Some factors affecting spherical oil agglomeration performance of coal fines

Spherical oil agglomeration of bituminous coal fines was carried out using diesel oil as a bridging liquid. The effects of parameters. such as the dosage of bridging liquid, the solid content of slurry, the agitation time and rate, the pH and surface active agent on the agglomeration performance, were investigated. When the bridging oil loading increased from 5 to 30 wt.%, the values of grade and recovery increased gradually. The grade increased from 0.62 to 0.79 and the recovery increased from 0.91 to 0.98. Under the test conditions reported, agitation time and rate did not significantly affect the grade and recovery values. When the solid content in the slurry increased from 5 to 25 wt.%, the grade values decreased front 0.75 to 0.6 and the recovery increased from 0.95 to 0.99, Laser particle size analyses of the agglomerate and tailing fractions showed that the agglomerates and tailings contained coarser and finer particles than the particles of the corresponding feed. However, the amounts of particles under 0.8 mum in the agglomerate fractions were higher than that of the tailing fractions. Variation of the pH of the slurry changed the agglomeration performance. The grade values were 0.78 and 0.72 for the pHs of 3.1 and 11, respectively. The addition of surface active agent (Triton X-100) caused a decrease in the recovery. However, the Triton X-100 in the slurry did not significantly change the grade of the final product. (C) 2002 Elsevier Science B.V. All rights reserved.