
sieve.

Observation & Calculations:
Total mass of sand taken = 505g
1) Differential analysis:
Sieve
#
Screen
opening
diameter(mm)
Mass
retained
in
screen(g)
Percentage
mass
retained
Average
particle
size
(mm)
Mass
fraction
retained
7 1 0 0 - 0
6 0.5 80 15.93625498 0.75 0.15936255
5 0.355 156 31.07569721 0.4275 0.310756972
4 0.212 220 43.8247012 0.2835 0.438247012
3 0.15 30 5.976095618 0.181 0.059760956
2 0.106 10 1.992031873 0.128 0.019920319
1 0.063 4 0.796812749 0.0845 0.007968127
Pan 0 2 0.398406375 0.0315 0.003984064
Total 502 100%

2.Comulative analysis:
Sieve
#
Screen
opening
diameter
(mm)
Mass
retained
in
screen
(g)
Percentage
mass
retained
Cumulative
w.t %
undersize
Cumulative
w.t%
oversize
7
1 0 0 100 0
6
0.5 80 15.93625498 84.06374502 15.93625498
5
0.355 156 31.07569721 52.98804781 47.01195219
4
0.212 220 43.8247012 9.163346614 90.83665339
3
0.15 30 5.976095618 3.187250996 96.812749
0
0.1
0.2
0.3
0.4
0.5
0 0.2 0.4 0.6 0.8 1 1.2
Massfractionretained
Screen opening diameter(mm)
Mass fraction retained

2
0.106 10 1.992031873 1.195219124 98.80478088
1
0.063 4 0.796812749 0.398406375 99.60159363
Pan
0 2 0.398406375 0 100
Total 502 100%
Percentage mass loss during sieve analysis =
wt−wf
wt
×100 =
505−502
505
×100
= 0.59%<<2%
0
20
40
60
80
100
120
0 0.2 0.4 0.6 0.8 1 1.2
Screen opening diameter(mm
comparison of comulative analysis of undersize & oversize
Comulative wt% undersize Comulative wt% oversize

Applications of sieve analysis:
1. Many separation processes and reactions depends on the amount of
available surface area so sieve analysis is a very important technique i.e.
greater the surface area more extent of reaction.
2. Some applications of sieve analysis are as follows:
 Of limestone and shale for the manufacturing of cement.
 Of coal for combustion and hydrogenation to liquid fuel.
 Of cane and beets for recovery sugar.
 Of some flora for recovery of natural drugs and so on.
 Gold and Silver Mining Industry, required particles which 80% -200
mesh before feeding into extraction plant.
3. In petroleum industries which explore and produce crude oil, sieve analysis
is used to describe the population of formation sand grain size. Sieve
analysis became the accepted method for characterizing both the
formation sand and the gravel to be used to control sand production.
Sieve analysis technique also used in cement industry to separate the oversize
particles from the required size so that mixing of raw material becomes easy

Solid handling bench apparatus experiment.
Apparatus
The apparatus of solid handling consists of a bench which contains multiple
equipment’s which are as follows:
 Framework with platform and background
 Cylindrical hopper
 Variable speed ball mill
 “V” cone shaped solid mixing vessel with variable speed motor
 Transparent horizontal angle of repose cylinder.
The basic picture of solid handling apparatus is shown below
Part 1: “V” shape blender
The V-Blender is made of two hollow cylindrical shells joined at an angle of 75° to
90°. The blender container is mounted on trunnions to allow it to tumble. As the
V-blender tumbles, the material continuously splits and recombines, with the
mixing occurring as the material free-falls randomly inside the vessel. The

repetitive converging and diverging motion
of material combined with increased
frictional contact between the material and
the vessel's long, straight sides result in
gentle yet homogenous blending. Figure 1
shows a V-Blender.
The primary mechanism of blending in a V-
Blender is diffusion. Diffusion blending is
characterized by small scale random
motion of solid particles. Blender movements increase the mobility of the
individual particles and thus promote diffusive blending. Diffusion blending occurs
where the particles are distributed over a freshly developed interface. In the
absence of segregating effects, the diffusive blending will in time lead to a high
degree of homogeneity. V-Blenders are therefore preferred when precise blend
formulations are required. They are also well suited for applications where some
ingredients may be as low as five percent of the total blend size. Normal blend
times are typically in the range of 5 to 15 minutes depending on the properties of
material to be blended charging of material into the V-Blender is through either of
the two ends or through the apex port. Studies on V-blenders have demonstrated
that for solid powders which have similar size and shape, there is no mechanism
to move the powders across the line of symmetry of the blender. For such
materials, care must then be taken to load each side of the blender equally to
ensure the desired homogeneity of blends.
Blending efficiency is affected by the volume of the material loaded into the
blender. The recommended fill-up volume for the V-Blender is 50 to 60% of the
total blender volume. For example, if the fill of material in the blender is
increased from 50% of the total volume to 70% of the total volume, the time
taken for homogenous blending may be doubled.
Blender speed may also be a key to mixing efficiency. At lower blender speeds,
the shear forces are low. Though higher blending speeds provide more shear, it
can lead to greater dusting resulting in segregation of fines. This means that the
fines become air-borne and settle on top of the powder bed once the blender has

