chari:

In some kilns the return dust from BF and Gas cooling section directly mixes with the kiln feed ,In that case how to find out the ratio of conversion.can it be done by the mass balance theory?

Yes, as long as the dust streams from raw mill bag-filter and kiln gas conditioning tower both return directly to the kiln, the 'raw meal to clinker ratio' is the same as calculated in my first post above.

 See http://www.cemnet.com/cs/forums/permalink/3737/3759/ShowThread.aspx#3759

 Regards,

 Ted.

thank you sir,

 I have taken the mass balance of the circuit and found your calculation is perfect to 100%.