Abstract: To solve the problems of excess of abrasion of steel balls and high power consumption used for grinding of the duplex inlet & outlet coal mill, a method that can calculate the initial balls loading, the period and quantity of adding balls for the mill is presented on the basis of building up the models of steal balls’ abrasion and motion. Setting #E coal mill as example, period and quantity of adding balls are confirmed accurately in consideration of variation of power, the maximum capacity and fineness of coal powder, compensatory quantity of each grade of balls are also calculated. Results of comparison with #B coal mill which uses traditional initial loading balls and adding balls method show that the abrasion of steel balls and consumption of power of #E coal mill is lower than #B coal mill obviously, so that the economic benefit of power plant is significantly improved.

Key words: steel ball abrasion, ball replenishing period, ball replenishing matching, pulverized coal-fineness, economic benifit