The report includes the Manufacturing Processes of different kind of refractories at the company and also insights about the machinery used in a Refractory Industry.

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An
Internship Report
On
Duration: 19.01.2018-17.02.2018
In partial fulfillment of requirements for the degree of
Bachelor of Technology
in
Mechanical Engineering
By
Nitin Kumar
Enrollment No. 14EPPME017
Under the supervision of
Mr. Shailender Singh
&
Mr. Pradeep Kumar Yadav
During Academic Session 2017-2018
Department of Mechanical Engineering
Pratap Institute of Technology & Science
Palsana, Sikar-332001, Rajasthan, India

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CERTIFICATE
This is to certify that the internship’s work titled “An Internship in Refractory Industry” that is
being submitted by Nitin Kumar is in partial fulfilment of the requirements for the award of
Bachelor of Technology, is a record of bonafide work done under our guidance. The contents of
this internship work, in full or in parts, have neither been taken from any other source nor have
been submitted to any other Institute or University for award of any degree or diploma.
Mr. Pradeep Kumar Yadav Mr. Shailender Singh
(Industry Guide) (Faculty Internship Guide)

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CANDIDATE’S DECLARATION
I declare that this written submission represents my ideas in my own words and where others ideas
or words have been included. I have adequately cited and referenced the original sources. I also
declare that I have adhered to all principles of academic honesty and integrity and have not
mispresented or fabricated or falsified any idea/data/fact/source in my submission. I understand
that my violation of the above will be cause of disciplinary action by the institute and can also
evoke penal action from the source which have thus not been properly cited or from whom proper
permission has not been taken when needed.
Nitin Kumar
Enrollment No. 14EPPME017

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PREFACE
Industrial training plays a vital role in the progress of future engineers. Not only does it provide
insights about the industry concerned, it also bridges the gap between theory and practical
knowledge. I was fortunate that I was provided with an opportunity of undergoing industrial
training at ORIENT REFRACTORIES LTD., Bhiwadi. The experience gained during this period
was fascinating to say the least. It was a tremendous feeling to observe the operation of different
equipment and processes. It was overwhelming for me to notice how such a refractory industry is
being monitored and operated with proper coordination to obtain desired results. During my
training I realized that in order to be a successful Mechanical Engineer one needs to possess a
sound theoretical base along with the acumen for effective practical application of the theory. Thus,
I hope that this industrial training serves as a stepping stone for me in future and help me carve a
niche for myself in this field.

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ACKNOWLEDGEMENT
My indebtedness and gratitude to the many individuals who have helped to shape this report in its
present form cannot be adequately conveyed in just a few sentences. Yet I must record my
immense gratitude in those who helped me undergo this valuable learning experience at ORIENT
REFRACTORIES LTD., Bhiwadi.
I am highly obliged to Mr. Pradeep Kumar Yadav Mechanical Maintenance Department for
providing me this opportunity to learn at ORL. I thank Mr. Ajay Shekhawat for guiding me through
the whole training period and sharing his deep knowledge about the production process as well as
maintenance of the equipments.
I am grateful to Mr. Rajpal Jajoria for his simple yet effective explanation of ORL as a whole and
guiding me about various other aspects of career as a Mechanical Engineer.
Last but not the least I am thankful to Almighty God, my parents, family and friends for their
immense support and cooperation throughout the training period.

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LIST OF FIGURES
Figure No. Figure Title Page No.
Figure 1.1 Products from Refractories Industry 11
Figure 1.2 Zirconia Nozzles and Inserts 16
Figure 1.3 Flow Diagram of Manufacturing Process of Zirconia products 17
Figure 1.4 Bottom Purging Refractories & Top Purging Lances 20
Figure 1.5 Flow Diagram of Manufacturing Process of Slide Gate Refractories 23
Figure 1.6 Flow Diagram of Manufacturing Process of Continuous Casting Refractories 28
Figure 1.7 Flow Diagram of Reprocessing Plant 31
Figure 1.8 Jaw Crusher 34
Figure 1.9 Roll Crusher 35
Figure 1.10 Cold Isostatic Press 36
Figure 1.11 Hydraulic Press-400T 37
Figure 1.12 Dust Collection System 39
Figure 1.13 Settling Chamber 40
Figure 1.14 Baffle Chamber 40
Figure 1.15 Baghouse 41
Figure 1.16 Wet Scrubber 42
Figure 1.17 Electrostatic Precipitator 43
Figure 1.18 Ball Mill 45

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LIST OF CONTENTS
1. Certificate 2
2. Candidate’s Declaration 3
3. Preface 4
4. Acknowledgement 5
5. List of Figures 6
6. List of Contents 7
7. Company Overview 8-9
8. Products from Refractory 11
9. Introduction 12
10. Refractory Materials 13
11. Classification of Refractories 14-15
12. Zirconia Department 16
13. Manufacturing of Zirconia Products 17-19
14. Precast and Castable Department 20
15. Manufacturing of Top Purging Lances & Bottom Purging Refractories 21
16. Manufacturing Process of Slide Gate Refractories 22-26
17. Manufacturing Process of Continuous Casting Refractories 27-30
18. Reprocessing Plant 31-32
19. Machines used in Industry 33
(i) Crusher 33-35
(ii) Cold Isostatic Press 36
(iii) Hydraulic Press 37-38
(iv) Dust Collector 39-44
(v) Ball Mill 45
20. Findings 46
21. Bibliography 47

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Orient Refractories manufactures a wide range of Refractory and Monolithic products for the iron
and steel industry and its clients include large domestic integrated steel producers and mini steel
plants such as Steel Authority of India, Mukund Steel, Tata Iron and Steel Company, RINL-Vizag,
Sunflag Iron, Lloyd Steel, Usha Martin and Jindal Group.
ORL also deploys a large number of refractory specialists on site with customers in order to
develop individual complete solutions and provide total refractory management services. The
company has an in-house research and development facility that is recognized by the Government
of India.
ORL got listed recently as it entered into a scheme of arrangement with Orient Abrasives Limited
(OAL) and their respective shareholders for demerger of the refractory business of OAL into
Orient Refractories Ltd. The demerger was carried out in November 2011 and the stock got listed
on 9th
March 2012.
ORL is in the business of manufacturing and marketing Special Refractory Products, Systems and
Services to the Steel Industry with Global Presence.
ORL is a market leader for Special Refractories in India and has many Global Partners for its
international quality products. ORL is a global partner for over 500 customers in India and across
the world.
ORL produces more than 40,000 tons of refractory per annum customized products and system
solutions. Refractory material is used to provide thermal insulating lining in Furnaces, Kilns,
Reactors, etc. The refractory material is mainly used in Iron & Steel Industry, Metal Smelters,
Cement, Glass Industries, etc.
Headquartered in New Delhi, India, ORL’s manufacturing facility is located in Bhiwadi,
Rajasthan.

