The pyro operation consists of a 4 stages of cyclone separators and a Rotary Kiln. There are two cyclones in the stage 01 and whereas from stage 02,03 and 04 consisted with single cyclone. The discharge stream of the 4th cyclone is directed to the Rotary Kiln and followed by a clinker cooler. Kiln is a hollow cylindrical tube with refractory lining inside to withstand for the high temperature. The discharge end of the Kiln is connected to the cooler operated by grates.
Raw meal from the storage silo is initially fed to the top stage of the cyclone and transported to subsequent stages via pneumatic transport. Cyclone geometry with pneumatic air transport is caused to absorb heat from the gas to raw material and subjected to different physical and chemical reactions on it.
The main energy source for the pyro processing is coal which the material is pulverized by coal mill. Raw coal is grinded and finely grinded coal is stored in a silo and is fed to kilns via pneumatic transport. The flame propagates and the main burner which in Palavi operation it is used only single burner in the whole process. The burner is positioned along the kiln axis from the kiln outlet side making countercurrent flow of material and exhaust air. Temperature of the flame is approximately yield up to 2000 degrees of Celsius to heat up material up to 1450 degrees of Celsius.
The material at the kiln feed is around 90 degrees of Celsius would reach up to 850 degrees of Celsius when it discharges to the kiln m after passing through cyclone stages of the preheater. The feed that entered the Kiln at the inlet is gradually travelled towards the outlet with to the rotation of the Kiln and kiln inclination of 2-3 degrees. The feed is entered to the kiln at the temperature of 850oC and at the burning zone it is required to heat up to 1450 degrees of Celsius to generate C3S (Alite) which is the main mineral component of the clinker. Partially calcined material at the kiln inlet is undergone with calcinations liberating carbon dioxide (CO2) to form (CaO) during the motion through kiln at the temperature gradient of low temperature to high temperature. The major oxide in the process is CaO is subjected to react with other oxides as silica, alumina and iron oxide presented in the Raw Meal, at elevated temperatures forming the clinker compounds, namely Di-calcium Silicate or Belite (C2S), Tri- calcium Silicate or Alite(C3S), Tri-calcium Aluminate or Aluminate (C3A) and Tetra Calcium Alumino-Ferrite (C4AF). This process within the preheater and the kiln is called calcination and mineralization yield in the product of clinker.