LR Lime Shaft Kiln (Low Reactive)

Low reactive quicklime is used for the production of AAC (autoclaved aerated concrete) and sand lime bricks.

The above figure shows AAC production requires low reactivity quicklime.

LR series lime shaft kiln functions on the principle of counter flow. Combustion gases flow from bottom to top traversing the feedstock; while fuel is only added towards the end of the burning zone. Upon completion of the combustion process higher energy input can be used to raise the peak temperature in the burning zone. Thus, the CaO crystallites fuse and reduce the specific surface of burnt lime. This process produces low reactive lime, which is ideal for the production of aerated concrete and sand lime bricks.

The radially arranged and horizontally adjustable liquid cooled burners, which are positioned at the lower end of the burning zone, enable a uniform heat distribution over the cross section of the kiln shaft. Releasing energy from the fuel combustion at the lower end of the burning zone, where the kiln charge is already completely calcined, allows very high burning temperatures which are required to partially sinter the product in order to reduce its reactivity.

The raw material to be calcined is charged at the top of the kiln. It is then preheated by the combustion gases in counter-current before reaching the burning zone. In the burning zone the material is calcined and – depending on the product specification – more or less sintered by means of fuel introduced together with primary combustion air through the radially arranged burners.

Cooling air is introduced at the discharge of the kiln to cool the product in a counter-current manner. The heated cooling air travels upwards to the burning zone and is used there as secondary combustion air. The exhaust gases are directed from the top of the kiln to a dust cleaning system.

The kiln charge consists of crushed and screened limestone or dolomite. The grain sizes are typically 40 to 80 mm or smaller. The kiln shafts are also completely filled with the material to be processed but the kiln charge passes the lime kiln at a higher speed – typically two meters per hour.

LR series lime shaft kiln consists of feeding system, loading system, limestone distributor, calcination system, quicklime discharging system, dust removing system, final product silo, PLC control system.

TECHNICAL DATA OF LR SERIES LIME SHAFT KILN