Recently we started production of SRC with 97.5 LSF, 2.35 SM, and 0.75 AM raw meal composition. After that free lime become normal (i.e 1.1 - 1.20). Do you think that with OPC we were operating with high alumina modulus? (Continuation question)

I don't think the high free CaO was associated with the alumina modulus itself. However, the mix of raw materials must have changed in the switch to SRC production. Which raw materials have reduced significantly? Whichever one is the most likely culprit. We can rule out the coal as presumably this remains the same blend as when OPC was produced.