APPLICABILITY OF THE REICHERT SPIRAL FOR CLEANING BITUMINOUS AND LIGNITIC COALS - A PILOT-SCALE STUDY

The Reichert spiral which has been particularly developed for the bene ficiation of fine coal in the size range of -3+0.1 mm is considered as an alternative for fine coal jig, cyclone, and flotation. A systemati c study has been carried out to test the separation efficiency of the Reichert spiral on a bituminous coal and lignite. The effect of partic le size, pulp density, the presence of fines, and the number of cleani ng stages has been studied as a function of separation density. It is shown that cleaning of coal at densities below 1.5 g/cm(3) seems ineff icient under optimum operating conditions. The Reichert spiral is capa ble of cleaning the bituminous coal more efficiently than lignite in v iew of the smaller number of cleaning stages. Lignite, however, requir es lower separation densities compared to the bituminous coal. The eff ect of various parameters on spiral performance is delineated with the aim of developing an optimum strategy for cleaning low quality coals.