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This facility began commercial production in 1986. The division also has an allied plant based in
Salem, Tamilnadu for manufacturing monolithics.
The Bhiwadi facility is spread over 27 acres of land. The refractory facility is divided into 3
independent sub-divisions one each for the manufacture of slide gate plates, continuous casting
refractories and castables and pre-cast shapes. The division currently produces more than 70,000
pieces of slide gate plate, 30,000 pieces of Continuous Casting Refractory products and over 2000
tons of castables and mortars on a monthly basis.

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I visited following departments and focused on Basic Mechanical Components, Production process
and Mechanical Maintenance.
1. Slide Gate Refractories (SGR)
2. Continuous Casting Refractories (CCR)
3. Precast and Castable Department
4. Zirconia Department
5. Bond Department
6. Mechanical Workshop

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PRODUCTS FROM ORIENT REFRACTORIES LTD.
Isostatically Pressed Continuous Casting Refractories
Castables Slide Gate Plates
Slag Arresting Darts Nozzles and Well Blocks
Top Purging Lances Tundish Nozzles
Bottom Purging Refractories
Fig1.1: Products from Refractories Industry

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INTRODUCTION
A Refractory is a material that retains its shape and chemical identity when subjected to high
temperatures and is used in applications that require extreme resistance to heat. Specifically,
refractories must be able to withstand temperatures above 538 o
C (1,000 o
F). Refractories are
mechanically strong and heat resistant to withstand rapid temperature change and corrosion and
erosion by molten metal, glass, slag and hot gas. Refractories are used in kilns, furnaces, boilers,
incinerators, and other applications.
Refractory is a class of materials which are produced from non-metallic minerals. They are the
primary materials used in the internal lining of industrial furnaces and possess capability to
withstand heat and pressure, and are used in steel, aluminium, glass, cement, petrochemicals, non-
ferrous metals, thermal power plants and ceramic industries. These are produced in special shapes
are custom made to suit the requirements of the various industries. Today, the iron and steel
industry uses approximately 70% of all refractories produced.

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REFRACTORY MATERIALS
Refractory materials must be chemically and physically stable at high temperatures. Depending
upon the operating environment, they must be resistant to thermal shock, be chemically inert, and
have specific ranges of thermal conductivity and the coefficient of thermal expansion.
The oxides of aluminium (alumina), silicon (silica) and magnesium (magnesia) are the most
important materials used in the manufacturing of refractories. Another oxide usually found in
refractories is the oxide of calcium (lime). Fire clays are also widely used in the manufacture of
refractories.
Refractories must be chosen according to the conditions they face. Some applications require
special refractory materials. Zirconia is used when the material must withstand extremely high
temperatures. Silicon carbide and carbon (graphite) are two other refractory materials used in some
very serve temperature conditions, but they can’t be used in contact with oxygen, as they will
oxidize and burn.
Binary compounds such as tungsten carbide or boron nitride can be very refractory. Hafnium
carbide is the most refractory binary compound known, with a melting point of 3890 o
C. The
ternary compound tantalum hafnium carbide has one of the highest melting points of all known
compounds (4215 o
C).

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CLASSIFICATION OF REFRACTORIES
Refractories are classified into number of ways on the basis of chemical properties of their
constituent substances, their refractories, method of manufacture and physical form.
1) Classification Based on Chemical Composition
Refractories are typically classified on the basis of their chemical behavior, i.e., their
reaction to the type of slags. Accordingly, the refractory materials are three classes – Acid, Basic
& Neutral.
Acid Refractories:
Acid refractories are those which are attacked by alkalis (basic slags). These are used in
areas where slag and atmosphere are acidic. Examples of acid refractories are:
(i) Silica (SiO2)
(ii) Zirconia (ZrO2)
(iii) Aluminosilicate
Neutral Refractories:
Neutral refractories are chemically stable to both acids and bases and are used in areas
where slag and atmosphere are either acidic or basic. The common examples of these materials
are:
(i) Carbon graphite
(ii) Chromites (Cr2O3)
(iii) Alumina
Out of these graphite is the least reactive and is extensively used in metallurgical furnaces
where the process of oxidation can be controlled.
Basic Refractories:
Basic refractories are those which are attacked by acid slags but stable to alkaline slags,
dusts and fumes at elevated temperatures. Since they do not react with alkaline slags, these
refractories are of considerable importance for furnace linings where the environment is alkaline;
for example, non-ferrous metallurgical operations. The most important basic raw materials are:
(i) Magnesia (MgO) – caustic, sintered and fused magnesia
(ii) Dolomite (CaO.MgO) – sintered and fused dolomite
(iii) Chromite – main part of chrome ore

