Quantitative evaluation of energy efficiency for steel slag comminution in a fluidized bed opposed jet mill

Abstract

Exploring a scientific quantitative evaluation for energy efficiency and its improvement in jet milling process is of great significance for energy saving and emission reduction. In this study, three classical comminution breakage models, E-S breakage probability model, A-b breakage model and E-M breakage model, were modified by conducting comminution experiments with an improved single particle impact comminution equipment. Based on modified breakage models, new formulas, describing relationship between the comminution energy efficiency and breakage characteristic, were proposed and verified with the variation of system holdup, inlet pressure and feeding initial particle size on energy efficiency in a lab scale fluidized bed opposed jet mill. Results show that modified breakage models all well fitted the comminution results, and modified E-M breakage model was with the biggest accuracy. The energy efficiency calculated from the three new models is basically consistent with the change of comminution conditions, varying from 0.15% to 1.35%, which represents great improvement potentiality. The proposal of energy efficiency model would provide foundation for the subsequent quantitatively evaluation on energy utilization and efficiency improvement of steel slag ultra-fine grinding by fluidized bed opposed jet mill with waste heat steam.