| abstract |
Natural coal containing inorganic impurities may be deashed by the selective flocculation process using a novel flocculant which is a water-soluble or water-dispersible copolymer having a molecular weight from about 100,000 to about 30,000,000 comprising a hydrophilic monomeric unit having a solubility in water greater than 15% by weight at 20 DEG C. and a hydrophobic monomeric unit having a solubility in water less than 10% by weight at 20 DEG C. in proportions of 99:1 to 20:80% by weight. |