Ultrafine coal (-150 mu m) can be effectively cleaned using advanced separa
tion techniques such as column flotation, however, dewatering it to below 2
0 percent moisture level using the conventional dewatering techniques is di
fficult. A comparative flocculation filtration study was performed for enha
ncing dewatering of ultrafine coal using vacuum, hyperbaric, and centrifuga
l filters. The cationic and anionic flocculants were added into the slurry
individually or in combinations.
Vacuum filtration results showed that use of flocculants increased filtrati
on rate by several times and/or substantially reduced cake moisture. Combin
ed use of anionic and cationic flocculants showed further improvement. Addi
tion of flocculants significantly increased filtration rate of hyperbaric f
iltration and reduced cake moisture in centrifugal filtration. Anionic floc
culant was more effective in enhancing fine coal dewatering than cationic f
locculant in vacuum filtration while cationic flocculant was more effective
in high shear centrifugal filtration. A new approach on using flocculants
in vacuum filtration is proposed for enhanced fine coal dewatering. (C) 200
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