Rotary Kiln Operating Temperature and Refractory Lining Introduction

Limestone is heated to about 900°C by 1150°C kiln flue gas in the preheater, and about 30% of it is decomposed. It is pushed into the rotary kiln by a hydraulic push rod, and the limestone is sintered at 1200°C in the rotary kiln. Decomposition into CaO and CO2.

There are roughly three types of refractory materials for the lining, one is magnesia-alumina spinel bricks for the calcined zone, high-alumina bricks for the transition zone, clay bricks for the preheating zone, and refractory fiber or lightweight bricks for the heat insulation layer. The kiln surface temperature of the two forms is 300-350℃; one kind of calcined zone is spinel light and heavy composite brick, and the surface temperature of the shell is below 250°C; The body surface temperature is also 250°C or less.

In the 16.1~19.55m of the calcination zone, andalusite bricks are used instead of spinel composite bricks, the surface temperature of the kiln shell is lowered, the weight of the kiln body is reduced, and the performance of hanging the kiln skin is also good. After 2 years of use, the kiln skin is removed, and the andalusite bricks are well preserved. , The composite spinel brick peels off seriously. Because the density of andalusite is lower than that of spinel, if all the calcined zone is made of andalusite bricks, the weight of the kiln body can be reduced by 35t, and the temperature of the shell can be reduced by 100°C.

Calcined magnesia-chrome bricks were changed to magnesia-aluminum spinel bricks, and later changed to composite phosphate bricks. Dislocation masonry, and later changed to composite masonry of prefabricated blocks and castables. Metal anchors are embedded in the prefabricated blocks and castables, which are directly consolidated on the steel shell. A layer of heat insulation material is embedded in the prefabricated blocks and castables, The kiln shell is lowered from 320°C to 222°C, and further improved by adding a layer of NJS nano-scale microporous heat insulation felt in the cylinder, so that the shell is reduced from 220°C to 176°C.