Cyclone processing of green liquor dregs (GLD) with results measured and interpreted by ICP-OES and NIR spectroscopy

An experimental design in cyclone drying parameters for green liquor sludge led to an efficient drying of the material and an interpretation of optimal cyclone parameters. The obtained dried materials were analyzed by ICP-OES and NIR spectroscopy. The inorganic analysis showed that a partial separation of toxic chemicals is possible and the NIR results could be used as an extra way of interpreting the results of the experimental design. The conclusion is that besides drying, also a change in chemical composition occurs as an effect of cyclone treatment. The NIR method is fast and requires little sample preparation while the ICP-OES method gives more direct inorganic results but is more demanding in time for sample handling and measurement.