The first reaction zone of rotary kiln system is known as the preheating zone. Here the charge gets heated up to about 800℃ before entering the calcining zone. Bricks in this area are prone to chemical attack from gases containing alkali and sulphur. Thermal insulating property of the refractories in this area results in substantial fuel savings.
Dalmia’s high strength energy-saving ALITE bricks, specially developed with alkali/sulphur resistance properties are best suited to withstand abrasion from kiln feed.
This is the zone within the kiln system where the raw materials undergo calcination. Temperature in this zone varies from 800℃ to 1200℃ . Here CaCO3 (calcium carbonate) gets converted into free lime and CO2 (carbon-dioxide) is driven off.
Dalmia’s DALCR anti-coating high alumina bricks have excellent resistance to abrasion with coating repellent properties.
This is the zone where the last of the kiln feed is calcined. The physical transition zone is that portion of the kiln that lies between the calcining zone and the burning (or) the clinkering zone of the kiln. Temperature of this zone varies from 1200℃ to 1400℃. This is a critical zone of the kiln since liquid formation starts here causing high level of chemical attack on refractory. Very often second tuyere of the kiln is located in this area causing additional mechanical stress on the refractory.
Dalmia’s DALSINT dual-bonded high alumina bricks with low porosity and low permeability are perfectly suited to fight chemical attack.
The final stage of clinker compound formation occurs in this zone where some of the reactions are exothermic. Temperature in this zone varies from 1400℃ to 1510℃. Clinker liquid phase is predominantly present in this area and the kiln lining is under coating. Most important property for refractory in this area is coating friendliness, which indicates the ease with which the coating can form on its surface and stick on it.
Dalmia’s DALSINT dual-bonded high alumina bricks come with thermal properties like shock resistance and low conductivity.
This is the zone where cement clinker is formed and is about to enter the cooler. Temperature in this area comes down from 1510℃ to 1300℃. This is another very critical area of the kiln which is subjected to tremendous abrasion from clinker balls and also axial thrust at the retainer area. Outlet tuyere is also located in this area which increases the mechanical stress on refractories. Refractory in this area should have high abrasion resistance, mechanical strength and flexibility.
Dalmia’s DALSINT dual-bonded high alumina bricks have excellent resistance to chemical attack along with thermal properties like shock resistance.
This is the kiln tip area where clinker falls into the cooler at about 1300℃. This area is often lined with either brick or castable. Refractory in this area should have high thermal shock resistance and high abrasion resistance.
Dalmia’s anti-coating high alumina bricks are known for their resistance to abrasion and superior coating repellent properties
The hood provides a cover to the outlet discharge area of the kiln as well as the hot part of the cooler with bull nose. The burner passes through the kiln hood and extends up to the kiln outlet. This area is subjected to abrasion from dust carried through secondary air and becomes more challenging for refractories when tertiary air duct is also connected through the kiln hood.
Dalmia’s low cement based special castable DALRESISTAL is highly resistant to abrasion and alkali attack.
The burner pipe passes through the kiln hood at the kiln’s hot end, arranged more or less along the kiln’s centre line. Fuel is projected into the kiln at high velocity through the burner pipe. Very often burner pipe is subjected to tremendous abrasion at the bottom from dust coming up from cooler. Refractory for burner pipe should have high refractoriness, high thermal shock resistance and abrasion resistance.
Dalmia’s anti-coating SiC based castables are highly resistant to abrasion and alkali attack making them most suitable for burner pipes