been stopped. There is also a critical speed which, if approached will diminish
blending efficiency considerably. As the revolutions per minute increase, the
centrifugal forces at the extreme points of the blender will exceed the gravitation
forces required for blending. Consequently, the powder shall tend to gravitate to
the outer walls of the blender shell. As the size of the blender increases, the
rotational speed decreases usually in proportion to the peripheral speed of the
blender extreme. V-Blenders are designed to operate at 50% to 80% of the critical
speed.
Discharge from the V-blender is normally through the apex port which is fitted
with a discharge valve.
Principle of V shape blender:
The basic principle of v shape blender is tumbling action the cylinder is rotatable
first material are lifted up with the motion of blender and then allow to fall freely
due to gravity this is the basic principle used in “V” shape blender.
Applications of V-Blenders:
V-Blenders designs are most often used for the dry blending of free flowing solids.
This blender is often used for pharmaceuticals, but the mixing action's slight shear
limits the blender's use for some very soft powders or granules. V-Blenders are
generally used for the following:
 Food products  Ceramics Powders
 Milk powder  Pigments
 Coffee  Pesticides and Herbicides
 Dry flavors  Plastic powders
 Fertilizers  Animal feed
 Baby foods  Cosmetics

Advantages and Disadvantages of V-Blender
1) Advantages:
 Particle size reduction and attrition are minimized due to the absence of
any moving blades. Hence it can be used for fragile materials
 Charging and discharging of material is easy.
 The shape of blender body results in a near complete discharge of product
material, clearly an added advantage over horizontal blenders.
 The absence of shaft projection eliminates product contamination.
 V-blenders are easy to clean.
2) Disadvantages:
 They require high headroom for installation and operation.
 They are not suited for blending particles of different sizes and densities
which may segregate at the time of discharge.

Part 2: Angle of repose
The maximum angle to the horizontal at which rocks, soil, etc. will remain without
sliding is called angle of repose.
The angle of repose can range from 0° to 90°.
Different material has different angle of repose due to size, nature and roughness
of the particle of that compound.
Factor affecting angle of repose:
There are following factors which affect the angle of repose of materials
 Coarser the particles steeper the angle of repose as compared to the fine
particles.

 Gravity also affects the angle of repose grater the gravitational force lesser
the angle of repose
 Internal friction also affects the angle of repose greater the internal friction
more the angle of repose as shown below
This is because internal friction of sand particles is much greater then
cement and gravel.
 Moisture in the substance also affects the angle of repose by increasing the
cohesive forces between the particles as shown below
This is because moist sand has greater cohesive forces as compared to the
dry sand
Methods in determining the angle of repose:
 Tilting box method:
This method is appropriate for fine-grained, non-cohesive materials, with
individual particle size less than 10 mm. The material is placed within a box with a
transparent side to observe the granular test material. It should initially be level

and parallel to the base of the box. The box is slowly tilted at a rate of
approximately 0.3 degrees/second. Tilting is stopped when the material begins to
slide in bulk, and the angle of the tilt is measured.
 Fixed funnel method:
The material is poured through a funnel to form a cone. The tip of the funnel
should be held close to the growing cone and slowly raised as the pile grows, to
minimize the impact of falling particles. Stop pouring the material when the pile
reaches a predetermined height or the base a predetermined width. Rather than
attempt to measure the angle of the resulting cone directly, divide the height by
half the width of the base of the cone. The inverse tangent of this ratio is the
angle of repose.
 Revolving cylinder method:
The material is placed within a cylinder with at least one transparent face. The
cylinder is rotated at a fixed speed and the observer watches the material moving
within the rotating cylinder. The effect is similar to watching clothes tumble over
one another in a slowly rotating clothes dryer. The granular material will assume a
certain angle as it flows within the rotating cylinder. This method is
recommended for obtaining the dynamic angle of repose, and may vary from the
static angle of repose measured by other methods. When describing the angle of
repose for a substance, always specify the method used.
Angle of repose of different materials:
Material Angle of repose (Degree)
Wheat 27
Urea 27
Sand 45
Ashes 40
Bark 45
Corn flour 30-40
Wheat flour 45

Applications:
 The angle of repose is sometimes used in the design of equipment for the
processing of particulate solids. For example, it may be used to design an
appropriate hopper or silo to store the material, or to size a conveyor belt
for transporting the material. It can also be used in determining whether or
not a slope (of a stockpile, or uncompact gravel bank, for example) will
likely collapse; the talus slope is derived from angle of repose and
represents the steepest slope a pile of granular material will take. This
angle of repose is also crucial in correctly calculating stability in vessels.
 It is also commonly used by mountaineers as a factor in analyzing avalanche
danger in mountainous areas.
Angle of internal friction and angle of repose
 Angle of repose
The angle of repose is the maximum angle that a surface can be tilted from
the horizontal, such that an object on it is just able to stay on the surface
without it sliding down. let us first look at the diagram of the situation.
When the object is just about to move, the size of friction is given by
Fr = uR. The object is also in equilibrium (the object is about to move, but

it is not moving yet!) so taking the forces acting along the plane, we can
say,
Resolving forces perpendicular to the plane, we have,
Now, we take the ratio of these expressions:
Now by using trigonometric identities we get
Through this formula we can calculate the angle of repose.
 Angle of internal friction:
Angle of friction is defined as the angle made between the normal reaction
force and the resultant force of normal reaction force and friction. Let us
first explore this definition and attempt to express the angle of friction in
terms of a formula.
Now again by applying trigonometry identities we get

