Laser-induced breakdown spectroscopy (LIBS); laser ablation; stability; monitoring;NEUTRON-ACTIVATION ANALYSIS; SPECTROMETRY; SULFUR; LIBS; ENVIRONMENT; FLUORINE; AEROSOLS; CHLORINE; CONCRETE; COAL

Mastering the change of cement raw materials composition in real time has important significance to timely adjusting the proportion of raw materials and improving the quality of cement products. As a result, a greater need for online chemical sensors is evolving. Laser-induced breakdown spectroscopy (LIBS) possesses many of the characteristics required for such online chemical sensing, and is a promising technique for field measurements in harsh industrial environments. In this work, we developed a LIBS device for online cement raw materials quality monitoring in the way of ejecting gas-powder mixture, and enhanced the measurement stability through approaches including powder concentration of the ejected gas-powder stream stabilization, pulsed laser power stabilization, and optical efficiency enhancement.

QUANTITATIVE-ANALYSIS; PARAMETERS; SAMPLES; LIBS

A calibration method based on homogeneous material for correcting laser-induced breakdown spectroscopy (LIBS) measurement-error bias in the case of dust pollution under laboratory conditions is proposed. The measured plasma spectra of the sample can be corrected by measuring the spectral integral of the homogeneous material. Thus, we can effectively minimize the dust pollution effect on LIBS and guarantee its precision. Results show that the mean absolute errors of CaO, MgO, Fe2O3, Al2O3, and SiO2 in cement samples are decreased notably from 1.02%, 0.06%, 0.15%, 0.57%, and 0.80% to 0.41%, 0.02%, 0.04%, 0.35%, and 0.39%, respectively. Combination of this calibration method with the traditional optical dustproof methods will significantly extend the LIBS equipment maintenance cycle and make preliminary preparations for the next practical industrial application. (C) 2017 Optical Society of America