Grinding analysis of Indian coal using response surface methodology

Abstract

The present work discusses a systematic approach to model grinding parameters of coal in a ball mill. A three level Box–Behnken design combined with response surface methodology using second order model was applied to the experiments done according to the model requirement. Three parameters ball charge (numbers 10–20), coal content (100–200 g) and the grinding time (4–8 min) were chosen for the experiments as well as for the modeling work. Coal fineness is defined as the d80 (80 % passing size). A quadratic model was developed to show the effect of parameters and their interaction with fineness of the product. Three different sizes (4, 1 and 0.65 mm) of Indian coal were used. The model equations for each fraction were developed and different sets of experiments were performed. The predicted values of the fineness of coal were in good agreement with the experimental results (R2 values of d80 varies between 0.97 and 0.99). Fine size of three different coal sizes were obtained with larger ball charge with less grinding time and less solid content. This work represents the efficient use of response surface methodology and the Box–Behnken design use for grinding of Indian coal.