Optical sorting of lignite and its effects on process economics

Impact of the optical sorting on lignite processing has been discussed. Experimental study covered sink-float tests, visible light-color (VIS) sorting, and near-infrared (NIR) sorting of an unconventional lignite sample. Results showed that significant impacts on process economics and recovery could be achieved by implementing optical sorting to lignite cleaning. Operational and investment costs per ton of clean lignite were also investigated when optical sorting was implemented. Also, within approximately similar ash levels, it was observed that NIR sorting results had better efficiency and ash removal performance than VIS sorting.