Model for the rheological parameters of coking coal and water slurry with calcium hydroxide additive

Abstract

Coking coal is extensively utilized in steel manufacturing industries for the preparation of coke because of their quality of leaving very less ash after burning. The effect of chemical additive, hydrated lime (for 0.05, 0.1, 0.5, 1, 1.5, and 2% of solids mass), in coking coal and water slurry (CCWS) are examined at the mass concentrations of 20 and 25%. Significant drop in shear stress is observed after addition of hydrated lime to the CCWS. This study includes the investigation of settling characteristics, pH, and rheology of the CCWS. Settling concentration of CCWS varied for a longer duration such as up to 48 h and then became constant. Physical interaction of particles in CCWS with time found to be influencing the rheology of CCWS with time. Hence, the rheology of CCWS with and without additives is investigated for soaking time intervals of 0, 24, 28, 48 and 72 h. Rheological parameters such as flow index (n), yield stress (τ _o) and flow consistency index (K) are numerically modeled and the results are found in close vicinity to the experimental values. pH of CCWS was found to be increasing with increasing concentration of calcium hydroxide in the CCWS.

Keywords:

• Hydrated lime
• additives
• coking coal

Acknowledgments

This scientific study was conducted in the water resources simulation laboratory, Civil Engineering Department, IIT, Delhi.