Therefore, from above discussion we conclude that angle of friction is equal
to angle of repose the only difference between them is the defination.
Part 3: Loading & Unloading
A hopper is a large, pyramidal shaped container used in industrial processes to
hold particulate matter that has been collected from expelled air. Hoppers are
usually installed in groups to allow for a greater collection quantity. They are
employed in industrial processes that use air pollution control devices such as
dust collectors, electrostatic precipitators, and baghouses/fabric filters. Most
hoppers are made of steel.
Hopper
There are basically two types of flow pattern which usually observe in hoppers or
silo:
1. Mass flow
2. Funnel flow
 Mass flow
In a mass flow hopper, all the material inside the hopper moves down the walls
and exits. The flow is based upon a first-in, first-out principle and is uniform and
reliable upon discharge. Moisture content, temperature, age, oil content, and

solid levels must be regulated to ensure effective flow. The basic flow pattern of
mass flow is shown in the figure.
USAGE
Mass flow hoppers are used in virtually every type of industry and come in a
variety of sizes. Hoppers are most often used for raw material and product
storage as well as feeders for different processes.
Sr.# Diameter of hopper Time to flow out
(s)
Flow type Mass flow rate
1
2
3

 FUNNEL FLOW:
In funnel flow, the material along the funnel walls remains stationary, while
the material in the center falls through the outlet creating a rat hole, or
channel. Funnel flow hoppers have a greater angle from the center of the
cone as shown below.
USAGE
Funnel flow is versatile and can be used in many of the same applications as mass
flow. A funnel flow design is most effective when the solid particulate is coarse,
free-flowing and not prone to caking. Also, funnel flow is used when segregation
is not important.
There are two types of hoppers, conical and wedge-shaped. The hopper shown
below to the right is conical whereas a wedge-shaped hopper is a trough with a
narrow slit, as shown to the left. Conical hoppers must be steeper to promote the
same amount of flow but wedge-shaped hoppers require a conveyer to collect the
materials that exit from it.

Experiment:
Crushing of material of required size by jaw crusher and doing sieve
analysis on that material
Required Materials:
1. Stack of Sieves including pan and cover (ASTMA) standard.
2. Jaw crusher
Theory:
Crusher is size reduction equipment. A crusher is a machine designed to reduce
large rocks into smaller, more manageable particles. Crusher is a machine which is
used to crush heavy size particle into small size, also it’s a primary size reducer.
Crusher are low speed machine for coarse reduction of large particles Approx. size
of reduced of material from a crusher ranges from 150mm to 250 mm.
Types of crusher
 Jaw crushers
 Gyratory crushers
 Double role crushers
 Jaw crusher
Jaw crusher is a type of crusher which produces coarse particle. Feed size of the
jaw crusher is 1500mm-40mm and the product size is from 50mm-5mm. Rpm for
jaw crusher is between 200-400.
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.
The simple picture of jaw crusher is shown on the next page.

 Crushing chamber
The volume or cavity between the two jaws is called 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.

Angle between two jaws is between 20-30 degree. Larger lumps caught between
upper part of the jaw and broken into small piece by impact force. Small pieces
come to narrower space at the bottom where compressive force do a sufficient
size reduction and product obtained.
Types of jaw crusher:
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
 Blake jaw crusher
A crusher with one fixed jaw plate and one pivoted at the top so as to give
the greatest movement on the smallest lump. Motion is imparted to the
lower end of the crushing jaw by toggle joint operated by eccentric. This
machine, or some modification of it, is used for reducing run-of-mine ore or
coal to a size small enough to be taken by the next crusher in the series
during the first stage of crushing.
 Dodge jaw crusher
In the Dodge crusher, the moving jaw is pivoted at the bottom. The
minimum movement is thus at the bottom and a more uniform product is
obtained, although the crusher is less widely used because of its tendency
to choke. The large opening at the top enables it to take very large feed and
to effect a large size reduction. This crusher is usually made in smaller sizes
than the Stag crusher, because of the high fluctuating stresses that are
produced in the members of the machine.
 Universal jaw crusher
In this jaw crusher the pivot point is at the middle. The product produced
from this type of crusher is of moderate size.
Principle of jaw crusher:
A jaw crusher uses compressive force for breaking of particle. A Jaw Crusher
reduces large size rocks or ore by placing the rock into compression. A fixed jaw,
mounted in a "V" alignment is the stationary breaking surface, while the movable
jaw exerts force on the rock by forcing it against the stationary plate.

