Hai,
We are facing oversize ball formation (i.e,. 50mm to 100mm size) and contributing high Fcao. Can any body suggest how to Control this issue. LSF in kiln feed we are maintaining 105 to 107, SM= 2.3 to 2.4%, Liquid= 27.5 to 28%, we are using fly ash addition in raw mills & fuel used for firing in kiln is Coal (16 to 18% ash).
by
bk
Hello BK,
This type of balling is normally due to buildups from the smokebox/calciner falling into the kiln inlet. If the lumps of buildup are large enough they can become worn into round balls as they move down the kiln. Because of their size, these balls cannot clinkerise completely in the burning zone and their centres are composed of unburnt material having a very high free lime content.
These balls can also be caused by broken out pieces of meal rings which sometimes occur near the kiln inlet.
See this discussion for a typical example of this phenomenon;-
http://www.cemnet.com/Forum/thread/150028/re-boulder-formation.html
The cause of the slabs and buildups falling into the kiln inlet is invariably an excessive sulphur recirculation cycle due to high CO (too little O2) at the kiln inlet.
What is the SO3, K2O and Chloride content of your hot meal?
Do you frequently have high CO/low O2 content in the gases at the kiln inlet?
Have you broken open the largest balls and analysed their centres (for free lime, SO3, K2O and Chloride)?
Do you regularly experience buildups/slabs falling into the kiln inlet?
Regards,
Ted.
Dear sir,
Thank you for your help.
bk