Interaction characteristics between different CWS dispersants and coals VII Properties variation of acid-base deashed coals and their effect on the slurryability

The effects of acid-base deashing treatment on the organic constituents, surface properties and slurryability of Hebi, Huainan, and Jingyuan coals have been studied. The results show that many properties of coal are changed by deashing treatment. The content of ash, volatile, sulfur and oxygen of the acid-base treated coals decreases compared with that of the raw coal. However, the content of moisture, phenolic hydroxyl oxygen, total and aromatic carbon in the treated increases. The slurryability of coal is weakened by acid-base treatment. Under the given conditions of coal particles distribution, additive and its dosage, as compared with raw coal, the CWS concentration under the viscosity of 1000 mPa·s decreases by 4.6%, 6.6% and 4.4% for Hebi, Huainan and Jingyuan coals, respectively. The adsorption amounts of different dispersants on the deashed coals and Zeta potentials increase. Evidently, the lower slurryability of the acid-base treated coals is mainly due to the change of organic constituents and surface properties of the coals.