Advantages of Jaw Crusher:
 Simple construction makes for easy maintenance
 Stable performance
 High crushing ratio
 Low operational cost
 High capacity
 Adjustable discharge port
Industrial Applications
Crushers are used
 Heavy duty mining
 Cement industry
 Fertilizers industry
 Plaster of Paris Plant
 Animal (Cattle) Feed plants
 Herbal plants
 Cement plants
 Coconut Shell Plant
 Salt Plant
 Mines and Minerals
 Agro Based industries
 Others where size reduction required
Differential analysis:
Total mass of sand taken = 3.00Kg
Total mass taken for sieve analysis = 1.587Kg
Sieve
#
Screen
opening
diameter(inc
hes)
Mass
retained in
screen(Kg)
Percentage
mass
retained
Average
particle size
Mass
fraction
retained
3 0.2 0.83 52.2999369 ---- 0.5229993
4 0.187 0.12 7.56143667 0.1935 0.0756143
7 0.111 0.28 17.6433522 0.149 0.1764
8 0.937 0 0 0.524 0

10 0.0787 0.004 0.25204788 0.50785 0.0025
14 0.0555 0.125 7.87649653 0.0671 0.0787
25 0.028 0.03 1.89035916 0.04175 0.0189
Pan 0 0.198 12.4763705 0.014 0.1247
Total 1.587Kg 100% 1
2.Comulative analysis:
Sieve
#
Screen opening
diameter(inches
)
Mass
retained in
screen(g)
Percentage
mass
retained
Cumulative
wt%
undersize
Cumulativ
e wt%
oversize
3 0.2 0.83 52.299936 47.7000630
1
52.299936
4 0.187 0.12 7.5614366
7
40.1386263
4
59.861373
7 0.111 0.28 17.643352
2
22.4952741 77.504725
8 0.937 0 0 22.4952741 77.504725
10 0.0787 0.004 0.2520478
8
22.2432262
1
77.756773
14 0.0555 0.125 7.8764965
3
14.3667296
8
85.633270
25 0.028 0.03 1.8903591 12.4763705 87.523629
Pan 0 0.198 12.476370 0 100
0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.05 0.1 0.15 0.2 0.25
Massfractionretained
sieve opening diameter(inches)
Mass fraction retained

0 Total 1.587 1
0
20
40
60
80
100
120
0 0.05 0.1 0.15 0.2 0.25
screen opening diameter(inches)
Chart Title

Ball Mill & Pebble Mill
The ball mill and the Pebble both are secondary is a
type of grinder used to grind and blend materials for
use in mineral dressing processes, paints,
pyrotechnics, ceramics and selective laser sintering.
Principle
Both works on the principle of Tumbling action i.e. impact and attrition: size reduction is done
by impact as the balls drop from near the top of the shell.
Explanation
A ball mill consists of a hollow cylindrical shell rotating about its axis. The axis of the shell may
be either horizontal or at a small angle to the horizontal. It is partially filled with balls. The
grinding media is the balls, which may be made of steel (chrome steel), stainless steel, ceramic,
or rubber. The inner surface of the cylindrical shell is usually lined with an abrasion-resistant
material such as manganese steel or rubber. Less wear takes place in rubber lined mills. The
length of the mill is approximately equal to its diameter.
History
The general idea behind the ball mill is an ancient one, but it was not until the industrial
revolution and the invention of steam power that an effective ball milling machine could be
built. It is reported to have been used for grinding flint for pottery in 1870.
Working
In case of continuously operated ball mill, the material to be ground is fed from the left through
a 60° cone and the product is discharged through a 30° cone to the right. As the shell rotates,
the balls are lifted up on the rising side of the shell and then they cascade down (or drop down
on to the feed), from near the top of the shell. In doing so, the solid particles in between the
balls and ground are reduced in size by impact.

Procedure of Ball Mill
 Measure the inside diameter of the ball mill.
 Measure the size of the ball with the help of venire calipers.
 Fill the ball mill to about half of its volume with balls of the same diameter.
 Feed t ball mill with 250 g mass of sugar of homogenous size (obtained by screening) and
note the particle diameter.
 Before turn on the mill, set speed regulators to maximum.
 Measure the speed of rotation of the ball mill in the revolutions per minutes.
 Analyze the product with the help of screen and note the particle diameter
 Calculate the angle α (to which the balls are carried against the wall of the ball mill)
between perpendicular (top of the ball mill) and the point at which the outermost balls
lose contact with the wall of the mill.
 Calculate the critical speed of the ball mill.
 Describe the speed of the revolution of the ball mill as the percentage of the critical
speed.
Application
The ball mill is used for grinding materials such as coal, pigments, and feldspar for pottery.
Grinding can be carried out either wet or dry but the former is performed at low speed.
Blending of explosives is an example of an application for rubber balls. For systems with
multiple components, ball milling has been shown to be effective in increasing solid-
state chemical reactivity. Additionally, ball milling has been shown effective for production of
amorphous materials.
Advantages
Ball milling boasts several advantages over other systems: the cost of installation and grinding
medium is low; it is suitable for both batch and continuous operation, similarly it is suitable for
open as well as closed circuit grinding and is applicable for materials of all degrees of hardness.
Varieties
Aside from common ball mills there is a second type of ball mill called a planetary ball mill.
Planetary ball mills are smaller than common ball mills and mainly used in laboratories for
grinding sample material down to very small sizes. A planetary ball mill consists of at least one
grinding jar which is arranged eccentrically on a so-called sun wheel. The direction of
movement of the sun wheel is opposite to that of the grinding jars (ratio: 1:-2 or 1:-1 or else).
The grinding balls in the grinding jars are subjected to superimposed rotational movements, the
so-called Coriolis forces. The difference in speeds between the balls and grinding jars produces
an interaction between frictional and impact forces, which releases high dynamic energies. The
interplay between these forces produces the high and very effective degree of size reduction of
the planetary ball mill.

