Basic knowledge about refractory materials include in these slides . Hopefully these slides satisfies you what are you searching for.

1. Presented to : Engineer Nasir Iqbal
Noorani
Submitted by : Faizan FA-15-BME-83
Farhan FA-15-BME-84
khizar FA-15-BME-046
Subject :Engineering Materials

2. INTRODUCTION
 What are are refractory materials?
Materials that
 Withstand high temperatures and sudden changes
 Withstand action of molten slag, glass, hot gases etc
 Withstand load at service conditions
 Conserve heat
 Have low coefficient of thermal expansion
 Will not contaminate the load

3. Deffination
 A refractory material is a material that retains its
strength at high temperatures. ASTM C71 defines
refractories as "...non-metallic materials having those
chemical and physical properties that make them
applicable for structures, or as components of systems,
that are exposed to environments above 1,000 °F (811 K;
538 °C).
 Refractory materials are used in linings
for furnaces, kilns, incinerators, and reactors..

4.  Refractories are classified on the basis of therir chemical
composition.end use and manufacturing method.They can
be classified acidic basic and nutral refractories.A small
range of high melting point material like magnetia,bauxite
,fireclay and silica are used to produce refractories.

5. Refractory requirements:
 The refractory materials should be able to withstand
 High temperature
 Sudden changes of temperature
 Load at service conditions
 Chemical and abrasive action of phases
 The refractory material should not contaminate the material with which it is in
contact

6. Global Refractory Production

7. Industrial uses
 Refractories
Refractory lining of a furnace
arc
Refractory walls of a
furnace interior with burner
blocks

8. Properties of Refractories
 Melting point
 Temperature at which a ‘test pyramid’ (cone) fails to support its own weight
 Size
 Affects stability of furnace structure
 Bulk density
 Amount of refractory material within a volume (kg/m3)
 High bulk density = high volume stability, heat capacity and resistance
 Porosity
 Volume of open pores as % of total refractory volume
 Low porosity = less penetration of molten material

9. Properties
 Volume stability, expansion & shrinkage
 Permanent changes during refractory service life
 Occurs at high temperatures
 Reversible thermal expansion
 Phase transformations during heating and cooling
 Size and dimensional stability
 The size and shape of the refractories is an important feature in design since it
affects the stability of any structure. Dimensional accuracy and size is extremely
important to enable proper fitting of the refractory shape and to minimize the
thickness and joints in construction.

10. Types of refractory material
 On the basis of chemical composition and physical form
 Chemical composition:
 3 types
 1)Acid refractories(e.g silica bricks)
 2)Basic refractories(e.g magnetia bricks)
 3)Neutral refractories(e.g karborundum bricks)

11. Types
 There are three types of refractory material that we discussed in the
previous slide-
 1)Acid Refractory: This refractories are made up of acidic material
like zircon,fire clay and silica.
 2)Basic Refractories: This type is made up of basic material like
dolomite,magnetia.
 3)Neutral Refractory: Thus type is made up of alumina
,chromite,silicon carbide and mulite.we can not use acidic refractory
directly in the basic environment and vice versa because they will be
corroded.

12. physical form
 Shaped Refractories: Shaped refractories are those which have fixed shaped
when delivered to the user. These are what we call bricks. Brick shapes maybe
divided into two: standard shapes and special shapes. Standards shapes have
dimension. . Special shapes are specifically made for particular kilns and furnaces.
 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, gunning mixes

13. Classification on basis of temparature range
 Refractory:when temperature is between 1580-1780 e.g. fire clay
 High Refractory:when temperature is between 1780-2000 E.g. chromites
 Super refractory:when temperature is between >2000 E.g. zircons
Fire Clay Brics Chromite Bricks Zirconia Brics

14. Block Diagram of manufacturing refractory
 Raw Material Crushing Grinding
ScreeningStorageMixingMolding
Drying Firing Sizing
PackagingTo Despatch

15. sOme common refractory bricks used in industry
 Sillica bricks
 It contains 90-95 of silica and 2 of cao
 Cao is added to furnish the bond.
 Raw material is used quartz ,quartzite,and sand stone
 Crushed and groud with lime water..and this thik paste is then made into brick bye
hand moulding or machine pressing.
 then the bricks are dried into the drier and burnt into kilns
 The temperature is properly maintained
 First it is slowly raised in about 24 hours to about 1500˚C and it is maintained for 12
hours so as to allow quaqrtzite to be converted into crystobellite

16. Magnesia bricks
Magnesia bricks
There are two types of Magnesite bricks:
Burned Magnesite brick:
 · Material and Technique: magnesia as raw
material
 · Property: good high-temperature
performance, strong slag resistance
 · Application: used in permanent linings of EAF
and steel Convertors, lime kilns, glass tank
regenerators, torpedo cars and non-ferrous
furnaces

17. Monolithic Refractories
Monolithic refractory, the name generally given to all unshaped refractor
products, are materials installed as some form of suspension that ultimately
harden to form a solid mass.
Various means are employed in the placement of monolithic refractories like
ramming casting, spraying, sand slinging etc.

18. Applications
 > Nuclear engines
 > Missiles
 > Furnaces
 > Gas Turbines
 > Jet Engines

19. Thank You