Abstract: The preparation of superfine ground eggshell powder was carried out using an adjustable planetary ball mill.  Quadratic orthogonal rotary composite design combined with response surface methodology was used to optimize four operating parameters including grinding time, grinding speed, ball-to-material ratio and filling rate. The specific surface area of eggshell powder was investigated with regard to the four parameters. The optimal preparation conditions for superfine ground eggshell powder were filling rate of 21.46%, grinding time of 3.67 h, grinding speed of 421.83 r/min and ball-to-material ratio of 5.97 g/g. Under these conditions, the particle size d50 determined using a laser particle size analyzer was 3.49 μm, reaching micron-grade and the specific surface area was 1650.08 m2/kg.

Key words: eggshell, superfine grinding, parameter optimization