Preparation Of Clean Coal Samples Using The Roben Jig

This study compared three methods of removing mineral matter (washing) from coal: jigging coal particles in water using the Roben Jig, the float/sink method using traditional organic liquids (naptha, perchloroethylene, methylene bromide), and a full-sized industrial wash plant. Clean coal composites from six coal types (A, B, C, D, E, and F) were tested. All coals were washed using the Roben Jig and the float/sink method and seams E and F were also washed in an industrial wash plant. In each case, the Roben Jig was capable of producing a clean coal composites with coal quality characteristics (proximate analysis, FSI, S, calorific value, mineral analysis of ash, RoMax) very similar to that of the clean coal samples created by the organic liquids float/sink method and the industrial wash plant sample. The Gieseler fluidity and Ruhr dilatation values were lower in the traditional float/ sink method where the coal was exposed to organic liquids. There was very little difference in the Sapozhnikov Y values and small differences in the G Caking Index values. All six coal types were carbonized in a sole-heated oven and CSR was tested. Comparing the CSRs for the clean samples created by the Roben Jig and organic liquids for coals A, B, C, and D, in four out of five cases the CSR from the organic liquids treated samples was higher (differences ranging from 2 to 8 points). Coals E and F were washed using all three methods and the samples prepared in the organic liquids had the highest CSRs (differences ranging from 3 to 7). The clean coal samples from Coal F were carbonized in a moveable wall oven. CSRs ranged from 66.7 to 69.2, with the plant sample having the highest value. ASTM stability values ranged from 51.7 to 57.3 with the lowest value resulting from the organic liquids washed sample.