Efficiency
If the energy to produce new surface by single-particle
breakage is used as the basis for evaluating efficiency,
then the efficiency of ball milling has a more realistic
value of about 15% for the comminution of quartz and
soda-lime glass. In a second approach, comminution
efficiency is based on comparing the energy to produce
some size distribution parameter of the product from
ball milling with that by single-particle breakage. For
both materials, dry ball milling efficiency was found to
be in the range of 25%.
Power consumption
Grinding media consisting of steel balls, with typical
diameters from 25 to 75 mm, is already present in the mill along with any rock that has not yet
overflowed through the discharge end. Typical power consumption for a 5-m diameter by 7-m-
long ball mill is between 2.5 and 3.5 MW.
Critical speed
The "Critical Speed" for a grinding mill is defined as the rotational speed where centrifugal
forces equal gravitational forces at the mill shell's inside surface. This is the
rotational speed where balls will not fall away from the mill's shell.

Cake Filtration
Introduction
Cake filtration is basically a solid-liquid separation technique. Although we have
different filtration technique for the separation of solid and liquid but why we require cake
filtration technique? In normal filtration techniques like membrane filtration when we separate
solids with a higher percentage of solids like slurries by a filter membrane which is porous it
results in the formation of a layer of solids over the membrane which reduces or stop the
filtration process. In this case, we have to replace the membrane at some regular intervals. So in
this case, we required a special filtration technique called cake filtration.
Principal of cake filtration
The principal of cake filtration is very interesting and simple the slurry type
material which is required to be filtered is pressed between the plates to extract the liquid from it
in this way we can separate solids from liquid economically and effectively.
Cake filtration equipment
The equipment used for cake filtration are as follows:
1. Shell and leaf filter.
2. Rotary vacuum filter.
Operation & working
1. Shell and leaf filter
The labeled diagram of the shell and leaf filters are shown in the figure below

The material which is to be filtered is pumped into these machines and the compressional force is
applied to extract all the liquid from it as shown below:
When all the water is removed from the slurry then the compressional force is removed and then
the dried cake is also removed in the form of blocks. As shown below:

2. Rotary vacuum filter
The technique is well suited to slurries,
and liquids with a high solid content,
which could clog other forms of the filter.
The drum is pre-coated with a filter aid,
typically of diatomaceous earth (DE) or
Perlite. After pre-coat has been applied,
the liquid to be filtered is sent to the tub
below the drum. The drum rotates
through the liquid and the vacuum sucks
liquid and solids onto the drum precoat
surface, the liquid portion is "sucked" by
the vacuum through the filter media to the
internal portion of the drum, and the
filtrate pumped away. The solids adhere
to the outside of the drum, which then passes a knife, cutting off the solids and a small portion of
the filter media to reveal a fresh media surface that will enter the liquid as the drum rotates. The
knife advances automatically as the surface is removed.
Nature of material used for such filtration
The slurries types materials are used in the cake filtration which causes are difficult to filter with
normal filters.
Applications in different fields
Applications of cake filtration are in the following fields are as follows:
 Municipal water purification
 Savage water treatment
 Pharmaceutical industries
 Food processing
3. Centrifugal filters
A centrifuge is a piece of equipment that puts an object in rotation around a fixed axis (spins it in
a circle), applying a potentially strong force perpendicular to the axis of spin (outward). The
centrifuge works using the sedimentation principle, where the centripetal acceleration causes
denser substances and particles to move outward in the radial direction. At the same time, objects
that are less dense are displaced and move to the center
 Principles of centrifugal filter
In basket centrifuges, the solids & liquids are separated by centrifugal force using a filter media
(usually a cloth) mounted over supporting mesh, which is together supported inside the rotating
basket. The slurry to be filtered is fed through the feed nozzles to the basket and due to
centrifugal force, the liquid is forced out through the filter media while solids are retained within
the filter media inside the basket. These solids then separated or discharged by various

