Effect of dispersants on coal slime classification in a novel classification apparatus

The effects of the dispersants NaOH and Na 2 CO 3 on the classification of coal slimes was studied in a novel classification apparatus. A dispersion effect was characterized through slurry pH and transmittance measurements as well as zeta potential determinations of the slimes. The pH increased and the zeta potential became more negative, while the transmittance decreased with the increase in the NaOH and Na 2 CO 3 addition. The miscellany rates in the overflow decreased by 15.18%25 and 11.22%25 with NaOH and Na 2 CO 3 , respectively, while that in the underflow was 31.81%25 and 27.08%25, respectively. An ash-removal efficiency from the coal slurries increased by 20.03%25 and 10.50%25 with NaOH and Na 2 CO 3 , respectively. It was found that the largest difference in classification efficiency between these dispersants in the overflow was 26.05%25 and underflow was 14.86%25. At the high classification efficiency, the transmittance of the slurry decreased, indicating that better dispersion effect led to the higher classification efficiency of the coal slurry. NaOH showed to be a better dispersant for coal slimes classification than Na 2 CO 3 in the novel classification apparatus. © Wroclaw University of Science and Technology.

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