Laser excited fluorescence of black liquor was investigated as a possible monitoring technique for pulping processes. A nitrogen pumped dye laser was used to examine the fluorescence spectrum of black liquor solutions. Various excitation wavelengths were used between 290 and 403 nm. Black liquor fluorescence spectra were found to vary with both excitation wavelength and black liquor concentration. Laser excited fluorescence was found to be a sensitive technique for measurement of black liquor with good detection limits and linear response over a large dynamic range.
J J Horvath,
H G Semerjian,
"Laser Excited Fluorescence Studies Of Black Liquor", Proc. SPIE 0665, Optical Techniques for Industrial Inspection, (23 October 1986); doi: 10.1117/12.938752; https://doi.org/10.1117/12.938752