A comparative study of different flocculation filtration processes for ultrafine coal dewatering

Ultrafine coal (-100 mesh) can be effectively cleaned using advanced separation techniques: such as column flotation. However, the clean coal froth product contains about 80% water which has to be removed prior to its sale. A comparative flocculation filtration study was performed for enhancing dewatering of ultrafine coal using vacuum, hyperbaric, and centrifugal filters. Vacuum filtration results showed that use of flocculants: increased filtration rate by several times and substantially reduced cake moisture. Addition of flocculants significantly increased; filtration rate of hyperbaric filtration and reduced cake moisture in centrifugal filtration. Anionic flocculant was more effective in enhancing fine coal dewatering than cationic flocculant 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.