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Chemical characteristics of the furnace process usually determine the type of refractory
required. Theoretically, acid refractories should not be used in contact with basic slags, gases and
fumes whereas basic refractories can be used in alkaline environment.
2) Classification Based on Method of Manufacture
The refractories can be manufactured in either of the following methods:
a) Dry Press Process.
b) Fused Cast.
c) Hand Molded.
d) Formed (Normal, Fired or chemical bonded).
e) Unformed (Monolithic – Plastics Ramming mass, Gunning, Castable, Spraying).
3) Classification Based on Physical Form
Refractories are classified according to their physical form. These are the shapes and
unshaped refractories. The shaped is commonly known as refractory bricks and the unshaped as
“monolithic” refractories.
Shaped Refractories:
Shaped refractories are those which have fixed shaped when delivered to the user. These
are what we call bricks. Brick shapes may be divided into two: standard shapes and special shapes.
Standard shapes have dimension that are conformed to by most refractory manufactures
and are generally applicable to kilns and furnaces of the same type.
Special shapes are specifically made for particular kilns and furnaces. This may not
applicable to another furnaces or kiln of the same type. Shaped refractories are almost always
machine-pressed, thus, high uniformity in properties are expected. Special shapes are most often
hand-molded and are expected to exhibit slight variations in properties.
Unshaped Refractories:
Unshaped refractories are without definite form and are only given shape upon application.
It forms joint less lining and are better known as monolithic refractories. These are categorized as
Plastic refractories, ramming mixes, castables, gunning mixes, fettling mixes and mortars.

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ZIRCONIA DEPARTMENT
ORL manufacture complete range of zirconia nozzles used for the continuous casting of steel as a
Tundish refractory. Nozzles can be supplied as a solid piece or with outer high alumina body.
Zirconia nozzles are manufactured from different type of raw materials, chemical content, physical
specifications and sizes depending on the service application. High quality Zirconia is used as the
main material. In order to improve the thermal shock stability MgO, Y2O3, Cao stabilizing agents
are added to mix. These agents also improve the life of use.
Fig1.2: Zirconia Nozzles and Inserts

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MANUFACTURING PROCESS OF ZIRCONIA PRODUCTS
Fig1.3: Flow Diagram of Manufacturing Process of Zirconia Products
MIXING
The material is mixed in mixer for 10 minute intervals for two times and powder is mixed
for bonding. After that according to composition weighted liquid (Zuroplast, Optapix, Water) is
stirrer machine then the solution is sieved and mixed for 10 minutes. Then this mixture is
introduced in Sigma Mixture Machine for homogenization process for 40 minutes. Then the
homogenized mixture is sieved through 3mm sieve and this sieved mix is filled in PVC mould.
This mould is then kept in CIP for pressing up to 17000 PSI. pressed mould is than unloaded and
graded by grader. This grader mixture is then sieved in Vibro Sieve through 1.50mm sieve and
demagnetized and packed HDPE bag.
MIXING OF RAW MATERIALS
PRESSING
FIRING
DRYING
GROOVING
GAS FIRING
SURFACING
INSPECTION
PACKING

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PRESSING
The prepared mixed is shaped in hydraulic press. The mix is filled in mould on hydraulic
press and compressed with load 13.5 Ton and pressure 110 kg/cm2
relying on the material and
nature of nozzle. The nozzles are kept on a levelled surface as it is delicate and afterward following
inspected by quality department and checked for deformation.
FIRING
Firing is the process of bringing its humble, soft beginnings into a new, durable substance,
ceramic. During this procedure dried items go through a controlled warming process. As we know
the items without heat treatment are moderately weak and porous. The pressed items are kept in
electric furnace for firing from room temperature to 1670 o
C for almost 25 hours.
DRYING
Refractory nozzles require special heat-up to ensure that they perform as intended, and
avoid damage due to drying stresses. For drying controlled warmth is used. The first warmth
evacuates water, this progression is done with some cautions as fast warming can cause splits,
breaks and surface deformities. Drying is done in dryer from room temperature to 150 o
C for 20
hours and then cooled.
GROOVING
The grooves are made on the zirconia nozzles. For above 85 mm length nozzles 6 grooves
and below 85 mm length nozzles 4 grooves are made.
GAS FIRING
After making grooves the nozzles are kept in saggar box and introduced into the gas kiln
for firing at high temperature to provide strength at high temperatures. The nozzles are heated in
gas kiln from room temperature to 1660 o
C for 25 hours and then cooled.
SURFACING
The nozzles are checked for variations after cooling if any variation occurs surfacing is
done.

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INSPECTION
The nozzles are inspected accurately for dimensions.
PACKING AND DISPATCH
The nozzles are packed in cardboard box and a thin sheet is kept between the two sliding
surfaces. Proper labelling is done outside the box and ready to dispatch from godown.

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PRECAST AND CASTABLE DEPARTMENT
Precast shapes provide fast refractory lining replacement in recurring high-wear zones. Precast
shapes are manufactured under controlled conditions to a higher degree of completeness than
castables. This has significant advantages, as the conditions in a precast shop can be better
controlled than on site and the curing process can be done prior to installation of the precast shape
to avoid curing on site which is usually part of critical path during commissioning.
ORL manufactures precast shapes for a variety of industries. ORL has in-house designed curing
furnace and frequently controlled vibrating equipment, combined with special moulding
techniques to ensure highest product quality.
ORL manufactures the complete set of bottom purging refractories including the porus plug, PP
housing block, porus plug sleeve for a wide range of systems including GP II, GP III, IPV with
systems.
Fig1.4: Bottom Purging Refractories & Top Purging Lances

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MANUFACTURING PROCESS OF TOP PURGING LANCES
The castable is mixed with S.S. fiber (0.5 mm diameter/25 mm long), sodium dichromate
(Na2Cr2O7), molasses and water is mixed as per requirement. The ready mix is unloaded into the
hopper and cast the lance with same mix, during the casting of mix the lance should be in vertical
position and the pipe in the lance should be in centre position.
After 18 hours the mould is de-moulded and the lance is covered with wet gunny bags for
48 hours. After 48 hours the lance is kept in open air for 24 hours for air curing. The holes are
patched and the air flow is checked through pipe.
The drying is done from room temperature to 300 o
C for 60 hours and cooled slowly to
room temperature. The air flow is again checked after drying and coating is done on lance by
coating material.
The top purging lances are widely used in steel industries where the molten steel is mixed
by passing Argon(Ar) gas through it at 1600 o
C – 1700 o
C.
MANUFACTURING OF BOTTOM PURGING REFRACTORIES
The castable is mixed with fiber into the self-acting castable mixer. After mixing the mixed
is casted in mould and kept on vibrating table for agitation process at frequency 45 Hz.
After agitation process the mould is kept for setting up at room temperature. When the mould is
dried it gives a metallic sound. After that the blocks are kept in open air for 24-48 hours for drying.
After drying the blocks are kept in the kiln for firing process. The kiln firing is done from
room temperature to 270 o
C for 34 hours and then cooled.
After cooling the blocks are finished and packed for dispatching