discharging methods namely -
manually, bag lifting basket, through
scrapper, operated manually
pneumatically / hydraulically, for
which different models are available.
The most common type of centrifugal
filter used is top suspended
centrifuge.
The labeled diagram of suspended
basket centrifuge is shown in figure:
A common type of batch centrifuge
in industrial processing is the top
suspended centrifuge as shown in the
figure.
The perforated baskets range from
750 to 1200mm in diameter and from
450 to 750mm deep and turn at
speeds between 600 and 1800 r/min. the basket is held at the lower end of a free swinging
vertical shaft driven from above. A filter medium lines the perforated wall of the basket. Feed
slurry enters the rotating basket through an inlet pipe or chute. Liquor drains through the filter
medium into the casting and out a discharge pipe; the solids form a 50 to 150 mm of thick cake
inside the basket. The cake is kept wet with the water to remove all the soluble solids. When the
formation of cake is too high then in this case machine is shut off and the solids are discharged
by cutting them out with an unloader knife, which peels the cake from the filter medium and
drops it on the floor. After removing the cake machine is again ready for processing.
Clarifying Filters
Clarifying filters are the filters that removes all the small amounts of solids and liquid from
either liquid or gases. The particles are trapped inside the filter medium or on porous surfaces.
Clarification differs from screening in that pores in the filter medium are larger sometimes much
larger than the particles to be removed the particles are caught by surface forces and immobilized
on the surfaces or within the flow channels where they reduce the effective diameter of the
channel but usually do not block them completely.
Clarifiers are of two types:
 Liquid clarifiers
 Gas clarifiers
Liquid clarifiers:

Thickeners and clarifiers are both used to separate liquids and solids by settling. Thickeners are
used to concentrate solids, while clarifiers are used to purify liquids. The most common type of
clarifier used is circular clarifier.
Thickeners and clarifiers use slowly rotating rake arms to separate solid particulate. A liquid feed
with suspended solids is fed into a tank with a diameter of 5 to 500 feet. As the particles settle,
angled rake arms move the concentrated slurry toward the center of the tank, where it is
removed. Clear liquid overflows the top of the tank and is collected in a trough.
Equipment design is shown in the figure below:
The bridge-supported clarifier pictured above is used for primary wastewater treatment. After
large objects and grit have been screened out of the water, raw wastewater is fed into the primary
clarifier. In this stage, floating material and material that easily settles out will be removed,
resulting in a homogeneous effluent that can be further treated biologically in the secondary
clarifier, and a sludge discharge that can be treated or processed.
Uses:
Thickeners and clarifiers are often used in water and wastewater treatment plants to remove
solids, chemicals, microbes and other impurities. Thickeners and clarifiers are also used in the
paper industry, the uranium industry, and in alumina, coal, copper, and iron ore production.
Gas clarifiers:
Filter for gas cleaning includes pad filters for atmospheric dust and granular beds and bag filters
for process dusts. Air is cleaned by passing it through pads of cellulose pulp, cotton, felt. Glass
fiber, or metal screening; the pad material may be dry or coated with a viscous oil to act as a dust
holder; for light duty the pads are disposable; but in large scale gas cleaning they are frequently
rinsed and recoated with oil.

A simple diagram of a gas clarifiers is shown in the figure:
Granular beds filter contains stationary or moving beds of granules
ranging from 30 to 8 mesh in size in some designs =, to 12 to 40mm in
others. Efficiency is 99%even with extreme fine particles. In most cases
bag filters acts as clarifiers. With particles trapped within the fabric of
the bag. But with heavy dust loading a thin but definite cake of dust is
allowed to build up before discharged.

Double Roll Crushers
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.
Types of Crushers
 Jaw crushers
 Gyratory crushers
 Double role crushers
Double roll crusher
It consists of two counter rotating rolls which are mounted
horizontally on a rigid frame. The crushing area of the rolls are
totally enclosed in a fabricated housing. One of the rolls is fixed
in position while the other is a floating roll which can move
relative to fixed roll to control product size and release un-
crushable material by spring action. Both vertical spindle and
horizontal spindle type gap adjustment system are available in MSEL range. The roll surface can
be smooth or beaded depending on the type and size of the
feed material. The crushing element is a single piece steel
casting Roll mounted on taper hubs at both ends. Two rolls
rotate in opposite direction by means of motor and belts with
or without gear box. Smooth Roll Crusher can be provided with
spring loaded roll scraper for removing sticky material from roll
surface. Roll grinding arrangement can be supplied as an
optional item for grinding the roll surface without removing the
rolls from the crusher frame. Motorized or hand operated
centralized grease lubrication system can be provided on request.

Principle of roll crusher:
The basic principle of crushing in double roll crusher is compressional force generated by narrow
gap between the moving rollers.
Parts of roll crusher:
The main parts of roll crusher are as follows:
 Frames
 Rollers
 Bearings
 Belt
 Drivers
Frame” A cast-iron or steel-plate frame is used. The steel-plate frame is fabricated by welding.
The Plummer blocks of fixed roll assembly are integral with the frame. The Plummer Block for the
movable roll assembly are elastically positioned in horizontal direction with high-strength coil
springs or hydraulic accumulators selected for the type of crushing duty. This elastic mounting
includes a means of adjusting the roll-to-roll clearance (roll setting) and serves as a protective
feature for preventing motor over load or damage to the crusher, as the roll will yield and back
away when it grips hard foreign matters like tramp iron.
Rollers: Roller tyres are of smooth type, corrugated type or toothed type, depending on the
crushing duty. In the standard design each roll assembly consist of a roll boss with hexagonal
outer shape rigidly mounted on the roll shaft which permits easy replacement of roll tyre. The
roll tyres are held tight by means of bolts. This arrangement provides for easy tyre replacement
and minimizes parts subject to wear. The roll tyres are made of high manganese steel.

