232 posts
TimePosted 05/01/2013 11:26:06
xxxx says

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.




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38 posts
TimePosted 15/01/2013 13:02:39
faslan says

re Degree of calcination & high free lime in clinker

Dear xxxx,

Before dealing with calcination degrees, 

I want to warn you about the chemistry of clinker. The free lime can be a result of the not proper chemical composition of raw meal (hot meal)

Unburnt cores in clinker. This can be a result from balls, lumps coming from kiln. Inside of those materials are very hard for sintering.

What about your raw material burnability? Do you have quartz and coarse lime?

Please send me an e-mail and I can send you a spreadsheet.

Best Regards,


25 posts
TimePosted 23/07/2013 09:02:27
GLT says

re Degree of calcination & high free lime in clinker

Dear experts,

we have calcination degree from 57 % to75% (LOI HM 12% - 19%)  from IV stage pre heater, without pre heater calciner . could you please give me the information  about range of acceptable % of DOC after pre  heaters whitout calciner.

thank you in advance