Cleaning study of a low-rank lignite with DMS, Reichert spiral and flotation

Elementary ash and ±0.1 relative specific gravity curves showed that this low-rank coal can be classified as “difficult to clean” due to its high content of near-gravity materials at specific gravities lower than 1.7. However, about 50% and 40% of the raw coal (3571 kcal/kg) can be obtained as clean coal with calorific values of 5400 kcal/kg for the coarse fraction and 5600 kcal/kg for the fine fraction, by DMS and Reichert spiral methods, respectively. The ash contents (14-18%) and calorific values (6022-5582 kcal/kg) of the cleaned coarse and fine fractions are suitable for use in industry. Low calorific value (about 2500 kcal/kg) middling and tailing can be used in properly constructed thermal electric power plants.