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SLIDE GATE REFRACTORIES DEPARTMENT
MANUFACTURING PROCESS OF SLIDE GATE REFRACTORIES
MIXING OF RAW MATERIALS
AGEING AND HOMOGENIZATION
PRESSING
AIR DRYING
KILN FIRING
PREHEATING
TAR IMPREGNATION
TEMPERING
SHOT BLASTING
SPPR
NOZZLE/SLEEVE FIXING
SURFACING OF PLATES
CASSETTING STRIPPING

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Fig1.5: Flow Diagram of Manufacturing Process of Slide Gate Refractories
MIXING
The constituents of mix are bunched by Silo framework. The required measure of materials
is then blended with resin at 40-45 o
C for 10-12 minutes which at last creates green mix. The mix
is released from the Erich mixer beneath 80 o
C and after that screening of green mix is done to
isolate out the coarse from the fines. The mix is clustered by the quality. The mix is matured at 21-
22 o
C for 24 hours. After 8 hours of maturing, the mix goes for lab testing. The mix is tested by
Lab to check bulk density and bulk modulus.
PRESSING
The mix is shaped in hydraulic press. The mix is twofold squeezed at the weight between
20-315 kg/cm2
relying on the material and nature of the plate. In the first place to expel air from
the mix and the second to give the required shape. Nearness of bond and resin guarantees the
pressing of mix. The plates are kept on a levelled surface as it is delicate and afterward following
20 minutes inspected by the quality department.
Measurements, twists and breaks are checked. The plates are labelled with ok stamp after
assessment and kept in the racks. The quality code is said on the racks. After 24 hours’ plates go
for drying.
DRYING
Drying assumes a critical part as the procedure limits shrinkage amid terminating and
diminish breaking and bending. Controlled warmth is connected in two phase prepare. To begin
with, warmth evacuates water. This progression needs cautions control, as fast warming causes
splits and surface deformities. Drying is done in oven at 180 o
C. the plates are permitted to cool in
surrounding climate. The dried item is smaller than the green item, and is brittle which require
cautions dealing with, since a little effect will bring about disintegrating and breaking. The plates
are again checked for breaks.
AIR DRYING
FINISHING OF PLATES
PACKING AND DISPATCH

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FIRING
It is the procedure where dried items go through a controlled warming process. The green
items are moderately weak and porous. Firing decreases, the porosity and builds the quality of the
plates. The plates are unloaded from the shelves and are kept in a shut box of blocks with coke for
better thermal conductivity under firing. The plates are then let go in Shuttle Kiln at 1350 o
C. The
plates are then permitted to cool under encompassing climate to diminish the propensity of plates
to crack. The plates are then cleaned as coke adheres to the surface of the plates during firing.
Checking for deformities like splits, broken, overlay oxidation, dull sound etc.
PREHEATING
Slide plates are warmed before tar impregnation. Preheating of plates is done in shut vessel
at 250 o
C. Preheating of let go item improves impregnation. It is fundamental as though cool plates
are impregnated in hot tar then tar will frame layers on the plate surface which doesn’t eliminates
porosity and in the long run quality can’t be expanded.
TAR IMPREGNATION
The plates are inundated in the vessel of hot liquid tar pitch to impregnate the pores of the
slide plates to fill the greater part of the pores. Tar is impregnated at 200 o
C at 12-14 kg/cm2
pressure. Porosity affects chemical attack by molten slag, metal and gases. Decrease in porosity
increases strength and thermal conductivity.
TEMPERING
The plates are taken out from vessel and is then warmed to dissipate off about portion of
impregnated tar pitch and to carbonize the staying half, in this way storing it in the pores. This
decreases the porosity and increases the quality of the item and in addition wear safe property.
Plates are warmed in kiln at 570 o
C. at times tar impregnation and hardening is done twice to build
the quality as craved by the client.
SHOT BLASTING
It is an operation of forcibly propelling a stream of abrasive material against a surface under
high pressure to clean the overabundance tar on the plates. A centrifugal wheel is used to propel
the blasting material. Steel shot is generally used as impact media. The plates are set on the
conveyor line at 2-3” gap. 5-6 kg/cm2
of air pressure is kept up for shot feeding. The plates are
physically cleaned if there are a few stores in bore zone or at the surface. Apparent Porosity, Bulk
Density and Cold Crushing Strength of plate is checked in the Lab. Check for imperfections like
breaks, broken, twist, isolation etc.

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SPPR
Essentially 5 unique sorts of operations are performed in SPPR.
(i) Cassetting: At first, the bore and surface of the plates are cleaned using water jet.
Then the hub portion of the plate is cleaned and fixed with the plate using mortar.
The cassetted plate undergoes air drying at 150 o
C. further it goes for surfacing.
Some plates directly go for surfacing
(ii) Nozzle/Sleeve Fixing: Nozzle or sleeve is fixed on top and bottom plates. The
nozzle/sleeve is joined mortar bond and undergoes air drying under 250 o
C for 12
hours, whereas joining using resin bond undergoes air drying under 150 o
C for 8
hours.
(iii) Stripping: Some plates are stripped as per the requirements. The metal strip is
heated in induction furnace at about 800-1000 o
C for 45 seconds. The red hot strip
is set on the plate using hammer.
(iv) Repairing: Quality checked plates are only taken for repairing. Resin or mortar is
used in case of nozzle/sleeve fixing. The plate undergoes air drying as per the
schedule. Pin holes are filled using mortar. Then again the plates undergo air drying
at 110 o
C. The plate is then forwarded for surfacing. Repairing process is for top
plate as well as bottom plate.
SURFACING
The plates are then surfaced to level the sliding surface. It must be noticed that the plates
must be surfaced approximately as it limits the erosion between the sliding and stationary plate.
Surfacing is responsible for smooth rubbing of plates. Surfacing likewise accomplishes required
width of the plates.
AIR DRYING
Subsequent to surfacing, the plates are again dried in tunnel dryer under 250 o
C. in the
event of slide plates, evacuation of air and water is must.
FINISHING
The plates are checked for the patches, if preserves it is loaded with mortar. The sliding
surface of the plate is cleaned by Supper Lube No. 3 and Moly Paul 919. Super Lube guarantees
the smooth rubbing of the plates. As the name purposes, it limits the erosion between slide plates
while Moly Paul 919 is a high quality graphite containing material which increases the surface
quality of the plates. Then the cassetted surface is cleaned and painted in order to give a cleaner
appearance. The plates are labelled with make, heat capacity, bore, quality and manufacturing date.
This is to identify them after finishing. These labels are colour coded for domestic use and exports.

