Determination of free silica content in coal dust by Raman spectroscopy

To address the challenges associated with complex operations, extended detection periods, and mineral interference in the existing standard method for determining free silica content in workplace dust, the applicability of Raman spectroscopy for analyzing free silica content in coal dust was explored in this study. Raman spectroscopy from dry spot samples of coal dust containing varying masses of silica were collected. Subsequently, unary linear regression(ULR) and partial least squares regression(PLSR) models were established based on the relationship between characteristic silica peak data and silica mass load. The PLSR model demonstrated a remarkable fit, achieving a detection limit as low as 8.29 ng. The measurements of silica content in coal dust samples using the PLSR model and standard infrared spectroscopy were compared. The relative standard deviation values of three parallel experiments are 8.53% to 27.33%, and the detection values of Raman spectrum and infrared spectrum are consistent. Raman spectroscopy reduces the detection limit while ensuring the reliability of the results, and the detection process is simple.