Multiwavelength Raman Spectroscopy for the Evaluation of Lime Saturation in Cement Raw Mix as a Function of Clay Content

In this work we analyze the lime saturation module for different clay settings of raw material after raw grinding process by means of a multiwavelength Raman spectroscopy study, at excitation wavelengths of 450, 532, 633 and 780 nm. The data reveal that independently of the wavelength used, the results of the Raman shifts can be used to calculate the setpoint for controlling the alumina in the raw mix that needs to be adjusted to have the lime saturation within quality parameters, with a minimum variation compared with other techniques such as XRF and XRD, thus ensuring that the Clinker phases are formed under quality standards. The intensity ratios of Raman spectra were used to calculate LS values which were close to those obtained with the XRF technique. Therefore, this measurement approach can be used successfully as an effective and alternative non-destructive method to determine the LS of cement raw mix.