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PACKING AND DISPATCH
The plates are packed in cardboard box a thin sheet of cardboard is kept between 2 sliding
surface of the plates. This is to ensure the sliding surface must be safe in transportation. The plates
are tightened by ropes and packed in cardboard box. Proper labelling is also done outside the box.
These are kept in-house made wooden boxes. The box is strapped and shifted to finished goods
godown. Material is shipped from finished goods godown.

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CONTINUOUS CASTING REFRACTORIES DEPARTMENT
MANUFACTURING PROCESS OF CONTINUOUS CASTING
REFRACTORIES
MIXING OF RAW MATERIALS
AGEING AND HOMOGENIZATION
MOULD FILLING
ISOSTATIC PRESSING
AIR DRYING
FIRING
OPEN FIRING ROUTE
MACHINING
BUBBLE TESTING
ANTI-OXIDANT COATING
OPEN FIRING
HEAD COATING
CLOSED FIRING ROUTE
CLOSED FIRING
MACHINING
BUBBLE TESTING
ANTI-OXIDANT COATING
DRYING

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Fig1.6: Flow Diagram of Manufacturing of Continuous Casting Refractories
MIXING
The required measure of materials is then blended with resin at 40-45 o
C for around 10-12
minutes in two different mixtures (Erich and Sigma). The mix is clustered by the quality. The mix
is matured at 21-22 o
C for 24 hours. The mix is homogenized after 8 hours of ageing. Before
blending, the lump in the mix is treated by jaw crushers to achieve uniform mix. The mix is then
blended in module crusher and discharged from the machine after proper screening. After 8 hours
of ageing the green mix undergo homogenization. The material is then stored in hoppers.
ISOSTATIC PRESSING
The material in different hoppers are emptied in Silo of different mould filling stations.
The mix is discharged from the hopper in order to fill the mould. The filling station is equipped
with vibrating table and lifters which helps in mould filling and handling. The mould is then
transported to pressing area on trollies. A total of 5 cold isostatic presses are installed in CCR
department. The mould is dipped in vessel and isostatically pressed at a pressure of 17,500-20,000
psi. the mould is then taken out from the vessel and the assembly is then de-moulded. The products
are then kept in the racks and proper labelling is done on every product. Surface finish and
dimensions are checked.
DRYING
The racks are directly put in the air dryer via fork lift. Drying is a critical path as the
procedure results in increased quality and strength of the product. The process results in shrinkage
of the product. Drying is done in oven at 270 o
C. The products are cooled in surrounding
atmosphere.
FIRING
It is the procedure where dried items go through a controlled warming process. The
products are prone to cracks after drying. Firing increases, the strength and builds the quality of
the products and decreases the porosity slightly. The pressed products are unloaded from the
GLAZING MORTAR WRAPPING
FINAL INSPECTION
PACKING AND DISPATCH

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shelves and are kept in shut boxes. These products are then fired in kilns at 930 o
C. The products
are then permitted to cool under encompassing climate to diminish the propensity of products to
crack. MBS are fabricated on close firing route which are fired before machining whereas SEN
are on open firing route and are fired after anti-oxidant coating.
MACHINING
The green product is weak and deformed. This is due to the isostatic pressing. This method
of pressing guarantees binding of the mixture and low porosity but on the other hand, produces a
deformed shape. This is the reason why CCR are machined. The machining of different products
is done by means of lathe machines according to the existing production process. Dust collectors
are installed near the machining area to ensure clean working environment. The machined products
are forwarded for glazing.
GLAZING
Dip glazing is the procedure to protect the surface as well as to decrease the porosity of the
CCR. After the ceramic piece is completely dried, it is fired in the kiln, which makes the product
sturdier than the green product, but still porous. The glaze consists of powders that are pre-mixed
when heated sufficiently, melt and become a hard coating. The process ensures reduced porosity
and the glaze protects the surfaces of the product from the load of hot steel. The glaze acts as non-
sticky coat which prevents sticking of steel on the surface or inside the shroud. In case of MBS
and LS, the product is hanged on the trolley upside down. The surface is cleaned and washed, the
first coat is applied on the surface and then the product is dipped in the tank. The dip glazing units
as well as the manual spraying stations are installed in the facility. Required glazing furnace is also
installed.
BUBBLE TESTING
The product is loaded on a plate fitted with rubber sheet which is connected with an air-
line having pressure of 2kg/cm2
and the top of the product is closed with rubber gasket. Other
openings in the product are also closed. The soap solution is sprayed around the product. The
bubble formation is checked to find out whether there is any crack. The ok products are sent for
glazing and then packed in suitable.
ANTIOXIDANT COATING
Graphite is used as carbon source in the product, which oxidizes when come in contact
with hot metal. Also, test results show that unmodified graphite degrade and combust at 1000 o
C
in air. To prevent this, anti-oxidant coating is necessary. The coating must be homogeneous and
continue to delay the oxidation and degradation. This is one of the reason that refractories have
high oxidation resistance. Open firing route products are fired after anti-oxidant coating. Closed
firing route products are dried after coating at 200 o
C.