Bearings: Spherical roller bearings are used to support the rolls. The spherical roller bearings are
complete with labyrinth seals and packing for preventing entrance of dust and leakage of oil.
Belts: A belt is a loop of flexible material used to link two or more rotating shafts mechanically,
most often parallel. Belts may be used as a source of motion, to transmit power efficiently, or to
track relative movement.
Drive: The power of roll crusher motor is 2.2.KW, voltages are 400V and operated at 200RPM.
The standard Double roll crusher has independent belt drives from two motors, one motor for
each roll. This arrangement eliminates the need for an intermediate drive transmitting device
resulting in less space utilization and reducing the no-load power loss. In our lab we used single
driver to rotate single roller and with belts and gears we drive the other roller.
Important terms involved in roll crusher
 Angle of nipping
For rollers which have equal radius and length, tangents are drawn at the point of contact
of particle and the tangent of two roller meet to form angle of nip(2θ). The figure shows
the diagram of angle of nip of two rollers.
The formula to calculate angle of nip is as follows:
cos(θ) =
𝑅 +
𝐿
2
𝑅 +
𝑑
2
Here
 R is radius of roller  d is the diameter of the particle
 L is the separation between the roller  Θ is the Half of the angle of nip
Angle of nip has no such application but is used to calculate the particle feed and roller
diameter which we see further.

 Feed size
Crusher are usually classified on the basis of feed size i.e.
1. Primary
2. Secondary
3. Tertiary
A primary crusher receives the stone directly from a quarry after blasting, and produces
the first reduction in size. Then the output of the primary crusher is fed to a secondary
crusher, which further reduces the stone size. Some of the stone may pass through four
or more crushers before it is reduced to the desired size.
So the double roll crusher is secondary crusher which receive the feed crushed of the
jaw crusher.
In order to calculate the size of the feed which should feed into the crusher we use the
following formula
Size of particle feed=𝐷 𝑝 = 0.045𝑅 + 𝐿
 Size of roller
To solve for the radius of the rolls, it is
convenient to assume that the particle
to be crushed is spherical and roll
surfaces are smooth. The figure below
shows a spherical particle about to
enter the crushing zone of a roll
crusher. The nip angle is defined as
the angle that is tangent to the roll
surfaces at the points of contact
between the rolls and the particle.
Usually the nip angle is between 20 and 30 but in some large roll crushers it is up to 40
degrees. The formula used to calculate the radius of roller is shown below
𝑅 =
𝐿 − 𝐷𝑐𝑜𝑠𝜃
2(𝑐𝑜𝑠θ − 1)
Here,
R is radius of the roll
L is distance between rolls
D is diameter of the feed
Θ is Nip angle
 Crushing ratio
The Reduction Ratio is broadly defined as the ratio of the feed size to the product size in
any crushing operation. It is very useful in determining what a crusher can do, or is
doing, in the way of size reduction. It can also be used as a partial indicator of the
stresses the crusher will be subjected to during operation, an element in determining
the crusher capacity and as an indicator of crusher efficiency. However, there is no one

method of calculation which will provide a useful figure for all of these considerations,
so there are various types of Reduction Ratios in use, depending on how technical you
wish to get. Crushing ratio of some of the equipment is shown below:
Equipment Reduction ratios
1. Jaw crusher 1:6
2. Gyratory crusher 1:8
3. Head cone crusher 1:7
4. Double roll crusher 1:4
5. Hammer or impactor Up to 10:1
 Feed rate
Although in batch system we put the feed with our desire quantity so we can control the
flow rate whoever in batch system the feed rate depends on diameter of roller, width of
roller, roller speed distance between roller and bulk density of material to be crushed.
The formula used to calculate feed rate is shown below.
𝑄 = 60𝜋𝐷𝐿𝑊𝜔𝜌 𝑏(ton/h)
 Calculation of double roll crusher efficiency
The efficiency of the double roll crusher can be calculated by taking the ratio of surface
energy crated to the energy absorb by the substance the formula is shown below:
𝜂 𝑐 =
𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐𝑟𝑒𝑎𝑡𝑒𝑑 𝑏𝑦 𝑐𝑟𝑢𝑠ℎ𝑖𝑛𝑔
𝑡𝑜𝑡𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑏𝑠𝑜𝑟𝑏 𝑏𝑦 𝑎 𝑢𝑛𝑖𝑡 𝑚𝑎𝑠𝑠
Or
𝜂 𝑐 =
𝐸𝑠(𝐴 𝑠𝑠𝑝 − 𝐴 𝑠𝑠𝑓)
𝑊𝑎
Here,
𝐸𝑠 is the surface energy per unit area.
𝐴 𝑠𝑠𝑝is the area per unit mass of feed.
𝐴 𝑠𝑠𝑓 is the area per unit mass of feed.
𝑊𝑎 is the energy absorbed by the unit mass of solid.
References
https://www.scribd.com/doc/229884634/Double-Roll-Crusher-Machine-Design

