Study on the washability of the Kaitai coal, Guizhou Province China

Tonnage of coal samples were collected from Kaitai Coal field, Puan County, Guizhou Province and sieved into different particle size catalogs. The analysis of the overall coal suggested that the coal has low ash but high sulfur content of 3.17 wt.% with medium to high volatile content. The heating value of the coal is 31.668 mJ/kg. al sample with different particle size ranges were tested for float–sink using gravity separation method, in which ZnCl2 solutions with different density are used. It is showed that decreasing sulfur to 2.12 wt.% can give coal yield of 94.55%, suggesting that the coalʹs floatability is good with sulfur. The coal yield is only 85.4% when reducing sulfur to 1.5 wt.%, and 76.7% when sulfur is decreased to 1.2% through the ZnCl2 float–sink process. The δ ± 0.1 is 20.55, which is in the 20.1–30 range, suggest that Kaitai coal is difficult to float–sink for depyritisation. terization of the floated coal at different sizes showed that the organic sulfur may mainly be present in the small size, the pyrite sulfur is mainly present in the coal with bigger particle size, which can be easily removed through float–sink process. The ash in the small particle sized coal is mainly from kaolinite and quartz, while the pyrite is the main ash contributor to the coal with big size.