N Jaye
31 posts
TimePosted 27/04/2013 21:56:52
N Jaye says

boulder in kiln

we are facing a probleme of boulder in our kiln. 3 boulders during 10 days

we use coal 100%.

the cemistry  seem to  be correct. kiln feed : lsf104-104.  Ms 2.4-2.5  AR 1.3-1.4

oxygene in kiln outlet > 2%

Can you share with me your experience about boulder formation


Attached files


Know the answer to this question? Join the community and register for a free guest account to post a reply.

234 posts
TimePosted 29/04/2013 08:58:44
xxxx says

re boulder in kiln

Try to reduce AM .It will help .




Ted Krapkat
537 posts
TimePosted 30/04/2013 05:29:38

re boulder in kiln

Hello Yndiaye,

Have you broken open the clinker boulder to see if the centre of the ball is hard burnt or underburnt, or better still, analysed the different layers making up the boulder?

 Here are some other threads in this forum which discuss boulder formation;-







234 posts
TimePosted 30/04/2013 08:45:51
xxxx says

re boulder in kiln

Dear Ted

We are also facing the same problem but not in the form of big boulders but clinker balls of size upto 120-140mm diameter. Not all the clinker is like such balls .

Also the core,upper layer etc. is the same as seen inside boulder.

Please suggest to overcome this problem.

My parameters are

Raw Meal Fineness (14-15%) on 90 mic.

1.6-2% on 212 mic.

LSF 93.5 to 94.5

SM 2.24-2 .27

Fuel 80% Petcoke & 20% SouthAfrican Coal Mix

Fine Coal 3.5-4% on 90 mic.

Free Lime in clinker 1.8 to 3.5%

SO3 in Clinker 0.8 to 0.85%

SO3 in hot meal 1.5 to 3%

Kiln system is ILC (DDF calcinator)

Please suggest to monitor first than solution.