Mr. Ted had rightly suugested to reduce free lime in your clinker,you may do the following possible countermeasures:

1.Reduce Kiln Feed LSF to less than 100.If Kiln Feed LSF is more than 100 than you may not be able to reduce free lime inspite of overburning or providing more heat energy.

2. Finer grinding of raw mix to minimize coarser Calcite and Quartz cryustal grains if present.

Please send Kiln Feed LSF,SM ,AM and Raw Mix residue maintained in +90 & +212 micron so that appropriate measures may be suggested.