Quality Control Formula
Loss on ignition (LOI) (CO2 from Calcination)
Silica Modulus/Ratio (SM)
Alumina Modulus/Alumina iron ratio (AM)
Clinker with higher the Alumina modulus results in cement with high early strength
Lime saturation factor (LSF)
When the LSF approaches unity, the clinker is hard to burn and often shows the excessive free lime contents.
Bogue’s Formula for Cement Constituents
Degree of Calcination
Sulphur to Alkali Ratio
Higher sulphur to alkali ratio leads to pre-heater buildups affecting the kiln operation
Excess sulphur (gm SO3/ 100 kg clinker)
Above these limits, sulphur gives rise to coating problems in Pre-heater tower.
Insoluble residue can be used to measure amount of adulteration or contamination of cement with sand. Cement is soluble in dilute HClwhere as sand is insoluble. The amount of insoluble material determinesthe level of adulteration. In PPC (Fly-ash) cement; insoluble residue is used to estimate the percentage of fly-ash present in the cement.