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INSPETION
Before packing, the products are inspected by quality department for cracks, distortion,
surface finish and measurements are checked. The ok products are packed and dispatched.
Rejected products due to dimensions undergo machining. If the product dimensions are not
achieved after machining, it is crushed to form grains in reprocess plant. After testing it can be
refused.
PACKING
The products are wrapped using thermocol sheets and are kept in polythene bags and
dispatched according the requirement.

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REPROCESS DEPARTMENT
The diversity of refractory products used in refractories industries as iron or steel plants
requires that rigid control is maintained during all phases of the process (used refractory removal,
separation, packing, identification, transportation, processing and consumption of the reprocessed
refractory products).
The raw materials recovered through the recycling processes are held to strict quality
standards to assure maintained refractory performance.
The process of recycling used bricks and castables involves; the complete removal of any
contamination predominantly by hand; categorization by chemistry; crushing and screening. The
regular sampling of batches for chemical analysis ensures the consistency of the material, and
enables correct classification. The diversity of refractory products used in refractories industries
as iron or steel plants requires that rigid control is maintained during all phases of the process (used
refractory removal, separation, packing, identification, transportation, processing and
consumption of the reprocessed refractory products).
PROCESS OF REPROCESSING PLANT
Fig1.7: Flow Diagram of Reprocessing Plant
FEEDING PLATFORM
JAW CRUSHER(UPPER)
JAW CRUSHER(LOWER)
OVERHEAD TANK
ROLL CRUSHER
MAGNETIC
CONVEYOR
VIBRATING
SIEVE
DIFFERENT
GRAIN SIZE
MATERIALS
BUCKETELEVATOR
BUCKETELEVATOR

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The rejected products from the manufacturing division and also the used products from the
steel and iron industries are after segregating process are sent to reprocess plant and then they are
introduced into the hopper on feeding platform. The material is then introduced into the jaw crusher
where the material is crushed by the action of compressive force which is generated by the
movement of jaw.
The material is then passed to the another jaw crusher where material is again crushed for
fine crushing and then the material is forwarded down to the bucket elevator. From the bucket
elevator the filled buckets of materials by conveyor are introduced into the overhead tank.
In this overhead tank a vibrating motor is fixed with silo. The oversized materials are again
introduced into the lower jaw crusher for better crushing and fine material is introduced from silo
into the roll crusher.
Roll crusher is used for crushing the material into the fine grains size. The fine material is
now transferred to the second bucket elevator which transfers the material to the magnetic
conveyor.
The existing magnetic particles are separated by this magnetic conveyor and the material
is then introduced to the vibrating sieve. Through this vibrating sieve the material is discharged
and packed into the different size of bags according to the grain size of the materials.

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MACHINES USED IN REFRACTORIES INDUSTRY
CRUSHER:
A crusher is a machine designed to reduce large rocks into smeller 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.
(1) Jaw 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 is
called a fixed jaw while the other jaw called a swing jaw, moves back and forth relative to it, by a
cam or pitman mechanism, acting like a class II lever or a nutcracker.
The volume 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.

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Fig1.8: Jaw Crusher
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, Ni-hard (a
Ni-Cr alloyed cast iron).

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(2) Roll Crusher
Roll crushers are compression type crushers and were once widely used in refractory
industry. They have, within the last 10 or so years, fallen into dis-favor among refractory and
processing companies. The probable reason is because the large refractory requires very large
crushed product output with minimal cost, makes the roll crusher uncompetitive.
The roll crushers are not as productive as cone crushers, with respect to volume, and they
do have a little higher maintenance associated with them. Roll crushers do, however, give a very
close product size distribution, and if the ore is not too abrasive, they don’t have high maintenance
cost.
Through the feed opening, the raw materials fall to between the two rollers, after crushing,
the final products drop naturally. When there are unbreakable materials or the material is too hard,
the roller will concede automatically under the effects of spring and hydraulic pressure, which will
widen the clearance between the rollers and make the hard or unbreakable so as to damaging the
machine. The clearance between the two rollers can be adjusted to change the sizes of final
products.
Fig1.9: Roll Crusher
Roll crushers gives up to a minimum particle size of 2 mm, having maximum reduction
ratio 4:1 and produces very little dust or fines. This operation is generally stable operation. Roll
crushers are sometimes used as movable crushers attached to a crane, commonly named Bucket
Crushers.

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COLD ISOSTATIC PRESS:
Cold isostatic pressing uses fluid as a means of applying pressure to the mould at room
temperature. After removal the part still needs to be sintered. It is helpful in disturbing pressure
uniformly over the compaction material contained in a rubber bag. Cold isostatic pressing applies
pressure from multiple directions for achieving greater uniformity of compaction (high quality
parts) and increased shape capability, compared to uniaxial pressing.
Cold isostatic pressing is a materials processing technique in which high pressure is applied
to metal powder in a sealed elastomer container shaped for the application. The powder is
converted from a loose aggregate into a partially dense compact that has sufficient green strength
to permit careful handling and transfer to the following process operation.
Water treated with corrosion inhibitor is the usual pressurization medium. Compacting
pressures range from 17,500 psi to 20,000 psi with holding time 1 minute. Compaction is
performed at ambient temperature.
Fig1.10: Cold Isostatic Press
Common applications for cold isostatic pressing include consolation of ceramic powders,
compressing of graphite, refractories and electric insulators, and other fine ceramics for dental and
medical applications.
The technology is expanding into new applications such as pressing of sputtering targets,
coatings of valve parts in an engine to minimize wear of the cylinder heads, telecommunications,
electronics, aerospace and automotive.

