Refractory selection and Installation -1.pdf

Srinivas nerella

1. Cement Production Training FLSmidth, 2008, all rights reserved.


Refractory sélection and Installation (1)
Class # 18
Jovein cément,Iran

2. Cement Production Training FLSmidth, 2008, all rights reserved.

Refractory Installation
Fireclay and Alumina bricks
•Al
2O
3 Refractoriness
•Weak thermal conductivity
•Free K
20 (potassium oxide) attack
•Eutectic at 1200 °C with L/S
•Good mechanical resistance and abrasion
–35 - 43% kiln back-end and calcining zone
–75% security and upper transition
–80 - 85% nose-ring, lower transition

3. Cement Production Training FLSmidth, 2008, all rights reserved.

Refractory Installation
Fireclay and Alumina bricks

4. Cement Production Training FLSmidth, 2008, all rights reserved.
Refractory Installation
Magnesia as Refractory Material
Advantages Disadvantages
High thermal “conductivity”

High thermal “expansion”

Poor “flexibility” when heated
High “refractoriness”
(the fusion temperature
of pure MgO is 2 800 °C)
It is “basic” which limits
reactions with the kiln
loads themselves
therefore, it is never used pure

5. Cement Production Training FLSmidth, 2008, all rights reserved.
Refractory Installations
What is spinel ?
•In the case of spinel bricks , the term “spinel” restrictively
means the MgO*Al2O3 or MgAl2O4
• spinel bricks are magnesia and spinel based.
. High conductivity
. Difficulty to get coating
. High mechanical strength
when heated
. Abrasion resistance
. Flexible when heated
. High thermal expansion
• Due to high conductivity there use
under tire is delicate.
• Due to high thermal expansion, so mortar
is used to join the bricks together with in the
single ring but never between bricks and
shell, nor between two rings. Between ach
ring expansion will be covered by 0.8-2 mm
thick cardboard

6. Cement Production Training FLSmidth, 2008, all rights reserved.
Refractory Installation
Dolomite bricks
•Calcined dolomite 95 to 98% (CaO + MgO)
–weak mechanical resistance and thermal
shocks
–very good coatability
–high porosity (formation of silicate and ferrites)
–structural spalling (loss of coating)
–good thermal conductivity

7. Cement Production Training FLSmidth, 2008, all rights reserved.
Refractory Installation
Dolomite bricks
• The quality of these bricks is inversely proportional to
their Fe2O3 content , the latter should not exceed
1.5%.
• After the kiln stops and coating destroyed, it is
possible to restart using very thin dolomite bricks (80
mm).
•The brick is very sensitive to Humidity, which may it
cause decompose very rapidly.
•This brick is not recommended in a kiln with cyclical
stoppages.
•Thermal expansion is very high, axial and radial joints
must be respected.

8. Cement Production Training FLSmidth, 2008, all rights reserved.
Refractory Installation
Using Two shapes
• To lay bricks on a kiln, two different shape are usually used for
the same kiln diameter.

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Refractory Installation
Mixing table:

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Refractory Installation
Mixing table:

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Refractory Installation
Ring calculation

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Refractory Installation
Refractory thickness

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Refractory Installation
Lining of clinker kiln
The ring must be bordered upstream and downstream by low
conductivity bricks, to prevent the ring from heating up. So
Alumina bricks are laid.

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Refractory Installation
Lining of clinker kiln

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Refractory Installation
Brick laying method

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Refractory Installation
Brick laying method
Dolomite brick must
never be bonded

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Refractory Installation

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Refractory Installation
Expansions

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Refractory Installation

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Refractory Installation

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Refractory Installation
Key bricks:

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Refractory Installation

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Refractory Installation
Ring closing technique with steel plates:

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Refractory Installation
Thanks for attention