Cyclonic separation
Introduction
Cyclonic separation is a method of removing particulates from
an air, gas or liquid stream, without the use of filters, through
vortex separation. When removing particulate matter from
liquids, a hydrocyclone is used while from gas, a gas cyclone is
used. Rotational effects and gravity are used to separate
mixtures of solids and fluids. The method can also be used to
separate fine droplets of liquid from a gaseous stream.
Working
A high speed rotating (air)flow is established within a
cylindrical or conical container called a cyclone. Air flows in a
helical pattern, beginning at the top (wide end) of the cyclone
and ending at the bottom (narrow) end before exiting the
cyclone in a straight stream through the center of the cyclone
and out the top. Larger (denser) particles in the rotating
stream have too much inertia to follow the tight curve of the
stream, and strike the outside wall, then fall to the bottom of
the cyclone where they can be removed. In a conical system, as the rotating flow moves
towards the narrow end of the cyclone, the rotational radius of the stream is reduced, thus
separating smaller and smaller particles. The cyclone geometry, together with flow rate, defines
the cut point of the cyclone. This is the size of particle that will be removed from the stream
with a 50% efficiency. Particles larger than the cut point will be removed with a greater
efficiency, and smaller particles with a lower efficiency.
Uses
 Large scale cyclones are used in sawmills to remove sawdust from extracted air.
 Cyclones are also used in oil refineries to separate oils and gases, and in the cement
industry as components of kiln preheaters.
 Cyclones are increasingly used in the household, as the core technology in bagless types
of portable vacuum cleaners and central vacuum cleaners.
 Similar separators are used in the oil refining industry (e.g. for Fluid catalytic cracking) to
achieve fast separation of the catalyst particles from the reacting gases and vapors.
 Cyclones are also used in industrial and professional kitchen ventilation for separating
the grease from the exhaust air in extraction hoods.

Separation factor
The ratio of the centrifugal force over force due to gravity is called separation factor:
i.e.
𝐹𝑐
𝐹𝑔
=
𝑚𝑢 𝑡𝑎𝑛
2
/𝑟
𝑚𝑔
=
𝑢 𝑡𝑎𝑛
2
𝑟𝑔
A large diameter cyclone has small separation factor so its efficiency is small.
Helical Ribbon Mixer
Introduction
Helical ribbon mixer is used to mix the materials uniformly and effectively. We can achieve
desire mixing by changing the
time of mixing
Construction
A ribbon blender consists of a
U-shaped horizontal trough
containing a double helical
ribbon agitator that rotates
within. The agitator's shaft is
positioned in the center of
the trough and has welded
spokes on which the helical ribbons (also known as spirals) are welded. Since the ribbon
agitator consists of a set of inner and outer helical ribbons, it is referred to as a “double" helical
ribbon agitator. The gap between the ribbon’s outer edge and the internal wall of the container
ranges from 3 to 6 mm depending on the application. Figure shows internal and external ribbon
spirals on the agitator shaft located with the blender container.
The ribbon agitator is powered by a drive system comprised of a motor, gearbox, and couplings.
Ribbon blenders are generally powered by 10 HP to 15 HP motor for 1000 kg of product mass to
be blended. The specific power may range from 3 to 12 kW/m3 depending on the products to
be blended.
The agitator shaft exits the blender container at either end through the end plates bolted or
welded to the container. The area where the shaft exits the container is provided with a sealing
arrangement to ensure that material does not travel from the container to the outside and
vice-versa. The blender assembly along with the drive system components viz. motor, gearbox,
couplings and bearing supports is mounted on a supporting frame.

The charging of material in the blender is generally through nozzles or feed-hoppers mounted
on the top cover of the blender. The inlet cover also provides maintenance and cleaning access
to the inside of the blender. An external jacket can also be provided on the blender container
for applications which require heating or cooling of product material.
Operation
During the blending operation, the outer ribbons of the agitator move the material from the
ends to the center while the inner ribbons move the material from the center to ends. Radial
movement is achieved because of the rotational motion of the ribbons. The difference in the
peripheral speeds of the outer and inner ribbons results in axial movement of the material
along the horizontal axis of the blender. As a result of the radial and the counter-current axial
movement, homogenous blending is achieved in short time. Blending is generally achieved
within 15 to 20 minutes of start-up with a 90 to 95 percent or better homogeneity. The particle
size and its bulk density have the strongest influence on the mixing efficiency of the ribbon
blender. Ingredients with similar particle size and bulk densities tend to mix faster as compared
to ingredients with variation in these attributes
Applications of Ribbon Blenders
Ribbon blenders can be designed to operate in both batch and continuous modes. Batch type
blenders can be built up to capacities of 50 m3. The ribbon blender’s versatility for blending
solids combined with it ability to perform heating, cooling, coating, and other processes make it
a very popular blender. The following are the applications of the Ribbon Blender:
 Blending large volumes of dry solids.
 Dry powder to wet phase mixing.
 Mixing of bulk drugs, chemicals, and cosmetic powders.
 Dry Blending of capsule formulations.
 Lubrication of dry granules in large quantity.
 Heating, cooling, and drying of materials.
 Coating solid particles with small amounts of liquids to produce formulations.

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