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HYDRAULIC PRESS:
A hydraulic press is a device using a hydraulic cylinder to generate a compressive force. It
uses the hydraulic equivalent of a mechanical lever.
The hydraulic press depends upon Pascal’s principle-the pressure throughout a closed
system is constant. One part of the system is a piston acting as a pump, with a modest mechanical
force acting on a small cross sectional area, the other part is a piston with a larger area which
generates a correspondingly large mechanical force.
Since the hydraulic press works on the basis of Pascal’s law, its working is similar to the
hydraulic system. A hydraulic press consists of basic components used in a hydraulic system that
includes the cylinder, pistons, the hydraulic pipes, etc. the working of the press is very simple. The
system comprises of two cylinders, the fluid (usually oil) is poured in the cylinder having a small
diameter. This cylinder is known as the slave cylinder.
Fig1.11: Hydraulic Press – 400T

38. Page | 38
The piston in this cylinder is pushed so that it compresses the fluid in it that flows through
a pipe into the larger cylinder. The larger cylinder is known as the master cylinder. The pressure
is exerted on the larger cylinder and the piston in the master cylinder pushes the fluid back to the
original cylinder.
The force applied on the fluids by the smaller cylinder results in a larger force when pushed
in the master cylinder. The hydraulic press is mostly used for industrial purposes where a large
pressure is required for compressing the materials.
Unlike their mechanical counterparts, hydraulic presses can compress any material to a full
extent. Also, hydraulic presses take only half of the space that the mechanical ones take because
they have the ability to compress a large pressure in a cylinder having a less diameter.
Hydraulic presses are commonly used for forging, clinching, moulding, and metal forming
operations.

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DUST COLLECTOR:
A dust collector is a system used to enhance the quality of air released from industrial and
commercial processes by collecting dust and other impurities from air or gas. Designed to handle
high-volume dust loads, a dust collector system consists of a blower, dust filter, a filter-cleaning
system, and a dust receptacle or dust removal system. It is distinguished from air cleaners, which
use disposable filters to remove dust.
Dust collectors are used in many processes to either recover valuable granular solid or
powder from process streams, or to remove granular solid pollutants from exhaust gases prior to
venting to the atmosphere. Dust collection is an online process for collecting any process-
generated dust from the source point on a continuous basis.
Dust collectors may be single unit construction, or a collection of devices used to separate
particulate matter from the process air. They are often used as an air pollution control device to
maintain or improve air quality.
Fig1.12: Dust Collection System

40. Page | 40
TYPES OF DUST COLLECTORS
(1) Inertial Separators
Inertial separators separate dust from gas streams using a combination of forces, such
as centrifugal, gravitational, and inertial. These forces move the dust to an area where the
forces exerted by the gas stream are minimal. The separated dust is moved by gravity into
a hopper, where it is temporarily stored.
The three primary types of inertial separators are:
(i) Settling chambers
(ii) Baffle chambers
(iii) Centrifugal collectors
Neither settling chambers nor baffle chambers are commonly used in the ceramic
processing industry. However, their principles of operation are often incorporated into the
design of more efficient dust collectors.
(i) Settling chamber: A settling chamber consists of a large box installed in the
ductwork. The increase of cross section area at the chamber reduces the speed
of the dust-filled airstream and heavier particles settle out. Settling chambers
are simple in design and can be manufactured from almost any material.
However, they are seldom used as primary dust collectors because of their large
space requirements and low efficiency. A practical use is as precleaners for
more efficient collect.
Fig1.13: Settling Chamber
(ii) Baffle Chamber: Baffle chambers use a fixed baffle plate that causes the
conveying gas stream to make a sudden change of direction. Large-diameter
particles do not follow the gas stream but continue into a dead air space and
settle. Baffle chambers are used as precleaners.
Fig1.14: Baffle Chamber

41. Page | 41
(iii) Centrifugal collectors: Centrifugal collectors use cyclonic action to separate
dust particles from the gas stream. In a typical cyclone, the dust gas stream
enters at an angle and is spun rapidly. The centrifugal force created by the
circular flow throws the dust particles toward the wall of the cyclone. After
striking the wall, these particles fall into a hopper located underneath.
(2) Fabric Filters
Commonly known as baghouses, fabric collectors use filtration to separate dust
particulates from dusty gases. They are one of the most efficient and cost effective types
of dust collectors available and can achieve a collection efficiency of more than 99% for
very fine particulates. Dust-laden gases enter the baghouse and pass through fabric bags
that act as filters. The bags can be of woven or felted cotton, synthetic, or glass-fiber
material in either a tube or envelope shape.
Fig1.15: Baghouse
To ensure the filter bags have a long usage life they are commonly coated with a filter
enhancer (pre-coat). The use of chemically inert limestone (calcium carbonate) is most
common as it maximizes efficiency of dust collection (including fly ash) via formation of
what is called a dust cake or coating on the surface of the filter media. This not only traps
fine particulates but also provides protection for the bag itself from moisture, and oily or
sticky particulates which can bind the filter media. Without a pre-coat the filter bag allows
fine particulates to bleed through the bag filter system, especially during start-up, as the
bag can only do part of the filtration leaving the finer parts to the filter enhancer dust cake.
(3) Wet Scrubbers
Dust collectors that use liquid are known as wet scrubbers. In these systems, the
scrubbing liquid (usually water) comes into contact with a gas stream containing dust
particles. Greater contact of the gas and liquid streams yields higher dust removal
efficiency.

42. Page | 42
Fig1.16: Wet Scrubber
There is a large variety of wet scrubbers. However, all have one of three basic
configurations:
(i) Gas Humidification: The gas-humidification process agglomerates fine
particles, increasing the bulk, making collection easier.
(ii) Gas Liquid Contact: This is one of the most important factors affecting
collection efficiency. The particle and droplet come into contact by four
primary mechanisms:
(a) When water droplets placed in the path of a dust-laden gas stream, the
stream separates and flows around them. Due to inertia, the larger dust
particles will continue on in a straight path, hit the droplets, and become
encapsulated.
(b) Interception - Finer particles moving within a gas stream do not hit
droplets directly but brush against and adhere to them.
(c) Diffusion - When liquid droplets are scattered among dust particles, the
particles are deposited on the droplet surfaces by Brownian movement,
or diffusion. This is the principal mechanism in the collection of
submicrometre dust particles.
(d) Condensation nucleation - If a gas passing through a scrubber is cooled
below the dew point, condensation of moisture occurs on the dust
particles. This increase in particle size makes collection easier.
(iii) Gas Liquid Separation: Regardless of the contact mechanism used, as much
liquid and dust as possible must be removed. Once contact is made, dust
particulates and water droplets combine to form agglomerates. As the
agglomerates grow larger, they settle into a collector.
The "cleaned" gases are normally passed through a mist eliminator (demister
pads) to remove water droplets from the gas stream. The dirty water from the
scrubber system is either cleaned and discharged or recycled to the scrubber.
Dust is removed from the scrubber in a clarification unit or a drag chain tank.

