Dewatering performance of coal fines refuse slurry and development of the water recovery index

In the present investigation, flocculation and settling studies were carried out using a cationic flocculant. A new parameter water recovery index (WRI), i.e. the percentage of water recovered as the supernatant water, has been used to evaluate the performance of settling. This index was found to be a useful tool for analyzing the settling performance. The highest index value of 89.51% was obtained at 6% solid concentration, slurry pH 6.5, and at a flocculant dosage of 4.86gpt. The empirical model developed for the settling rate indicated a coefficient of correlation (R-2) of 0.99 between the experimental and predicted values.