Degree of calcination & high free lime in clinker

Dear All

We are having an ILC kiln with DDF calcinator with 5 stage prehater

The results of LOI of samples taken are as under

1. IV cyclone material LOI = 19.45% ( DC = 42.8%)

2.V cyclone material LOI = 1.98% (DC= 94.17%)

3.DDF cone material LOI = 0.32% (DC=99.06%)

4.Kiln Inlet Chamber material LOI= 0.45%(DC=98.67%)

DC= degree of calcination

Now can we relate the DC with high free lime in clinker (more than 2%).

Why the DDF cone & Inlet chamber DC is very high.

In my openion the gas velocity through the kiln is too high which is reflecting in high DC of chamber & DDF cone.high velocity could be due to heavy coating inside the kiln & chamber but our chamber pressure & preheater pressure are normal.

What is the possible solution to overcome this situation & reduce freelime? Should we reduce fuel rate in DDF or in Kiln or both.

If we reduce fuel in DDF or kiln our production gos down.

Please suggest.

ENGR