43. Page | 43
In both systems solid material settles on the bottom of the tank. A drag
chain system removes the sludge and deposits in into a dumpster or stockpile.
(4) Electrostatic Precipitators
Electrostatic precipitators use electrostatic forces to separate dust particles from
exhaust gases. A number of high-voltage, direct-current discharge electrodes are placed
between grounded collecting electrodes. The contaminated gases flow through the passage
formed by the discharge and collecting electrodes. Electrostatic precipitators operate on
the same principle as home "Ionic" air purifiers.
Fig1.17: Electrostatic Precipitator
The airborne particles receive a negative charge as they pass through the ionized field
between the electrodes. These charged particles are then attracted to a grounded or
positively charged electrode and adhere to it.
The collected material on the electrodes is removed by rapping or vibrating the
collecting electrodes either continuously or at a predetermined interval. Cleaning a
precipitator can usually be done without interrupting the airflow.
The four main components of all electrostatic precipitators are:
 Power supply unit, to provide high-voltage DC power.
 Ionizing section, to impart a charge to particulates in the gas stream.
 A means of removing the collected particulates.
 A housing to enclose the precipitator zone.

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The following factors affect the efficiency of electrostatic precipitators:
 Larger collection-surface areas and lower gas-flow rates increase efficiency
because of the increased time available for electrical activity to treat the dust
particles.
 An increase in the dust-particle migration velocity to the collecting electrodes
increases efficiency. The migration velocity can be increased by:
 Decreasing the gas viscosity.
 Increasing the gas temperature.
 Increasing the voltage field.
There are two main types of precipitators:
 High-voltage, single-stage - Single-stage precipitators combine an
ionization and a collection step. They are commonly referred to as Cottrell
precipitators.
 Low-voltage, two-stage - Two-stage precipitators use a similar principle;
however, the ionizing section is followed by collection plates.
Described below is the high-voltage, single-stage precipitator, which is widely used in
minerals processing operations. The low-voltage, two-stage precipitator is generally used
for filtration in air-conditioning systems.
(i) Plate Precipitators: The majority of electrostatic precipitators installed are the
plate type. Particles are collected on flat, parallel surfaces that are 8 to 12 in.
(20 to 30 cm) apart, with a series of discharge electrodes spaced along the
centerline of two adjacent plates. The contaminated gases pass through the
passage between the plates, and the particles become charged and adhere to the
collection plates. Collected particles are usually removed by rapping the plates
and deposited in bins or hoppers at the base of the precipitator.
(ii) Tubular precipitators: Tubular precipitators consist of cylindrical collection
electrodes with discharge electrodes located on the axis of the cylinder. The
contaminated gases flow around the discharge electrode and up through the
inside of the cylinders. The charged particles are collected on the grounded
walls of the cylinder. The collected dust is removed from the bottom of the
cylinder. Tubular precipitators are often used for mist or fog collection or for
adhesive, sticky, radioactive, or extremely toxic materials.
(iii) Unit Collectors: Unlike central collectors, unit collectors control
contamination at its source. They are small and self-contained, consisting of a
fan and some form of dust collector. They are suitable for isolated, portable, or
frequently moved dust-producing operations, such as bins and silos or remote
belt-conveyor transfer points.

45. Page | 45
BALL MILL
A ball mill is a type of grinder used to grind and blend materials for use in mineral dressing
processes, paints, pyrotechnics, ceramics and selective laser sintering. It works on the principle of
impact and attrition; size reduction is done by impact as the balls drop from near the top of the
shell.
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.
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.
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.
Fig1.18: Ball Mill
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.

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FINDINGS
For any academic discipline, especially practical streams like engineering field knowledge should
go hand in hand with theoretical knowledge. In college classes my quest for knowledge is satisfied
theoretically. Exposure to real field knowledge is obtained during such industrial training. I have
learnt a lot about manufacturing processes, maintenance of machines and many more things of
working in a refractory industry. I might have thoroughly learnt the theory behind these but
practical knowledge about these were mostly limited to books. At ORL I actually saw the
equipment used in refractory industry. Though the underlying principles remains same but there
are differences as far as practical designs are considered.
I also got to know additionally about other features not taught or known earlier. This has helped
to clarify my theoretical knowledge a lot. Apart from knowing about matters restricted to my own
discipline I also got to know some other things about the processing of materials and
manufacturing of various refractory products which I might not have necessarily read within in
my curriculum. Such industrial trainings, apart from boosting our knowledge give us some
practical insight into private sector and a feeling about the industry environment. The close
interactions with guides, many of whom are just some years senior to me have also helped me a
lot. It is they who, apart from throwing light on equipment, have also shown the different aspects
and constraints of private sector life. Discussions with them have not only satisfied our enquiries
about machines and processes but also enlightened about many others extracurricular concepts
which are also important. Thus my training in ORL has been a truly enlightening learning
experience.

47. Page | 47
BIBLIOGRAPHY
1. ORL Production Data Sheet
2. www.orientrefractories.com
3. https://en.m.wikipedia.org/wiki/Refractory
4. http://refractoryproducts.net/refractory-products
5. http://www.aggdesigns.com/Jaw-Crusher-info.htm#part1
6. https://www.google.co.in/amp/s/www.azom.com/amp/article.aspx%fArticleID=9905
7. Production Technology (vol. 1) by P.N. Rao
8. https://www.asminternational.org/web/ims/news/amp/-
/journal_content/56/10192/ASMHBA0001539/BOOK-ARTICLE