What Refractory Castables Are Used in Various Parts of The Cement Kiln?
                     What Refractory Castables Are Used 
in Various Parts of The Cement 
Kiln?
Cement kilns operate at very high temperatures; hence, the need for materials that 
can withstand high heats and tough environments. Refractory castables follow 
as one of the most vital materials. These are materials manufactured as cement-
based products that have a high tolerance for heat, wearing, and resistance to 
corrosive chemicals. Refractory castables are used within different parts of a cement 
kiln to ensure that the structure is intact and can operate over a long period of time.
What Are Refractory Castables?
Among all types of cementitious materials, refractory castables may develop the 
ability to resist high temperatures, usually above 1000 °C. They consist of a mixture 
of different types of aggregate, binders, and additives to impart proper mechanical 
properties and resistance to thermal conditions. These castables are mainly applied 
for kiln linings, furnaces, and similar equipment that faces very high temperatures 
from the inside.
Types of Refractory Castables
Refractory castables have been classified based on the chemical constitution and 
specific applications they may be designed to serve. A common category is the 
High
Alumina Refractory Castable Cement, which has a very high percentage 
of alumina, hence very resistant to thermal shock and chemical attack.
Refractory Castables in Various Parts of the Cement Kiln
Each part of the cement kiln has different thermal and mechanical needs; 
hence, refractory castable selection for each part is highly important. The 
outline of refractory castables used in different parts of the cement kiln is given 
below:
Preheater Cyclones and Ducts
Material Used: High alumina refractory castables
The raw meal exerts high temperature and chemical attack to the preheater cyclones 
and ducts. Thus, high alumina refractory castables cements are employed which 
offer excellent resistance towards thermal shock abrasion thereby resulting in 
longer service life.
Calciner
Material Used : Low cement castables
This section is where the raw meal undergoes partial calcination before it enters the 
kiln. The conditions there are pretty aggressive since the temperatures are fluctuating 
and the chemical reactions are taking place. Low cement castables, due to their high 
strength and durability, are perfect for lining this part of the kiln.
Burning Zone
Material Used: High Alumina Refractory Castable Cement
The reason being, the burning zone is the heart of the kiln, where raw material 
attains the highest temperature. It generally makes use of high alumina refractory 
castable cement on account of excellent thermal stability and resistance to clinker 
formation, which is very important in this high-temperature zone.
Cooling Zone
Material Used: Insulating castables
Purpose: The clinker cools down at this zone before discharge into the kiln. The 
insulating castables in this section provide protection against heat loss, whereas 
the kiln shell is prevented from undue thermal stress.
Kiln Hood
Material Used: Abrasion-resistant castables
Purpose: Clinker along with hot gases provides it with severe impact of abrasion. 
For this purpose, this area is lined with abrasion-resistant castables to decrease the
wear and tear and to extend the operating life. Benefits of Refractory Castables 
Used in Cement Kilns
Thermal Insulation: These refractory castables are offering excellent thermal 
insulation that reduces the case of heat dissipation and hence increases the energy 
efficiency of the kiln.
Durability: The refractory castables are designed in such a way that they are capable 
of resisting very adverse conditions, such as high temperature, chemical attack, and 
mechanical abrasion.
Ease of Application: Refractory castables can be cast into different shapes and 
sizes based on the needs of different parts of the kiln.
Conclusion
Refractory castables play an important role in the operations of cement kilns. 
Each section of the kiln requires a specific type of castable that would ensure optimal 
performance and longevity. Among these, high alumina refractory castable cement 
has emerged as one of the most usable because of its very good resistance to thermal 
shock and durability. Application of the correct types of refractory castables in each 
part of the kiln will allow cement manufacturers to increase efficiency and extend 
the life of the kiln, thus improving overall production.
Source Link:-
https://medium.com/@refmonindustries/what-refractory-castables-are-used-in- 
various-parts-of-the-cement-kiln-2951258bb6a6